Solid Biosciences
Annual Report 2018

Plain-text annual report

UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM 10-K (Mark One)☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal year ended December 31, 2018OR☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the transition period from to Commission File Number 001-38360 Solid Biosciences Inc.(Exact name of Registrant as specified in its Charter) Delaware 90-0943402(State or other jurisdiction ofincorporation or organization) (I.R.S. EmployerIdentification No.)141 Portland Street, Fifth FloorCambridge, MA 02139(Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: (617) 337-4680 Securities registered pursuant to Section 12(b) of the Act: Common Stock, $0.001 par value per share The Nasdaq Global Select Market(Title of each class) (Name of each exchange on which registered) Securities registered pursuant to Section 12(g) of the Act:None(Title of class) Indicate by check mark if the Registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. YES ☐ NO ☒Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. YES ☐ NO ☒Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorterperiod that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. YES ☒ NO ☐ Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during thepreceding 12 months (or for such shorter period that the Registrant was required to submit such files). YES ☒ NO ☐Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405) is not contained herein, and will not be contained, to the best of Registrant’s knowledge, in definitiveproxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ☐Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “largeaccelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. Large accelerated filer☐ Accelerated filer☐Non-accelerated filer☒ Smaller reporting company☐ Emerging growth company☒If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards providedpursuant to Section 13(a) of the Exchange Act. ☒Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Act). YES ☐ NO ☒As of June 29, 2018, the last business day of the Registrant’s most recently completed second fiscal quarter, the aggregate market value of the Registrant’s common stock held by non-affiliates was$598.7 million, based on the last reported sale price of such stock on the Nasdaq Global Select Market as of such date. The number of shares of Registrant’s common stock outstanding as of February 15, 2019 was 35,422,915. Table of Contents PagePART I1Item 1.Business1Item 1A.Risk Factors28Item 1B.Unresolved Staff Comments69Item 2.Properties69Item 3.Legal Proceedings69Item 4.Mine Safety Disclosures70PART II71Item 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities71Item 6.Selected Financial Data72Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations74Item 7A.Quantitative and Qualitative Disclosures About Market Risk86Item 8.Financial Statements and Supplementary Data86Item 9.Changes in and Disagreements With Accountants on Accounting and Financial Disclosure86Item 9A.Controls and Procedures86Item 9B.Other Information88PART III89Item 10.Directors, Executive Officers and Corporate Governance89Item 11.Executive Compensation93Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters103Item 13.Certain Relationships and Related Transactions, and Director Independence106Item 14.Principal Accounting Fees and Services108PART IV110Item 15.Exhibits, Financial Statement Schedules110Item 16.Form 10-K Summary112SIGNATURES113CONSOLIDATED FINANCIAL STATEMENTSF-2iCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSThis Annual Report on Form 10-K includes forward-looking statements, which involve risks and uncertainties. These forward-looking statements canbe identified by the use of forward-looking terminology, including the terms “believe,” “estimate,” “project,” “anticipate,” “expect,” “seek,” “predict,”“aim,” “continue,” “possible,” “intend,” “may,” “might,” “will,” “could,” “would” or “should” or, in each case, their negative, or other variations orcomparable terminology. These forward-looking statements include all matters that are not historical facts. They appear in a number of places throughout thisAnnual Report on Form 10-K. We derive many of our forward-looking statements from our operating budgets and forecasts, which are based upon manydetailed assumptions. While we believe that our assumptions are reasonable, we caution that it is very difficult to predict the impact of known factors, and, ofcourse, it is impossible for us to anticipate all factors that could affect our actual results. All forward-looking statements are based upon information availableto us on the date of this Annual Report on Form 10-K.The forward-looking statements in this Annual Report on Form 10-K include, among other things, statements about: •the timing, progress and results of preclinical studies and clinical trials for SGT-001 and our other product candidates; •our ability to obtain and maintain U.S. regulatory approval of SGT-001, and the timing and scope thereof; •our ability to obtain and maintain foreign regulatory approvals, and the timing and the scope thereof; •the size of the patient populations and potential market opportunity for SGT-001 and our other product candidates, if approved for commercialuse; •our manufacturing capabilities and strategy, including the scalability and commercial viability of our manufacturing methods and processes; •our plans to develop and commercialize SGT-001 and our other product candidates, if approved; •the pricing and reimbursement of SGT-001 and any other product candidates we may develop, if approved; •the establishment of sales, marketing and distribution capabilities and entry into agreements with third parties to market and sell SGT-001 or ourother product candidates, if approved; •the rate and degree of market acceptance and clinical utility of SGT-001 and any other product candidates we may develop and for which wemay receive approval; •our expectations related to our use of capital resources; •our estimates regarding expenses, ongoing losses, future revenue, capital requirements and need for and ability to obtain additional financing; •our intellectual property position; •our competitive and market position; •developments relating to our competitors and our industry; and •the impact of laws and regulations on our operations.By their nature, forward-looking statements involve risks and uncertainties because they relate to events and depend on circumstances that may ormay not occur in the future. We caution you that forward-looking statements are not guarantees of future performance and that our actual results ofoperations, financial condition, business and prospects may differ materially from those made in or suggested by the forward-looking statements contained inthis Annual Report on Form 10-K. In addition, even if our results of operations, financial condition, business and prospects are consistent with the forward-looking statements contained in this Annual Report on Form 10-K, those results may not be indicative of results in subsequent periods.You should read this Annual Report on Form 10-K completely and with the understanding that our actual future results may be materially differentfrom what we expect. We qualify all of our forward-looking statements by these cautionary statements.As used in this Annual Report on Form 10-K, the terms “Solid,” “the Company,” “we,” “us” and “our” refer to Solid Biosciences Inc. unless thecontext indicates otherwise.iiPART IItem 1.Business.OverviewOur mission is to cure Duchenne muscular dystrophy, or DMD, a genetic muscle-wasting disease predominantly affecting boys, with symptoms thatusually manifest between three and five years of age. DMD is a progressive, irreversible and ultimately fatal disease that affects approximately one in every3,500 to 5,000 live male births and has an estimated prevalence of 10,000 to 15,000 cases in the United States alone. DMD is caused by mutations in thedystrophin gene, which result in the absence or near-absence of dystrophin protein. Dystrophin protein works to strengthen muscle fibers and protect themfrom daily wear and tear. Without functioning dystrophin and certain associated proteins, muscles suffer excessive damage from normal daily activities andare unable to regenerate, leading to the build-up of fibrotic, or scar, and fat tissue. There is no cure for DMD and, for the vast majority of patients, there are nosatisfactory symptomatic or disease-modifying treatments. Our lead product candidate, SGT-001, is a gene transfer under investigation for its ability to drivefunctional dystrophin protein expression in patients’ muscles. Based on our preclinical program that included multiple animal species of differentphenotypes and genetic variations, we believe the mechanism of action of SGT-001, if our clinical trials prove to be successful, has the potential to slow oreven halt the progression of DMD, regardless of the type of genetic mutation or stage of the disease.SGT-001 has been granted Rare Pediatric Disease Designation, or RPDD, and Fast Track Designation, in the United States and Orphan DrugDesignations in both the United States and European Union. The safety and efficacy of SGT-001 are currently being evaluated in a Phase I/II clinical trialcalled IGNITE DMD.For patients suffering from DMD, symptoms usually begin to manifest between three and five years of age, when they fail to reach developmentalmilestones or experience motor function challenges, such as difficulty walking or climbing stairs. As the disease progresses, patients with DMD experiencefrequent falls; can no longer run, play sports or perform most daily functions; and are further weakened by physical activity. By their early teens, DMDpatients typically lose their ability to walk and ultimately become dependent on a wheelchair for mobility. By their 20s, patients essentially becomeparalyzed from the neck down and require a ventilator to breathe. Though disease severity and life expectancy vary, a DMD patient’s quality of lifedramatically decreases over time, with death typically occurring by early adulthood from either cardiac or respiratory complications.Our founders, who are personally touched by the disease, created a biotechnology company purpose-built to accelerate the discovery anddevelopment of meaningful therapies for all patients affected by DMD. Through this disease-focused business model, our research team, led by experts inDMD biology and drug development, along with key opinion leaders in DMD, continuously evaluate emerging science to identify high-potential productcandidates. Our selection process includes extensive diligence and initial pharmacology research with highly specific, predefined criteria, which provide uswith confidence in our development program decisions. Through this data-driven selection process, we have evaluated a number of programs and identifiedgene therapy as a potentially beneficial approach for DMD, and thus initiated development of our lead product candidate SGT-001. We will continue toapply this rigorous approach and reject the majority of the candidates we evaluate in our effort to develop only programs that we believe have the greatestlikelihood of becoming therapies for DMD patients.Our product candidatesSGT-001 is our lead gene transfer candidate. Gene transfer, a type of gene therapy, is designed to address diseases caused by mutated genes throughthe delivery of functional versions of those genes, called transgenes. The transgenes are then utilized by the body to produce proteins that are absent or notfunctional prior to treatment, potentially offering long-lasting beneficial clinical effects. SGT-001 is designed to address the underlying genetic cause ofDMD by delivering a synthetic transgene that produces dystrophin-like protein that is only expressed in muscles of the body, including cardiac andrespiratory muscles. Our SGT-001 vector is derived from a naturally occurring, non-pathogenic virus called adeno-associated virus, or AAV, which wasselected for its ability to efficiently enter skeletal, diaphragm and cardiac muscle tissues. The vector is designed to carry a synthetic dystrophin transgeneconstruct, called microdystrophin, that retains the most critical components of the full-size dystrophin gene yet is small enough to fit within AAV packagingconstraints. SGT-001 is designed to drive microdystrophin protein expression in affected muscles throughout the body. In our Investigational New DrugApplication-, or IND, enabling preclinical program, we have studied the efficacy, safety and durability of SGT-001 in multiple preclinical models and itsfunctional benefits in DMD animal studies. In contrast to other therapeutic approaches that are designed to target specific mutations in the dystrophin gene,we believe SGT-001 is a mutation agnostic approach.1In the fourth quarter of 2017, we initiated a randomized, controlled, open-label, single-ascending dose Phase I/II clinical trial, called IGNITE DMD, toevaluate SGT-001 in ambulatory and non-ambulatory males with DMD aged four to 17 years. The primary objectives of IGNITE DMD are to assess the safetyand tolerability of SGT-001, as well as efficacy as defined by microdystrophin protein expression. The clinical trial is also designed to assess muscle functionand mass, respiratory and cardiovascular function, serum and muscle biomarkers associated with microdystrophin production, patient reported outcomes andquality of life measures, among other endpoints. IGNITE DMD is anticipated to enroll 16 to 32 patients with DMD.In February 2019, we announced preliminary findings based on three-month biopsy data from the first three patients dosed with 5E13 vg/kg of SGT-001, the lowest dose outlined in the study protocol. In one patient, microdystrophin was detected via western blot below the five percent level ofquantification of the assay and in approximately 10 percent of fibers via immunofluorescence. There were also signs of co-localization of neuronal nitricoxide synthase (nNOS) and beta-sarcoglycan associated with microdystrophin expression. In the second and third patients, microdystrophin was detected viaimmunofluorescence at very low levels, but it was undetectable via western blot. Based on our preclinical data, we believe that a higher dose of SGT-001 mayresult in meaningfully higher levels of microdystrophin protein. Therefore, we have amended the protocol to dose escalate after three patients have beendosed instead of after four patients as originally planned. In addition, we received approval from the IGNITE DMD clinical study Data Safety MonitoringBoard, or DSMB, and University of Florida Investigational Review Board, or IRB, to begin dosing the next cohort of patients at 2E14 vg/kg. We plan tocontinue enrolling children in this cohort as soon as possible and intend to resume dosing adolescents in the future.Based on additional data from the clinical trial we will determine next steps for SGT-001 clinical development, including additional clinical trialsthat may include other patient populations, as well as the need for larger confirmatory clinical trials.If successfully developed and approved, we intend to commercialize SGT-001, and we may enter into licensing agreements or strategic collaborationsto do so in select markets.Taking into account the prevalence and incidence of DMD and the anticipated dosing requirements for gene transfer, we anticipate that there will be aneed for a substantial supply of SGT-001 for clinical trials and, if approved, for commercial markets. Through significant targeted investments to address thischallenge, we have developed a manufacturing process that we believe can scale to adequately meet our needs for clinical trials, commercial launch andbeyond.While we believe gene transfer may be able to slow or halt DMD disease progression, many patients would still suffer from the manifestations of thedisease, such as tissue damage to their muscles, inflammation, cardiac dysfunction and fibrosis. As part of our disease-focused business model, we are alsobuilding a portfolio of complementary disease modifying therapies to address these manifestations. Our portfolio currently includes an initial diseasemodifying candidate, Anti-LTBP4, a monoclonal antibody designed to reduce fibrosis and inflammation, as well as a number of emerging andcomplementary programs. Preclinical activities for the Anti-LTBP4 program are on-going.In addition to developing our pipeline of product candidates, we believe it is critical to invest time and resources in tools and technologies designedto help us more effectively understand DMD, accurately monitor disease progression and assist patients in daily life. As part of this goal, we are developingbiomarkers and sensors that may allow us to identify treatment targets faster, measure the therapeutic impact of potential product candidates better and reachdecision points earlier. In addition, through our Solid Suit program, we are developing wearable assistive devices with the goal of providing functional andtherapeutic benefits to DMD patients.2Our pipeline We seek to protect our proprietary and intellectual property position through a combination of patents, trade secret laws, proprietary know-how,continuing technological innovation, and entering into non-disclosure, confidentiality and invention assignment agreements. For our gene transfer programs,we have exclusively licensed three issued U.S. patents, one pending U.S. non-provisional patent application, and seven issued patents and eleven pendingpatent applications in foreign jurisdictions. We have filed four pending U.S. provisional patent applications, two pending PCT international patentapplications, and two pending patent applications in Taiwan. We intend to continue building out our intellectual property protection to further strengthenour position in the DMD field.Who we areSolid Biosciences was founded in 2013 by our Chief Executive Officer, Ilan Ganot, our Chairman of the Board, Andrey Zarur, our former President,Gilad Hayeem, our board member Matthew Arnold and our Head of Patient Advocacy Annie Ganot, with the goal of developing meaningful therapies forpatients with DMD. Solid is the English translation of Eytani, the Hebrew name of Ilan and Annie Ganot’s son, who was diagnosed with the disease in 2012.Our founders, unsatisfied with the existing therapeutic landscape, proceeded to raise funds to execute on our disease-focused business model. We assembled apassionate management team and scientific advisory board composed of individuals with extensive experience in DMD, gene therapy, product discovery,research and development, manufacturing, business strategy and finance.In 2015, we began exclusively licensing the elements of the construct for SGT-001 and other elements of our gene transfer program from theUniversity of Michigan, the University of Missouri and the University of Washington. Since then, we have continued to use our extensive network across theacademic, business and patient communities to identify, vet and pursue high-potential complementary product candidates to address the needs of DMDpatients.Since our inception, we have raised private capital from a group of top-tier corporate and private investors. In addition, three leading U.K.-based DMDcharities provided initial seed funding for our gene transfer program in return for equity in our company, and we have accepted additional contributions fromseveral DMD charities to fund our early-stage research programs. In January 2018, we completed our initial public offering resulting in net proceeds of$129.1 million, after deducting underwriting discounts and commissions and offering expenses.We operated as a Delaware limited liability company under the name Solid Biosciences, LLC until immediately prior to the effectiveness of ourregistration statement on Form S-1 on January 25, 2018, at which time we converted into a Delaware corporation pursuant to a statutory conversion andchanged our name to Solid Biosciences Inc.3MissionOur mission, which guides every aspect of our operations, is to cure DMD. Underscoring this mission, our disease-focused business model is foundedon the following fundamental values: •identify and develop meaningful therapies for all patients with DMD; •bring together the leading experts in DMD, science, technology, disease management and care; and •be guided by the needs of DMD patients.About Duchenne muscular dystrophyDMD is an X-chromosome-linked, muscle-wasting disease, predominantly affecting boys. Progressive, irreversible and ultimately fatal, DMD occursin approximately one in every 3,500 to 5,000 live male births and has an estimated prevalence of 10,000 to 15,000 cases in the United States alone. In DMD,mutations in the dystrophin gene result in the body’s inability to produce functioning dystrophin protein, which works to strengthen muscle fibers andprotect them from daily wear and tear. Dystrophin protein also serves as the cornerstone of the dystrophin glycoprotein complex, or DGC, a group of proteinsthat links the inner and outer components of muscle cells to ensure proper muscle function.Without dystrophin and the DGC, muscles suffer excessive damage from normal daily activities and are unable to regenerate, leading to the build-upof scar and fat tissue. More than 1,000 dystrophin gene mutations, which can be inherited or can occur spontaneously, have been identified in people withDMD.For patients suffering from DMD, symptoms usually begin to manifest between three and five years of age, when they fail to reach developmentalmilestones or experience motor function challenges, such as difficulty walking or climbing stairs. Muscle wasting initially presents in the legs and pelvicarea, then in the muscles of the shoulders, neck and arms. As the disease progresses, patients with DMD experience frequent falls, can no longer run, playsports or perform most daily functions, and are further weakened by physical activity. In addition to physical challenges, DMD also commonly involvescognitive difficulties and behavioral challenges.By their early teens, DMD patients typically lose their ability to walk and become dependent on a wheelchair for mobility. By their 20s, patientsessentially become paralyzed from the neck down and require a ventilator to breathe. Though disease severity and life expectancy vary, a patient’s quality oflife dramatically decreases over time, with death typically occurring by early adulthood from either cardiac or respiratory complications.Need for effective therapiesThere is no cure for DMD and, for the vast majority of patients, there are no satisfactory symptomatic or disease-modifying treatments.Glucocorticoid treatment, the current standard-of-care, has been shown to temporarily improve muscle strength, prolong the period of ambulation andslow the progression of DMD. However, glucocorticoid use is associated with well-known adverse events, such as severe weight gain, stunted growth,weakening of bone structure and metabolic dysfunctions, among others. The most commonly used glucocorticoids include prednisone and deflazacort(EMFLAZA).In recent years, certain regulators have conditionally approved two new therapies, eteplirsen (EXONDYS 51) and ataluren (Translarna), which targetspecific mutations in the dystrophin gene. These therapies are indicated for only a small portion of the DMD patient population, and their respective efficacyprofiles still need to be fully understood.Eteplirsen is an antisense oligonucleotide indicated for DMD patients who have a confirmed mutation of the dystrophin gene amenable to exon 51skipping, which affects approximately 13% of DMD patients. Eteplirsen is administered as a weekly intravenous infusion. In 2016, eteplirsen was grantedaccelerated approval from the U.S. Food and Drug Administration, or FDA, based on an increase in dystrophin in skeletal muscle observed in some patientswho received the therapy. However, the FDA concluded that a clinical benefit, including improved motor function, has not been established. As of September21, 2018, the European Medicines Agency’s or the EMA’s Committee for Medicinal Products for Human Use, or CHMP, adopted a negative opinion for aConditional Marketing Application for eteplirsen.Ataluren is a small molecule indicated for the treatment of patients who have DMD resulting from nonsense mutations in the dystrophin gene, whichalso affect approximately 13% of DMD patients. In 2014, ataluren received conditional4marketing authorization from the European Commission, and has since been approved in several other countries outside of the United States. Ataluren’sindication is currently limited to ambulatory patients five years of age and older. In February 2018, the FDA reiterated its denial of PTC Therapeutics, Inc.’sappeal of the complete response letter for the new drug application for ataluren.Current best practices for treating DMD patients also dictate a multidisciplinary approach to disease management, which includes physical andoccupational therapy to preserve strength, function and flexibility, orthopedic management to reduce the risk of scoliosis and other bone and joint problems,pulmonary, cardiac and gastrointestinal management, and psychosocial management to support behavior and learning.Burden of diseaseDespite recent therapeutic advances, DMD represents a significant societal and economic burden. The economic burden, estimated at $1.2 billionannually in the United States (excluding costly mortality and end-of-life care expenses), includes costs associated with hospital admissions, medication,frequent doctor visits and investment in assistive devices, as well as indirect costs related to productivity losses for the caregivers and costs due to pain,anxiety and social handicap. Of this amount, approximately 45% is represented by indirect costs. Only a small proportion of DMD patients are employed andmany caregivers reduce their hours or stop working altogether to care for their children, who progressively require more help with everyday tasks, such aseating, dressing and using the bathroom. In some cases, patients also experience serious mental health issues that require additional support and treatment.Solid’s 360-degree solutionWe aim to address the full spectrum of DMD disease manifestation, from its underlying genetic cause to other disorders that result from diseaseprogression. We are advancing corrective therapies, disease-modifying therapies and assistive devices, as well as tools to accelerate drug development.Gene transfer—A corrective therapyGene therapy is a therapeutic approach that aims to address diseases caused by gene mutations. A gene is a portion of deoxyribonucleic acid, or DNA,that provides the instructions for the body to construct proteins that perform functions needed for life. Genes are prone to mutations, which can either beinherited or occur spontaneously. While many mutations are harmless, some lead to the absence of crucial proteins, resulting in serious genetic diseases likeDMD.Gene transfer, a type of gene therapy, is designed to address diseases caused by mutated genes through the delivery of functional versions of thosegenes, called transgenes. The transgenes are then utilized by the body to produce proteins that are absent or not functional prior to treatment, potentiallyoffering long-lasting beneficial effects.We have focused our initial efforts on gene transfer because we believe it has the greatest potential to address the root cause of DMD: the absence ornear-absence of dystrophin protein. If successful, we believe gene transfer can slow or stop the progression of DMD in a majority of patients, irrespective oftheir genetic mutation, by producing long-term, muscle-specific expression of a functional dystrophin-like protein.Our gene transfer candidate, or vector, includes three components: •a viral capsid—a protein shell utilized as a vehicle to deliver a transgene to cells in the body; •a transgene—a functional gene intended to produce a functional protein; and •a promoter—a specialized DNA sequence that directs cells to produce the protein in specific tissues.SGT-001SGT-001, our lead gene transfer candidate, is designed to preserve muscle function in DMD patients after a single administration. The SGT-001vectoris comprised of a functional transgene and a muscle-specific promoter, which are delivered via an AAV capsid.The vector is modified to no longer self-replicate, yet retains its ability to effectively introduce new genetic material directly into patients’ cells. AAVvectors have been extensively studied in human clinical trials in multiple disease5indications, including in clinical trials of high-dose, systemically delivered AAV gene therapies being conducted by third parties.Capsid: The capsid of the SGT-001 vector is derived from a naturally occurring, non-pathogenic virus called AAV. There are several subtypes of AAVcapsids that differ based on the proteins that make up their structure. These capsids have affinities for different sites in the body. We selected the AAV9serotype capsid for clinical development based on our preclinical data, which demonstrated the capsid’s ability to enter skeletal, diaphragm and cardiacmuscle tissues, as well as its favorable tolerability reported in other gene transfer clinical programs.Transgene: Dystrophin, the largest gene in the body, exceeds the carrying capacity of AAV vectors. To overcome this challenge, we advanceddevelopment of the SGT-001 transgene, a synthetic, dystrophin-like gene that fits into AAV and has the ability to drive functional protein expression inskeletal, diaphragm and cardiac muscle tissue.The concept of a modified therapeutic dystrophin gene originated from research on Becker muscular dystrophy, or BMD, where researchersdiscovered that certain BMD patients had mutations in the dystrophin gene that drove expression of a functional form of dystrophin protein, allowingpatients to live relatively normal lives. This discovery led scientists to engineer a number of synthetic, dystrophin transgene constructs, calledmicrodystrophins, that retained only the most critical components of the full-size dystrophin gene yet were small enough to fit within AAV packagingconstraints. There are several types of microdystrophins that differ based on the configuration of their components. Microdystrophins were subsequentlydemonstrated to functionally protect muscle in mouse models of DMD.The SGT-001 microdystrophin construct, which is our lead clinical candidate for DMD, is based on three decades of development and optimizationwork at the University of Missouri and the University of Washington as well as other academic institutions. In preclinical studies, Jeffrey Chamberlain, Ph.D.,from the University of Washington, and Dongsheng Duan, Ph.D., from the University of Missouri, identified a proprietary configuration of geneticcomponents that, when administered systemically, produces functional microdystrophin protein expression that not only stabilizes muscle membranes andprotects muscle against injury, but also simultaneously restores the localization of DGC to the muscle membrane, notably increasing neuronal nitric oxidesynthase, or nNOS, concentration. In subsequent published studies, Drs. Duan and Chamberlain demonstrated in animal models that, in comparison to earlierconfigurations, nNOS-restoring microdystrophins were more effective in improving muscle function and resistance to fatigue.Promoter: The expression of the SGT-001 microdystrophin transgene is regulated by a modified, synthetic muscle-specific promoter cassette calledCK8, which is derived from the naturally occurring muscle creatine kinase promoter. Regulatory cassettes, such as CK8, are used to prompt gene expressionspecifically in muscle tissues. In comparison to other regulatory cassettes, we chose CK8 due to its small size and its ability to drive microdystrophintransgene expression in skeletal, diaphragm and cardiac muscle tissues. In our preclinical studies in small and large animal models, CK8 restrictedmicrodystrophin transgene expression to these muscles.SGT-001 preclinical programOur comprehensive preclinical program for SGT-001 was comprised of studies that inform efficacy, durability and safety, as well as dose response andthe kinetics of transgene expression. Our program includes three different animal species: mice, dogs and non-human primates, or NHPs. Our preclinicalstudies were performed by third-party collaborators.Well-established mouse and dog disease models for DMD offered us the opportunity to better evaluate the potential translatability of SGT-001 tohumans. While studies in dystrophic mice, such as the mdx mouse, provide important efficacy rationale, we chose to perform additional functional studies indystrophic dogs because they exhibit a more severe dystrophic phenotype and progress similarly to human patients at earlier stages of the disease. Dogmodels enabled us to assess various endpoints, including biodistribution, expression, durability and function in a large animal species.Because DMD is a disease defined by a lack of dystrophin protein, it is important to reliably detect microdystrophin expression in muscle after SGT-001 treatment. As part of our core preclinical program, we developed well-characterized and well-recognized analytic approaches to confirm transgeneexpression and localization, using the following assays: •Immunofluorescence: A qualitative method to determine if a transgene is expressed and localized to muscle membrane.6 •Western blot: A recognized method to quantify dystrophin expression. •Mass spectrometry: A highly sensitive analytical method to quantify transgene expression.We also employed immunofluorescence to confirm if our microdystrophin construct restored the DGC, including key proteins such as sarcoglycanand nNOS.Efficacy in dystrophic miceMultiple studies in both dystrophic, or mdx, and healthy, or wild-type, mice have demonstrated that a single intravenous administration of SGT-001induces measurable levels of microdystrophin protein expression. In all studies, microdystrophin protein expression was measured usingimmunofluorescence, Western blot and mass spectrometry.In an mdx dose-response study, a clear dose-dependent pattern of transgene expression was observed at day 28 by all three assays. As an example, at adose of 1E14 vg/kg, transgene expression as quantified by positive immunofluorescence staining in the quadriceps and heart muscle tissues was 50% and80%, respectively, of the full-length dystrophin levels quantified in healthy wild-type control muscles. Similar levels of microdystrophin expression werefound in all mdx studies completed to date. Efficacy studies performed in dystrophic mice treated with SGT-001 demonstrated significant, dose-responsiveimprovements in both muscle morphology and multiple physiological parameters. In a blinded efficacy study performed in mdx mice dosed at approximatelysix weeks of age, SGT-001 treatment showed a statistically significant improvement in grip strength, which assesses arm and leg strength, at multiple doses.In addition, using a treadmill exhaustion assay, the total distance run by the SGT-001-treated mdx mice was approximately two- to fifteen-fold longercompared to the untreated mice at all time points five-weeks post-dose.At study termination, muscle force was measured ex vivo in the extensor digitorum longus muscle in all animals. SGT-001-treated mdx mice, dosed ateither 2E14 or 4.5E14 vg/kg, exhibited a 1.3-fold increase in specific muscle force over untreated controls when compared to the untreated mdx mice.In a second efficacy study employing a more severe dystrophic mouse model, or DBA/2J-mdx, a version of SGT-001 was administered at a dose of1E15 vg/kg. Treated mice exhibited functional results that were similar to untreated wild-type animals. In the SGT-001-treated DBA/2J-mdx mice, thespecific muscle force was similar to wild-type mice. Further, the treated animals were protected against muscle damage associated with eccentric contractions,a type of contraction related to muscle lengthening under load that is known to be highly damaging to dystrophic muscles. In contrast, untreated DBA/2J-mdx mice showed significantly reduced specific force and no protection against eccentric contraction induced muscle damage.Efficacy in dystrophic dogsTwo independent studies in dystrophic dogs assessed durability of microdystrophin expression and efficacy, respectively. These studies wereperformed in two distinct dystrophic dog models (mixed breed dystrophic dogs, or cDMD, and Golden Retriever Muscular Dystrophy, or GRMD),collectively encompassing a number of genetic mutations that lead to the absence of dystrophin protein. This enabled us to assess SGT-001 across multiplemutations, which is more reflective of the composition of the DMD patient population. Both studies used a canine-optimized version of the microdystrophingene.In a long-term dose-ranging study, five three-month-old, juvenile cDMD dogs received an intravenous dose of either 5E13 vg/kg (n=1), 1E14 vg/kg(n=2), 3E14 vg/kg (n=1) or 5E14 vg/kg (n=1). In this study, muscle biopsies were collected from the skeletal muscles at one, three, six, 12, 16, 20, 24 and 30months after injection. Robust transgene expression was detected by immunofluorescence at all time points and at all of the dose levels. In animals dosedwith 1E14 vg/kg, approximately 70-90% of the muscle fibers were positive for microdystrophin. In treated muscle samples, transgene expression wasassociated with stabilization of the DGC, including nNOS. To date, all doses have been well tolerated and there has been no observed immune response to thetransgene. This study is currently ongoing.A blinded dose-ranging study in the GRMD model assessed the general safety and efficacy of the canine construct of SGT-001. The three dose levels(1E13, 1E14 and 2E14 vg/kg) were administered at three months of age and animals were followed for three months following administration. All doses werewell tolerated and there was no observed immune response to the transgene.7Dose-dependent transgene expression was detected in interim biopsies of skeletal muscles at day 28 and 45 and at the end of the study at day 91 inskeletal, diaphragm and cardiac muscles. A blinded histological evaluation of the muscle tissue revealed a reduction of dystrophic pathology at the higherdose levels. In the mid- and high-dose groups, all muscles biopsied at the end of the study exhibited improved pathology compared to low dose anduntreated controls. Biodistribution studies demonstrated dose dependent transgene expression that was only detectable in the muscle tissues.The observed dose response was detectable by both immunofluorescence and Western blot. Quantification by Western blot averaged less than 10% ofwild-type in the low-dose (1E13 vg/kg) animals. In the mid-dose animals, the level of expression among the skeletal muscles ranged from an average ofapproximately 20% to approximately 50% of wild-type control muscles. At 2E14 vg/kg, the level of expression ranged from 30% to 70% of wild-typedystrophin. This data also correlates to quantification of microdystrophin via mass spectrometry.Dose-dependent, sustained expression of microdystrophin not only correlated with histological improvements in muscle, but also providedstatistically significant improvements in measures of muscle function. At day 90, muscle force generation was improved in both the 1E14 vg/kg and 2E14vg/kg cohorts, indicating that the microdystrophin produced by SGT-001 is highly protective in a large animal dystrophic species.The efficacy data collectively described above in both dystrophic mouse and dog models was incorporated into an overall nonclinical model toinform dose selection for our clinical program.Manufacturing comparabilityAs part of our manufacturing process development, we have run comparability studies at each stage of our process scale-up. These comparabilitystudies were carried out using in vivo mouse models to ensure that our drug product produced at different scales is comparable to each other.SafetyAs part of our preclinical program, we performed necessary good laboratory practices, or GLP, toxicology studies to establish the overall safety profileof SGT-001 in wild-type mice and NHPs. The data and our conclusions from these studies were included in our IND submission to the FDA. Systemicadministration of SGT-001 was generally well tolerated in both species. We observed no evidence of test-article-related toxicity for up to 13 weeks aftersystemic administration of SGT-001 in either species that would prevent us from initiating clinical trials. In the NHP study, test-article-related effects wereself-limited, mild chemistry and hematology changes with no microscopic correlates at the end of the study. There was a transient and asymptomatic increasein liver function enzymes observed in NHPs starting on day 9, which returned to normal levels by day 21. We believe there were no other relevant test-article-related adverse events associated with SGT-001 administration in either GLP study. In the NHP toxicology study, a single animal from the high dose cohortwas euthanized after it did not recover from an anesthetic procedure. We believe this event was attributed to procedural errors. However, AAV vector cannotbe completely ruled out as a contributing factor to the toxicity that gave rise to the event.Clinical development of SGT-001We are developing SGT-001 for the treatment of DMD through a single intravenous administration. In the fourth quarter of 2017, we announced theinitiation of IGNITE DMD, a randomized, controlled, open-label, single-ascending dose Phase I/II clinical trial designed to evaluate SGT-001 in ambulatoryand non-ambulatory males with DMD aged four to 17 years. The primary objectives of IGNITE DMD are to assess the safety and tolerability of SGT-001, aswell as efficacy as defined by microdystrophin protein expression. The clinical trial is also designed to assess muscle function and mass, respiratory andcardiovascular function, serum and muscle biomarkers associated with microdystrophin production, patient reported outcomes and quality of life measures,among other endpoints. IGNITE DMD is anticipated to enroll 16 to 32 patients with DMD. Key inclusion criteria include: established clinical diagnosis ofDMD and documented dystrophin gene mutation predictive of DMD phenotype; anti-AAV9 antibodies below pre-specified thresholds; stable cardiac andpulmonary function; and a stable daily dose of oral corticosteroids for 24 weeks. There is no enrollment restriction in the clinical trial protocol based on apatient’s underlying dystrophin gene mutation.IGNITE DMD participants will be randomly assigned to either an active treatment group or a delayed treatment control group. The selection of ourstarting dose, 5E13 vg/kg, was based on safety and efficacy data observed in our preclinical studies. Dose escalation between cohorts and decisions regardingclinical trial progression will occur after review by the Data Safety Monitoring Board, or DSMB. Efficacy will be assessed by comparing microdystrophinprotein expression in muscle8biopsy before and 12 months after treatment for each patient. An intermediate biopsy at either 45 days, three months, six months or nine months will informthe time course of microdystrophin expression. Other endpoints will be compared against the control group. We anticipate that the delayed treatment controlgroup will be rolled into an active treatment phase after 12 months, as long as participants continue to meet clinical trial criteria. Long-term follow up willcontinue per regulatory guidelines.In February 2019, we announced preliminary findings based on three-month biopsy data from the first three patients dosed with 5E13 vg/kg of SGT-001, the lowest dose outlined in the study protocol. In one patient, microdystrophin was detected via western blot below the five percent level ofquantification of the assay and in approximately 10 percent of fibers via immunofluorescence. There were also signs of co-localization of neuronal nitricoxide synthase (nNOS) and beta-sarcoglycan associated with microdystrophin expression. In the second and third patients, microdystrophin was detected viaimmunofluorescence at very low levels, but it was undetectable via western blot. Based on our preclinical data, we believe that a higher dose of SGT-001 mayresult in meaningfully higher levels of microdystrophin protein. Therefore, we have amended the protocol to dose escalate after three patients have beendosed instead of after four patients as originally planned. In addition, we received approval from the IGNITE DMD clinical study DSMB and University ofFlorida IRB to begin dosing the next cohort of patients at 2E14 vg/kg. We plan to continue enrolling children in this cohort as soon as possible and intend toresume dosing adolescents in the future.Based on data from the clinical trial, we will determine next steps for SGT-001 clinical development, including additional clinical trials that mayinclude other patient populations, as well as the need for larger confirmatory clinical trials.Manufacturing SGT-001The prevalence and incidence of DMD, combined with average patient weight and anticipated dosing requirements for SGT-001, result in asubstantial supply need for clinical trials and, if approved, for commercial markets. To address this challenge, we developed a manufacturing process that webelieve will be scalable to meet clinical and commercial production needs for SGT-001.Our suspension-based process is founded on seminal work by scientists at the University of Florida and has been optimized for manufacturability byour internal process development scientists with the support of our Contract Development Manufacturing Organizations, or CDMO, partners. The processconsists of three steps. First, we produce two replication-incompetent Herpes Simplex Virus, or HSV, stocks, one containing our microdystrophin constructand the other containing the critical elements of the AAV9. Second, we then use these two HSV stocks to coinfect suspension-adapted human embryonickidney cells (HEK-293). Third, these cells are then purified and concentrated in our downstream process to produce our gene transfer candidate. Our team hasdeveloped the analytical testing methods needed to support consistency and strict standards of quality and potency. We believe that this approach willincrease our speed of development, ensure consistent quality and regulatory compliance, and reduce the risk of delay or unexpected production costs.Current status and plans for clinical and commercial scale-upWe believe that our investment in our scalable manufacturing process over the last several years will allow us to minimize the need for changesthroughout clinical development and upon potential commercialization, while ensuring supply at the high volume required. We are supplying our clinicaldevelopment program for SGT-001 with drug product produced at current good manufacturing practices, or cGMP, - compliant facilities located at partnerCDMOs. We are currently operating at 250-liter scale and have successfully produced multiple drug product batches at this scale. Our in-house scientists arecontinuing to work to increase the productivity and efficiency of our manufacturing process. In addition, we intend to establish the capability and capacity tosupply SGT-001 at commercial scale from multiple sources, including potentially building our own GMP facility to ensure redundancy and reliability.Complementary disease-modifying therapiesWhile we believe gene transfer may be able to slow or halt DMD disease progression, many patients would still suffer from the manifestations of thedisease, such as tissue damage to their muscles, impaired muscle strength, inflammation, cardiac dysfunction and fibrosis. We are building a portfolio ofcomplementary disease-modifying therapies designed to address these manifestations.Our portfolio currently includes Anti-LTBP4, our initial disease modifying candidate that is aimed at addressing fibrosis, as well as several emergingand complementary programs. We have chosen to focus our efforts on these programs9following rigorous preclinical testing and our assessment of clinical potential given natural human modifiers. If initial preclinical studies are successful, weenvision initiating additional studies for our disease-modifying programs in combination with SGT-001. We continue to assess additional emergingtherapeutic approaches from academia and industry through our highly focused product candidate selection process to further build our portfolio.Anti-LTBP4Anti-LTBP4 is a program with the goal of identifying and developing a monoclonal antibody intended to reduce fibrosis and inflammation bytargeting and stabilizing the LTBP4 protein. LTBP4 is highly expressed in muscle and, when stable, prevents fibrosis and inflammation by inhibiting theactivation of the TGF-beta pathway.The rationale for targeting LTBP4 originated from observations in DMD natural history studies. Researchers found that subsets of patients withgenetic variants in the LTBP4 gene maintained their ability to walk longer compared to patients in the study who did not. Researchers discovered that thesegenetic variants lead to reduced TGF-beta signaling. Elizabeth McNally, M.D., Ph.D., Director of the Center for Genetic Medicine at Northwestern University,hypothesized that stabilization of the LTBP4 protein in DMD patients could mimic the effect.In order to assess the efficacy of potential human antibody clinical candidates in preclinical models, mice expressing the human version of LTBP4were crossed with mdx mice to generate a DMD model that expressed human LTBP4 (hLTBP4:mdx). Preliminary studies showed that the hLTBP4:mdxanimals treated with an anti-LTBP4 antibody showed significantly lower levels of fibrosis and inflammation due to the stabilization of the LTBP4 protein.Tools to accelerate discovery and developmentWe believe it is critical to invest time and research into tools designed to help us more effectively measure disease progression and the therapeuticimpact of our product candidates. We are focused on developing biomarkers and sensors that will allow us to identify treatment targets faster, better measurethe therapeutic impact of potential product candidates and reach therapeutic decision points earlier.Blood-based and imaging biomarkersWe are working to identify non-invasive blood-based and imaging biomarkers that could potentially reduce or eliminate the need for muscle biopsiesin clinical trials, reducing stress on patients and allowing better evaluation of potential product candidates. We are developing a platform technology thatmay enable the non-invasive measurement of changes associated with increased dystrophin and dystrophin-like protein expression in DMD patients by usingestablished imaging techniques. We are also currently using leading, robust platforms to perform extensive analysis on blood-based samples to establishmolecular signatures based on various stages of DMD disease progression.Sensor-less mobility trackingWe are working to develop naturalistic motor function measurement at home with an ambient measurement system, which is based on sensors such asMicrosoft Kinect. This system uses infrared technology to detect body movement and is designed to collect mobility data for DMD patients withoutrequiring wearable sensors. If successful, this new non-invasive technology would enable us to understand in greater detail the therapeutic impact ofpotential product candidates as they relate to everyday activities, and could provide information to establish and measure clinical endpoints in future clinicaltrials.Assistive devicesSolid SuitIn partnership with Silicon Valley’s Seismic and Parent Project Muscular Dystrophy (PPMD), we are developing wearable assistive devices that mayhave both functional and therapeutic benefits, with the goal of helping patients perform day-to-day activities with greater ease and preserving their musclefunction. We refer to these devices as the Solid Suit. This work is being done with the insight and oversight of technology innovators and engineering anddisease experts, and each step is informed by input from the patient community. The Solid Suit utilizes cutting-edge technologies to power soft, light-weightcomfortable exoskeletons with the potential to offset muscle fatigue and augment muscle strength. We are developing10the Solid Suit in three separate components, two of which are currently in prototype development, and the third has initiated design development.Intellectual propertyOur commercial success depends in part on our ability to obtain and maintain proprietary or intellectual property protection for our productcandidates, including SGT-001, and other know-how, to operate without infringing, misappropriating or otherwise violating the intellectual property rightsof others, and to prevent others from infringing, misappropriating or otherwise violating our intellectual property rights. We also rely on patents, trade secrets,know-how and continuing technological innovation to develop and maintain our proprietary and intellectual property position.As of February 15, 2019, we have filed four pending U.S. provisional patent applications, two pending PCT international patent applications, and twopending patent applications in Taiwan. For our gene transfer programs, we have exclusively licensed three issued U.S. patents, one pending U.S. non-provisional patent application, and seven granted patents and eleven pending patent applications in foreign jurisdictions. The issued U.S. patents areprojected to expire between 2021 and 2028, excluding any patent term adjustments and any patent term extensions, and any U.S. patents that may issue fromthe pending U.S. non-provisional patent application and U.S. provisional patent applications (assuming U.S. non-provisional patent applications are timelyfiled with respect to such provisional patent applications and all other applicable requirements are satisfied) would be projected to expire between 2036 and2039, excluding any patent term adjustments and any patent term extensions.With respect to our gene transfer programs, we exclusively licensed patent families that relate to microdystrophin genes. With respect to SGT-001, weexclusively licensed one issued U.S. patent and one pending U.S. non-provisional patent application, which generally claim the structural elements of SGT-001 and the promoter sequence used in SGT-001. This issued U.S. patent is projected to expire in 2028, excluding any patent term adjustments and anypatent term extensions. Relating to SGT-001, we also own one pending U.S. provisional patent application, one pending PCT international patentapplication, and one pending patent application in Taiwan. Any patents that may be issued from the pending PCT and Taiwanese patent applications and ourpending U.S. provisional patent application (assuming a U.S. non-provisional patent application is timely filed with respect to such provisional patentapplication and all other applicable requirements are satisfied) would be projected to expire between 2036 and 2039, excluding any patent term adjustmentsand any patent term extensions. Substantive prosecution of our patent applications has not yet commenced at the U.S. Patent and Trademark Office, orUSPTO. We cannot predict whether such pending patent applications will result in the issuance of a patent that effectively protects SGT-001, or if such issuedpatent or any of our licensor’s issued patents will effectively prevent others from commercializing competitive products. In any event, patent prosecution is alengthy process, during which the scope of the claims initially submitted for examination by the patent offices in various jurisdictions are often significantlynarrowed by the time they issue, if they issue at all.With respect to our Anti-LTBP4 program, we do not currently own or in-license any issued patents or patent applications relating to such productcandidate. We have exercised an exclusive option to negotiate for licenses of certain patents and patent applications relating to Anti-LTBP4 from IkaikaTherapeutics, LLC. Ikaika Therapeutics, LLC is only required to negotiate the terms of a potential license agreement with us for certain specified periods oftime and we may be unable to enter into such a definitive license agreement within the required timeframe or under terms that are acceptable to us. If we areunable to enter into such a definitive license agreement, we will not have any license to such patents and patent applications.The term of individual patents depends upon the legal term for patents in the countries in which they are obtained. In most countries, including theUnited States, the patent term is 20 years from the earliest filing date of a non-provisional patent application. In the United States, a patent’s term may belengthened by patent term adjustment, which compensates a patentee for administrative delays by the USPTO in examining and granting a patent, or may beshortened if a patent is terminally disclaimed over an earlier filed patent. The term of a patent that covers a drug or biological product may also be eligible forpatent term extension when FDA approval is granted, subject to certain limitations and provided statutory and regulatory requirements are met (for moreinformation, please see “Business— Government regulation and product approval —U.S. patent term restoration and marketing exclusivity”). In the future, ifand when our product candidates receive approval from the FDA or foreign regulatory authorities, we expect to apply for patent term extensions on issuedpatents we may obtain in the future covering those products, depending upon the length of the clinical trials for each product and other factors. There can beno assurance that any of our pending patent applications will issue or that we will benefit from any patent term extension or favorable adjustment to the termof any of our patents.11As with other biotechnology and pharmaceutical companies, our ability to maintain and solidify our proprietary and intellectual property position forour product candidates will depend on our success in obtaining effective patent claims and enforcing those claims if granted. However, our owned andlicensed pending patent applications, and any patent applications that we may in the future file or license from third parties may not result in the issuance ofpatents. We also cannot predict the breadth of claims that may be allowed or enforced in our patents. Any issued patents that we may receive in the futuremay be challenged, invalidated or circumvented. In addition, because of the extensive time required for clinical development and regulatory review of aproduct candidate we may develop, it is possible that, before any of our product candidates can be commercialized, any related patent may expire or remainin force for only a short period following commercialization, thereby limiting protection such patent would afford the respective product and anycompetitive advantage such patent may provide.In addition to patents, we rely upon unpatented trade secrets and know-how and continuing technological innovation to develop and maintain ourcompetitive position. We seek to protect our proprietary information, in part, by executing confidentiality agreements with our collaborators and scientificadvisors, and non-competition, non-solicitation, confidentiality, and invention assignment agreements with our employees and consultants. We have alsoexecuted agreements requiring assignment of inventions with selected scientific advisors and collaborators. The confidentiality agreements we enter into aredesigned to protect our proprietary information and the agreements or clauses requiring assignment of inventions to us are designed to grant us ownership oftechnologies that are developed through our relationship with the respective counterparty. We cannot guarantee, however, that these agreements will affordus adequate protection of our intellectual property and proprietary information rights.We also seek trademark protection in the United States and internationally where available and when appropriate. We currently own U.S. federalregistrations for the marks SOLID, SOLID GT and SOLID BIOSCIENCES and a European Union registration for the mark SOLID GT.Strategic partnerships and collaborations/licensesWe have certain obligations under licensing agreements with third parties that include annual maintenance fees and payments that are contingentupon achieving various development, commercial and regulatory milestones. Pursuant to many of these license agreements, we are required to makemilestone payments if certain development, regulatory and commercial sales milestones are achieved, and may have certain additional research fundingobligations. Also, pursuant to the terms of many of these license agreements, when and if commercial sales of a licensed product commence, we must payroyalties to our licensors on net sales of the respective licensed products.University of Washington License AgreementIn 2015, we entered into a license agreement with the University of Washington, acting through UW CoMotion, under which we obtained anexclusive, royalty-bearing, sublicensable, worldwide license under certain patent applications owned by the University of Washington relating to novelmicro-dystrophins to develop, manufacture, and commercialize products for use in the treatment of DMD and related disease indications caused by a lack offunctional dystrophin. We have the right to grant sublicenses to third parties contingent upon written approval by the University of Washington prior toexecuting such sublicense, which approval may not be unreasonably withheld.In consideration for the rights granted by the agreement, we paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2015. We are required to reimburse the University of Washington for costs incurred in applying for, prosecuting and maintainingpatents and pay up to an aggregate of approximately $1 million upon the achievement of certain milestones. There were no milestones achieved during theyears ended December 31, 2018 and 2016. In October 2017, the first milestone was achieved under this agreement. The milestone payment was recorded as aresearch and development expense in the fourth quarter of 2017. We must also pay royalties of a low single digit percentage of future sales by us and oursublicensees of products developed under the licensed patent rights. In addition, we must pay an annual maintenance fee until certain milestones areachieved, at which time a minimum annual royalty requirement will replace such maintenance fee and will apply to us and our sublicensees.We are obligated to use our commercially reasonable efforts, consistent with sound and reasonable business practices and judgment, to commercializethe inventions covered by the licensed patent rights and to make and sell products based on that patent as soon as practicable and maximize sales thereof.12The University of Washington controls the prosecution and maintenance of the licensed patents in consultation with us and at our expense. Incountries in which we have not requested prosecution or maintenance of licensed patents, the University of Washington may prosecute and maintain suchlicensed patents at its own cost. We have the first right to enforce such licensed patents at our expense. However, we may not enter into any settlement in anymanner relating to the licensed patents without the University of Washington’s prior written consent.The license agreement remains in effect until the expiration of the last-to-expire patent licensed under the agreement. We may terminate theagreement at any time upon providing sixty days’ written notice to the University of Washington. The University of Washington may terminate theagreement upon our uncured, material breach of the agreement or if we enter into an insolvency-related event.The University of Missouri License AgreementIn 2015, we entered into a license agreement with the Curators of the University of Missouri, or the University of Missouri, a public corporation ofMissouri, under which we obtained an exclusive, royalty-bearing, sublicensable, worldwide license under certain patents and patent applications owned bythe University of Missouri relating to a novel synthetic microdystrophin gene to make, sell and distribute products for use in the treatment of DMD andrelated disease indications resulting from a lack of functional dystrophin.In consideration for the rights granted by the agreement, we paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2015. We are required to reimburse the University of Missouri for costs incurred in applying for, prosecuting and maintaining thelicensed patents and pay up to an aggregate of approximately $1 million upon the achievement of certain milestones for each product developed based onthe licensed patents. There were no milestones achieved during the years ended December 31, 2018 and 2016. In October 2017, the first milestone wasachieved under this agreement. The milestone payment was recorded as a research and development expense in the fourth quarter of 2017. We must pay aroyalty of a low single digit percentage of future sales by us or our sublicensees of products developed using the licensed patents. In addition, we must pay anannual maintenance fee until certain milestones are achieved, after which time a minimum annual royalty will replace such maintenance fee.Under the agreement, we granted the University of Missouri a non-exclusive, royalty-free, irrevocable, paid-up license, with the right to grantsublicenses to non-profit, academic, educational or governmental institutions, to practice and use improvements made by us using the licensed patent rights,solely for non-commercial research purposes.We are obligated to use our reasonable best efforts to introduce products based on the licensed patent rights into the commercial market as soon aspossible, consistent with sound and reasonable business practices and judgment, and thereafter to keep such products reasonably available to the public.The University of Missouri controls the prosecution and maintenance of the licensed patents in consultation with us and at our expense. In countriesin which we have not requested prosecution or maintenance of licensed patents, the University of Missouri may prosecute and maintain such licensed patentsat its own cost. We have the first right to enforce such licensed patents at our expense. However, any settlement, consent judgment or other voluntarydisposition of litigation that materially limits the scope, validity or enforceability of the licensed patent or admits fault or wrongdoing on the part of theUniversity of Missouri must be pre-approved in writing by the University of Missouri.The license agreement remains in effect until the expiration of the last-to-expire patent or the abandonment of the last to be abandoned patentapplication licensed under the agreement. The University of Missouri may terminate the agreement, or render the license granted thereunder non-exclusive,in individual countries if we and our sublicensees fail to achieve certain milestones. We may terminate the license agreement at any time upon providing sixmonths’ written notice to the University of Missouri and paying a termination fee. Each of the University of Missouri and we may also terminate theagreement for an uncured default or breach of the agreement by the other party. Our ability to cure such breach only applies to the first two notices of suchbreach provided by the University of Missouri, and thereafter, the University of Missouri may terminate the agreement for our default or breach of theagreement upon thirty days’ written notice without an opportunity to cure such default or breach.The University of Michigan License AgreementIn 2016, we entered into a license agreement with the Regents of the University of Michigan, or the University of Michigan, a constitutionalcorporation of Michigan, under which we obtained an exclusive, royalty-bearing, sublicensable,13worldwide license to make, sell and distribute products under certain patents owned by the University of Michigan related to microdystrophin and utrophinspectrin-like nucleic acid sequences for any use that, but for this agreement, would comprise an infringement of a valid claim included in the licensed patentrights.In consideration for the rights granted by the agreement, we paid a one-time license fee and a separate fee to cover past patent prosecution costs. Werecorded the upfront license fee as a research and development expense in 2016. We are required to reimburse the University of Michigan for costs incurred inapplying for, prosecuting and maintaining patents, and pay up to an aggregate of approximately $1 million upon the achievement of certain milestones.There were no milestones achieved during the years ended December 31, 2018, 2017 and 2016. We must also pay royalties of a low single-digit percentage offuture sales by us or our sublicensees of products developed using the licensed rights, with a minimum annual royalty after certain milestones are achieved. Inaddition, we must pay an annual maintenance fee in any year in which the minimum annual royalty is not reached.Under the agreement, the University of Michigan reserves for itself and its affiliates the right to use the licensed rights for non-commercial research,public service, internal and educational purposes and the right to grant the same limited non-commercial rights to other non-profit research institutions.We are obligated to use commercially reasonable efforts to bring one or more products based on the licensed patents to market through a diligenceprogram for utilizing the licensed patents, to continue diligent marketing efforts throughout the term of the agreement, and to make reasonable amounts ofsuch products commercially available, in each case consistent with prudent business practices and judgment.The University of Michigan controls the prosecution and maintenance of the licensed patents in consultation with us and at our expense. In countriesin which we have not requested prosecution or maintenance of licensed patents, the University of Michigan may prosecute and maintain such licensedpatents at its own cost. We have the first right to enforce such licensed patents at our expense. However, we may only enter into a settlement with the adviceand consent of the University of Michigan.The license agreement remains in effect until the expiration of the last-to-expire patent licensed under the agreement. The University of Michiganmay terminate the agreement upon our uncured material breach of the agreement, including failure to make required payments under the agreement or toachieve certain milestones, or if we become insolvent or bankrupt. We may terminate the license agreement at any time upon providing sixty days’ writtennotice to the University of Michigan.Harvard College License AgreementsIn 2016 and 2017, we entered into license agreements with the President and Fellows of Harvard College, or Harvard College, under which weobtained non-exclusive, royalty-bearing, sublicensable, worldwide licenses to use certain intellectual property owned by Harvard College to develop,manufacture, and commercialize products for use in the treatment of DMD.In consideration for the rights granted by each agreement, we paid one-time, non-refundable license fees, which were recorded as a research anddevelopment expense in 2016 and 2017. We are required to pay an annual license maintenance fee until certain milestones are achieved, after which time theannual maintenance fee will increase annually. Such annual maintenance fees will further increase if we grant certain rights to a sublicensee or strategicpartner with whom we collaborate on the development and commercialization of licensed products. The annual maintenance fees are creditable againstroyalty payments. We also must pay milestone payments within thirty days after achieving certain milestones. There were no milestones achieved during theyears ended December 31, 2018, 2017 and 2016 under either agreement. We must pay a royalty on future sales by us or our sublicensees of productsdeveloped using the licensed technology.The license agreements each remain in effect for an initial term of fifteen years, with automatic three-year renewal periods thereafter unless one of theparties provides notice of non-renewal. We may terminate the license agreements at any time upon providing sixty days’ written notice to Harvard College.Harvard College may terminate the agreements in the event we become bankrupt or insolvent. Both Harvard College and we may also terminate theagreements for an uncured material breach of the agreements by the other party.14Other License AgreementsIn 2016, we entered into a license agreement with Life Technologies Corporation, or Life Technologies. In consideration for obtaining a non-exclusive, royalty-free, worldwide license to use certain technologies and associated know-how to develop our product candidates, we paid a one-time, non-refundable license fee. This fee was recorded as a research and development expense in 2016. The license agreement will remain effective in perpetuity unlessearlier terminated. Life Technologies has the right to terminate the agreement upon our material, uncured breach of the agreement or in the event that itdetermines that continued performance of the agreement may violate any laws. We are obligated to diligently pursue regulatory approval necessary for thedevelopment, manufacture and sale of the licensed products. We have the right to terminate the agreement at any time upon providing thirty days’ writtennotice to Life Technologies.CompetitionThe biotechnology and pharmaceutical industries are characterized by rapidly changing technologies, significant competition and a strong emphasison intellectual property. This is also true in treatments of DMD, as well as in gene therapy. While we believe that our focus, strength of team, expertise ingene therapy, scientific knowledge and intellectual property provide us with competitive advantages, we face competition from several different sources,including large and small biopharmaceutical companies, academic research institutions, government agencies and public and private research institutions.Not only must we compete with other companies that are focused on gene transfer technology, but any product candidates that we successfully develop andcommercialize will compete with existing therapies and new therapies that may become available in the future.Many of our competitors have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing,clinical trials, regulatory approvals and product marketing than we do. These competitors also compete with us in recruiting and retaining qualified scientificand management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementaryto, or necessary for, our programs. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources beingconcentrated among a smaller number of our competitors. Smaller or early stage companies may also prove to be significant competitors, particularly throughcollaborative arrangements with large and established companies.We are aware of several companies and research institutions focused on developing systemic gene transfers for DMD, including Pfizer Inc., with aproduct candidate currently in Phase 1 clinical development, and Sarepta Therapeutics, Inc., with a product candidate currently in Phase I/II clinical trialdevelopment. In addition, there are two therapies, which are intended to be disease modifying, that are currently approved for DMD by certain regulators.These products are eteplirsen (EXONDYS 51) and ataluren (Translarna), each of which is indicated for approximately 13% of DMD patients. Any advances ingene transfer technology made by a competitor may be used to develop therapies that could compete with our lead product candidate or other productcandidates we may develop.Government regulation and product approvalU.S. government regulation and product approvalIn the United States, biologic products including gene therapy products, such as our lead product candidate, are licensed for marketing by the FDAunder the Public Health Service Act, or PHS Act, and regulated by the FDA under the Federal Food, Drug, and Cosmetic Act, or FD&C Act, as well as by otherfederal, state and local statutes and regulations. Both the FD&C Act and the PHS Act and their corresponding rules and regulations govern, among otherthings, the testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, advertising and other promotionalpractices involving biologic products. FDA approval must be obtained before conducting human clinical testing of biologic products. Additionally, eachclinical trial protocol for a gene therapy product candidate is reviewed by the FDA and, in limited instances, the U.S. National Institutes of Health, or the NIH,through its Office of Biotechnology Activities’ Recombinant DNA Advisory Committee, or RAC. FDA must license a biologic product before it may bemarketed within the United States.Within the FDA, the Center for Biologics Evaluation and Research, or the CBER, regulates gene therapy products. Within CBER, the review of genetherapy and related products is consolidated in the Office of Tissues and Advanced Therapies, or the OTAT, and the FDA has established the Cellular, Tissueand Gene Therapies Advisory Committee to advise CBER on its reviews. CBER, which works closely with the NIH and the RAC, makes recommendations tothe NIH on gene therapy issues and engages in a public discussion of scientific, safety, ethical and societal issues related to proposed and ongoing genetherapy protocols. The FDA has licensed human gene therapies products for sale in the United States, and the agency has provided guidance for thedevelopment of other gene therapy products. This guidance includes a growing body of guidance documents on chemistry, manufacturing and control, orCMC, clinical investigations and other areas of gene therapy development, all of which are intended to facilitate the industry’s development of gene therapyproducts.15U.S. biologic products development processThe process required by the FDA before a biologic product may be marketed in the United States generally involves the following: •completion of preclinical laboratory tests and in vivo studies according to the FDA’s GLP requirements and applicable requirements for thehumane use of laboratory animals or other applicable regulations; •submission to the FDA of an application for an IND, which allows human clinical trials to begin unless the FDA objects within 30 days; •approval by an institutional review board, or IRB, reviewing each clinical site before each clinical trial may be initiated; •approval by an institutional biosafety committee, or IBC, assessing the safety of the clinical research and identifying any potential risk to publichealth or the environment; •performance of adequate and well controlled human clinical trials according to the FDA’s regulations commonly referred to as good clinicalpractices, or GCPs, and any additional requirements for the protection of human research subjects and their health information, to establish thesafety, potency and purity of the proposed biologic product for its intended use; •preparation and submission to the FDA of a biologics license application, or BLA, for marketing approval that includes substantive evidence ofsafety, purity and potency from results of preclinical testing and clinical trials, and detailed information about the CMC for the product, reportsof the outcomes and full data sets of the clinical trials and proposed labeling and packaging for the product; •review of the product candidate by an FDA advisory committee, if applicable; •satisfactory completion of an FDA inspection of the manufacturing facility or facilities where the biologic product candidate is produced toassess compliance with cGMP requirements and to assure that the facilities, methods and controls are adequate to preserve the biologic productcandidate’s identity, safety, strength, quality and purity; •potential FDA audit of the nonclinical and clinical trial sites that generated the data in support of the BLA; •payment of user fees; •FDA review and licensure of the BLA; and •compliance with any post-approval requirements, including the potential requirement to implement a Risk Evaluation and Mitigation Strategy,or REMS, and the potential requirement to conduct post-approval studies.Before testing any biologic product candidate in humans, including a gene therapy product candidate, the product candidate must undergopreclinical testing. Preclinical tests, also referred to as nonclinical studies, include laboratory evaluations of product chemistry, toxicity and formulation, aswell as in vivo studies to assess the potential safety and activity of the product candidate and to establish a rationale for therapeutic use. The conduct ofcertain nonclinical studies must comply with federal regulations and requirements, including GLPs.If a gene therapy trial is conducted at, or sponsored by, institutions receiving NIH funding for recombinant DNA research, prior to the submission ofan IND to the FDA, a protocol and related documents must be submitted to, and the study registered with, the NIH Office of Biotechnology Activities, orOBA, pursuant to the NIH Guidelines for Research Involving Recombinant DNA Molecules, or NIH Guidelines. Compliance with the NIH Guidelines ismandatory for investigators at institutions receiving NIH funds for research involving recombinant DNA. However, many companies and other institutions,not otherwise subject to the NIH Guidelines, voluntarily follow them. NIH is responsible for convening the RAC that discusses protocols that raise novel orparticularly important scientific, safety or ethical considerations at one of its quarterly public meetings. The OBA will notify the FDA of the RAC’s decisionregarding the necessity for full public review of a gene therapy protocol. RAC proceedings and reports are posted to the OBA website and may be accessed bythe public.The clinical trial sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any availableclinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. An IND is an exemption from the FD&C Act that allows anunapproved product to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer aninvestigational product to humans. Some preclinical tests may continue even after the IND is submitted. The IND automatically becomes effective 30 daysafter receipt by the FDA, unless the FDA places the clinical trial on a full clinical hold or partial clinical hold. In such a case, the IND16sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. With gene therapy protocols, if the FDA allows the IND toproceed, but the RAC decides that full public review of the protocol is warranted, the FDA will request at the completion of its IND review that the sponsordelay initiation of the protocol until after completion of the RAC review process. The FDA also may impose clinical holds on a biologic product candidate atany time before or during clinical trials due to safety concerns or non-compliance. If the FDA imposes a clinical hold, trials may not recommence withoutFDA authorization and then only under terms authorized by the FDA.In addition, the FDA may impose a partial clinical hold at any time before or during clinical trials. A partial clinical hold is a delay or suspension ofonly part of the clinical work requested under the IND (e.g., a specific protocol or part of a protocol is not allowed to proceed; however, other protocols orparts of the protocol are allowed to proceed under the IND). If the FDA requires that progress to the next study is contingent on (i) FDA review of additionaldata and (ii) subsequent specific permission for the study to proceed, this represents a partial clinical hold.Human clinical trials under an INDClinical trials involve the administration of the biologic product candidate to healthy volunteers or subjects under the supervision of qualifiedinvestigators, generally physicians not employed by, or under the control of, the trial sponsor. Clinical trials are conducted under written study protocolsdetailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria, and the parameters to be used tomonitor subject safety, including stopping rules that assure a clinical trial will be stopped if certain adverse events should occur. Each protocol and anyamendments to the protocol must be submitted to the FDA as part of the IND. Clinical trials must be conducted and monitored in accordance with the FDA’sregulations comprising the GCP requirements, including the requirement that all research subjects provide informed consent.Further, each clinical trial must be reviewed and approved by an IRB at or servicing each institution at which the clinical trial will be conducted. AnIRB is charged with protecting the welfare and rights of trial participants and considers such items as whether the risks to individuals participating in theclinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the form and content of the informed consent thatmust be signed by each clinical trial subject or his or her legal representative, reviews and approves the study protocol and must monitor the clinical trialuntil completed. Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safetymonitoring board or committee, or DSMB. This group provides authorization as to whether or not a trial may move forward at designated check points basedon access that only the group maintains to available data from the study. Clinical trials involving recombinant DNA also must be reviewed by an IBC a localinstitutional committee that reviews and oversees basic and clinical research and utilizes recombinant DNA at that institution. The IBC assesses the safety ofthe research and identifies any potential risk to public health or the environment.Human clinical trials are typically conducted in three sequential phases that may overlap or be combined: •Phase I. The investigational biologic product is initially introduced into a small group of healthy human subjects and tested for safety, dosagetolerance, absorption, metabolism, distribution, excretion and, if possible, to gain an early understanding of its effectiveness. In the case of someproduct candidates for severe or life-threatening diseases, especially when the product candidate may be too inherently toxic to ethicallyadminister to healthy volunteers, the initial human testing is often conducted in patients. Phase I clinical trials of gene therapies are typicallyconducted in patients rather than healthy volunteers. •Phase II. The biologic product candidate is evaluated in a limited patient population to identify possible adverse effects and safety risks, topreliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance, optimal dosage and dosingschedule. •Phase III. Phase III clinical trials are commonly referred to as “pivotal” studies, which typically denotes a study that presents the data that theFDA or other relevant regulatory agency will use to determine whether or not to approve a biologic product. In Phase III clinical trials, theinvestigational biologic product is administered to an expanded patient population, generally at multiple geographically dispersed clinical trialsites in adequate and well controlled clinical trials to generate sufficient data to statistically confirm the potency and safety of the product forapproval. These clinical trials are intended to establish the overall risk/benefit ratio of the product candidate and provide an adequate basis forproduct labeling.17Post-approval clinical trials, sometimes referred to as Phase IV clinical trials, may be conducted after initial approval. These clinical trials are used togain additional experience from the treatment of patients in the intended therapeutic indication, particularly for long-term safety follow-up.During all phases of clinical development, regulatory agencies require extensive monitoring and auditing of all clinical activities, clinical data andclinical trial investigators. Annual progress reports detailing the results of the clinical trials must be submitted to the FDA.Written IND safety reports must be promptly submitted to the FDA, the NIH and the investigators for serious and unexpected adverse events, anyfindings from other trials, in vivo laboratory tests or in vitro testing that suggest a significant risk for human subjects, or any clinically important increase inthe rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor must submit an IND safety report within15 calendar days after the sponsor determines that the information qualifies for reporting. The sponsor also must notify the FDA of any unexpected fatal orlife-threatening suspected adverse reaction within seven calendar days after the sponsor’s initial receipt of the information.The FDA or the sponsor or its DSMB may suspend a clinical trial at any time on various grounds, including a finding that the research subjects orpatients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if theclinical trial is not being conducted in accordance with the IRB’s requirements or if the biologic product candidate has been associated with unexpectedserious harm to patients.Information about certain clinical trials must be submitted within specific timeframes to the NIH for public dissemination on its ClinicalTrials.govwebsite.Expanded Access to an Investigational Drug for Treatment UseExpanded access, sometimes called “compassionate use,” is the use of investigational new drug products outside of clinical trials to treat patientswith serious or immediately life-threatening diseases or conditions when there are no comparable or satisfactory alternative treatment options. The rules andregulations related to expanded access are intended to improve access to investigational drugs for patients who may benefit from investigational therapies.FDA regulations allow access to investigational drugs under an IND by the company or the treating physician for treatment purposes on a case-by-case basisfor: individual patients (single-patient IND applications for treatment in emergency settings and non-emergency settings); intermediate-size patientpopulations; and larger populations for use of the drug under a treatment protocol or Treatment IND Application.When considering an IND application for expanded access to an investigational product with the purpose of treating a patient or a group of patients,the sponsor and treating physicians or investigators will determine suitability when all of the following criteria apply: patient(s) have a serious orimmediately life-threatening disease or condition, and there is no comparable or satisfactory alternative therapy to diagnose, monitor, or treat the disease orcondition; the potential patient benefit justifies the potential risks of the treatment and the potential risks are not unreasonable in the context or condition tobe treated; and the expanded use of the investigational drug for the requested treatment will not interfere with initiation, conduct, or completion of clinicalinvestigations that could support marketing approval of the product or otherwise compromise the potential development of the product.On December 13, 2016, the 21st Century Cures Act established (and the 2017 Food and Drug Administration Reauthorization Act later amended) arequirement that sponsors of one or more investigational drugs for the treatment of a serious disease(s) or condition(s) make publicly available their policy forevaluating and responding to requests for expanded access for individual patients. Although these requirements were rolled out over time, they have nowcome into full effect. This provision requires drug and biologic companies to make publicly available their policies for expanded access for individualpatient access to products intended for serious diseases. Sponsors are required to make such policies publicly available upon the earlier of initiation of aPhase II or Phase III study; or 15 days after the drug or biologic receives designation as a breakthrough therapy, fast track product, or regenerative medicineadvanced therapy. In addition, on May 30, 2018, the Right to Try Act, was signed into law. The law, among other things, provides a federal framework for certainpatients to access certain investigational new drug products that have completed a Phase I clinical trial and that are undergoing investigation for FDAapproval. Under certain circumstances, eligible patients can seek treatment without enrolling in clinical trials and without obtaining FDA permission underthe FDA expanded access program.18There is no obligation for a drug manufacturer to make its drug products available to eligible patients as a result of the Right to Try Act, but the manufacturermust develop an internal policy and respond to patient requests according to that policy.Additional regulation for gene therapy clinical trialsIn addition to the regulations discussed above, there are a number of additional standards that apply to clinical trials involving the use of genetherapy. The FDA has issued various guidance documents regarding gene therapies, which outline additional factors that the FDA will consider at each of theabove stages of development, which relate to, among other things: the proper preclinical assessment of gene therapies; the CMC information that should beincluded in an IND application; the proper design of tests to measure product potency in support of an IND or BLA application; and measures to observedelayed adverse effects in subjects who have been exposed to investigational gene therapies when the risk of such effects is high. Further, the FDA usuallyrecommends that sponsors observe subjects for potential gene therapy-related delayed adverse events for a 15-year period, including a minimum of five yearsof annual examinations followed by ten years of annual queries, either in person or by questionnaire. The FDA has issued various guidance documentsregarding gene therapies, including draft guidance released in July 2018 relating to gene therapies for human retinal disorders and gene therapies for rarediseases, and on January 15, 2019, the FDA issued a statement that it would issue additional guidance to facilitate the development of gene therapy products.The NIH and the FDA have a publicly accessible database, the Genetic Modification Clinical Research Information System, which includesinformation on gene therapy trials and serves as an electronic tool to facilitate the reporting and analysis of adverse events on these trials.Compliance with cGMP requirementsManufacturers of biologics must comply with applicable cGMP regulations, including quality control and quality assurance and maintenance ofrecords and documentation. Manufacturers and others involved in the manufacture and distribution of such products also must register their establishmentswith the FDA and certain state agencies. Both domestic and foreign manufacturing establishments must register and provide additional information to theFDA upon their initial participation in the manufacturing process. Establishments may be subject to periodic, unannounced inspections by governmentauthorities to ensure compliance with cGMP requirements and other laws. Discovery of problems may result in a government entity placing restrictions on aproduct, manufacturer or holder of an approved BLA, and may extend to requiring withdrawal of the product from the market. The FDA will not approve aBLA unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistentproduction of the product within required specification.Concurrent with clinical trials, companies usually complete additional preclinical studies and must also develop additional information about thephysical characteristics of the biologic product candidate as well as finalize a process for manufacturing the product candidate in commercial quantities inaccordance with cGMP requirements. To help reduce the risk of the introduction of adventitious agents or of causing other adverse events with the use ofbiologic products, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. Themanufacturing process must be capable of consistently producing quality batches of the product candidate and, among other requirements, the sponsor mustdevelop methods for testing the identity, strength, quality, potency and purity of the final biologic product. Additionally, appropriate packaging must beselected and tested, and stability studies must be conducted to demonstrate that the biologic product candidate does not undergo unacceptable deteriorationover its shelf life.U.S. review and approval processesAfter the completion of clinical trials of a biologic product, FDA licensure of a BLA must be obtained before commercial marketing of the biologicproduct. The BLA must include results of product development, laboratory and animal studies, human studies, information on the manufacture andcomposition of the product, proposed labeling and other relevant information. In addition, under the Pediatric Research Equity Act, a BLA or supplement toa BLA must contain data to assess the safety and effectiveness of the biologic product for the claimed indications in all relevant pediatric subpopulations andto support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submissionof data or full or partial waivers.Under the Prescription Drug User Fee Act, or PDUFA, as amended, each BLA must be accompanied by a significant user fee. Under federal law, thesubmission of most applications is subject to an application user fee, which for federal fiscal year 2019 is $2,588,478 for an application requiring clinicaldata. The sponsor of an approved application is also subject to an annual program fee, which for fiscal year 2019 is $309,915. Fee waivers or reductions areavailable in certain circumstances, including a waiver of the application fee for the first application filed by a small business. Additionally, no user fees are19assessed on BLAs for product candidates designated as orphan drugs, unless the product candidate also includes a non-orphan indication.The FDA reviews a BLA within 60 days of submission to determine if it is substantially complete before the agency accepts it for filing. The FDA mayrefuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event,the BLA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA accepts it for filing. Oncethe submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA.The FDA reviews the BLA to determine, among other things, whether the proposed product is safe and potent, or effective, for its intended use, andhas an acceptable purity profile, and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity,safety, strength, quality, potency and purity. The FDA may refer applications for novel biologic products or biologic products that present difficult questionsof safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as towhether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but itconsiders such recommendations carefully when making decisions. During the biologic product approval process, the FDA also will determine whether aREMS, is necessary to assure the safe use of the biologic product. REMS use risk minimization strategies beyond the professional labeling to ensure that thebenefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to usethe product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential adverse events andwhether the product is a new molecular entity. A REMS could include medication guides, physician communication plans and elements to assure safe use,such as restricted distribution methods, patient registries and other risk minimization tools. If the FDA concludes a REMS is needed, the sponsor of the BLAmust submit a proposed REMS; the FDA will not approve the BLA without a REMS, if required.Before approving a BLA, the FDA will inspect the facilities at which the product candidate is manufactured. The FDA will not approve the productcandidate unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistentproduction of the product within required specifications. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites toassure that the clinical trials were conducted in compliance with IND study requirements and GCP requirements. cGMP, GLP and GCP compliance requiressignificant expenditure of time, money and effort in the areas of training, recordkeeping, production and quality control.Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the BLA does not satisfy its regulatory criteriafor approval and deny approval. Data obtained from clinical trials are not always conclusive and the FDA may interpret data differently than how we wouldinterpret the same data. On the basis of the BLA and accompanying information, including the results of the inspection of the manufacturing facilities, theFDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the biologic product with specificprescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require substantialadditional testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDA’ssatisfaction in a resubmission of the BLA, the FDA will issue an approval letter. If the agency decides not to approve the BLA in its present form, the FDAwill issue a complete response letter that usually describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies identified maybe minor, for example, requiring labeling changes; or major, for example, requiring additional clinical trials. Additionally, the complete response letter mayinclude recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, theapplicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application.If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use mayotherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings orprecautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing or dispensing in theform of a REMS, or otherwise limit the scope of any approval. In addition, the FDA may require post-marketing clinical trials, sometimes referred to asPhase IV clinical trials, designed to further assess a biologic product’s safety and effectiveness, and testing and surveillance programs to monitor the safety ofapproved products that have been commercialized.The FDA has agreed to specified performance goals in the review of BLAs under the PDUFA. One such goal is to review standard BLAs in ten monthsafter the FDA accepts the BLA for filing, and priority BLAs in six months, whereupon a review decision is to be made. The FDA does not always meet itsPDUFA goal dates for standard and priority BLAs and its review goals are subject to change from time to time. The review process and the PDUFA goal datemay be extended by three20months if the FDA requests or the BLA sponsor otherwise provides additional information or clarification regarding information already provided in thesubmission within the last three months before the PDUFA goal date.Biosimilars and exclusivityThe Patient Protection and Affordable Care Act and the companion Health Care and Education Reconciliation Act, or the Health Care Reform Law,which was signed into law on March 23, 2010, included a subtitle called the Biologics Price Competition and Innovation Act of 2009, or BPCIA. That Actestablished a regulatory scheme authorizing the FDA to approve biosimilars and interchangeable biosimilars.Under the BPCIA, a manufacturer may submit an application for licensure of a biologic product that is “biosimilar to” or “interchangeable with” apreviously approved biological product or “reference product.” In order for the FDA to approve a biosimilar product, it must find that there are no clinicallymeaningful differences between the reference product and proposed biosimilar product in terms of safety, purity and potency. For the FDA to approve abiosimilar product as interchangeable with a reference product, the agency must find that the biosimilar product can be expected to produce the same clinicalresults as the reference product, and (for products administered multiple times) that the biologic and the reference biologic may be switched after one hasbeen previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date of approval of thereference product. The FDA may not approve a biosimilar product until 12 years from the date on which the reference product was approved. Even if aproduct is considered to be a reference product eligible for exclusivity, another company could market a competing version of that product if the FDAapproves a full BLA for such product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstratethe safety, purity and potency of their product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. Atthis juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed bystate pharmacy law.Pediatric exclusivityPediatric exclusivity is another type of non-patent exclusivity in the United States and, if granted, provides for the attachment of an additional sixmonths of marketing protection to the term of any existing regulatory exclusivity or patent protection, including the non-patent and orphan exclusivity. Thissix-month exclusivity may be granted if an application sponsor submits pediatric data that fairly respond to a written request from the FDA for such data. Thedata do not need to show the product to be effective in the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDA’srequest, the additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA within the statutory timelimits, whatever statutory or regulatory periods of exclusivity or patent protection cover the product are extended by six months. Thus, pediatric exclusivityadds six months to existing exclusivity periods applicable to biological products under the BPCIA—namely, the four-year period during which the FDA willnot consider an application for a biosimilar product, and the 12-year period during which the FDA will not approve a biosimilar application.Orphan drug designationUnder the Orphan Drug Act, the FDA may designate a biologic product as an “orphan drug” if it is intended to treat a rare disease or condition(generally meaning that it affects fewer than 200,000 individuals in the United States, or more in cases in which there is no reasonable expectation that thecost of developing and making a biologic product available in the United States for treatment of the disease or condition will be recovered from sales of theproduct). Orphan product designation must be requested before submitting a BLA. After the FDA grants orphan product designation, the identity of thetherapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan product designation does not convey any advantage in, or shortenthe duration of, the regulatory review and approval process.If a product with orphan status receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled toorphan product exclusivity, meaning that the FDA may not approve any other applications to market the same drug or biologic product for the sameindication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity or if the partyholding the exclusivity fails to assure the availability of sufficient quantities of the drug to meet the needs of patients with the disease or condition for whichthe drug was designated. This is the case despite an earlier court opinion holding that the Orphan Drug Act unambiguously required the FDA to recognizeorphan exclusivity regardless of a showing of clinical superiority.21Competitors, however, may receive approval of different products for the same indication for which the orphan product has exclusivity or obtainapproval for the same product but for a different indication for which the orphan product has exclusivity. Orphan medicinal product status in the EuropeanUnion has similar, but not identical, benefits.Expedited development and review programsThe FDA is authorized to expedite the review of BLAs in several ways. Under the Fast Track program, the sponsor of a biologic product candidatemay request the FDA to designate the product for a specific indication as a Fast Track product concurrent with or after the filing of the IND. Biologic productsare eligible for Fast Track designation if they are intended to treat a serious or life-threatening condition and demonstrate the potential to address unmetmedical needs for the condition. Fast Track designation applies to the combination of the product candidate and the specific indication for which it is beingstudied. In addition to other benefits, such as the ability to have greater interactions with the FDA, the FDA may initiate review of sections of a Fast TrackBLA before the application is complete, a process known as rolling review.Any product submitted to the FDA for marketing, including under a Fast Track program, may be eligible for other types of FDA programs intended toexpedite development and review, such as breakthrough therapy designation, priority review and accelerated approval. •Breakthrough therapy designation. To qualify for the breakthrough therapy program, product candidates must be intended to treat a serious orlife-threatening disease or condition and preliminary clinical evidence must indicate that such product candidates may demonstrate substantialimprovement on one or more clinically significant endpoints over existing therapies. The FDA will seek to ensure the sponsor of a breakthroughtherapy product candidate receives intensive guidance on an efficient drug development program, intensive involvement of senior managersand experienced staff on a proactive, collaborative and cross-disciplinary review and rolling review. •Priority review. A product candidate is eligible for priority review if it treats a serious condition and, if approved, it would be a significantimprovement in the safety or effectiveness of the treatment, diagnosis or prevention compared to marketed products. FDA aims to complete itsreview of priority review applications within six months as opposed to 10 months for standard review. •Accelerated approval. Drug or biologic products studied for their safety and effectiveness in treating serious or life-threatening illnesses andthat provide meaningful therapeutic benefit over existing treatments may receive accelerated approval. Accelerated approval means that aproduct candidate may be approved on the basis of adequate and well controlled clinical trials establishing that the product candidate has aneffect on a surrogate endpoint that is reasonably likely to predict a clinical benefit, or on the basis of an effect on a clinical endpoint other thansurvival or irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity and prevalence of the conditionand the availability or lack of alternative treatments. As a condition of approval, the FDA may require that a sponsor of a drug or biologicproduct candidate receiving accelerated approval perform adequate and well controlled post-marketing clinical trials. In addition, the FDAcurrently requires as a condition for accelerated approval pre-approval of promotional materials. •Regenerative advanced therapy. With passage of the 21st Century Cures Act, or the Cures Act, in December 2016, Congress authorized the FDAto accelerate review and approval of products designated as regenerative advanced therapies. A product is eligible for this designation if it is aregenerative medicine therapy that is intended to treat, modify, reverse or cure a serious or life-threatening disease or condition and preliminaryclinical evidence indicates that the product candidate has the potential to address unmet medical needs for such disease or condition. Thebenefits of a regenerative advanced therapy designation include early interactions with the FDA to expedite development and review, benefitsavailable to breakthrough therapies, potential eligibility for priority review and accelerated approval based on surrogate or intermediateendpoints.None of these expedited programs change the standards for approval but they may help expedite the development or approval process of productcandidates.Post-approval requirementsAfter regulatory approval of a product is obtained, there may be a number of post-approval requirements. For example, as a condition of approval of aBLA, the FDA may require post-marketing testing and surveillance to monitor the product’s safety or efficacy. In addition, holders of an approved BLA arerequired to keep extensive records, to report certain adverse reactions and production problems to the FDA, to provide updated safety and efficacyinformation and to comply with requirements concerning advertising and promotional labeling for their products. Also, quality control and manufacturingprocedures must continue to conform to cGMP regulations and practices, as well as the manufacturing conditions of approval22set forth in the BLA. The FDA periodically inspects manufacturing facilities to assess compliance with cGMP requirements, which impose certain procedural,substantive and recordkeeping requirements. Accordingly, manufacturers must continue to expend time, money and effort in the area of production andquality control to maintain compliance with cGMP and other aspects of regulatory compliance.The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Products may be promoted onlyfor the approved indications and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws andregulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significantliability. If a company is found to have promoted off-label uses, it may become subject to adverse public relations and administrative and judicialenforcement by the FDA, the Department of Justice, or the Office of the Inspector General of the Department of Health and Human Services, as well as stateauthorities. This could subject a company to a range of penalties that could have a significant commercial impact, including civil and criminal fines andagreements that materially restrict the manner in which a company promotes or distributes drug products.U.S. patent term restoration and marketing exclusivityDepending upon the timing, duration and specifics of FDA approval of product candidates, some of a sponsor’s U.S. patents may be eligible forlimited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent restoration term of up to five years as compensation for patent terms lost during product development and FDAregulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’sapproval date. The patent term restoration period generally is one-half the time between the effective date of an IND and the submission date of a BLA plusthe time between the submission date of a BLA and the approval of that application. Only one patent applicable to an approved biologic product is eligiblefor the extension, the application for the extension must be submitted prior to the expiration of the patent, and only those claims covering the approved drug,a method for using it or a method for manufacturing it may be extended. Moreover, a given patent may only be extended once based on a single product. TheUSPTO in consultation with the FDA, reviews and approves the application for any patent term extension or restoration.Government regulation outside of the U.S.In addition to regulations in the United States, a manufacturer is subject to a variety of regulations in foreign jurisdictions to the extent it chooses tosell any products in those foreign countries. Even if a manufacturer obtains FDA approval of a product, it must still obtain the requisite approvals fromregulatory authorities in foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Because biologicallysourced materials are subject to unique contamination risks, their use may also be restricted in some countries.Clinical trial approval in the European UnionPursuant to the currently applicable Clinical Trials Directive 2001/20/EC and the Directive 2005/28/EC on Good Clinical Practice, an applicant mustobtain approval from the competent national authority of the European Union Member State, or the EU Member State, in which the clinical trial is to beconducted. If the clinical trial is conducted in different EU Member States, the competent authorities in each of these EU Member States must provide theirapproval for the conduct of the clinical trial. Furthermore, the applicant may only start a clinical trial at a specific study site after the competent ethicscommittee has issued a favorable opinion. In April 2014, the European Union adopted a new Clinical Trials Regulation (EU) No 536/2014, which is set toreplace the current Clinical Trials Directive 2001/20/EC. The new Clinical Trials Regulation will be directly applicable to and binding in all EU MemberStates without the need for any national implementing legislation. Clinical Trials Regulation (EU) No 536/2014 was published on June 16, 2014 but is notexpected to apply until later in 2019.PRIME designationIn March 2016, the EMA, launched the PRIority MEdicines, or PRIME, initiative to foster research and development of medicines that may offer amajor therapeutic advantage over existing treatments, or benefit patients without treatment options. PRIME aims to strengthen clinical trial designs tofacilitate the generation of high-quality data for the evaluation of an application for marketing authorization. To be accepted for PRIME, a medicine has toshow its potential to benefit patients23with unmet medical needs based on preclinical and/or early clinical data. These medicines are considered priority medicines within the European Union.After an investigational candidate has been selected for PRIME, developers are assigned a rapporteur from the CHMP, to provide continuous supportand help to build knowledge ahead of a marketing authorization application, or MAA. A multidisciplinary group of experts will provide broader guidance onthe overall development plan and regulatory strategy of the product. Companies are also eligible for accelerated assessment at the time of their regulatoryapplication.Marketing authorizationIn the European Union, marketing authorizations for medicinal products may be obtained through several different procedures founded on the samebasic regulatory process.The centralized procedure provides for the grant of a single marketing authorization by the European Commission that is valid across the EuropeanEconomic Area (i.e. the EU as well as Iceland, Liechtenstein and Norway). The centralized procedure is compulsory for medicinal products produced bycertain biotechnological processes, products designated as orphan medicinal products, and products with a new active substance indicated for the treatmentof certain diseases. It is optional for those products that are highly innovative or for which a centralized process is in the interest of patients. Under thecentralized procedure in the European Union, the maximum timeframe for the evaluation of an MAA is 210 days, excluding clock stops, when additionalwritten or oral information is to be provided by the applicant in response to questions asked by the CHMP. Accelerated evaluation may be granted by theCHMP in exceptional cases. These are defined as circumstances in which a medicinal product is expected to be of a “major public health interest.” Threecumulative criteria must be fulfilled in such circumstances: the seriousness of the disease, such as severely disabling or life-threatening diseases, to betreated; the absence or insufficiency of an appropriate alternative therapeutic approach; and anticipation of high therapeutic benefit. In these circumstances,the EMA ensures that the opinion of the CHMP is given within 150 days.Specifically, the grant of marketing authorization in the European Union for products containing viable human tissues or cells such as gene therapymedicinal products is governed by Regulation 1394/2007/EC on advanced therapy medicinal products, read in combination with Directive 2001/83/EC ofthe European Parliament and of the Council, commonly known as the Community code on medicinal products. Regulation 1394/2007/EC lays down specificrules concerning the authorization, supervision, and pharmacovigilance of gene therapy medicinal products, somatic cell therapy medicinal products, andtissue engineered products. Manufacturers of advanced therapy medicinal products must demonstrate the quality, safety, and efficacy of their products toEMA which provides an opinion regarding the application for marketing authorization. The European Commission grants or refuses marketing authorizationin light of the opinion delivered by EMA.The decentralized procedure provides for approval by one or more other concerned EU Member States of an assessment of an application formarketing authorization conducted by one EU Member State, known as the reference EU Member State. In accordance with this procedure, an applicantsubmits an application for marketing authorization to the reference EU Member State and the concerned EU Member States. This application is identical tothe application that would be submitted to the EMA for authorization through the centralized procedure. The reference EU Member State prepares a draftassessment and drafts of the related materials within 120 days after receipt of a valid application. The resulting assessment report is submitted to theconcerned EU Member States which, within 90 days of receipt, must decide whether to approve the assessment report and related materials.If a concerned EU Member State cannot approve the assessment report and related materials due to concerns relating to a potential serious risk topublic health, disputed elements may be referred to the European Commission, whose decision is binding on all EU Member States. In accordance with themutual recognition procedure, the sponsor applies for national marketing authorization in one EU Member State. Upon receipt of this authorization thesponsor can then seek the recognition of this authorization by other EU Member States. Authorization in accordance with either of these procedures willresult in authorization of the medicinal product only in the reference EU Member State and in the other concerned EU Member States.A marketing authorization may be granted only to an applicant established in the European Union. Regulation No. 1901/2006 provides that, prior toobtaining a marketing authorization in the European Union, an applicant must demonstrate compliance with all measures included in a PediatricInvestigation Plan, or PIP, approved by the Pediatric Committee of the EMA, covering all subsets of the pediatric population, unless the EMA has granted aproduct-specific waiver, class waiver, or a deferral for one or more of the measures included in the PIP.24In specific circumstances, E.U. legislation on Conditional Marketing Authorizations for Medicinal Products for Human Use, or conditional marketingauthorization, enables applicants to obtain a conditional marketing authorization prior to obtaining the comprehensive clinical data required for anapplication for a full marketing authorization. Such conditional approvals may be granted for product candidates (including medicines designated as orphanmedicinal products) if the risk-benefit balance of the product candidate is positive, it is likely that the applicant will be in a position to provide the requiredcomprehensive clinical trial data, the product fulfills unmet medical needs and the benefit to public health of the immediate availability on the market of themedicinal product concerned outweighs the risk inherent in the fact that additional data are still required. A conditional marketing authorization may containspecific obligations to be fulfilled by the marketing authorization holder, including obligations with respect to the completion of ongoing or new studies,and with respect to the collection of pharmacovigilance data.Conditional marketing authorizationConditional marketing authorizations are valid for one year, and may be renewed annually, if the risk-benefit balance remains positive, and after anassessment of the need for additional or modified conditions and/or specific obligations. The timelines for the centralized procedure described above alsoapply with respect to the review by the CHMP of applications for a conditional marketing authorization.The requirements and processes governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country.In all cases, the clinical trials are conducted in accordance with GCPs and the applicable regulatory requirements of the country or countries in which theclinical trial is performed, as well as the ethical principles that have their origin in the Declaration of Helsinki (whichever provides the greater protection tothe clinical trial participants).General Data Protection RegulationThe collection, use, disclosure, transfer, or other processing of personal data regarding individuals in the EU, including personal health data, issubject to the EU General Data Protection Regulation, or the GDPR, which became effective on May 25, 2018. The GDPR is wide-ranging in scope andimposes numerous requirements on companies that process personal data, including requirements relating to processing health and other sensitive data,obtaining consent of the individuals to whom the personal data relates, providing information to individuals regarding data processing activities,implementing safeguards to protect the security and confidentiality of personal data, providing notification of data breaches, and taking certain measureswhen engaging third-party processors. The GDPR also imposes strict rules on the transfer of personal data to countries outside the EU, including the U.S., andpermits data protection authorities to impose large penalties for violations of the GDPR, including potential fines of up to €20 million or 4% of annual globalrevenues, whichever is greater. The GDPR also confers a private right of action on data subjects and consumer associations to lodge complaints withsupervisory authorities, seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. Compliance with the GDPRwill be a rigorous and time-intensive process that may increase the cost of doing business or require companies to change their business practices to ensurefull compliance.Healthcare law and regulationHealthcare providers and third-party payors play a primary role in the recommendation and prescription of products that are granted marketingapproval. Arrangements with providers, consultants, third-party payors and customers are subject to broadly applicable fraud and abuse, anti-kickback, falseclaims laws, reporting of payments to physicians and teaching physicians and patient privacy laws and regulations and other healthcare laws and regulationsthat may constrain business and/or financial arrangements. Restrictions under applicable federal and state healthcare laws and regulations, include thefollowing: •the federal Anti-Kickback Statute, which prohibits, among other things, persons and entities from knowingly and willfully soliciting, offering,paying, receiving or providing remuneration, directly or indirectly, in cash or in kind, to induce or reward either the referral of an individual for,or the purchase, order or recommendation of, any good or service, for which payment may be made, in whole or in part, under a federalhealthcare program such as Medicare and Medicaid; •the federal civil and criminal false claims laws, including the civil False Claims Act, and civil monetary penalties laws, which prohibitindividuals or entities from, among other things, knowingly presenting, or causing to be presented, to the federal government, claims forpayment that are false, fictitious or fraudulent or knowingly making, using or causing to made or used a false record or statement to avoid,decrease or conceal an obligation to pay money to the federal government; •the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which created additional federal criminal laws that prohibit,among other things, knowingly and willfully executing, or attempting to25 execute, a scheme to defraud any healthcare benefit program or making false statements relating to healthcare matters; •HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, and their respective implementingregulations, including the Final Omnibus Rule published in January 2013, which impose obligations, including mandatory contractual terms,with respect to safeguarding the privacy, security and transmission of individually identifiable health information; •the federal false statements statute, which prohibits knowingly and willfully falsifying, concealing or covering up a material fact or making anymaterially false statement in connection with the delivery of or payment for healthcare benefits, items or services; •the federal transparency requirements known as the federal Physician Payments Sunshine Act, under the Health Care Reform Law, whichrequires certain manufacturers of drugs, devices, biologics and medical supplies to report annually to the Centers for Medicare & MedicaidServices, or CMS, within the United States Department of Health and Human Services, information related to payments and other transfers ofvalue made by that entity to physicians and teaching hospitals, as well as ownership and investment interests held by physicians and theirimmediate family members; and •analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to healthcare items orservices that are reimbursed by non-governmental third-party payors, including private insurers.Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevantcompliance guidance promulgated by the federal government in addition to requiring manufacturers to report information related to payments to physiciansand other health care providers or marketing expenditures. State and foreign laws also govern the privacy and security of health information in somecircumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.Pharmaceutical insurance coverage and health care reformIn the United States and markets in other countries, patients who are prescribed treatments for their conditions and providers performing theprescribed services generally rely on third-party payors to reimburse all or part of the associated health care costs. Significant uncertainty exists as to thecoverage and reimbursement status of products approved by the FDA and other government authorities. Thus, even if a product candidate is approved, salesof the product will depend, in part, on the extent to which third-party payors, including government health programs in the United States such as Medicareand Medicaid, commercial health insurers and managed care organizations, provide coverage and establish adequate reimbursement levels for, the product.The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement ratethat the payor will pay for the product once coverage is approved. Third-party payors are increasingly challenging the prices charged, examining the medicalnecessity and reviewing the cost-effectiveness of medical products and services and imposing controls to manage costs. Third-party payors may limitcoverage to specific products on an approved list, also known as a formulary, which might not include all of the approved products for a particular indication.The Trump Administration has also taken executive actions to undermine or delay implementation of the Health Care Reform Law. Since January2017, President Trump has signed two Executive Orders designed to delay the implementation of certain provisions of the Health Care Reform Law orotherwise circumvent some of the requirements for health insurance mandated by the Health Care Reform Law. One Executive Order directs federal agencieswith authorities and responsibilities under the Health Care Reform Law to waive, defer, grant exemptions from, or delay the implementation of any provisionof the Health Care Reform Law that would impose a fiscal or regulatory burden on states, individuals, healthcare providers, health insurers, or manufacturersof pharmaceuticals or medical devices. The second Executive Order terminates the cost-sharing subsidies that reimburse insurers under the Health CareReform Law. Several state Attorneys General filed suit to stop the administration from terminating the subsidies, but their request for a restraining order wasdenied by a federal judge in California on October 25, 2017. In addition, CMS has recently proposed regulations that would give states greater flexibility insetting benchmarks for insurers in the individual and small group marketplaces, which may have the effect of relaxing the essential health benefits requiredunder the Health Care Reform Law for plans sold through such marketplaces. Further, on June 14, 2018, U.S. Court of Appeals for the Federal Circuit ruledthat the federal government was not required to pay more than $12 billion in Health Care Reform Law risk corridor payments to third-party payors whoargued were owed to them. The effects of this gap in reimbursement on third-party payors, the viability of the Health Care Reform Law marketplace,providers, and potentially our business, are not yet known.26More recently, with enactment of the Tax Cuts and Jobs Act of 2017, which was signed by the President on December 22, 2017, Congress repealed the“individual mandate.” The repeal of this provision, which requires most Americans to carry a minimal level of health insurance, will become effective in2019. According to the Congressional Budget Office, the repeal of the individual mandate will cause 13 million fewer Americans to be insured in 2027 andpremiums in insurance markets may rise. Additionally, on January 22, 2018, President Trump signed a continuing resolution on appropriations for fiscal year2018 that delayed the implementation of certain Health Care Reform Law-mandated fees, including the so-called “Cadillac” tax on certain high costemployer-sponsored insurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise taxon non-exempt medical devices. The Congress will likely consider other legislation to replace elements of the Health Care Reform Law, during the nextCongressional session.Further, there have been several recent U.S. congressional inquiries and proposed federal and proposed and enacted state legislation designed to,among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the costs ofdrugs under Medicare and reform government program reimbursement methodologies for drug products. For example, there have been several recent U.S.congressional inquiries and proposed federal and proposed and enacted state legislation designed to, among other things, bring more transparency to drugpricing, review the relationship between pricing and manufacturer patient programs, reduce the costs of drugs under Medicare and reform governmentprogram reimbursement methodologies for drug products. At the federal level, Congress and the Administration have each indicated that it will continue toseek new legislative and/or administrative measures to control drug costs. For example, on May 11, 2018, the Administration issued a plan to lower drugprices. Under this blueprint for action, the Administration indicated that the Department of Health and Human Services will: take steps to end the gaming ofregulatory and patent processes by drug makers to unfairly protect monopolies; advance biosimilars and generics to boost price competition; evaluate theinclusion of prices in drug makers’ ads to enhance price competition; speed access to and lower the cost of new drugs by clarifying policies for sharinginformation between insurers and drug makers; avoid excessive pricing by relying more on value-based pricing by expanding outcome-based payments inMedicare and Medicaid; work to give Part D plan sponsors more negotiation power with drug makers; examine which Medicare Part B drugs could benegotiated for a lower price by Part D plans, and improving the design of the Part B Competitive Acquisition Program; update Medicare’s drug-pricingdashboard to increase transparency; prohibit Part D contracts that include “gag rules” that prevent pharmacists from informing patients when they could payless out-of-pocket by not using insurance; and require that Part D plan members be provided with an annual statement of plan payments, out-of-pocketspending, and drug price increases.At the state level, individual states are increasingly aggressive in passing legislation and implementing regulations designed to controlpharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access andmarketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. Inaddition, regional health care authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products andwhich suppliers will be included in their prescription drug and other health care programs. These measures could reduce the ultimate demand for ourproducts, once approved, or put pressure on our product pricing. We expect that additional state and federal healthcare reform measures will be adopted in thefuture, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduceddemand for our product candidates or additional pricing pressures.Environmental regulationsWe are also subject to regulation under the Occupational Safety and Health Act, the Environmental Protection Act, the Toxic Substances Control Act,the Resource Conservation and Recovery Act and other present and potential federal, state or local regulations. These and other laws govern our use,handling and disposal of various biological and chemical substances used in, and waste generated by, our operations. Our research and development involvesthe controlled use of hazardous materials, chemicals and viruses.EmployeesAs of December 31, 2018, we employed 111 full-time employees, including 85 in research and development and 26 in general and administrativepositions. 32 of our employees hold Ph.D. or M.D. degrees. Corporate InformationWe were originally formed as SOLID Ventures Management, LLC in March 2013 as a Delaware limited liability company. In October 2013, wechanged our name to Solid Ventures, LLC and in June 2015 we changed our name to Solid27Biosciences, LLC. Immediately prior to the effectiveness of our registration statement on Form S-1 on January 25, 2018, we converted into a Delawarecorporation pursuant to a statutory conversion and changed our name to Solid Biosciences Inc. In addition, immediately following the statutory conversion,entities formed solely for the purpose of holding membership interests in our limited liability company were merged with and into us. We refer to thecorporate conversion and the mergers collectively as the Corporate Conversion. Our principal executive offices are located at 141 Portland Street, Fifth Floor,Cambridge, Massachusetts 02139 and our telephone number is (617) 337-4680. Our website address is www.solidbio.com. The information contained in, oraccessible through, our website does not constitute a part of this Annual Report on Form 10-K.We make available free of charge on our website our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-Kand amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act, as soon as reasonably practicable after weelectronically file such material with, or furnish it to, the SEC.Item 1A.Risk Factors.You should carefully consider the following risk factors, in addition to the other information contained in this Annual Report on Form 10-K, including thesection of this report titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our financial statements andrelated notes. If any of the events described in the following risk factors and the risks described elsewhere in this Annual Report on Form 10-K occurs, ourbusiness, operating results and financial condition could be seriously harmed and the trading price of our common stock could decline. This Annual Reporton Form 10-K also contains forward-looking statements that involve risks and uncertainties. Our actual results could differ materially from thoseanticipated in the forward-looking statements as a result of factors that are described below and elsewhere in this Annual Report on Form 10-K.Risks related to our financial position and need for capital requirementsWe have incurred significant net losses since inception and anticipate that we will continue to incur net losses for the foreseeable future and may neverachieve or maintain profitability.Since inception, we have incurred significant net losses. Our net losses were $74.8 million, $53.2 million and $23.8 million million for the years endedDecember 31, 2018, 2017 and 2016, respectively. As of December 31, 2018, we had an accumulated deficit of $199.1 million. To date, we have devotedsubstantially all of our efforts to research and development, including clinical development of our gene transfer product candidate, SGT-001, as well as tobuilding out our management team and infrastructure. We expect that it could be several years, if ever, before we have a commercialized product. We expectto continue to incur significant expenses and increasing operating losses for the foreseeable future. We anticipate that our expenses will increasesubstantially if, and as, we: •continue to enroll patients in IGNITE DMD and continue clinical development of SGT-001; •move other current or future product candidates into clinical trials; •continue research and preclinical development of our other product candidate, Anti-LTBP4; •seek to identify additional product candidates; •seek marketing approvals for our product candidates that successfully complete clinical trials, if any; •establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval; •arrange for manufacture of larger quantities of our product candidates for clinical development and potential commercialization; •maintain, expand, protect and enforce our intellectual property portfolio; •hire and retain additional clinical, quality control and scientific personnel; •build out new facilities or expand existing facilities to support our activities; •acquire or in-license other drugs, technologies and intellectual property; and •add operational, financial and management information systems and personnel.28To become and remain profitable, we must develop and eventually commercialize one or more product candidates with significant market potential. This willrequire us to be successful in a range of challenging activities, and our expenses will increase substantially as we seek to complete clinical trials of SGT-001,obtain marketing approval for SGT-001, develop and validate commercial-scale manufacturing processes, manufacture, market and sell any future productcandidates for which we may obtain marketing approval and satisfy any post-marketing requirements. We may never succeed in any or all of these activitiesand, even if we do, we may never generate revenue that is significant or large enough to achieve profitability. If we do achieve profitability, we may not beable to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would decrease the value of our companyand could impair our ability to raise capital, maintain our research and development efforts, expand our business or continue our operations. A decline in thevalue of our company also could cause stockholders to lose all or part of their investment.We will need additional funding, which may not be available on acceptable terms, or at all. Failure to obtain this necessary capital when needed mayforce us to delay, limit or terminate our product development efforts or other operations.We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, conduct clinicaltrials of, and seek marketing approval for, SGT-001 and our other product candidates. In addition, if we obtain marketing approval for SGT-001 and our otherproduct candidates, we expect to incur significant expenses related to product sales, marketing, manufacturing and distribution. We also incur additionalcosts associated with operating as a public company. While we believe that our cash, cash equivalents and available-for-sale securities as of December 31,2018 will enable us to fund our operating expenses and capital expenditure requirements through the first quarter of 2020, we anticipate that we will needadditional funding to complete the development of SGT-001 and our other product candidates.Our future capital requirements will depend on many factors, including: •the progress and results of IGNITE DMD and future clinical trials of SGT-001 and our other product candidates; •the costs, timing and outcome of regulatory review of SGT-001 and our other product candidates; •the scope, progress, results and costs of discovery, laboratory testing, manufacturing, preclinical development and clinical trials for otherproduct candidates that we may pursue in the future, if any; •the costs associated with our manufacturing process development and evaluation of third-party manufacturers; •whether we decide to construct and validate our own manufacturing facility and the associated costs; •revenue, if any, received from commercial sale of SGT-001 or our other product candidates, should any of our product candidates receivemarketing approval; •the costs of preparing, filing and prosecuting patent applications, maintaining, defending and enforcing our intellectual property rights anddefending intellectual property-related claims; •the outcome of any lawsuits filed against us; •the terms of our current and any future license agreements and collaborations; and •the extent to which we acquire or in-license other product candidates, technologies and intellectual property.Identifying potential product candidates and conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process thattakes years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve product sales. Inaddition, our product candidates, if approved, may not achieve commercial success. Our product revenue, if any, will be derived from or based on sales ofproduct candidates that may not be commercially available for many years, if at all. Accordingly, we will need to continue to rely on additional financing toachieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all.Raising additional capital may cause dilution to our existing stockholders, restrict our operations or require us to relinquish rights to our technologies,SGT-001 or our other product candidates.We may seek additional capital through a combination of public and private equity offerings, debt financings, strategic partnerships and alliances andlicensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, ownership of our commonstock will be diluted and the terms may include liquidation or other preferences that adversely affect the rights of our current stockholders. The incurrence ofindebtedness would result in increased fixed payment obligations and could involve restrictive covenants, such as limitations on our ability to incuradditional debt, limitations on our ability to acquire or license intellectual property rights and other operating restrictions that29could adversely impact our ability to conduct our business. If we raise additional funds through strategic partnerships and alliances and licensingarrangements with third parties, we may have to relinquish valuable rights to our technologies, SGT-001 or our other product candidates, or grant licenses onterms unfavorable to us.We have never generated revenue from product sales and do not expect to do so for the next several years, if ever.Our ability to generate revenue from product sales and achieve profitability depends on our ability, alone or with collaborative partners, to successfullycomplete the development of, and obtain the regulatory approvals necessary to commercialize, SGT-001 and our other product candidate, Anti-LTBP4, andany other product candidates that we may pursue in the future. We do not anticipate generating revenue from product sales for the next several years, if ever.Our ability to generate future revenue from product sales depends heavily on our success in: •completing research and development of SGT-001 and our other product candidates in a timely and successful manner; •seeking and obtaining regulatory and marketing approvals for any product candidates for which we complete clinical trials; •launching and commercializing SGT-001 and any other product candidates for which we obtain regulatory and marketing approval byestablishing a sales force and marketing and distribution infrastructure or, alternatively, collaborating with a commercialization partner; •maintaining and enhancing a commercially viable, sustainable, scalable, reproducible and transferable manufacturing process for SGT-001 andour other product candidates that is compliant with cGMPs; •establishing and maintaining supply and manufacturing relationships with third parties that can provide adequate, in both amount and quality,products and services to support clinical development and the commercial demand for SGT-001 and our other product candidates, if approved; •obtaining market acceptance, if and when approved, of SGT-001 and our other product candidate as a viable treatment option by patients, themedical community and third-party payors; •qualifying for coverage and adequate reimbursement by government and third-party payors for SGT-001 and our other product candidates bothin the U.S. and internationally; •effectively addressing any competing technological and market developments; •negotiating favorable terms in any collaboration, licensing or other arrangements into which we may enter and performing our obligations undersuch arrangements; •maintaining, protecting, enforcing and expanding our portfolio of intellectual property rights, including patents, trademarks, trade secrets andknow-how; •avoiding and defending against intellectual property infringement, misappropriation and other claims; •implementing additional internal systems and infrastructure, as needed; and •attracting, hiring and retaining qualified personnel.Our limited operating history may make it difficult for our stockholders to evaluate the success of our business to date and to assess our future viability.We are a development-stage company founded in 2013. Our operations to date, with respect to the development of SGT-001 and other potential productcandidates, have been limited to organizing and staffing our company, business planning, raising capital, acquiring rights to our technology, identifyingSGT-001 as a potential gene transfer product candidate and undertaking preclinical studies and a clinical trial of that product candidate and establishingresearch and development and manufacturing collaborations. We have not yet demonstrated the ability to complete clinical trials of SGT-001 or any otherproduct candidate, obtain marketing approvals, manufacture a commercial-scale product or conduct sales and marketing activities necessary for successfulcommercialization. Consequently, any predictions our stockholders make about our prospects may not be as accurate as they could be if we had a longeroperating history.30Our independent registered public accounting firm has included an explanatory paragraph relating to our ability to continue as a going concern in itsreport on our audited financial statements included in this Annual Report on Form 10-K.The report from our independent registered public accounting firm for the year ended December 31, 2018 includes an explanatory paragraph stating that ourlosses from operations and required additional funding to finance our operations raise substantial doubt about our ability to continue as a going concern. Ifwe are unable to obtain sufficient funding, our business, prospects, financial condition and results of operations will be materially and adversely affected andwe may be unable to continue as a going concern. If we are unable to continue as a going concern, we may have to liquidate our assets and may receive lessthan the value at which those assets are carried on our audited financial statements, and it is likely that investors will lose all or a part of their investment. Ifwe seek additional financing to fund our business activities in the future and there remains substantial doubt about our ability to continue as a goingconcern, investors or other financing sources may be unwilling to provide additional funding to us on commercially reasonable terms or at all.Risks related to the development of our product candidatesSGT-001 is a gene transfer candidate based on a novel technology, which makes it difficult to predict the time and cost of development and of subsequentlyobtaining regulatory approval. To our knowledge, a limited number of gene transfer products have been approved for commercialization in the UnitedStates and the European Union.We have concentrated our research and development efforts on SGT-001 for the treatment of DMD and our future success depends on our successfuldevelopment of that product candidate. Our risk of failure is high. We have experienced, and may experience additional, problems or delays in developingSGT-001. Any such problems or delays would cause unanticipated costs, and any development problems may not be solved. For example, we or another partymay uncover a previously unknown risk associated with SGT-001, the adeno-associated virus, or AAV, vector, toxicity or other issues that may be moreproblematic than we currently believe and this may prolong the period of observation required for obtaining, or result in the failure to obtain, regulatoryapproval or may necessitate additional clinical testing.In addition, the product specifications and the clinical trial requirements of the FDA, the European Commission, the European Medicines Agency, or theEMA, and other regulatory authorities and the criteria these regulators use to determine the safety and efficacy of a product candidate vary substantiallyaccording to the type, complexity, novelty and intended use and market of such product candidate. The regulatory approval process for novel productcandidates such as ours is unclear and can be more expensive and take longer than for other, better known or more extensively studied product candidates. Toour knowledge, a limited number of gene transfer products have been approved for commercialization in the United States and the European Union. As aresult, it is difficult to determine how long it will take or how much it will cost to obtain regulatory approvals for SGT-001 in either the United States or theEuropean Union. Approvals by the European Commission may not be indicative of what the FDA may require for approval and vice versa.If the FDA or other regulatory agencies continue to express safety concerns even though the full clinical hold has been lifted, additional preclinical studies orclinical trials involving SGT-001, further amendments to the SGT-001 enrollment criteria and/or clinical trial protocol or changes to our manufacturingprocess may be needed and difficult to implement and/or complete. In such instance, our progress in the development of SGT-001 may be significantlyslowed or stopped and the associated costs may be significantly increased, adversely affecting our business.In addition, we may not be able to obtain institutional review board committee, or IRB, or data safety monitoring board committee approvals for IGNITEDMD as a result of the clinical hold, and any related risks or otherwise, which could further delay our ability to open new trial sites and enroll patients intothe clinical trial. Any delay in enrolling patients or inability to continue or complete our clinical trial of SGT-001, as a result of the since-resolved fullclinical hold or otherwise, will delay or terminate our clinical development plans for SGT-001, may require us to incur additional clinical development costsand could impair our ability to ultimately obtain FDA approval for SGT-001. Delays in the completion of any clinical trial of SGT-001, our lead productcandidate, or any other product candidate will increase our costs, slow down our product candidate development and approval process and delay orpotentially jeopardize our ability to commence product sales and generate revenue. In addition, many of the factors that cause, or lead to, a delay in thecommencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of SGT-001 or our product candidates.31Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit theircommercial potential or result in significant negative consequences following any potential marketing approval.During the conduct of clinical trials, patients may experience changes in their health, including illnesses, injuries, discomforts or a fatal outcome. Often, it isnot possible to determine whether the product candidate being studied caused these conditions. For instance, after dosing the first patient, we reported anunexpected serious adverse event in IGNITE DMD, which resulted in a full clinical hold that has since been lifted by the FDA. In addition, it is possible thatas we test SGT-001 or our other product candidates in larger, longer and more extensive clinical programs, or as use of these product candidates becomesmore widespread if they receive regulatory approval, illnesses, injuries, discomforts and other adverse events that were observed in earlier clinical trials, aswell as conditions that did not occur or went undetected in previous clinical trials, will be reported by subjects. Many times, side effects are only detectableafter investigational products are tested in large-scale, Phase III clinical trials or, in some cases, after they are made available to patients on a commercial scaleafter approval. If additional clinical experience indicates that SGT-001 or any other product candidate has side effects or causes serious or life-threateningside effects, the development of the product candidate may fail or be delayed, or, if the product candidate has received regulatory approval, such approvalmay be revoked.There have been several significant adverse side effects in gene therapy treatments in the past, including reported cases of leukemia and death seen in otherclinical trials using other vectors. While new recombinant vectors have been developed with the intent to reduce these side effects, gene therapy is still arelatively new approach to disease treatment and additional adverse side effects could develop. Patients will create antibodies to the AAV vector and asecond administration of gene transfer might not be successful. There also is the potential risk of delayed adverse events following exposure to gene therapyproducts due to persistent biologic activity of the genetic material or other components of products used to carry the genetic material. Possible adverse sideeffects that may occur with treatment with gene therapy products include an immunologic reaction early after administration that could substantially limitthe effectiveness of the treatment or represent safety risks for patients. Additionally, in previous clinical trials involving AAV vectors for gene therapy, somesubjects experienced the development of a positive ELISPOT test associated with T-cell responses, which is of unclear clinical translatability. If T-cells areactivated, the cellular immune response system may trigger the removal of transduced cells. If our gene transfer candidate demonstrates a similar effect, wemay decide or be required to halt or delay further clinical development of SGT-001.As part of our preclinical program, we performed necessary good laboratory practices, or GLP, toxicology studies to establish the overall safety profile ofSGT-001 in wild-type mice and non-human primates, or NHPs. The data and our conclusions from these studies were included in our IND submission to theFDA. Systemic administration of SGT-001 was generally well tolerated in both species. We observed no evidence of test-article-related toxicity for up to 13weeks after systemic administration of SGT-001 in either species that would prevent us from initiating clinical trials. In the NHP study, test-article-relatedeffects were self-limited, mild chemistry and hematology changes with no microscopic correlates at the end of the study. There was a transient andasymptomatic increase in liver function enzymes observed in NHPs starting on day 9, which returned to normal levels by day 21. We believe there were noother relevant test-article-related adverse events associated with SGT-001 administration in either GLP study. In the NHP toxicology study, a single animalfrom the high dose cohort was euthanized after it did not recover from an anesthetic procedure. We believe this event was attributed to procedural errors.However, AAV vector cannot be completely ruled out as a contributing factor to the toxicity that gave rise to the event.In addition to side effects caused by SGT-001 and our other product candidates, the administration process or related procedures also can cause adverse sideeffects. For example, integration of AAV DNA into the host cell’s genome has been reported to occur. Further, our AAV delivery system has not beenvalidated in human clinical trials previously, and if such delivery system does not meet the safety criteria or cannot provide the desired efficacy results, thenwe may be forced to suspend or terminate our development of SGT-001. In addition, the relatively high dosing requirements for SGT-001 may amplify therisk of adverse side effects relating to the AAV vector.When James M. Wilson, M.D., Ph.D., resigned from our Scientific Advisory Board he cited emergingconcerns about the possible risks of high systemic dosing of AAV. If any such adverse side effects were to occur in the future and we are unable todemonstrate that they were not caused by the administration process or related procedures, the FDA, the European Commission, the EMA or other regulatoryauthorities could order us to cease further development of, or deny approval of, SGT-001 or our other product candidate for any or all targeted indications.Even if we are able to demonstrate that any serious adverse events are not product-related, such occurrences could affect patient recruitment or the ability ofenrolled patients to complete the clinical trial.Additionally, if SGT-001 or our other product candidates receive marketing approval, the FDA could require us to adopt a Risk Evaluation and MitigationStrategy, or REMS, to ensure that the benefits outweigh the risks, which may include, among32other things, a medication guide outlining the risks of the product for distribution to patients and a communication plan to health care practitioners.Furthermore, if we or others later identify undesirable side effects caused by SGT-001 or our other product candidates, several potentially significant negativeconsequences could result, including: •regulatory authorities may suspend or withdraw approvals of such a product candidate; •regulatory authorities may require additional warnings on the label; •we may be required to change the way a product candidate is administered or conduct additional clinical trials; •we could be sued and held liable for harm caused to patients; and •our reputation may suffer.We have never completed a clinical trial, and may be unable to do so for any product candidates we may develop, including SGT-001.We will need to successfully complete clinical trials in order to obtain FDA approval to market SGT-001 or our other product candidates. We have limitedexperience in preparing, submitting and prosecuting regulatory filings, and have not previously submitted a biologics license application, or BLA, for anyproduct candidate. We cannot be sure that submission of an IND will result in the FDA allowing clinical trials to begin or to begin as proposed, or that, oncebegun, issues will not arise that suspend or terminate such clinical trials. Carrying out later-stage clinical trials and the submission of a successful BLA is acomplicated process. This may be particularly true for design of a pivotal trial for the treatment of DMD as the FDA has not given clear guidance as to thenecessary endpoints for approval of a treatment for DMD. In addition, we have had limited interactions with the FDA and cannot be certain how manyclinical trials of SGT-001 or our other product candidates will be required or how such trials should be designed. Consequently, we may be unable tosuccessfully and efficiently execute and complete necessary clinical trials in a way that leads to BLA submission and approval of SGT-001 or our otherproduct candidates. We may require more time and incur greater costs than our competitors and may not succeed in obtaining regulatory approvals of productcandidates that we develop. Failure to commence or complete, or delays in, clinical trials, could prevent us from or delay us in commercializing SGT-001 andour other product candidates.In March 2018, the FDA placed a full clinical hold on SGT-001 following an unexpected serious adverse event in IGNITE DMD. In connection with thelifting of the clinical hold, we made changes to the IGNITE DMD protocol, including the addition of IV glucocorticoids in the initial weeks postadministration of SGT-001 and enhanced monitoring measures that include a panel for complement activation. The amended protocol also specifies thateculizumab will be available as a treatment option if complement activation is observed. These changes to the IGNITE DMD protocol, and any other suchchanges that may be made in the future, may impact our development timeline and result in increased costs and expenses.Success in preclinical studies or early clinical trials, including our IGNITE DMD clinical trial, may not be indicative of results obtained in later trials.Results from preclinical studies or early clinical trials, including our IGNITE DMD clinical trial, are not necessarily predictive of future clinical trial resultsand are not necessarily indicative of final results. There is a high failure rate for gene therapy and biologic products proceeding through clinical trials. Manycompanies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials even after achieving promisingresults in preclinical testing and earlier-stage clinical trials. Data obtained from preclinical and clinical activities are subject to varying interpretations, whichmay delay, limit or prevent regulatory approval. We also may experience regulatory delays or rejections as a result of many factors, including due to changesin regulatory policy during the period of our product candidate development. Our preclinical studies for SGT-001 in animals have been limited and we haveonly recently dosed a human patient with SGT-001. SGT-001 or our other product candidates may fail to show the desired safety and efficacy in clinicaldevelopment despite positive results in preclinical studies. This failure would cause us to abandon SGT-001 or our other product candidates.We may encounter substantial delays in our clinical trials or we may fail to demonstrate safety and efficacy to the satisfaction of applicable regulatoryauthorities.Before obtaining marketing approval from regulatory authorities for the sale of SGT-001 or our other product candidates, we must conduct extensive clinicaltrials to demonstrate the safety and efficacy of the product candidate for its intended indications. Clinical testing is expensive, time-consuming and uncertainas to outcome. We cannot guarantee that any clinical33trials will be conducted as planned or completed on schedule, if at all. A failure of one or more clinical trials can occur at any stage of testing. Events thatmay prevent successful or timely completion of clinical development include: •delays in reaching a consensus with regulatory authorities on trial design; •delays in reaching agreement with the appropriate external parties on dose escalation; •delays in enrolling patients in IGNITE DMD for SGT-001; •delays in reaching agreement on acceptable terms with prospective contract research organizations, or CROs, and clinical trial sites; •delays in opening clinical trial sites or obtaining required IRB or independent ethics committee approval at each clinical trial site; •delays in recruiting suitable subjects to participate in our clinical trials, including because such trials may be placebo-controlled trials andpatients are not guaranteed to receive treatment with our product candidates; •failure by us, any CROs we engage or any other third parties to adhere to clinical trial requirements; failure to perform in accordance with FDAgood clinical practices, or GCPs, or applicable regulatory guidelines in the European Union and other countries; •delays in the testing, validation, manufacturing and delivery of SGT-001 or our other product candidates to the clinical sites, including delaysby third parties with whom we have contracted to perform certain of those functions; •delays in subjects completing participation in a trial or returning for post-treatment follow-up; •clinical trial sites or subjects dropping out of a trial; •selection of clinical endpoints that require prolonged periods of clinical observation or analysis of the resulting data; •imposition of a clinical hold by regulatory authorities as a result of a serious adverse event or after an inspection of our clinical trial operations,trial sites or manufacturing facilities; •occurrence of serious adverse events in trials of the same class of agents conducted by other sponsors; or •changes in regulatory requirements and guidance that require amending or submitting new clinical protocols.Additionally, if the results of any clinical trials are inconclusive or if there are safety concerns or serious adverse events associated with SGT-001 or our otherproduct candidates, we may: •be delayed or fail in obtaining marketing approval for SGT-001 or our other product candidates; •obtain approval for indications or patient populations that are not as broad as we intended or desired; •obtain approval with labeling that includes significant use or distribution restrictions or safety warnings; •be subject to changes in the way the products are administered; •be required to perform additional clinical trials to support approval or be subject to additional post-marketing testing requirements; •have regulatory authorities withdraw, or suspend, their approval of the product or impose restrictions on its distribution in the form of amodified REMS; •be sued and held liable for harm caused to patients; or •experience damage to our reputation.Our product development costs will increase if we experience delays in testing or marketing approvals. In addition, if we make manufacturing or otherchanges to SGT-001 or our other product candidates, we may need to conduct additional studies to bridge our modified product candidates to earlierversions. We do not know whether any of our preclinical studies or clinical trials will begin as planned, will need to be restructured or will be completed onschedule, or at all. We may also determine to change the design or protocol of one or more of our clinical trials, which could result in delays. Significantpreclinical study or clinical trial delays also could shorten any periods during which we may have the exclusive right to34commercialize our product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercializeour product candidates.If our third-party clinical trial vendors fail to comply with strict regulations, the clinical trials for SGT-001 or our other product candidates may bedelayed or unsuccessful.We do not have the personnel capacity to conduct or manage the clinical trials that will be necessary for the development of SGT-001 or our other productcandidates. For IGNITE DMD we are relying, and for any future clinical trials we expect we will rely, on third parties to assist us in managing, monitoring andconducting our clinical trials. If these third parties fail to comply with applicable regulations or do not adequately fulfill their obligations under the terms ofour agreements with them, we may not be able to enter into alternative arrangements without undue delay or additional expenditures and, therefore, theclinical trials for SGT-001 or our other product candidates may be delayed or unsuccessful.Furthermore, the FDA can be expected to inspect some or all of the clinical sites participating in our clinical trials to determine if our clinical trials are beingconducted according to GCPs. If the FDA determines that these clinical sites are not in compliance with applicable regulations, we may be required to delay,repeat or terminate the clinical trials.We may find it difficult to enroll patients in our clinical trials, which could delay or prevent us from proceeding with clinical trials of SGT-001 or our otherproduct candidates.Identifying and qualifying patients to participate in any clinical trials of SGT-001 and our other product candidates is critical to our success. The timing ofany clinical trials depends on our ability to recruit patients to participate as well as complete required follow-up periods. If patients are unwilling or unable toparticipate in our gene therapy clinical trials, including because of negative publicity from adverse events related to our product candidates, other approvedgene therapies or the biotechnology or gene therapy fields, or due to competitive clinical trials for similar patient populations, clinical trials in productsemploying our vector or our platform or for other reasons, the timeline for recruiting patients, conducting clinical trials and obtaining regulatory approval ofSGT-001 may be delayed. We may also experience delays if patients withdraw from the clinical trial or do not complete the required monitoring period. Additionally, for IGNITE DMD, the trial protocol requires two patients to be simulatneously randomized, one to receive SGT-001 and one to be placed in thedelayed-treatment control group. These delays could result in increased costs, delays in advancing SGT-001 or our other product candidates, delays in testingthe effectiveness of SGT-001 and our other product candidates or termination of clinical trials altogether.We may not be able to identify, recruit and enroll a sufficient number of patients, or those with required or desired characteristics, to complete any clinicaltrials in a timely manner. Patient enrollment and trial completion is affected by many factors, including: •size of the patient population and the process for identifying subjects; •design of the trial protocol; •eligibility and exclusion criteria, including that some patients may have pre-existing antibodies to AAV vectors precluding them from beingable to receive AAV-mediated gene transfer; •restrictions on our ability to conduct clinical trials, including full and partial clinical holds on ongoing or planned clinical trials; •perceived risks and benefits of the product candidate under study; •perceived risks and benefits of gene therapy-based approaches to the treatment of diseases; •release or disclosure of data from our completed or ongoing clinical trials; •availability of competing therapies and clinical trials; •severity of the disease; •proximity and availability of clinical trial sites for prospective subjects; •ability to obtain and maintain subject consent; •risk that enrolled subjects will drop out before completion of the trial; •patient referral practices of physicians;35 •ability to monitor subjects adequately during and after treatment; and •in the case of pivotal trials, the risk that patients may opt not to enroll because they are not assured treatment with our product candidate.Our ability to successfully initiate, enroll and complete a clinical trial in any foreign country is subject to numerous risks unique to conducting business inforeign countries, including: •different standards for the conduct of clinical trials; •absence in some countries of established groups with sufficient regulatory expertise for review of gene therapy protocols; •difficulty in identifying and partnering with qualified local consultants, physicians and partners; and •the potential burden of complying with a variety of foreign laws, medical standards and regulatory requirements, including the regulation ofpharmaceutical and biotechnology research and products.Even if we complete the necessary clinical trials, we cannot predict when, or if, we will obtain regulatory approval to commercialize SGT-001 or our otherproduct candidates and the approval may be for a more narrow indication than we seek.We cannot commercialize SGT-001 or our other product candidates until the appropriate regulatory authorities have reviewed and approved the productcandidate. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state and local statutes and regulationsrequire the expenditure of substantial time and financial resources and we may not be able to obtain the required regulatory approvals. Even if our productcandidates meet their safety and efficacy endpoints in clinical trials, the regulatory authorities may not complete their review processes in a timely manner, orwe may not be able to obtain regulatory approval. Additional delays may result if an FDA advisory committee or other regulatory authority recommends non-approval or restrictions on approval. In addition, we may experience delays or rejections based upon additional government regulation from futurelegislation or administrative action or changes in regulatory authority policy during the period of product development, clinical trials and the regulatoryreview process.Even if we receive regulatory approval, regulatory authorities may approve a product candidate for more limited indications than requested or they mayimpose significant limitations in the form of narrow indications, warnings or a REMS. Regulatory authorities may require precautions or contra-indicationswith respect to conditions of use or they may grant approval subject to the performance of costly post-marketing clinical trials. In addition, regulatoryauthorities may not approve the labeling claims that are necessary or desirable for the successful commercialization of our product candidates. Any of theforegoing scenarios could materially harm the commercial prospects for our product candidates. Even if we obtain regulatory approval for a product candidate, our product candidates will remain subject to regulatory oversight.Even if we obtain any regulatory approval for SGT-001 or our other product candidates, we will be subject to ongoing regulatory requirements formanufacturing, labeling, packaging, storage, advertising, promotion, sampling, record-keeping and submission of safety and other post-market information.Any regulatory approvals that we receive for our product candidates may also be subject to a REMS, limitations on the approved indicated uses for which theproduct may be marketed or conditions of approval, or requirements for potentially costly post-marketing testing, including Phase IV clinical trials, andsurveillance to monitor the quality, safety and efficacy of the product. Advertising and promotional materials must comply with FDA rules and are subject toFDA review, in addition to other potentially applicable federal and state laws.If we fail to comply with applicable regulatory requirements following approval of SGT-001 or our other product candidates, a regulatory authority may,among other things, suspend or withdraw regulatory approval, narrow the product label, restrict the marketing or manufacturing of the product, suspend anyongoing clinical trials or seize or detain the product or otherwise require the withdrawal of the product from the market.36Even if we obtain and maintain approval for SGT-001 or our other product candidates from the FDA, we may never obtain approval for our productcandidates outside of the United States, which would limit our market opportunities and adversely affect our business.Even if we receive FDA approval of SGT-001 or our other product candidates in the United States, approval of a product candidate in the United States by theFDA does not ensure approval of such product candidate by regulatory authorities in other countries or jurisdictions, and approval by one foreign regulatoryauthority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. Future sales of our product candidates outside of theUnited States will be subject to foreign regulatory requirements governing clinical trials, manufacturing and marketing approval. Approval procedures varyamong jurisdictions and can involve requirements and administrative review periods different from, and more onerous than, those in the United States,including additional preclinical studies or clinical trials. In many countries outside the United States, a product candidate must be approved forreimbursement before it can be approved for sale in that country. We intend to submit a marketing authorization application, or MAA, to the EMA forapproval of SGT-001 in the European Union, but obtaining such approval from the European Commission following the opinion of the EMA is a lengthy andexpensive process. Regulatory authorities in countries outside of the United States and the European Union also have requirements for approval of productcandidates with which we must comply prior to marketing in those countries. Obtaining foreign regulatory approvals and compliance with foreign regulatoryrequirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of SGT-001 or our other productcandidates in certain countries.Further, clinical trials conducted in one country may not be accepted by regulatory authorities in other countries. Also, regulatory approval for SGT-001 orour other product candidates may be withdrawn. If we fail to comply with the regulatory requirements, our target market will be reduced, and our ability torealize the full market potential of our product candidates will be harmed.Regulatory requirements governing gene therapy products are periodically updated and may continue to change in the future.The FDA has established the Office of Tissues and Advanced Therapies, or the OTAT, within the Center for Biologics Evaluation and Research, or the CBER,to consolidate the review of gene therapy and related products, and has established the Cellular, Tissue and Gene Therapies Advisory Committee to adviseCBER in its review. Gene therapy clinical trials conducted at institutions that receive funding for recombinant DNA research from the U.S. National Institutesof Health, or the NIH, also are potentially subject to review by the RAC; however, the NIH announced that the Office of Biotechnology Activities’Recombinant DNA Advisory Committee, or the RAC, will soon only publicly review clinical trials if the trials cannot be evaluated by standard oversightbodies and pose unusual risks. Although the FDA decides whether individual gene therapy protocols may proceed, the RAC public review process, ifundertaken, can delay the initiation of a clinical trial, even if the FDA has reviewed the trial design and details and approved its initiation. Conversely, theFDA can put an IND on a clinical hold even if the RAC has provided a favorable review or an exemption from in-depth, public review. If we were to engagean NIH-funded institution to conduct a clinical trial, that institution’s institutional biosafety committee, or IBC, as well as its IRB would need to review theproposed clinical trial to assess the safety of the trial. In addition, adverse developments in clinical trials of gene therapy products conducted by others maycause the FDA or other oversight bodies to change the requirements for approval of our product candidates. Similarly, the EMA may issue new guidelinesconcerning the development and marketing authorization for gene therapy products and require that we comply with these new guidelines.In addition, ethical, social and legal concerns about gene therapy, genetic testing and genetic research could result in additional regulations or prohibitingthe processes we may use. Federal and state agencies, congressional committees and foreign governments have expressed their intentions to further regulatebiotechnology. More restrictive regulations or claims that our product candidates are unsafe or pose a hazard could prevent us from commercializing anyproducts. New government requirements may be established that could delay or prevent regulatory approval of our product candidates under development. Itis impossible to predict whether legislative changes will be enacted, regulations, policies or guidance changed, or interpretations by agencies or courtschanged, or what the impact of such changes, if any, may be.As we advance our product candidates through clinical development, we will be required to consult with these regulatory and advisory groups, and complywith applicable guidelines. These regulatory review committees and advisory groups and any new guidelines they promulgate may lengthen the regulatoryreview process, require us to perform additional studies, increase our development costs, lead to changes in regulatory positions and interpretations, delay orprevent approval and commercialization of SGT-001 or our other product candidates or lead to significant post-approval limitations or restrictions.37Delay or failure to obtain, or unexpected costs in obtaining, the regulatory approval necessary to bring a potential product to market could decrease ourability to generate sufficient product revenue.We may not be able to benefit from orphan drug designation for SGT-001 or any of our product candidates.The FDA and EMA granted SGT-001 orphan drug designation for the treatment of DMD in August 2016 and September 2016, respectively. The designationof SGT-001 as an orphan drug does not guarantee that any regulatory agency will accelerate regulatory review of, or ultimately approve, that productcandidate, nor does it limit the ability of any regulatory agency to grant orphan drug designation to product candidates of other companies that treat the sameindications as our product candidate prior to our product candidate receiving exclusive marketing approval.We may lose orphan drug exclusivity if the FDA or EMA determines that the request for designation was materially defective or if we cannot assure sufficientquantity of the applicable drug to meet the needs of patients with DMD.Even if we maintain orphan drug exclusivity for SGT-001 or obtain orphan drug exclusivity for our other product candidate, the exclusivity may noteffectively protect the product candidate from competition because regulatory authorities still may authorize different drugs for the same condition or thesame drug for the same condition if it is determined by the FDA to be clinically superior to the product with orphan drug exclusivity.We may seek a breakthrough therapy designation for SGT-001 or our other product candidates, but we might not receive such designation, and even if wedo, such designation may not lead to a faster development or regulatory review or approval process.We may seek a breakthrough therapy designation for SGT-001 or our other product candidates; however, we cannot assure our stockholders that SGT-001 orour other product candidates will meet the criteria for that designation. A breakthrough therapy is defined as a therapy that is intended, alone or incombination with one or more other therapies, to treat a serious condition, and preliminary clinical evidence indicates that the therapy may demonstratesubstantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early inclinical development. For therapies and biologics that have been designated as breakthrough therapies, interaction and communication between the FDA andthe sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffectivecontrol regimens. Therapies designated as breakthrough therapies by the FDA may also be eligible for priority review if supported by clinical data at the timethe new drug application is submitted to the FDA.Designation as a breakthrough therapy is within the discretion of the FDA. Accordingly, even if we believe that one of our product candidates meets thecriteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to make such designation. Even if we receivebreakthrough therapy designation, the receipt of such designation for a product candidate may not result in a faster development or regulatory review orapproval process compared to drugs considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. Inaddition, even if one or more of our product candidates qualify as breakthrough therapies, the FDA may later decide that the product candidate no longermeets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.Accelerated approval by the FDA, even if granted for SGT-001 or our other product candidates, may not lead to a faster development or regulatory reviewor approval process and it does not increase the likelihood that our product candidates will receive marketing approval.We may seek approval of SGT-001 or our other product candidates using the FDA’s accelerated approval pathway. A product may be eligible for acceleratedapproval if it treats a serious or life-threatening condition and generally provides a meaningful advantage over available therapies. In addition, it mustdemonstrate an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit or on a clinical endpoint that can be measured earlier thanirreversible morbidity or mortality, or IMM, that is reasonably likely to predict an effect on IMM or other clinical benefit. The FDA or other applicableregulatory agency makes the determination regarding whether a surrogate endpoint is reasonably likely to predict long-term clinical benefit. Given thatexpression of microdystrophin has not yet been established to predict long-term clinical benefit, it is not currently accepted, and it is possible the FDA and/orother applicable regulatory agencies could decide never to accept it, as a surrogate endpoint for the accelerated approval pathway.38As a condition of approval, the FDA may require that a sponsor of a drug or biologic product candidate receiving accelerated approval perform adequate andwell-controlled post-marketing clinical trials. These confirmatory trials must be completed with due diligence. In addition, the FDA currently requires as acondition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.Even if we do receive accelerated approval, we may not experience a faster development or regulatory review or approval process, and receiving acceleratedapproval does not provide assurance of ultimate FDA approval.A potential regenerative medicine advanced therapy designation by the FDA for our product candidates may not lead to a faster development orregulatory review or approval process, and it does not increase the likelihood that our product candidates will receive marketing approval.We may seek a regenerative medicine advanced therapy designation, or RMAT, for some of our product candidates. A regenerative medicine advancedtherapy is defined as cell therapies, therapeutic tissue engineering products, human cell and tissue products, and combination products using any suchtherapies or products. Gene therapies, including genetically modified cells, that lead to a durable modification of cells or tissues may meet the definition of aregenerative medicine therapy. The regenerative medicine advanced therapy program is intended to facilitate efficient development and expedite review ofregenerative medicine advanced therapies, which are intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition. A new drugapplication or a BLA for a regenerative medicine advanced therapy may be eligible for priority review or accelerated approval through (1) surrogate orintermediate endpoints reasonably likely to predict long-term clinical benefit or (2) reliance upon data obtained from a meaningful number of sites. Benefitsof such designation also include early interactions with FDA to discuss any potential surrogate or intermediate endpoint to be used to support acceleratedapproval. A regenerative medicine therapy that is granted accelerated approval and is subject to post-approval requirements may fulfill such requirementsthrough the submission of clinical evidence, clinical studies, patient registries, or other sources of real world evidence, such as electronic health records; thecollection of larger confirmatory data sets; or post-approval monitoring of all patients treated with such therapy prior to its approval.Designation as a regenerative medicine advanced therapy is within the discretion of the FDA. Accordingly, even if we believe one of our product candidatesmeets the criteria for designation as a regenerative medicine advanced therapy, the FDA may disagree and instead determine not to make such designation. Inany event, the receipt of a regenerative medicine advanced therapy designation for a product candidate may not result in a faster development process, reviewor approval compared to drugs considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. In addition,even if one or more of our product candidates qualify as regenerative medicine advanced therapies, the FDA may later decide that the biological products nolonger meet the conditions for qualification.The FDA has granted Rare Pediatric Disease Designation, or RPDD, to SGT-001; however, a BLA for SGT-001 may not meet the eligibility criteria for apriority review voucher upon approval.The FDA has granted RPDD to SGT-001. RPDD does not guarantee that a BLA for such drug will meet the eligibility criteria for a rare pediatric diseasepriority review voucher at the time the application is approved. We will need to request a rare pediatric disease priority review voucher in our BLA for SGT-001. The use of a priority review voucher allows for a drug to be reviewed by the FDA within six months. However, the FDA may determine that a BLA forSGT-001 does not meet the eligibility criteria for a priority review voucher upon approval. Moreover, even if SGT-001 does satisfy those criteria, the productwill need to be licensed before September 30, 2022 in order to be granted a rare disease priority review voucher.The FDA has granted fast track designation for SGT-001. However, such designation may not actually lead to a faster development or regulatory review orapproval process. We might not receive such designation for our other product candidates.If a therapy is intended for the treatment of a serious condition and nonclinical or clinical data demonstrate the potential to address unmet medical need forthis condition, a drug sponsor may apply for FDA fast track designation. The FDA has granted fast track designation to SGT-001; however, fast trackdesignation does not ensure that we will receive marketing approval or that approval will be granted within any particular timeframe. We may not experiencea faster development or regulatory review or approval process with fast track designation compared to conventional FDA procedures. In addition, the FDAmay withdraw fast track designation if it believes that the designation is no longer supported by data from our clinical development program. Fast trackdesignation alone does not guarantee qualification for the FDA’s priority review procedures.39We may seek priority review designation for SGT-001 or our other product candidates, but we might not receive such designation, and even if we do, suchdesignation may not lead to a faster development or regulatory review or approval process.If the FDA determines that a product candidate offers a treatment for a serious condition and, if approved, the product would provide a significantimprovement in safety or effectiveness, the FDA may designate the product candidate for priority review. A priority review designation means that the goalfor the FDA to review an application is six months, rather than the standard review period of ten months. We may request priority review for our productcandidates, however, we cannot assume that SGT-001 or our other product candidates will meet the criteria for that designation. The FDA has broaddiscretion with respect to whether or not to grant priority review status to a product candidate, so even if we believe a particular product candidate is eligiblefor such designation or status, the FDA may decide not to grant it. Moreover, a priority review designation does not necessarily mean a faster development orregulatory review or approval process or necessarily confer any advantage with respect to approval compared to conventional FDA procedures. Receivingpriority review from the FDA does not guarantee approval within the six-month review cycle or at all. We face significant competition and our competitors may achieve regulatory approval before us or develop therapies that are more advanced or effectivethan ours, which may adversely affect our ability to successfully market or commercialize SGT-001 or our other product candidates.We operate in a highly competitive segment of the biopharmaceutical market. We face competition from many different sources, including larger and better-funded pharmaceutical, specialty pharmaceutical and biotechnology companies, as well as from academic institutions, government agencies and private andpublic research institutions. Our product candidates, if successfully developed and approved, will compete with established therapies as well as with newtreatments that may be introduced by our competitors. There are a variety of product candidates, including gene therapies, in development for DMD. Many ofour competitors have significantly greater financial, product candidate development, manufacturing and marketing resources than we do. Largepharmaceutical and biotechnology companies have extensive experience in clinical testing and obtaining regulatory approval for their products, and mergersand acquisitions within these industries may result in even more resources being concentrated among a smaller number of larger competitors. Our commercialopportunity could be reduced or eliminated if competitors develop and commercialize products that are safer, more effective, have fewer or less severe sideeffects, have broader market acceptance, are more convenient or are less expensive than any product candidate that we may develop.We are aware of several companies focused on developing gene therapies in various indications, as well as several companies addressing other methods formodifying genes and regulating gene expression. Any advances in gene therapy technology made by a competitor may be used to develop therapies thatcould compete against SGT-001 or any future gene therapy product candidates we develop.We may fail to capitalize on other potential product candidates that may represent a greater commercial opportunity or for which there is a greaterlikelihood of success.The success of our business depends upon our ability to develop and commercialize SGT-001 and our other product candidates. Because we have limitedresources, we may forego or delay pursuit of opportunities with certain programs or product candidates or for indications that later prove to have greatercommercial potential than SGT-001 or our other product candidates. Our spending on current and future research and development programs may not yieldany commercially viable product candidates. If we do not accurately evaluate the commercial potential for a particular product candidate, we may relinquishvaluable rights to that product candidate through strategic collaborations, licensing or other arrangements in cases in which it would have been moreadvantageous for us to retain sole development and commercialization rights to such product candidate. Alternatively, we may allocate internal resources toa product candidate in a therapeutic area in which it would have been more advantageous to enter into a partnering arrangement. If any of these events occur,we may be forced to abandon our development efforts with respect to a particular product candidate or fail to develop a potentially successful productcandidate. Risks related to the manufacturing and commercialization of SGT-001 and our other product candidatesWe may not be successful in finding strategic collaborators for continuing development of SGT-001 or our other product candidates or successfullycommercializing or competing in the market for certain indications.We may seek to establish strategic partnerships for developing SGT-001 or our other product candidates due to capital costs required to develop, manufactureand commercialize our product candidates. We may not be successful in our efforts to40establish such strategic partnerships or other alternative arrangements because our research and development pipeline may be insufficient, SGT-001 may bedeemed to be at too early of a stage of development for collaborative effort or third parties may not view SGT-001 as having the requisite potential todemonstrate safety and efficacy. We cannot be certain that, following a strategic transaction, we will achieve an economic or business benefit that justifiessuch transaction.If we seek to but are unable to reach agreements with suitable collaborators on a timely basis, on acceptable terms or at all, we may have to curtail, reduce ordelay the development of a product candidate, delay its potential commercialization, reduce the scope of any sales or marketing activities or increase ourexpenditures and undertake development, manufacturing or commercialization activities independently. If we elect to fund our own independentdevelopment or commercialization activities, we will need to obtain additional expertise and additional capital, which may not be available to us onacceptable terms or at all. If we fail to enter into collaborations and do not have sufficient funds or expertise to undertake the necessary development,manufacturing and commercialization activities, we may not be able to further develop SGT-001 or our other product candidates. We have limited gene transfer manufacturing experience and could experience production problems and delays in obtaining regulatory approval of ourmanufacturing processes, which could result in delays in the development or commercialization of SGT-001 or our other product candidates.The manufacturing process we use to produce SGT-001 is complex and has not been validated for commercial use. We have no experience manufacturingSGT-001 and our other product candidates. Building our own manufacturing facility, if we decide to do so in the future, would require substantial additionalinvestment, would be time-consuming and may be subject to delays, including those resulting from compliance with regulatory requirements. In addition,building a manufacturing facility may cost more than we currently anticipate. Although we may establish our own manufacturing facility to support acommercial launch, if we are unable to do so or otherwise decide not to do so, we may be unable to produce commercial materials or meet demand, if anyshould develop, for SGT-001 and our other product candidates. Any such failure could delay or prevent our commercialization of SGT-001 or our otherproduct candidates. The production of SGT-001 requires processing steps that are more complex than those required for most chemical pharmaceuticals.Moreover, unlike chemical pharmaceuticals, the physical and chemical properties of a gene transfer such as ours generally cannot be fully characterized. As aresult, assays of the finished product may not be sufficient to ensure that the product will perform in the intended manner. Accordingly, we employ multiplesteps to control our manufacturing process to assure that the process works and that SGT-001 is made strictly and consistently in compliance with the process.As a result of the limited number of FDA approvals for gene transfer products to date, the timeframe required for us to obtain approval for a cGMP genetherapy manufacturing facility in the United States is uncertain. We must supply all necessary documentation in support of a BLA or other MAA on a timelybasis and must adhere to the FDA’s and the European Union’s cGMP requirements before SGT-001 and our other product candidates can obtain marketingapproval. In order to obtain approval, we will need to ensure that all of our processes, methods and equipment are compliant with cGMP requirements, andperform extensive audits of contract laboratories, manufacturers and suppliers.We currently rely on third-party manufacturers for our SGT-001 supply. In order to produce sufficient quantities of SGT-001 for clinical trials and initial U.S.commercial demand, we will need to increase the scale of our manufacturing process at our third-party manufacturers, and potentially through our owncommercial-scale manufacturing facility. We may need to change our current manufacturing process. We may not be able to produce sufficient quantities ofSGT-001 due to several factors, including equipment malfunctions, facility contamination, material shortages or contamination, natural disasters, disruptionin utility services, human error or disruptions in the operations of our suppliers. For example, through our contract manufacturer we have performed andreleased within specifications manufacturing runs of SGT-001 for clinical supply and have experienced variability with respect to the success and yield ofthese runs. We continue to engage in process development activities to improve the reproducibility, reliability and consistency of yields of ourmanufacturing process. While we are able to produce for more than one patient from a single batch, additional manufacturing runs will be required to producenecessary or adequate supply for IGNITE DMD and there is no guarantee that all of those runs will be within specifications or produce adequate supply. If weare not able to produce sufficient supply on the timeline expected, our overall development schedule for SGT-001 could be delayed, and we could incuradditional expense.If supply from a manufacturing facility is interrupted, there could be a significant disruption in supply of SGT-001 or our other product candidates. Further,we may not be able to enter into arrangements with additional third-party manufacturers on favorable terms or at all. Use of new third-party manufacturerscould increase the risk of delays in production or insufficient supplies of our product candidates as we transfer our manufacturing technology to thesemanufacturers and as they gain experience manufacturing our product candidates.41In addition, product manufacturers and their facilities are subject to payment of user fees and continual review and periodic inspections by the FDA and otherregulatory authorities for compliance with cGMP requirements and adherence to commitments made in the BLA or foreign marketing application. If we, or aregulatory authority, discover previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems withthe facility where the product is manufactured, a regulatory authority may impose restrictions relative to that product, the manufacturing facility or us,including requiring recall or withdrawal of the product from the market or suspension of manufacturing.In addition, the FDA, the EMA and other foreign regulatory authorities may require us to submit samples of any lot of any approved product together with theprotocols showing the results of applicable tests at any time. Under some circumstances, the FDA, the EMA or other foreign regulatory authorities mayrequire that we not distribute a lot until the agency authorizes its release. Lot failures or product recalls could cause us to delay or abandon clinical trials orproduct launches.We also may encounter problems hiring and retaining the experienced specialist scientific, quality control and manufacturing personnel needed to operateour manufacturing process, which could result in delays in our production or difficulties in maintaining compliance with applicable regulatory requirements. Any problems in our manufacturing process or facilities could make us a less attractive collaborator for potential partners, including larger pharmaceuticalcompanies and academic research institutions, which could limit our access to additional attractive development programs. Problems in our manufacturingprocess or facilities also could restrict our ability to meet market demand for SGT-001, our other product candidates or future product candidates.Although we may establish our own SGT-001 manufacturing facility, we expect to utilize third parties to conduct our product manufacturing for theforeseeable future. Therefore, we are subject to the risk that these third parties may not perform satisfactorily or meet regulatory requirements.Until such time, if ever, as we establish a manufacturing facility that has been properly validated to comply with FDA cGMP requirements, we will not be ableto independently manufacture material for our current and future clinical programs. For clinical trials of SGT-001, we intend to utilize materials manufacturedby cGMP-compliant third-party suppliers. Even following our potential establishment of a validated cGMP manufacturing facility, we intend to utilize third-party manufacturing capabilities in order to provide multiple sources of supply. In the event that the establishment of our own manufacturing facility isdelayed or not otherwise pursued and if these third-party manufacturers do not successfully carry out their contractual duties, meet expected deadlines ormanufacture SGT-001 in accordance with regulatory requirements or if there are disagreements between us and these third-party manufacturers, we may notbe able to complete, or may be delayed in completing, the clinical trials required for approval of SGT-001. In such instances, we may need to locate anappropriate replacement third-party relationship, which may not be readily available or on acceptable terms, which would cause additional delay or increasedexpense prior to the approval of our product candidates.Additionally, we rely on our third-party manufacturers for their compliance with the cGMP and their maintenance of adequate quality control, qualityassurance and qualified personnel. Furthermore, all of our third-party suppliers and manufacturers are engaged with other companies to supply and/ormanufacture materials or products for such companies, which exposes them to regulatory risks for the production of such materials and products. FDAinspections may identify compliance issues at third-party manufacturer facilities or at the facilities of third-party suppliers that may disrupt production ordistribution, or require substantial resources to correct and prevent recurrence of any deficiencies, and could result in fines or penalties by regulatoryauthorities. In addition, discovery of problems with a product or the failure to comply with applicable requirements may result in restrictions on a product,manufacturer or holder of an approved BLA, including withdrawal or recall of the product from the market or other voluntary, FDA-initiated or judicialaction, including fines, injunctions, civil penalties, license revocations, seizure, total or partial suspension of production or criminal penalties, any of whichcould significantly and adversely affect supplies of our product candidates.In addition, we do not currently have long-term supply or manufacturing arrangements in place for the production of SGT-001 at commercial scale. Althoughwe intend to establish additional sources for long-term supply, potentially including our own commercial-scale cGMP-compliant manufacturing facility andone or more third-party manufacturers, if the gene therapy industry were to grow, we may encounter increasing competition for the materials necessary for theproduction of SGT-001. We may experience difficulties in scaling up production beyond clinical batches. Furthermore, demand for third-party cGMPmanufacturing facilities may grow at a faster rate than existing manufacturing capacity, which could disrupt our ability to find and retain third-partymanufacturers capable of producing sufficient quantities of SGT-001 for future clinical trials or to meet initial commercial demand in the United States. Wecurrently rely, and expect to continue to rely, on42additional third parties to manufacture materials for our product candidates and to perform quality testing. Even following the potential establishment of ourown cGMP-compliant manufacturing capabilities, we intend to maintain third-party manufacturers for these materials, as well as to serve as additional sourcesof SGT-001, which will expose us to risks including: •reduced control of manufacturing activities; •the inability of certain contract manufacturing organizations, or CMOs, to produce our product candidates in the necessary quantities, or incompliance with current cGMP or in compliance with pertinent regulatory requirements and within our planned time frame and cost parameters; •termination or nonrenewal of manufacturing and service agreements with third parties in a manner or at a time that is costly or damaging to us;and •disruptions to the operations of our third-party manufacturers and our and their suppliers caused by conditions unrelated to our business oroperations, including the bankruptcy of the manufacturer or supplier.Any of these events could lead to clinical trial delays or failure to obtain regulatory approval, or impact our ability to successfully commercialize SGT-001 orour other product candidates. Some of these events could be the basis for FDA action, including injunction, recall, seizure or total or partial suspension ofproduct manufacture. If we are unable to establish sales, distribution and marketing capabilities or enter into agreements with third parties to market and sell SGT-001 and ourother product candidates, we will be unable to generate any product revenue.We currently have no sales, distribution or marketing organization. To successfully commercialize any product candidate that may result from ourdevelopment programs, we will need to develop these capabilities, either on our own or with others. The establishment and development of our owncommercial team or the establishment of a contract sales force to market any product candidate we may develop will be expensive and time-consuming andcould delay any product launch. Moreover, we cannot be certain that we will be able to successfully develop this capability. We may enter intocollaborations regarding SGT-001 and our other product candidates with other entities to utilize their established marketing and distribution capabilities, butwe may be unable to enter into such agreements on favorable terms, if at all. If any future collaborators do not commit sufficient resources to commercializeour product candidates, or we are unable to develop the necessary capabilities on our own, we will be unable to generate sufficient product revenue to sustainour business. We compete with many companies that currently have extensive, experienced and well-funded sales, distribution and marketing operations torecruit, hire, train and retain marketing and sales personnel. We also face competition in our search for third parties to assist us with the sales and marketingefforts of SGT-001 and our other product candidates. Without an internal team or the support of a third party to perform marketing and sales functions, wemay be unable to compete successfully against these more established companies.If we are unable to establish medical affairs capabilities, we will be unable to establish an educated market of physicians to administer SGT-001 or ourother product candidates.We currently have no medical affairs team. If we are unable to successfully build a medical affairs team to address scientific and medical questions andprovide expert guidance and education in the application, administration and utilization of SGT-001 and our other product candidates to physicians, we maynot be able to establish an educated market for our products. The establishment and development of our own medical affairs team will be expensive and time-consuming and could delay any product launch. Moreover, we cannot be certain that we will be able to successfully develop this capability.If the market opportunities for SGT-001 are smaller than we believe they are, our revenue prospects may be adversely affected and our business may suffer.We currently focus our research and product development on treatments for DMD. Our understanding of the patient population with this disease is based onestimates in published literature and by DMD foundations. These estimates may prove to be incorrect and new studies may reduce the estimated incidence orprevalence of this disease. The number of patients in the United States, the European Union and elsewhere may turn out to be lower than expected, patientsmay not be otherwise amenable to treatment with our product candidate or patients may become increasingly difficult to identify and access.Further, there are several factors that could contribute to making the actual number of patients who receive SGT-001 less than the potentially addressablemarket. These include the lack of widespread availability of, and limited reimbursement for,43new therapies in many underdeveloped markets. Further, the severity of the progression of a degenerative disease such as DMD up to the time of treatmentwill likely diminish the therapeutic benefit conferred by a gene therapy due to irreversible cell damage.Certain patients’ immune systems might prohibit the successful delivery of certain gene therapy products, thereby potentially limiting the population ofpatients amenable to gene transfer.As with many AAV-mediated gene therapy approaches, certain patients’ immune systems might prohibit the successful delivery of certain gene therapyproducts, thereby potentially limiting the population of patients amenable to gene transfer. While we are working to better understand the prevalence ofantibodies to AAV, or seroprevalence, as it relates to gene therapies for DMD, the exact DMD-wide seroprevalence is currently unknown and it varies by AAVserotype and age. We may not be able to address this potentially limiting factor for gene therapy as a treatment for certain patients. The commercial success of any of our product candidates, including SGT-001, if approved, will depend upon market acceptance by physicians, patients,third-party payors and others in the medical community.Even with the requisite approvals from the FDA in the United States, the European Commission in the European Union and other regulatory authoritiesinternationally, the commercial success of SGT-001 will depend, in part, on the acceptance of physicians, patients and health care payors of gene therapyproducts in general, and SGT-001 in particular, as medically necessary, cost-effective and safe. Any product that we commercialize may not gain acceptanceby physicians, patients, health care payors and others in the medical community due to ethical, social, medical and legal concerns. If these products do notachieve an adequate level of acceptance, we may not generate significant product revenue and may not become profitable. The degree of market acceptanceof gene therapy products and, in particular, SGT-001, if approved for commercial sale, will depend on multiple factors, including: •the efficacy and safety of SGT-001 as demonstrated in clinical trials; •the efficacy and potential and perceived advantages of SGT-001 over alternative treatments; •the cost of treatment relative to alternative treatments; •the clinical indications for which SGT-001 is approved by the FDA or the European Commission; •the willingness of physicians to prescribe new therapies; •the willingness of the target patient population to try new therapies; •the prevalence and severity of any side effects; •product labeling or product insert requirements of the FDA, the EMA or other regulatory authorities, including any limitations or warningscontained in a product’s approved labeling; •relative convenience and ease of administration; •the strength of marketing and distribution support; •the timing of market introduction of competitive products; •the availability of products to meet market demand; •publicity concerning our product candidates or competing products and treatments; •any restrictions on the use of our products together with other medications; and •favorable third-party payor coverage and adequate reimbursement.Even if a potential product candidate displays a favorable efficacy and safety profile in preclinical studies and clinical trials, market acceptance of theproduct will not be fully known until after it is launched.Our efforts to educate the medical community and third-party payors on the benefits of SGT-001 and our other product candidates may require significantresources and may never be successful. Such efforts may require more resources than are typically required due to the complexity and uniqueness of ourpotential product candidates. If SGT-001 or our other product candidates are approved but fail to achieve market acceptance among physicians, patients orthird-party payors, we will not be able to generate significant revenue from any such product.44Our gene transfer approach utilizes a vector derived from a virus, which may be perceived as unsafe or may result in unforeseen adverse events. Negativepublic opinion and increased regulatory scrutiny of gene therapy may damage public perception of the safety of our SGT-001 gene transfer productcandidate and adversely affect our ability to conduct our business or obtain regulatory approvals for SGT-001.Gene transfer remains a novel technology and public perception may be influenced by claims that gene transfer is unsafe, and gene transfer may not gain theacceptance of the public or the medical community. In particular, our success will depend upon physicians who specialize in the treatment of DMDprescribing treatments that involve the use of SGT-001 in lieu of, or in addition to, other treatments with which they are more familiar and for which greaterclinical data may be available. More restrictive government regulations or negative public opinion may delay or impair the development andcommercialization of SGT-001 or demand for any product candidate we may develop. A public backlash developed against gene therapy following the deathof a patient in 1999 during a gene therapy clinical trial of research subjects with ornithine transcarbamylase, or OTC, deficiency, a rare disorder in which theliver lacks a functional copy of the OTC gene. The death of the clinical trial subject was due to complications of adenovirus vector administration.Dr. James M. Wilson, former chair of our Scientific Advisory Board, was a co-investigator of the 1999 trial while he was Director of the Institute for HumanGene Therapy of the University of Pennsylvania. Serious adverse events in our clinical trials, including the event that led to the full clinical hold on IGNITEDMD, which has since been lifted by the FDA, or other clinical trials involving gene transfer products or our competitors’ products, even if not ultimatelyattributable to the relevant product candidates, and the resulting publicity, could result in increased government regulation, unfavorable public perception,potential regulatory delays in the testing or approval of SGT-001, stricter labeling requirements for SGT-001 if approved and a decrease in demand for SGT-001.Failure to comply with ongoing regulatory requirements could cause us to suspend production or put in place costly or time-consuming remedialmeasures.The regulatory authorities may, at any time following approval of a product for sale, audit the manufacturing facilities for such product. If any suchinspection or audit identifies a failure to comply with applicable regulations, or if a violation of product specifications or applicable regulations occursindependent of such an inspection or audit, the relevant regulatory authority may require remedial measures that may be costly or time-consuming toimplement and that may include the temporary or permanent suspension of a clinical trial or commercial sales or the temporary or permanent closure of amanufacturing facility.Any contamination in our manufacturing process, shortages of materials or failure of any of our key suppliers to deliver necessary components could resultin interruption in the supply of our product candidates and delays in our clinical development or commercialization schedules.Given the nature of biologics manufacturing, there is a risk of contamination in our manufacturing processes. Any contamination could materially adverselyaffect our ability to produce SGT-001 on schedule and could cause reputational damage.Some of the materials required in our manufacturing process are derived from biologic sources. Such materials are difficult to procure and may be subject tocontamination or recall. A material shortage, contamination, recall or restriction on the use of biologically derived substances in the manufacture of SGT-001could adversely impact or disrupt the commercial manufacturing or the production of clinical material, which could materially and adversely affect ourdevelopment timelines.The insurance coverage and reimbursement status of newly approved products is uncertain. Failure to obtain or maintain adequate coverage andreimbursement for our product candidates, if approved, could limit our ability to market those products and decrease our ability to generate productrevenue.There is significant uncertainty related to third-party coverage and reimbursement of newly approved products. We expect the cost of a single administrationof gene transfer products, such as those we are developing, to be substantial, when and if they achieve regulatory approval. We expect that coverage andreimbursement by government and private payors will be essential for most patients to be able to afford these treatments. Accordingly, sales of SGT-001, ifapproved, will depend substantially, both domestically and abroad, on the extent to which the costs of SGT-001 will be paid by health maintenance,managed care, pharmacy benefit and similar health care management organizations, or will be reimbursed by government authorities, private health coverageinsurers and other third-party payors. Coverage and reimbursement by a third-party payor may depend upon several factors, including the third-party payor’sdetermination that use of a product is: •a covered benefit under its health plan; •safe, effective and medically necessary;45 •appropriate for the specific patient; •cost-effective; •durable and a one-time treatment; and •neither experimental nor investigational.Obtaining coverage and reimbursement for a product from third-party payors is a time-consuming and costly process that could require us to provide to thepayor supporting scientific, clinical and cost-effectiveness data. If coverage and reimbursement are not available, or are available only at limited levels, wemay not be able to successfully commercialize SGT-001 and our other product candidates. Even if coverage is provided, the approved reimbursement amountmay not be adequate to realize a sufficient return on our investment.To our knowledge, a limited number of gene transfer products have been approved for coverage and reimbursement by the Centers for Medicare & MedicaidServices, or the CMS, the agency responsible for administering the Medicaid program. It is difficult to predict what the CMS will decide with respect tocoverage and reimbursement for fundamentally novel products such as ours, as there is no body of established practices and precedents for these types ofproducts either in the United States or the European Union. For example, several cancer drugs have been approved for reimbursement in the United States andhave not been approved for reimbursement in certain European Union member states and vice versa. It is difficult to predict what third-party payors willdecide with respect to the coverage and reimbursement for SGT-001 and our other product candidates.Governments outside the United States tend to impose strict price controls, which may adversely affect our revenue, if any.Outside the United States, international operations generally are subject to extensive government price controls and other market regulations, and increasingemphasis on cost-containment initiatives in the European Union, Canada and other countries may put pricing pressure on us. In general, the prices oftherapeutics outside the United States are substantially lower than in the United States. Other countries may allow companies to fix their own prices fortherapeutics, but monitor and control company profits. Additional foreign price controls or other changes in pricing regulations could restrict the amount thatwe are able to charge for our product candidates. Accordingly, in markets outside the United States, the reimbursement for our product candidates may bereduced compared with the United States and may be insufficient to generate commercially reasonable product revenue.Additionally, in countries where the pricing of gene therapy products is subject to governmental control, pricing negotiations with governmental authoritiescan take considerable time after the receipt of marketing approval for a product. Political, economic and regulatory developments may further complicatepricing negotiations, and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various European Unionmember states and parallel distribution, or arbitrage between low-priced and high-priced member states, can further reduce prices. To obtain reimbursement orpricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to otheravailable therapies. Reimbursement of our products may be unavailable or limited in scope or amount, which would adversely affect our revenue, if any.If we obtain approval to commercialize SGT-001 and our other product candidates outside of the United States, in particular in the European Union, avariety of risks associated with international operations could materially adversely affect our business.We expect that we will be subject to additional risks in commercializing SGT-001 and our other product candidates outside the United States, including: •different regulatory requirements for approval of therapeutics in foreign countries; •reduced protection for intellectual property rights; •the existence of additional third-party patent rights of potential relevance to our business; •unexpected changes in tariffs, trade barriers and regulatory requirements; •economic weakness, including inflation, or political instability in particular foreign economies and markets; •compliance with tax, employment, immigration and labor laws for employees living or traveling abroad;46 •foreign currency fluctuations, which could result in increased operating expenses and reduced revenue, and other obligations incident to doingbusiness in another country; •foreign reimbursement, pricing and insurance regimes; •production shortages resulting from any events affecting material supply or manufacturing capabilities abroad; and •business interruptions resulting from geopolitical actions, including war and terrorism or natural disasters including earthquakes, typhoons,floods and fires.The failure to comply with applicable foreign regulatory requirements may result in, among other things, fines, suspension, variation or withdrawal ofregulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.Additionally, on June 23, 2016, the electorate in the United Kingdom voted in favor of leaving the European Union, commonly referred to as Brexit. OnMarch 29, 2017, the country formally notified the European Union of its intention to withdraw pursuant to Article 50 of the Lisbon Treaty. The UnitedKingdom has a period of a maximum of two years from the date of its formal notification to negotiate the terms of its withdrawal from, and future relationshipwith, the European Union. If no formal withdrawal agreement is reached between the United Kingdom and the European Union, then it is expected the UnitedKingdom's membership of the European Union will automatically terminate two years after the submission of the notification of the United Kingdom'sintention to withdraw from the European Union. Discussions between the United Kingdom and the European Union focused on finalizing withdrawal issuesand transition agreements are ongoing. However, limited progress to date in these negotiations and ongoing uncertainty within the UK Government andParliament sustains the possibility of the United Kingdom leaving the European Union on March 29, 2019 without a withdrawal agreement and associatedtransition period in place, which is likely to cause significant market and economic disruption. Since a significant proportion of the regulatory framework inthe United Kingdom is derived from European Union directives and regulations, the referendum could materially impact the regulatory regime with respect tothe clinical testing and approval of our product candidates in the United Kingdom or the European Union. If we seek to conduct any of our clinical trials inthe United Kingdom, we will need to comply with any changes to the United Kingdom’s regulatory regime. Any delay in obtaining, or an inability to obtain,any marketing approvals, as a result of Brexit or otherwise, would prevent us from commercializing our product candidates in the United Kingdom and/or theEuropean Union and restrict our ability to generate revenue and achieve and sustain profitability. If any of these outcomes occur, we may be forced to restrictor delay efforts to seek regulatory approval in the United Kingdom and/or European Union for our product candidates, which could significantly andmaterially harm our business.If we engage in future acquisitions or strategic collaborations, this may increase our capital requirements, dilute our stockholders, cause us to incur debtor assume contingent liabilities and subject us to other risks.We may evaluate various acquisitions and strategic collaborations, including licensing or acquiring complementary products, intellectual property rights,technologies or businesses. Any potential acquisition or strategic collaboration may entail numerous risks, including: •increased operating expenses and cash requirements; •the assumption of additional indebtedness or contingent liabilities; •assimilation of operations, intellectual property and products of an acquired company, including difficulties associated with integrating newpersonnel; •the diversion of our management’s attention from our existing product candidates and initiatives in pursuing such acquisition or strategiccollaboration; •retention of key employees, the loss of key personnel and uncertainties in our ability to maintain key business relationships; •risks and uncertainties associated with the other party to such a transaction, including the prospects of that party and their existing products orproduct candidates and regulatory approvals; and •our inability to generate revenue from acquired technology and/or products sufficient to meet our objectives in undertaking the acquisition orcollaboration or even to offset transaction costs.47In addition, if we undertake acquisitions, we may issue dilutive securities, assume or incur debt obligations, incur large one-time expenses and acquireintangible assets that could result in significant future amortization expense. Moreover, we may not be able to locate suitable acquisition or collaborationopportunities and this inability could impair our ability to grow or obtain access to technology or products that may be important to the development of ourbusiness.Risks related to our business operationsOur future success depends on our ability to retain key employees, consultants and advisors and to attract, retain and motivate qualified personnel.We are highly dependent on members of our executive team, the loss of whose services may adversely impact the achievement of our objectives. While wehave entered into employment agreements with certain of our executive officers, any of them could leave our employment at any time. We currently do nothave “key person” insurance on any of our employees. The loss of the services of one or more of our current key employees might impede the achievement ofour research, development and commercialization objectives.Recruiting and retaining other qualified employees, consultants and advisors for our business, including scientific and technical personnel, also will becritical to our success. There currently is a shortage of skilled individuals with substantial gene therapy experience, which is likely to continue. As a result,competition for skilled personnel, including in gene therapy research and vector manufacturing, is intense and the turnover rate can be high. We may not beable to attract and retain personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies and academicinstitutions for individuals with similar skill sets. In addition, the failure to succeed in preclinical or clinical trials or applications for marketing approval maymake it more challenging to recruit and retain qualified personnel. The inability to recruit, or loss of services of certain executives, key employees,consultants or advisors, may impede the progress of our research, development and commercialization objectives.If we are unable to manage expected growth in the scale and complexity of our operations, our performance may suffer.If we are successful in executing our business strategy, we will need to expand our managerial, operational, financial and other systems and resources tomanage our operations, continue our research and development activities and, in the longer term, build a commercial infrastructure to supportcommercialization of SGT-001 and any other product candidate that is approved for sale. Future growth would impose significant added responsibilities onmembers of management. It is likely that our management, finance, development personnel, systems and facilities currently in place may not be adequate tosupport this future growth. Our need to effectively manage our operations, growth and any future product candidates requires that we continue to developmore robust business processes and improve our systems and procedures in each of these areas and to attract and retain sufficient numbers of talentedemployees. We may be unable to successfully implement these tasks on a larger scale and, accordingly, may not achieve our research, development andgrowth goals.Our employees may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements, whichcould cause significant liability for us and harm our reputation.We are exposed to the risk of employee fraud or other misconduct, including intentional failures to comply with FDA regulations or similar regulations ofcomparable foreign regulatory authorities, provide accurate information to the FDA or comparable foreign regulatory authorities, comply with manufacturingstandards, comply with federal and state healthcare fraud and abuse laws and regulations and similar laws and regulations established and enforced bycomparable foreign regulatory authorities, report financial information or data accurately or disclose unauthorized activities to us. Employee misconductcould also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and serious harm to ourreputation. This could include violations of HIPAA, other U.S. federal and state law, and requirements of non-U.S. jurisdictions, including the EuropeanUnion Data Protection Directive. It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent thisactivity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions orlawsuits stemming from a failure to be in compliance with such laws, standards, regulations, guidance or codes of conduct. If any such actions are institutedagainst us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business and resultsof operations, including the imposition of significant fines or other sanctions.48Enacted and future legislation may increase the difficulty and cost for us to obtain marketing approval of and commercialize our product candidates andmay affect the prices we may set.Our business and financial prospects could be affected by changes in health care spending and policy in the United States and abroad. We operate in a highlyregulated industry and new laws or judicial decisions, or new interpretations of existing laws or decisions, related to health care availability, the method ofdelivery or payment for health care products and services could negatively impact our business, operations and financial condition.For example, in the United States there is significant interest in promoting health care reform, as evidenced by the enactment of the Patient Protection andAffordable Care Act and the companion Health Care and Education Reconciliation Act, or the Health Care Reform Law. The Health Care Reform Lawincreased federal oversight of private health insurance plans and included a number of provisions designed to reduce Medicare expenditures and the cost ofhealth care generally, to reduce fraud and abuse, and to provide access to increased health coverage.The Health Care Reform Law also imposed substantial changes to the U.S. system for paying for health care, including programs to extend medical benefits tomillions of individuals who have lacked insurance coverage. Generally, implementation of the Health Care Reform Law has thus far included significantcost-saving, revenue and payment reduction measures with respect to, for example, several government health care programs that might cover our products inthe United States, should they be commercialized, including Medicaid and Medicare. Additional downward pricing pressure associated with the Health CareReform Law includes that the Health Care Reform Law established and provided significant funding for a Patient-Centered Outcomes Research Institute tocoordinate and fund Comparative Effectiveness Research, as those terms are defined in the Health Care Reform Law. While the stated intent of ComparativeEffectiveness Research is to develop information to guide providers to the most efficacious therapies, outcomes of Comparative Effectiveness Research couldinfluence the reimbursement or coverage for therapies that are determined to be less cost-effective than others. Should any of our products be approved forsale, but then determined to be less cost-effective than alternative therapies, the levels of reimbursement for these products, or the willingness to reimburse atall, could be adversely impacted.Another provision of the Health Care Reform Law, generally referred to as the Physician Payment Sunshine Act or Open Payments Program, has imposed newreporting and disclosure requirements for pharmaceutical and medical device manufacturers and distributors with certain FDA-approved products, such asapproved vaccines, with regard to payments or other transfers of value made to certain U.S. health care practitioners, such as physicians and academic medicalcenters, and with regard to certain ownership interests held by physicians in reporting entities. The CMS publishes information from these reports on apublicly available website, including amounts transferred and the physician and teaching hospital identities.Under the Physician Payment Sunshine Act, we are required to collect and report detailed information regarding certain financial relationships we have withphysicians and teaching hospitals. Our compliance with these rules may also impose additional costs.With enactment of the Tax Cuts and Jobs Act of 2017, which was signed by the President on December 22, 2017, Congress repealed the “individualmandate.” The repeal of this provision, which requires most Americans to carry a minimal level of health insurance, will become effective in 2019. Accordingto the Congressional Budget Office, the repeal of the individual mandate will cause 13 million fewer Americans to be insured in 2027 and premiums ininsurance markets may rise. Further, each chamber of the Congress has put forth multiple bills designed to repeal or repeal and replace portions of the HealthCare Reform Law. Although none of these measures has been enacted by Congress to date, Congress may consider other legislation to repeal and replaceelements of the Health Care Reform Law. The Congress will likely consider other legislation to replace elements of the Health Care Reform Law, during thenext Congressional session.We will continue to evaluate the effect that the Health Care Reform Law and its possible repeal and replacement could have on our business. It is possiblethat repeal and replacement initiatives, if enacted into law, could ultimately result in fewer individuals having health insurance coverage or in individualshaving insurance coverage with less generous benefits. While the timing and scope of any potential future legislation to repeal and replace Health CareReform Law provisions is uncertain in many respects, it is also possible that some of the Health Care Reform Law provisions that generally are not favorablefor the research-based pharmaceutical industry could also be repealed along with Health Care Reform Law coverage expansion provisions. Accordingly, suchreforms, if enacted, could have an adverse effect on anticipated revenue from product candidates that we may successfully develop and for which we mayobtain marketing approval and may affect our overall financial condition and ability to develop commercialize product candidates.The Trump Administration has also taken executive actions to undermine or delay implementation of the Health Care Reform Law. Since January 2017,President Trump has signed two Executive Orders designed to delay the implementation of certain49provisions of the Health Care Reform Law or otherwise circumvent some of the requirements for health insurance mandated by the Health Care Reform Law.One Executive Order directs federal agencies with authorities and responsibilities under the Health Care Reform Law to waive, defer, grant exemptions from,or delay the implementation of any provision of the Health Care Reform Law that would impose a fiscal or regulatory burden on states, individuals,healthcare providers, health insurers, or manufacturers of pharmaceuticals or medical devices. The second Executive Order terminates the cost-sharingsubsidies that reimburse insurers under the Health Care Reform Law. Several state Attorneys General filed suit to stop the administration from terminating thesubsidies, but their request for a restraining order was denied by a federal judge in California on October 25, 2017. In addition, CMS has recently proposedregulations that would give states greater flexibility in setting benchmarks for insurers in the individual and small group marketplaces, which may have theeffect of relaxing the essential health benefits required under the Health Care Reform Law for plans sold through such marketplaces. Further, on June 14,2018, U.S. Court of Appeals for the Federal Circuit ruled that the federal government was not required to pay more than $12 billion in Health Care ReformLaw risk corridor payments to third-party payors who argued were owed to them. The effects of this gap in reimbursement on third-party payors, the viabilityof the Health Care Reform Law marketplace, providers, and potentially our business, are not yet known.The costs of prescription pharmaceuticals in the United States has also been the subject of considerable discussion in the United States, and members ofCongress and the Administration have stated that they will address such costs through new legislative and administrative measures. The pricing ofprescription pharmaceuticals is also subject to governmental control outside the United States. In these countries, pricing negotiations with governmentalauthorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries,we may be required to conduct a clinical trial that compares the cost effectiveness of our product candidates to other available therapies. If reimbursement ofour products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our ability to generate revenues and become profitablecould be impaired.Specifically, there have been several recent U.S. congressional inquiries and proposed federal and proposed and enacted state legislation designed to, amongother things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, reduce the costs of drugsunder Medicare and reform government program reimbursement methodologies for drug products. At the federal level, Congress and the Trumpadministration have each indicated that it will continue to seek new legislative and/or administrative measures to control drug costs. For example, on May11, 2018, the Administration issued a plan to lower drug prices. Under this blueprint for action, the Administration indicated that the Department of Healthand Human Services will: take steps to end the gaming of regulatory and patent processes by drug makers to unfairly protect monopolies; advancebiosimilars and generics to boost price competition; evaluate the inclusion of prices in drug makers’ ads to enhance price competition; speed access to andlower the cost of new drugs by clarifying policies for sharing information between insurers and drug makers; avoid excessive pricing by relying more onvalue-based pricing by expanding outcome-based payments in Medicare and Medicaid; work to give Part D plan sponsors more negotiation power with drugmakers; examine which Medicare Part B drugs could be negotiated for a lower price by Part D plans, and improving the design of the Part B CompetitiveAcquisition Program; update Medicare’s drug-pricing dashboard to increase transparency; prohibit Part D contracts that include “gag rules” that preventpharmacists from informing patients when they could pay less out-of-pocket by not using insurance; and require that Part D plan members be provided withan annual statement of plan payments, out-of-pocket spending, and drug price increases.At the state level, individual states are increasingly aggressive in passing legislation and implementing regulations designed to control pharmaceutical andbiological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing costdisclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regionalhealth care authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which supplierswill be included in their prescription drug and other health care programs. These measures could reduce the ultimate demand for our products, if approved, orput pressure on our product pricing. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which couldlimit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our productcandidates or additional pricing pressures.The Drug Supply Chain Security Act imposes new obligations on manufacturers of pharmaceutical products related to product tracking and tracing.Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceuticalproducts. We are not sure whether additional legislative changes will be enacted, or whether the current regulations, guidance or interpretations will bechanged, or what the impact of such changes on our business, if any, may be.50There have been a number of federal and state legislative changes made over the last few years regarding the pricing of pharmaceutical and biologic products.Concerns about drug pricing have been expressed by members of Congress and the President.It is likely that federal and state legislatures within the United States and foreign governments will continue to consider changes to existing health carelegislation. We cannot predict the reform initiatives that may be adopted in the future or whether initiatives that have been adopted will be repealed ormodified. The continuing efforts of the government, insurance companies, managed care organizations and other health care payors of to contain or reducecosts of health care may adversely affect: •the demand for any product candidates for which we may obtain regulatory approval; •our ability to set a price that we believe is fair for our products; •our ability to obtain coverage and reimbursement approval for a product; •our ability to generate revenue and achieve or maintain profitability; and •the level of taxes that we are required to pay.Our relationships with customers, physicians and third-party payors will be subject, directly or indirectly, to federal and state health care fraud and abuselaws, false claims laws, health information privacy and security laws, and other health care laws and regulations. If we are unable to comply, or have notfully complied, with such laws, we could face substantial penalties.If we obtain FDA approval for SGT-001 or our other product candidates and begin commercializing those products in the United States, our operations willbe directly or indirectly through our prescribers, customers and purchasers, subject to various federal and state fraud and abuse laws and regulations,including, without limitation, the federal Health Care Program Anti-Kickback Statute, the federal civil and criminal laws and the Physician PaymentSunshine Act and regulations. These laws will impact, among other things, our proposed sales, marketing and educational programs. In addition, we may besubject to patient privacy laws by both the federal government and the states in which we conduct our business. The laws that will affect our operationsinclude, but are not limited to: •the federal Health Care Program Anti-Kickback Statute, which prohibits, among other things, persons or entities from knowingly and willfullysoliciting, receiving, offering or paying any remuneration (including any kickback, bribe or rebate), directly or indirectly, overtly or covertly, incash or in kind, in return for the purchase, recommendation, leasing or furnishing of an item or service reimbursable under a federal health careprogram, such as the Medicare and Medicaid programs. This statute has been interpreted to apply to arrangements between pharmaceuticalmanufacturers on the one hand, and prescribers, purchasers and formulary managers on the other. The Health Care Reform Law amended theintent requirement of the federal Anti-Kickback Statute. A person or entity no longer needs to have actual knowledge of this statute or specificintent to violate it; •federal civil and criminal false claims laws and civil monetary penalty laws, which prohibit, among other things, individuals or entities fromknowingly presenting, or causing to be presented, claims for payment or approval from Medicare, Medicaid or other government payors that arefalse or fraudulent. The Health Care Reform Law provides and recent government cases against pharmaceutical and medical devicemanufacturers support the view that Federal Anti-Kickback Statute violations and certain marketing practices, including off-label promotion,may implicate the False Claims Act; •the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which created new federal criminal statutes that prohibit aperson from knowingly and willfully executing a scheme or from making false or fraudulent statements to defraud any health care benefitprogram, regardless of the payor (e.g., public or private); •HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its implementingregulations, and as amended again by the final HIPAA omnibus rule, Modifications to the HIPAA Privacy, Security, Enforcement, and BreachNotification Rules Under HITECH and the Genetic Information Nondiscrimination Act; Other Modifications to HIPAA, published in January2013, which imposes certain requirements relating to the privacy, security and transmission of individually identifiable health informationwithout appropriate authorization by entities subject to the rule, such as health plans, health care clearinghouses and health care providers; •federal transparency laws, including the federal Physician Payment Sunshine Act, that require certain manufacturers of drugs, devices, biologicsand medical supplies for which payment is available under Medicare,51 Medicaid or the Children’s Health Insurance Program, with specific exceptions, to report annually to the CMS information related to: (i)payments or other “transfers of value” made to physicians and teaching hospitals and (ii) ownership and investment interests held by physiciansand their immediate family members; •state and foreign law equivalents of each of the above federal laws, state laws that require drug manufacturers to report information related topayments and other transfers of value to physicians and other health care providers or marketing expenditures and state laws governing theprivacy and security of health information in certain circumstances, many of which differ from each other in significant ways and may not havethe same effect, thus complicating compliance efforts in certain circumstances, such as specific disease states; and •state and foreign laws that govern the privacy and security of health information in some circumstances, many of which differ from each other insignificant ways and often are not preempted by HIPAA, thus complicating compliance efforts.Because of the breadth of these laws and the narrowness of the statutory exceptions and safe harbors available, it is possible that some of our businessactivities could be subject to challenge under one or more of such laws. If our operations are found to be in violation of any of the laws described above orany other government regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines, exclusion fromparticipation in government health care programs, such as Medicare and Medicaid, imprisonment and the curtailment or restructuring of our operations.The risk of our being found in violation of these laws is increased by the fact that many of them have not been fully interpreted by the regulatory authoritiesor the courts, and their provisions are open to a variety of interpretations. Any action against us for violation of these laws, even if we successfully defendagainst it, could cause us to incur significant legal expenses and divert our management’s attention from the operation of our business. The shiftingcompliance environment and the need to build and maintain robust and expandable systems to comply with multiple jurisdictions with different complianceand/or reporting requirements increases the possibility that we may run afoul of one or more of the requirements.Product liability lawsuits against us could cause us to incur substantial liabilities and could limit commercialization of any product candidate that we maydevelop.We face an inherent risk of product liability exposure related to the testing of SGT-001, our other product candidates and any future product candidate inpreclinical studies and clinical trials and may face an even greater risk if we commercialize any product candidate that we may develop. If we cannotsuccessfully defend ourselves against claims that our product candidates caused injuries, we could incur substantial liabilities. Regardless of merit oreventual outcome, liability claims may result in: •decreased demand for any product candidate that we may develop; •loss of revenue; •substantial monetary awards to trial participants or patients; •significant time and costs to defend the related litigation; •withdrawal of clinical trial participants; •the inability to commercialize any of our product candidates; and •injury to our reputation and significant negative media attention.Although we maintain product liability insurance coverage, such insurance may not be adequate to cover all liabilities that we may incur. We anticipate thatwe will need to increase our insurance coverage each time we commence a clinical trial and if we successfully commercialize any product candidate.Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfyany liability that may arise.If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that couldhave a material adverse effect on the success of our business.We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the generation,handling, use, storage, treatment, manufacture, transportation and disposal of, and exposure to, hazardous materials and wastes, as well as laws andregulations relating to occupational health and safety. Our operations involve the use of hazardous and flammable materials, including chemicals and virusesand other biologic materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of thesematerials52and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use ofhazardous materials, we could be held liable for any resulting damages. We also could incur significant costs associated with civil or criminal fines andpenalties. We do not carry specific biological or hazardous waste insurance coverage, and our property, casualty and general liability insurance policiesspecifically exclude coverage for damages and fines arising from biological or hazardous waste exposure or contamination. Although we maintain workers’compensation insurance for certain costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials or otherwork-related injuries, this insurance may not provide adequate coverage against potential liabilities. Accordingly, in the event of contamination or injury, wecould be held liable for damages or be penalized with fines in an amount exceeding our resources, and our clinical trials or regulatory approvals could besuspended.In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations, which havetended to become more stringent over time. These current or future laws and regulations may impair our research, development or production efforts. Failureto comply with these laws and regulations also may result in substantial fines, penalties or other sanctions or liabilities.Our internal computer systems, or those of our collaborators, contractors or consultants, may fail or suffer security breaches, which could result in amaterial disruption of our product development.Despite the implementation of security measures, our internal computer systems and those of our current and any future collaborators and other contractors orconsultants are vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electricalfailures. Such systems are also vulnerable to service interruptions or to security breaches from inadvertent or intentional actions by our employees, third-partyvendors and/or business partners, or from cyber-attacks by malicious third parties. Cyber-attacks are increasing in their frequency, sophistication andintensity, and have become increasingly difficult to detect. Cyber-attacks could include the deployment of harmful malware, ransomware, denial-of-serviceattacks, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information. Cyber-attacks also could include phishing attempts or e-mail fraud to cause payments or information to be transmitted to an unintended recipient.While we are not aware of any such material system failure, accident, cyber-attack or security breach to date, if such an event were to occur and causeinterruptions in our or our collaborators’, contractors’ or consultants’ operations, it could result in a material disruption of our development programs and ourbusiness operations, whether due to a loss of our trade secrets or other proprietary information or other similar disruptions. For example, the loss of clinicaltrial data from preclinical studies or clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover orreproduce the data. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriatedisclosure of confidential or proprietary information, we could incur liability, our competitive position could be harmed and the further development andcommercialization of SGT-001 and our other product candidates could be delayed.Risks related to our intellectual propertyWe heavily rely on certain in-licensed patents and other intellectual property rights in connection with our development of SGT-001 and may be requiredto acquire or license additional patents or other intellectual property rights to continue to develop and commercialize SGT-001.Our ability to develop and commercialize SGT-001 and other product candidates is heavily dependent on licenses to patent rights and other intellectualproperty granted to us by third parties. In particular, we have licensed certain patents and patent applications from the University of Michigan, the Universityof Missouri and the University of Washington that are important or necessary to the development of SGT-001 and other elements of our gene transferprogram. Our existing license agreements impose, and we expect that future license agreements will impose, various diligence, development andcommercialization obligations, milestone payments, royalties and other obligations on us. If we fail to comply with our obligations under these agreements,we may be subject to damages, which may be significant, and the licensor may have the right to terminate the license, in which event we may not be able todevelop or market product candidates or technologies covered by the license, including SGT-001. In addition, certain of these license agreements are notassignable by us without the consent of the respective licensor, which may have an adverse effect on our ability to engage in certain transactions.Under our existing license agreements, we do not have, and under future license agreements we may not have, the right to control the preparation, filing andprosecution of patent applications, or the maintenance, enforcement and defense of the patents and patent applications that we license from third parties. Forexample, under our inbound license agreements with the University of Michigan, the University of Missouri and the University of Washington, each of theapplicable licensors53controls the prosecution of patent applications and the maintenance of patents and patent applications. Therefore, we cannot be certain that these patents andapplications will be prosecuted, maintained, enforced and defended in a manner consistent with the best interests of our business. If our licensors fail tomaintain, enforce or defend such patents, or lose rights to those patents or patent applications, the rights we have licensed may be reduced or eliminated andour right to develop and commercialize any of our product candidates that are the subject of such licensed rights, including SGT-001, could be adverselyaffected. For more information, see Part I, Item 1, “Business—Strategic partnerships and collaborations/licenses”.Moreover, licenses to additional third-party intellectual property, technology and materials are required for our development programs but may not beavailable in the future or may not be available on commercially reasonable terms. For example, we are aware of certain third-party patents related to certainmicrodystrophin constructs, which, if in force at the time of SGT-001’s commercialization, may be claimed by third parties to cover SGT-001. In addition,third parties may claim that the AAV vector we are developing for use in SGT-001 are covered by patents held by them. We believe that we would have validdefenses to any such claims; however, if any such claims were ultimately successful, we might require a license to continue to use and sell SGT-001 and suchAAV vector. Such licenses may not be available on commercially reasonable terms, or at all. The licensing or acquisition of third-party intellectual propertyrights is a competitive area, and several more established companies may pursue strategies to license or acquire third-party intellectual property rights that wemay consider attractive. These established companies may have a competitive advantage over us due to their size, capital resources and greater clinicaldevelopment and commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights tous. We also may be unable to license or acquire third-party intellectual property rights on terms that would allow us to make an appropriate return on ourinvestment. Moreover, even if we are able to obtain such licenses, they may only be non-exclusive, which could permit competitors and other third parties touse the same intellectual property in competition with us.We may collaborate with non-profit and academic institutions to accelerate our preclinical research or development under written agreements with theseinstitutions. These institutions may provide us with an option to negotiate a license to any of the institution’s rights in technology resulting from thecollaboration. Regardless of such option, we may be unable to negotiate a license within the required timeframe or under terms that are acceptable to us. If weare unable to do so, the institution may offer the intellectual property rights to other parties, potentially blocking our ability to pursue our program.If we are unable to successfully obtain rights to any third-party intellectual property rights that are required for the development and commercialization ofSGT-001 or any of our other product candidates, and such third-party intellectual property rights are successfully asserted against us, we may be liable fordamages, which may be significant, and we may be required to cease the development and commercialization of SGT-001 or our other product candidates.If we are unable to obtain and maintain patent protection for our product candidates, or if the scope of the patent protection obtained is not sufficientlybroad, our competitors could develop and commercialize products similar or identical to ours, and our ability to successfully commercialize our productcandidates may be adversely affected.Our success depends, in large part, on our and our licensors’ ability to seek, obtain, maintain, enforce and defend patent rights in the United States and othercountries with respect to SGT-001, our other product candidates and our future innovation related to our manufacturing technology. Our licensors and wehave sought, and we intend to continue to seek, to protect our proprietary position by filing patent applications in the United States and, in at least somecases, one or more countries outside the United States related to SGT-001 and certain other product candidates that are important to our business. However,we cannot predict whether the patent applications we and our licensors are currently pursuing will issue as patents or whether the claims of any issued patentswill provide us with a competitive advantage.Moreover, we currently do not own any issued patents; we own two pending PCT international patent applications, two pending applications in Taiwan andthree provisional patent applications in the United States. We cannot predict whether or in which jurisdictions the pending applications will result inissuance of patents that effectively protect any of our product candidates or will effectively prevent others from commercializing competitive products.Further, each of the provisional patent applications is not eligible to become an issued patent until, among other things, we file a non-provisional patentapplication within 12 months of the filing date of each provisional patent application. If we do not timely file a non-provisional patent application in respectof a provisional patent application, we may lose our priority date with respect to such provisional patent application and any patent protection on theinventions disclosed in such provisional patent application. While we intend to timely file non-provisional patent applications relating to our provisionalpatent applications, we cannot predict whether such future patent applications will result in the issuance of patents that effectively protect any of our productcandidates or will effectively prevent others from commercializing competitive products.54We also currently do not own or license any issued patents or pending patent applications with respect to our product candidate Anti-LTBP4. While we haveexercised an exclusive option to negotiate a license for issued patents and pending patent applications relating to such product candidate, we are stillrequired to negotiate and enter into a definitive agreement pursuant to which we could license rights to the optioned patents and we may be unable to enterinto such a definitive agreement within the required timeframe or under terms that are acceptable to us. If we are unable to do so, the party who has granted usour option may offer the patent rights to other parties. If we are unable to secure a license to any issued patents and pending patent applications relating toAnti-LTBP4, we may need to cease our development of such product candidate.We may not be able to file, prosecute, maintain, enforce, defend or license all patents that are necessary to our business.The patent prosecution process is expensive, time-consuming and complex, and we and our licensors may not be able to file, prosecute, maintain, enforce,defend or license all necessary or desirable patents and patent applications at a reasonable cost or in a timely manner.It is also currently unknown what claims may, if ever, issue from pending applications included in our patent rights. Additionally, certain of our in-licensedU.S. patent rights lack corresponding foreign patents or patent applications, and therefore we will be unable to obtain patent protection for our productcandidates in certain jurisdictions. We or our licensors may not be able to obtain or maintain patent protection with respect to SGT-001 or our other productcandidates.Changes in either the patent laws or their interpretation in the United States and other countries may diminish our ability to protect our inventions, obtain,maintain and enforce our intellectual property rights, and more generally, could affect the value of our intellectual property rights or narrow the scope of ourlicensed patents or future owned patents. It is also possible that we will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection.Although we enter into non-disclosure and confidentiality agreements with parties who have access to confidential or patentable aspects of our research anddevelopment output, such as our employees, corporate collaborators, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors andother third parties, any of these parties may breach the agreements and disclose such output before a patent application is filed, thereby jeopardizing ourability to seek patent protection.The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has, inrecent years, been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highlyuncertain. Patent applications included in our current and future patent rights may not result in patents being issued that protect our product candidates,effectively prevent others from commercializing competitive products or otherwise provide any competitive advantage. In fact, patent applications may notissue as patents at all. Even assuming patents issue from patent applications in which we have rights, changes in either the patent laws or interpretation of thepatent laws in the United States and other jurisdictions may diminish the value of our patents or narrow the scope of our patent protection.Other parties have developed products that may be related or competitive to our own and such parties may have filed or may file patent applications, or mayhave received or may receive patents, claiming inventions that may overlap or conflict with those claimed in our patent applications or issued patents. Wemay not be aware of all third-party intellectual property rights potentially relating to SGT-001, Anti-LTBP4 or our other current or future product candidates.In addition, we cannot provide any assurances that any of the inventions disclosed in our patent applications will be found to be patentable, including overthird-party or our own prior art patents, publications or other disclosures, or will issue as patents. Even if our patent applications issue as patents, we cannotprovide any assurances that such patents will not be challenged or ultimately held to be invalid or unenforceable. Publications of discoveries in the scientificliterature often lag behind the actual discoveries, and patent applications in the United States and in other jurisdictions are typically not published until18 months after filing, or, in some cases, at all. Therefore, we cannot know with certainty whether the inventors of our licensed patents and applications werethe first to make the inventions claimed in those patents or pending patent applications, or that they were the first to file for patent protection of suchinventions. Similarly, should we own any issued patents or patent applications in the future, we may not be certain that we were the first to file for patentprotection for the inventions claimed in such patents or patent applications. Furthermore, given the differences in patent laws in the United States, Europeand other foreign jurisdictions, for example, the availability of grace periods for filing patent applications and what can be considered as prior art, we cannotmake any assurances that any claims in our pending and future patent applications in the United States or other jurisdictions will issue, or if they do issue,whether they will issue in a form that provides us with any meaningful competitive advantage. Similarly, we cannot make any assurances that if thepatentability, validity, enforceability or scope of our pending or future patents and patent applications in the United States or foreign jurisdictions arechallenged55by any third party, that the claims of such pending or future patents and patent applications will survive any such challenge in a form that provides us withany meaningful competitive advantage. For example, we are aware of certain third-party patents and publications related to certain microdystrophinconstructs. While we believe that our owned or in-licensed patents and patent applications claim novel and non-obvious features of microdystrophinconstructs that are not described in such third-party patents or publications, such third-party patents and publications may have earlier priority or publicationdates and may be asserted as prior art against our owned or in-licensed patents and applications. Any such challenge, if successful, could limit or eliminatepatent protection for our products and product candidates or otherwise materially harm our business. As a result, the issuance, scope, validity, enforceabilityand commercial value of our patent rights cannot be predicted with any certainty.Moreover, the coverage claimed in a patent application can be significantly reduced before the patent is issued, and its scope can be reinterpreted afterissuance. Even if patent applications we license or may own in the future do issue as patents, they may not issue in a form that will provide us with anymeaningful protection, prevent competitors or other third parties from competing with us or otherwise provide us with any competitive advantage. Anypatents that we license or may own in the future may be challenged, narrowed, circumvented, or invalidated by third parties. Consequently, we do not knowwhether any of our product candidates will be protectable or remain protected by valid and enforceable patents. Our competitors or other third parties may beable to circumvent our patents by developing similar or alternative products in a non-infringing manner.The degree of patent protection we require to successfully compete in the marketplace may be unavailable. We cannot provide any assurances that any of thepatents or patent applications included in our patent rights include or will include claims with a scope sufficient to protect SGT-001 and our other productcandidates or otherwise provide any competitive advantage. In addition, the laws of foreign countries may not protect our proprietary rights to the sameextent as the laws of the United States. Furthermore, patents have a limited lifespan. In the United States, the natural expiration of a patent is generally twentyyears after it is filed. Certain extensions may be available, however, the life of a patent, and the protection it affords, is limited. Given the amount of timerequired for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly aftersuch candidates are commercialized. As a result, our patent rights may not provide us with adequate and continuing patent protection sufficient to excludeothers from commercializing products similar or identical to our product candidates, including biosimilar versions of such products.Our licensed patents, and any patents we may own in the future, may be challenged, narrowed, invalidated or held unenforceable.Even if we acquire patent protection that we expect should enable us to maintain some competitive advantage, third parties, including competitors, maychallenge the validity, enforceability or scope thereof, which may result in such patents being narrowed, invalidated or held unenforceable. In litigation, acompetitor could claim that our in-licensed patents or any patents we may own in the future are not valid or enforceable for a number of reasons. If a courtagrees, we would lose our rights to those challenged patents. Third parties also may raise similar claims before administrative bodies in the United States orabroad, even outside the context of litigation. Such proceedings could result in the revocation or cancellation of or amendment to our licensed patents andany patents we may own in the future in such a way that they no longer cover SGT-001 or our other product candidates.Even if issued, the issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our current and future patent rights maybe challenged in the courts or patent offices in the United States and abroad. For example, we may be subject to a third-party submission of prior art to theU.S. Patent and Trademark Office, or USPTO, challenging the validity of one or more claims of patents included in our patent rights. Such submissions mayalso be made prior to a patent’s issuance, precluding the granting of a patent based on one of the pending patent applications included in our patent rights.We may become involved in opposition, derivation, revocation, reexamination, post-grant and inter partes review, or interference proceedings challengingone or more patents included in our patent rights. For example, competitors may claim that they invented the inventions claimed in patents or patentapplications included in our patent rights, such as the microdystrophin we use in SGT-001, prior to the inventors of such patents or patent applications, ormay have filed one or more patent applications before the filing of the patents or patent applications included in our patent rights. A competitor who canestablish an earlier filing or invention date may also assert that we are infringing their patents and that we therefore cannot practice our technology related toour product candidates as claimed in the patents or patent applications included in our patent rights. Competitors may also contest patents or patentapplications included in our patent rights by showing that the claimed subject matter was not patent-eligible, was not novel or was obvious or that the patentclaims failed any other requirement for patentability or enforceability. In addition, we may in the future be subject to claims by our or our licensors’ current orformer employees or consultants asserting an ownership right in the patents or patent applications included in our patent rights as an inventor or co-inventor,as a result of the work they performed.An adverse determination in any such submission or proceeding may result in loss of exclusivity or freedom to operate or in patent claims being narrowed,invalidated or held unenforceable, in whole or in part, which could limit our ability to stop56others from using or commercializing similar therapeutics, without payment to us, or could limit the duration of the patent protection covering our productcandidates. Such challenges may also result in our inability to manufacture or commercialize our product candidates without infringing third-party patentrights, and we may be required to obtain a license from third parties, which may not be available on commercially reasonable terms or at all, or we may needto cease the development, manufacture and commercialization of one or more of our product candidates. In addition, if the breadth or strength of protectionprovided by the patents and patent applications included in our patent rights is threatened, it could dissuade companies from collaborating with us to license,develop or commercialize current or future product candidates. Such proceedings also may result in substantial cost and require significant time from ourscientists and management, even if the eventual outcome is favorable to us.Even if they are unchallenged, the patents and pending patent applications included in our patent rights may not provide us with any meaningful protectionor prevent competitors from designing around our patent claims to circumvent our patent rights by developing similar or alternative therapeutics in a non-infringing manner. For example, a third party may develop a competitive therapeutic that provides benefits similar to one or more of our product candidatesbut that uses a vector or an expression construct that falls outside the scope of our patent protection. If the patent protection provided by the patents andpatent applications we license or pursue with respect to our product candidates is not sufficiently broad to impede such competition, our ability tosuccessfully commercialize our product candidates could be negatively affected.Our intellectual property licenses with third parties may be subject to disagreements over contract interpretation, which could narrow the scope of ourrights to the relevant intellectual property or technology or increase our financial or other obligations to our licensors.We currently depend, and will continue to depend, on our license, collaboration and other similar agreements. Further development and commercialization ofSGT-001 and our other current and future product candidates may require us to enter into additional license, collaboration or other similar agreements. Theagreements under which we currently license intellectual property or technology from third parties are complex, and certain provisions in such agreementsmay be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to bethe scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under therelevant agreement. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensingarrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates.If any of our licenses or material relationships are terminated or breached, we may: •lose our rights to develop and market SGT-001 or our other product candidates; •lose patent protection for SGT-001 or our other product candidates; •experience significant delays in the development or commercialization of SGT-001 or our other product candidates; •not be able to obtain any other licenses on acceptable terms, if at all; or •incur liability for damages.These risks apply to any agreements that we may enter into in the future for SGT-001 and our other current and future product candidates.If we fail to comply with our obligations in the agreements under which we license intellectual property rights from third parties or otherwise experiencedisruptions to our business relationships with our licensors, we could lose license rights that are important to our business.We have certain obligations under licensing agreements with third parties that include annual maintenance fees and payments that are contingent uponachieving various development, commercial and regulatory milestones. Pursuant to many of these license agreements, we are required to make milestonepayments if certain development, regulatory and commercial sales milestones are achieved, and may have certain additional research funding obligations.Also, pursuant to the terms of many of these license agreements, when and if commercial sales of a licensed product commence, we must pay royalties to ourlicensors on net sales of the respective licensed products.57We have entered into license agreements with third parties and may need to obtain additional licenses from one or more of these same third parties or fromothers to advance our research or allow our commercialization of SGT-001 or other product candidates. It is possible that we may be unable to obtainadditional licenses at a reasonable cost or on reasonable terms, if at all. In that event, we may be required to expend significant time and resources to redesignSGT-001, our other product candidates or the methods for manufacturing them or to develop or license replacement products, all of which may not be feasibleon a technical or commercial basis. If we are unable to do so, we may be unable to develop or commercialize SGT-001 or our other product candidates. Wecannot provide any assurances that third-party patents or other intellectual property rights do not exist that might be enforced against our manufacturingmethods, product candidates or any technologies we may develop, resulting in either an injunction prohibiting our manufacture or sales, or, with respect toour sales, an obligation on our part to pay royalties and/or other forms of compensation to third parties.In each of our existing license agreements, and we expect in our future agreements, patent prosecution of our licensed technology is controlled solely by thelicensor, and we may be required to reimburse the licensor for their costs of patent prosecution. If our licensors fail to obtain and maintain patent or otherprotection for the proprietary intellectual property we license from them, we could lose our rights to the intellectual property or our exclusivity with respectto those rights, and our competitors could market competing products using the intellectual property. Further, in each of our license agreements our licensorshave the first right to bring any actions against any third party for infringing on the patents we have licensed. Our license agreements also require us to meetdevelopment thresholds to maintain the license, including establishing a set timeline for developing and commercializing product candidates. Disputes mayarise regarding intellectual property subject to our licensing agreements, including: •the scope of rights granted under the license agreement and other interpretation-related issues; •the extent to which our products or processes infringe on intellectual property of the licensor that is not subject to the licensing agreement; •the sublicensing of patent and other rights under our collaborative development relationships; •our diligence obligations under the license agreement and what activities satisfy those diligence obligations; •the inventorship or ownership of inventions and know-how resulting from the joint creation or use of intellectual property by our licensors andus and our partners; and •the priority of invention of licensed patented inventions.If disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms,we may be unable to successfully develop and commercialize SGT-001 or our other product candidates. In spite of our best efforts, our licensors mightconclude that we have materially breached our license agreements and might therefore terminate the license agreements, thereby resulting in disputes orlitigation, which could cause us to incur substantial costs and distract management’s time, and if we are unsuccessful, we could lose our ability to developand commercialize products covered by these license agreements. If these licenses are ultimately terminated by the licensor, or if the underlying patents failto provide the intended exclusivity, competitors would have the freedom to seek regulatory approval of, and to market, products identical to ours.Third parties may initiate legal proceedings alleging that we are infringing, misappropriating or otherwise violating their intellectual property rights, theoutcome of which would be uncertain and could have a material adverse effect on the success of our business.Our commercial success depends upon our ability and the ability of our future collaborators to develop, manufacture, market and sell SGT-001 and our othercurrent and future product candidates without infringing, misappropriating or otherwise violating the proprietary rights and intellectual property of thirdparties. The biotechnology and pharmaceutical industries are characterized by extensive and complex litigation regarding patents and other intellectualproperty rights. We or our licensors may in the future become party to, or be threatened with, adversarial proceedings or litigation regarding intellectualproperty rights with respect to SGT-001 or our other product candidates, including interference proceedings, post grant review and inter partes review beforethe USPTO. Our competitors or other third parties may assert infringement claims against us, alleging that, among other things, our therapeutics,manufacturing methods, formulations or administration methods are covered by their patents.Given the vast number of patents in our field of technology, we cannot be certain or guarantee that a court would hold that SGT-001 or any of our otherproduct candidates does not infringe an existing patent or a patent that may be granted in the future. Many companies and institutions have filed, andcontinue to file, patent applications related to gene therapy and58related manufacturing methods. Some of these patent applications have already been allowed or issued and others may issue in the future. Since this area iscompetitive and of strong interest to pharmaceutical and biotechnology companies, there will likely be additional patent applications filed and additionalpatents granted in the future, as well as additional research and development programs expected in the future. Furthermore, because patent applications cantake many years to issue, may be confidential for 18 months or more after filing and can be revised before issuance, there may be applications now pendingthat may later result in issued patents that may be infringed by the manufacture, use, sale or importation of our product candidates and we may or may not beaware of such patents. If a patent holder believes the manufacture, use, sale or importation of one of our product candidates infringes its patent, the patentholder may sue us even if we have licensed other patent protection for our product candidates. Moreover, we may face patent infringement claims from non-practicing entities that have no relevant product revenue and against whom our licensed patent portfolio may therefore have no deterrent effect.It is also possible that we have failed to identify relevant third-party patents or applications for which we may need a license to develop and commercializeSGT-001 and our other product candidates. For example, applications filed before November 29, 2000 and certain applications filed after that date that willnot be filed outside the United States remain confidential until patents issue. Moreover, it is difficult for industry participants, including us, to identify allthird-party patent rights that may be relevant to our product candidates because patent searching is imperfect due to differences in terminology amongpatents, incomplete databases and the difficulty in assessing the meaning of patent claims. We may fail to identify relevant patents or patent applications ormay identify pending patent applications of potential interest but incorrectly predict the likelihood that such patent applications may issue with claims ofrelevance to our product candidates. In addition, we may be unaware of one or more issued patents that would be infringed by the manufacture, sale or use ofa current or future product candidate, or we may incorrectly conclude that a third-party patent is invalid, unenforceable or not infringed by our activities.Additionally, pending patent applications that have been published can, subject to certain limitations, be later amended in a manner that could cover ourproduct candidates.Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future, regardless of their merit. Thereis a risk that third parties may choose to engage in litigation with us to enforce or to otherwise assert their patent or other intellectual property rights againstus. For example, as discussed above, third parties may claim that the microdystrophin or the AAV vector we are developing for use in SGT-001 is covered bypatents held by them. Even if we believe such claim, or other intellectual property claims alleged by third parties are without merit, there is no assurance thatwe would be successful in defending such claims. A court of competent jurisdiction could hold that these third-party patents are valid, enforceable andinfringed, which could materially and adversely affect our ability to commercialize SGT-001 or our other product candidates covered by the asserted third-party patents. In order to successfully challenge the validity of any such U.S. patent in federal court, we would need to overcome a presumption of validity.As this burden is a high one requiring us to present clear and convincing evidence as to the invalidity of any such U.S. patent claim, there is no assurance thata court of competent jurisdiction would invalidate the claims of any such U.S. patent. Similarly, there is no assurance that a court of competent jurisdictionwould find that SGT-001 or our other product candidates did not infringe a third-party patent. Patent and other types of intellectual property litigation can involve complex factual and legal questions, and their outcome is uncertain. If we are found, orbelieve there is a risk that we may be found, to infringe, misappropriate or otherwise violate a third party’s intellectual property rights, and we areunsuccessful in demonstrating that such intellectual property rights are invalid or unenforceable, we could be required or may choose to obtain a license fromsuch third party to continue developing, manufacturing and marketing our product candidates. However, we may not be able to obtain any required licenseon commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors and other thirdparties access to the same technologies licensed to us, and it could require us to make substantial licensing and royalty payments. We could be forced,including by court order, to cease developing, manufacturing and commercializing the infringing product candidate, including SGT-001. In addition, wecould be found liable for monetary damages, including treble damages and attorneys’ fees, if we are found to have willfully infringed a patent or otherintellectual property right. A finding of infringement, misappropriation or other violation of intellectual property rights, or claims that we have done so,could prevent us from manufacturing and commercializing our product candidates or force us to cease some or all of our business operations.Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.Litigation or other legal proceedings relating to intellectual property claims, with or without merit, is unpredictable and generally expensive and time-consuming. Competitors may infringe patents that we may own in the future or the patents of our licensing partners or we may be required to defend againstclaims of infringement. Even if resolved in our favor,59litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could distract our technical andmanagement personnel from their normal responsibilities. Furthermore, because of the substantial amount of discovery required in connection withintellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. Inaddition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts orinvestors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Such litigation or proceedingscould substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distributionactivities.We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustainthe costs of such litigation or proceedings more effectively than we can because of their greater financial resources and more mature and developedintellectual property portfolios. Accordingly, despite our efforts, we may not be able to prevent third parties from infringing or misappropriating orsuccessfully challenging our intellectual property rights. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedingscould have a material adverse effect on our ability to compete in the marketplace.Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, fee payment and otherrequirements imposed by government patent agencies, and our patent protection could be reduced or eliminated for non-compliance with theserequirements.Periodic maintenance fees, renewal fees, annuity fees and various other government fees on patents and/or applications will be due to be paid to the USPTOand various government patent agencies outside of the United States over the lifetime of our licensed patents and applications and any patents and patentapplications we may own in the future. The USPTO and various non-U.S. government patent agencies require compliance with several procedural,documentary, fee payment and other similar provisions during the patent application process. We employ reputable intellectual property law firms and otherprofessionals to help us comply and we are also dependent on our licensors to take the necessary action to comply with these requirements with respect to ourlicensed intellectual property. In many cases, an inadvertent lapse can be cured by payment of a late fee or by other means in accordance with the applicablerules. There are situations, however, in which non-compliance can result in abandonment or lapse of the patent or patent application, resulting in partial orcomplete loss of patent rights in the relevant jurisdiction. In such an event, potential competitors might be able to enter the market and this circumstancecould have a material adverse effect on our business.Some intellectual property that we have in-licensed may have been discovered through government-funded programs and thus may be subject to federalregulations such as “march-in” rights, certain reporting requirements, and a preference for U.S. manufacturing. Compliance with such regulations maylimit our exclusive rights, and limit our ability to contract with non-U.S. manufacturers.Some of the intellectual property rights we have licensed, including such rights licensed from the University of Michigan, the University of Missouri and theUniversity of Washington, are stated to have been generated through the use of U.S. government funding and may therefore be subject to certain federalregulations. As a result, the U.S. government may have certain rights to intellectual property embodied in our current or future product candidates pursuant tothe Bayh-Dole Act of 1980, or Bayh-Dole Act. These U.S. government rights in certain inventions developed under a government-funded program include anon-exclusive, non-transferable, irrevocable worldwide license to use inventions for any governmental purpose. In addition, the U.S. government has theright to require us to grant exclusive, partially exclusive or non-exclusive licenses to any of these inventions to a third party if it determines that: (i) adequatesteps have not been taken to commercialize the invention, (ii) government action is necessary to meet public health or safety needs or (iii) government actionis necessary to meet requirements for public use under federal regulations (also referred to as “march-in rights”). The U.S. government also has the right totake title to these inventions if we, or the applicable licensor, fail to disclose the invention to the government and fail to file an application to register theintellectual property within specified time limits. Intellectual property generated under a government funded program is also subject to certain reportingrequirements, compliance with which may require us or the applicable licensor to expend substantial resources. In addition, the U.S. government requires thatany products embodying the subject invention or produced through the use of the subject invention be manufactured substantially in the United States. Themanufacturing preference requirement can be waived if the owner of the intellectual property can show that reasonable but unsuccessful efforts have beenmade to grant licenses on similar terms to potential licensees that would be likely to manufacture substantially in the United States or that under thecircumstances domestic manufacture is not commercially feasible. This preference for U.S. manufacturers may limit our ability to contract with non-U.S.product manufacturers for products covered by such intellectual property. To the extent any of our current or future intellectual property is generated throughthe use of U.S. government funding, the provisions of the Bayh-Dole Act may similarly apply.60We may not be able to protect our intellectual property and proprietary rights throughout the world.Filing, prosecuting, maintaining, enforcing and defending patents on product candidates in all countries throughout the world would be prohibitivelyexpensive, and our intellectual property rights in some countries outside the United States could be less extensive than those in the United States. Althoughour license agreements grant us worldwide rights, certain of our in-licensed U.S. patents lack corresponding foreign patents or patent applications. Forexample, the issued U.S. patents we license from the University of Michigan do not have any corresponding foreign patents or patent applications. Thus, wewill not have the opportunity to obtain patent protection for the subject matter of such patents outside the United States. In addition, the laws of some foreigncountries do not protect intellectual property rights to the same extent as federal and state laws in the United States even in jurisdictions where we and ourlicensors pursue patent protection. Consequently, we and our licensors may not be able to prevent third parties from practicing our inventions in all countriesoutside the United States, even in jurisdictions where we and our licensors pursue patent protection, or from selling or importing products made using ourinventions in and into the United States or other jurisdictions. Competitors may use our inventions in jurisdictions where we and our licensors have notpursued and obtained patent protection to develop their own products and may export otherwise infringing products to territories where we have patentprotection, but where enforcement is not as strong as it is in the United States. These products may compete with our product candidates and our patents orother intellectual property rights may not be effective or sufficient to prevent them from competing.Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systemsof certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets and other intellectual property rights,particularly those relating to biotechnology products, which could make it difficult for us to stop the infringement of our patents, if pursued and obtained, orthe marketing of competing products in violation of our intellectual property and proprietary rights generally. Proceedings to enforce our intellectualproperty and proprietary rights in foreign jurisdictions could (i) result in substantial costs and divert our efforts and attention from other aspects of ourbusiness, (ii) put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and (iii) provoke thirdparties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not becommercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significantcommercial advantage from the intellectual property that we develop or license.If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.In addition to the protection afforded by patents, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that isnot patentable or that we elect not to patent, processes for which patents are difficult to enforce and any other elements of the discovery and developmentprocesses of SGT-001 and our other product candidates that involve proprietary know-how, information or technology that is not covered by patents. Ourmanufacturing process is protected by trade secrets. However, trade secrets can be difficult to protect and some courts inside and outside the United States areless willing or unwilling to protect trade secrets.We seek to protect our proprietary know-how, trade secrets and processes, in part, by entering into confidentiality agreements and, if applicable, materialtransfer agreements, consulting agreements or other similar agreements with our employees, consultants, scientific advisors, CROs, manufacturers andcontractors. These agreements typically limit the rights of third parties to use or disclose our confidential information. However, we may not be able toprevent the unauthorized disclosure or use of our technical know-how or other trade secrets by the parties to these agreements, despite the existence generallyof confidentiality agreements and other contractual restrictions. We cannot guarantee that we have entered into such agreements with each party that mayhave or have had access to our trade secrets or proprietary processes. Monitoring unauthorized uses and disclosures is difficult and we do not know whetherthe steps we have taken to protect our proprietary know-how and trade secrets will be effective. If any of our employees, collaborators, CROs, manufacturers,consultants, advisors and other third parties who are parties to these agreements breaches or violates the terms of any of these agreements, we may not haveadequate remedies for any such breach or violation. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive,and time-consuming, and the outcome is unpredictable. As a result, we could lose our trade secrets. We also seek to preserve the integrity and confidentialityof our data and trade secrets by maintaining physical security of our premises and physical and electronic security of our information technology systems.While we have confidence in these security measures, they may still be breached, and we may not have adequate remedies for any breach.In addition, our trade secrets may otherwise become known or be independently discovered by competitors. Competitors could purchase our productcandidates, if approved, and attempt to replicate some or all of the competitive advantages we derive from our development efforts, willfully infringe,misappropriate or otherwise violate our intellectual property rights, design around our protected know-how and trade secrets, or develop their owncompetitive technologies that fall outside of our intellectual property rights. If any of our trade secrets were to be lawfully obtained or independentlydeveloped by a competitor, we would have no right to prevent them, or those to whom they communicate such trade secrets, from using that technology orinformation to compete with us. If our trade secrets are not adequately protected so as to protect our market against competitors’ products and technologies,our competitive position could be adversely affected.61We may be subject to claims asserting that our employees, consultants or advisors have wrongfully used or disclosed alleged trade secrets of their currentor former employers or claims asserting ownership of what we regard as our own intellectual property.Certain of our employees, consultants or advisors are currently, or were previously, employed at universities or other biotechnology or pharmaceuticalcompanies, including our competitors or potential competitors, as well as our academic partners. Although we try to ensure that our employees, consultantsand advisors do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that these individuals or we haveused or disclosed intellectual property, including trade secrets or other proprietary information, of any such individual’s current or former employer.Litigation may be necessary to defend against these claims. If we fail in defending any such claims, in addition to paying monetary damages, we may losevaluable intellectual property rights or personnel. An inability to incorporate such technologies or features would have a material adverse effect on ourbusiness and may prevent us from successfully commercializing our product candidates. Moreover, any such litigation or the threat of such litigation mayadversely affect our ability to hire employees or contract with independent contractors. A loss of key personnel or their work product could hamper or preventour ability to commercialize our product candidates. Even if we are successful in defending against such claims, litigation could result in substantial costsand be a distraction to management.In addition, while it is our policy to require our employees and contractors who may be involved in the conception or development of intellectual property toexecute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who, in fact,conceives or develops intellectual property that we regard as our own. Moreover, even when we obtain agreements assigning intellectual property to us, theassignment of intellectual property rights may not be self-executing or the assignment agreements may be breached, and we may be forced to bring claimsagainst third parties, or defend claims that they may bring against us, to determine the ownership of what we regard as our intellectual property. Moreover,individuals executing agreements with us may have preexisting or competing obligations to a third party, such as an academic institution, and thus anagreement with us may be ineffective in perfecting ownership of inventions developed by that individual.Changes in U.S. patent law could diminish the value of patents in general, thereby impairing our ability to protect our product candidates.Changes in either the patent laws or the interpretation of the patent laws in the United States could increase the uncertainties and costs surrounding theprosecution of patent applications and the enforcement or defense of issued patents. On September 16, 2011, the Leahy-Smith America Invents Act, or theLeahy-Smith Act, was signed into law. The Leahy-Smith Act includes several significant changes to U.S. patent law. Prior to March 2013 in the United States,assuming that other requirements for patentability are met, the first to make the claimed invention was entitled to the patent, while outside the United States,the first to file a patent application was entitled to the patent. After March 2013, under the Leahy-Smith Act, the United States transitioned to a first inventorto file system in which, assuming that other requirements for patentability are met, the first inventor to file a patent application will be entitled to the patenton an invention regardless of whether a third party was the first to invent the invention. The Leahy-Smith Act also includes a number of significant changesthat affect the way patent applications will be prosecuted and may also affect patent litigation. These include allowing third-party submission of prior art tothe USPTO during patent prosecution and additional procedures to attack the validity of a patent through various post-grant proceedings administered by theUSPTO. The USPTO developed new regulations and procedures to govern administration of the Leahy-Smith Act, and many of the substantive changes topatent law associated with the Leahy-Smith Act, and in particular, the first to file provisions, only became effective on March 16, 2013. Accordingly, it is notclear what, if any, impact the Leahy-Smith Act will have on the operation of our business as, among other reasons, the USPTO must still implement variousregulations. However, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patentapplications and the enforcement or defense of our issued patents.The patent positions of companies engaged in the development and commercialization of biologics and pharmaceuticals are particularly uncertain. Twocases involving diagnostic method claims and “gene patents” have been decided by the Supreme Court of the United States, or the Supreme Court. OnMarch 20, 2012, the Supreme Court issued a decision in Mayo Collaborative Services v. Prometheus Laboratories, Inc., or Prometheus, a case involvingpatent claims directed to a process of measuring a metabolic product in a patient to optimize a drug dosage for the patient. According to the Supreme Court,the addition of well understood, routine or conventional activity such as “administering” or “determining” steps was not enough to transform an otherwisepatent-ineligible natural phenomenon into patent-eligible subject matter. On July 3, 2012, the USPTO issued a guidance memo to patent examinersindicating that process claims directed to a law of nature, a natural phenomenon or a naturally occurring relation or correlation that do not include additionalelements or steps that integrate the natural principle into the claimed invention such that the natural principle is practically applied and the patent claimamounts62to significantly more than the natural principle itself should be rejected as directed to patent-ineligible subject matter. On June 13, 2013, the Supreme Courtissued its decision in Association for Molecular Pathology v. Myriad Genetics, Inc., or Myriad, a case involving patent claims held by Myriad Genetics, Inc.relating to the breast cancer susceptibility genes BRCA1 and BRCA2. Myriad held that an isolated segment of naturally occurring DNA, such as the DNAconstituting the BRCA1 and BRCA2 genes, is not patent-eligible subject matter, but that complementary DNA may be patent-eligible.In 2014, the USPTO issued a guidance to its patent examiners for evaluating claims for patent subject matter eligibility under the relevant statute (35 U.S.C. §101). This guidance was in response to a series of decisions from the U.S. Supreme Court on patent claims reciting judicial exceptions, including AbstractIdeas, Laws of Nature/Natural Principles, Natural Phenomena and/or Natural Products. Based on judicial decisions and public feedback, several supplementsto this guidance and additional memoranda and materials have since been issued and are continually being issued, while the current eligibility guidance hasbeen incorporated into the latest (9th) edition of the MPEP (Manual for Patent Examination Procedure), last revised in January 2018. The current subjectmatter eligibility guideline instructs USPTO examiners to follow a two-part test, set forth in the U.S. Supreme Court decisions Alice/Mayo, as the only testthat should be used to evaluate the eligibility of claims under examination, including claims directed to natural products and principles including allnaturally occurring nucleic acids. Certain claims of our licensed patents and patent applications contain, and any future patents we may obtain may contain,claims that relate to specific recombinant DNA sequences that are naturally occurring at least in part and, therefore, could be the subject of future challengesmade by third parties. In addition, the current USPTO subject matter eligibility guidance and the constantly evolving case law, together with contemplatedcongressional action, could all impact our ability to pursue similar patent claims in patent applications we may prosecute in the future.We cannot assure our stockholders that our efforts to seek patent protection for our product candidates will not be negatively impacted by the decisionsdescribed above, rulings in other cases or changes in guidance or procedures issued by the USPTO. We cannot fully predict what impact the Supreme Court’sdecisions in Prometheus and Myriad may have on the ability of life science companies to obtain or enforce patents relating to their products in the future.These decisions, the guidance issued by the USPTO and rulings in other cases or changes in USPTO guidance or procedures could have a material adverseeffect on our existing patent rights and our ability to protect and enforce our intellectual property in the future.Moreover, although the Supreme Court has held in Myriad that isolated segments of naturally occurring DNA are not patent-eligible subject matter, certainthird parties could allege that activities that we may undertake infringe other gene-related patent claims, and we may deem it necessary to defend ourselvesagainst these claims by asserting non-infringement and/or invalidity positions, or paying to obtain a license to these claims. In any of the foregoing or inother situations involving third-party intellectual property rights, if we are unsuccessful in defending against claims of patent infringement, we could beforced to pay damages or be subjected to an injunction that would prevent us from utilizing the patented subject matter.If we do not obtain patent term extension for patents relating to SGT-001 or our other product candidates, our business may be materially harmed.Depending upon the timing, duration and specifics of any FDA marketing approval of SGT-001 and our other product candidates, one or more U.S. patentsthat we license or may own in the future may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Actof 1984, or the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent extension term of up to five years as compensation for patentterm lost during the FDA regulatory review process based on the first regulatory approval for a particular drug or biologic. A patent term extension cannotextend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent may be extended and only those claimscovering the approved drug, a method for using it or a method for manufacturing it may be extended. However, we may not be granted an extension becauseof, for example, failing to exercise due diligence during the testing phase or regulatory review process, failing to apply within applicable deadlines, failing toapply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope ofpatent protection afforded could be less than we request. In addition, to the extent we wish to pursue patent term extension based on a patent that we in-license from a third party, we would need the cooperation of that third party. If we are unable to obtain patent term extension or the term of any suchextension is less than we request, our competitors may be able to enter the market sooner.If our trademarks and trade names are not adequately protected, then we may not be able to build name recognition and our business may be adverselyaffected.We have registered trademarks with the USPTO for the marks “SOLID BIOSCIENCES”, “SOLID GT” and “SOLID”. Once registered, our trademarks or tradenames may be challenged, infringed, diluted, tarnished, circumvented or declared generic63or determined to be infringing on other marks. We may not be able to protect our rights to these trademarks and trade names, which we need to build namerecognition among potential partners or customers in our markets of interest. At times, competitors may adopt trade names or trademarks similar to ours,thereby impeding our ability to build brand identity and possibly leading to market confusion. In addition, there could be potential trade name or trademarkinfringement, dilution or tarnishment claims brought by owners of other registered trademarks or trademarks that incorporate variations of our registered orunregistered trademarks or trade names. Over the long term, if we are unable to establish name recognition based on our trademarks and trade names, then wemay not be able to compete effectively and our business may be adversely affected. Our efforts to enforce or protect our proprietary rights related totrademarks, trade secrets, domain names, copyrights or other intellectual property may be ineffective and could result in substantial costs and diversion ofresources.Intellectual property rights and regulatory exclusivity rights do not necessarily address all potential threats.The degree of future protection afforded by our intellectual property rights is uncertain because intellectual property rights have limitations, and may notadequately protect our business or permit us to maintain our competitive advantage. For example: •others may be able to make gene therapy products that are similar to our product candidates but that are not covered by the claims of the patentsthat we license or may own in the future; •we, or our current or future license partners or collaborators, might not have been the first to make the inventions covered by the issued patent orpending patent applications that we license or may own in the future; •we, or our current and future license partners or collaborators, might not have been the first to file patent applications covering certain of our ortheir inventions; •others may independently develop similar or alternative products or duplicate any of our processes without infringing our owned or licensedintellectual property rights; •others may circumvent our regulatory exclusivities, such as by pursuing approval of a competitive product candidate via the traditionalapproval pathway based on their own clinical data, rather than relying on the abbreviated pathway provided for biosimilar applicants; •it is possible that our pending licensed patent applications or those that we may own in the future will not lead to issued patents; •issued patents that we hold rights to now or in the future may be held invalid or unenforceable, including as a result of legal challenges by ourcompetitors; •others may have access to the same intellectual property rights licensed to us; •our competitors might conduct research and development activities in countries where we do not have patent rights and then use theinformation learned from such activities to develop competitive products for sale in our major commercial markets; •we may not develop additional proprietary technologies that are patentable; •the patents or other intellectual property rights of others may have an adverse effect on our business; and •we may choose not to file a patent for certain trade secrets or know-how, and a third party may subsequently file a patent covering suchintellectual property.Risks related to ownership of our common stockOur executive officers, directors and principal stockholders maintain the ability to control all matters submitted to our stockholders for approval.Our executive officers and directors and principal stockholders, in the aggregate, beneficially own shares representing approximately 66.9% of our capitalstock as of February 15, 2019. As a result, if these stockholders were to choose to act together, they would be able to control all matters submitted to ourstockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would control the election ofdirectors and approval of any merger, consolidation or sale of all or substantially all of our assets.64This concentration of voting power may: •delay, defer or prevent a change in control; •entrench our management and our board of directors; or •delay or prevent a merger, consolidation, takeover or other business combination involving us on terms that other stockholders may desire.A significant number of our total outstanding shares may be sold into the market in the near future, which could cause the market price of our commonstock to drop significantly, even if our business is performing well.Sales of a substantial number of shares of our common stock in the public market could occur at any time. These sales, or the perception in the market thatholders of a large number of shares intend to sell shares, could reduce the market price of our common stock. As of February 15, 2019, we had outstanding35,422,915 shares of common stock. Our remaining outstanding shares of common stock may be freely sold in the public market at any time to the extentpermitted by Rules 144 and 701 under the Securities Act of 1933, as amended, or the Securities Act, or to the extent such shares have already been registeredunder the Securities Act and are held by non-affiliates of ours. Moreover, as of February 15, 2019, holders of an aggregate of approximately 23.3 millionshares of our common stock have rights, subject to certain conditions, to require us to file registration statements covering their shares or to include theirshares in registration statements that we may file for ourselves or other stockholders. In addition, on January 29, 2018, we filed a Registration Statement onForm S-8 to register approximately 5.0 million shares reserved for future issuance under our 2018 Omnibus Incentive Plan will become eligible for sale in thepublic market in the future, subject to certain legal and contractual limitations. These shares can be freely sold in the public market upon issuance, subject toblack-out periods and volume limitations applicable to affiliates.The price of our common stock has been and may in the future be volatile and fluctuate substantially, which could result in substantial losses for holders ofour common stock.Our stock price has been and may in the future be volatile. The stock market in general and the market for biopharmaceutical or pharmaceutical companies inparticular, has experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility,our stockholders may not be able to sell their shares of common stock at or above the price they paid for their shares. The market price for our common stockmay be influenced by many factors, including: •results of clinical trials of SGT-001 or our other product candidates or those of our competitors; •the success of competitive products or technologies; •regulatory or legal developments in the United States, the European Union and other countries; •the recruitment or departure of key personnel; •the level of expenses related to any of our product candidates, or our clinical development programs and our commercialization efforts; •the results of our efforts to discover, develop, acquire or in-license additional product candidates; •actual or anticipated changes in our development timelines; •our ability to raise additional capital; •our inability to obtain or delays in obtaining adequate product supply for any approved product or inability to do so at acceptable prices; •disputes or other developments relating to proprietary rights, including patents, litigation matters and our ability to obtain patent protection forour product candidates; •significant lawsuits, including patent or stockholder litigation; •variations in our financial results or those of companies that are perceived to be similar to us; •changes in the structure of health care payment systems; •market conditions in the pharmaceutical and biotechnology sectors;65 •general economic, industry and market conditions; and •the other factors described in this “Risk factors” section.If our quarterly operating results fall below the expectations of investors or securities analysts, the price of our common stock could decline substantially.Furthermore, any quarterly fluctuations in our operating results may, in turn, cause the price of our stock to fluctuate substantially.In the past, following periods of volatility in the market price of a company’s securities, securities class-action litigation often has been instituted against thatcompany. We and certain of our executive officers and board members have been named as defendants in purported class action lawsuits. This litigation, andany additional litigation instituted against us, could cause us to incur substantial costs to defend such claims and divert management’s attention andresources.An active trading market for our common stock may not be sustained.Prior to our initial public offering, which occurred on January 26, 2018, there was no public market for our common stock. Although our common stock islisted on the Nasdaq Global Select Market, given the limited trading history of our common stock, there is a risk that an active trading market for our sharesmay not continue to develop or be sustained. If an active market for our common stock does not continue to develop or is not sustained, it may be difficult forour stockholders to sell shares without depressing the market price for the shares, or at all.We are an “emerging growth company,” and the reduced disclosure requirements applicable to emerging growth companies may make our common stockless attractive to investors.We are an “emerging growth company,” or EGC, as defined in the Jumpstart our Business Startups Act of 2012, or the JOBS Act. We will remain an EGC untilthe earliest of: (i) the last day of the fiscal year in which we have total annual gross revenues of $1.07 billion or more; (ii) December 31, 2023; (iii) the date onwhich we have issued more than $1.0 billion in nonconvertible debt during the previous three years; and (iv) the date on which we are deemed to be a largeaccelerated filer under the rules of the Securities and Exchange Commission, or the SEC. For so long as we remain an EGC, we are permitted and intend torely on exemptions from certain disclosure requirements that are applicable to other public companies that are not emerging growth companies. Theseexemptions include: •not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act, or Section 404; •not being required to comply with any requirement that may be adopted by the Public Company Accounting Oversight Board regardingmandatory audit firm rotation or a supplement to the auditor’s report providing additional information about the audit and the financialstatements; •being permitted to provide only two years of audited financial statements, in addition to any required unaudited interim financial statements,with correspondingly reduced “Management’s Discussion and Analysis of Financial Condition and Results of Operations” disclosure; •reduced disclosure obligations regarding executive compensation; and •an exemption from the requirement to seek nonbinding advisory votes on executive compensation or golden parachute arrangements.We may choose to take advantage of some, but not all, of the available exemptions. We have taken advantage of reduced reporting burdens in our otherfilings with the Securities and Exchange Commission. In particular, we have not included all of the executive compensation information that would berequired if we were not an EGC. We cannot predict whether investors will find our common stock less attractive if we rely on certain or all of theseexemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for our common stock and our stockprice may be more volatile.We incur increased costs as a result of operating as a public company, and our management is now required to devote substantial time to new complianceinitiatives.As a public company, and particularly after we are no longer an EGC, we incur significant legal, accounting and other expenses that we did not incur as aprivate company. In addition, the Sarbanes-Oxley Act and rules subsequently implemented by the SEC and Nasdaq have imposed various requirements onpublic companies, including establishment and66maintenance of effective disclosure and financial controls and corporate governance practices. Our management and other personnel devote a substantialamount of time to these compliance initiatives. Moreover, these rules and regulations will increase our legal and financial compliance costs and will makesome activities more time-consuming and costly. For example, we expect that these rules and regulations may make it more difficult and more expensive forus to obtain director and officer liability insurance. Pursuant to Section 404, we will be required to furnish a report by our management on our internal control over financial reporting, including, once we are nolonger an EGC, an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. To achievecompliance with Section 404 within the prescribed period, we will be engaged in a process to document and evaluate our internal control over financialreporting, which is both costly and challenging. In this regard, we will need to continue to dedicate internal resources, engage outside consultants and adopta detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes, validatethrough testing that controls are functioning as documented and implement a continuous reporting and improvement process for internal control overfinancial reporting. Despite our efforts, there is a risk that neither we nor our independent registered public accounting firm will be able to conclude withinthe prescribed timeframe that our internal control over financial reporting is effective as required by Section 404. This could result in an adverse reaction inthe financial markets due to a loss of confidence in the reliability of our financial statements.We have identified material weaknesses in our internal control over financial reporting. If we are unable to remediate these material weaknesses, or if weidentify additional material weaknesses in the future or otherwise fail to maintain an effective system of internal controls, we may not be able to accuratelyor timely report our financial condition or results of operations, which may adversely affect our business and stock price.We have identified material weaknesses in our internal control over financial reporting. A material weakness is a deficiency, or a combination of deficiencies,in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financialstatements will not be prevented or detected on a timely basis. If we are unable to remediate these material weaknesses, or if we identify additional materialweaknesses in the future or otherwise fail to maintain an effective system of internal controls, we may not be able to accurately or timely report our financialcondition or results of operations, which may adversely affect investor confidence in us and, as a result, our stock price.In connection with the audits of our consolidated financial statements as of and for the years ended December 31, 2015 and December 31, 2016, we identifiedmaterial weaknesses in our internal control over financial reporting. The material weaknesses we identified were as follows: •We did not design or maintain an effective control environment commensurate with our financial reporting requirements. We lacked a sufficientnumber of professionals with an appropriate level of accounting knowledge, training and experience to appropriately analyze, record anddisclose accounting matters timely and accurately. Additionally, the limited personnel resulted in our inability to consistently establishappropriate authorities and responsibilities in pursuit of our financial reporting objectives, as demonstrated by, among other things, ourinsufficient segregation of duties in our finance and accounting functions. This material weakness contributed to the additional materialweaknesses detailed below. •We did not design and maintain formal accounting policies, procedures and controls to achieve complete, accurate and timely financialaccounting, reporting and disclosures, including controls over the preparation and review of account reconciliations and journal entries.Additionally, we did not design and maintain controls over the appropriate cut-off, classification and presentation of accounts and disclosuresin the financial statements. •We did not design and maintain formal accounting policies, processes and controls to analyze, account for and disclose complex transactions.Specifically, we did not design and maintain controls to analyze, account for and disclose complex transactions, including variable interestentities, preferred units, the preferred unit tranche right and equity-based compensation.Each of the control deficiencies could result in a misstatement of our accounts or disclosures that would result in a material misstatement of our annual orinterim consolidated financial statements that would not be prevented or detected, and accordingly, we determined that these control deficiencies constitutematerial weaknesses.These material weaknesses also resulted in a restatement of our previously issued 2015 annual consolidated financial statements and adjustments to our 2016annual consolidated financial statements, which were recorded prior to their issuance.We are in the process of implementing measures designed to improve our internal control over financial reporting and remediate the control deficiencies thatled to the material weaknesses, including hiring additional finance and accounting personnel and initiating design and implementation of our financialcontrol environment, including the establishment of67formal accounting policies and procedures, financial reporting controls and controls to account for and disclose complex transactions.We cannot assure our stockholders that the measures we have taken to date, and actions we may take in the future, will be sufficient to remediate the controldeficiencies that led to our material weaknesses in our internal control over financial reporting or that they will prevent or avoid potential future materialweaknesses. If we are unable to successfully remediate our existing or any future material weaknesses in our internal control over financial reporting, oridentify any additional material weaknesses, the accuracy and timing of our financial reporting may be adversely affected, we may be unable to maintaincompliance with securities law requirements regarding timely filing of periodic reports in addition to applicable stock exchange listing requirements,investors may lose confidence in our financial reporting, and our share price may decline as a result.Provisions in our certificate of incorporation and our bylaws and under Delaware law could make an acquisition of us, which may be beneficial to ourstockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.Provisions in our certificate of incorporation and our bylaws may discourage, delay or prevent a merger, acquisition or other change in control of us thatstockholders may consider favorable, including transactions in which our stockholders might otherwise receive a premium for their shares. These provisionsalso could limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of ourcommon stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrateor prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members ofour board of directors. Among other things, these provisions: •establish a classified board of directors such that not all members of our board are elected at one time; •allow the authorized number of our directors to be changed only by resolution of our board of directors; •limit the manner in which stockholders can remove directors from the board; •establish advance notice requirements for stockholder proposals that can be acted on at stockholder meetings and nominations to our board ofdirectors; •require that stockholder actions must be effected at a duly called stockholder meeting and prohibit actions by our stockholders by writtenconsent; •limit who may call stockholder meetings; •authorize our board of directors to issue preferred stock without stockholder approval, which could be used to institute a stockholder rights plan,or so-called “poison pill,” that would work to dilute the stock ownership of a potential hostile acquirer, effectively preventing acquisitions thathave not been approved by our board of directors; and •require the approval of the holders of at least two-thirds of the votes that all our stockholders would be entitled to cast to amend or repeal certainprovisions of our certificate of incorporation or bylaws.Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, or theDGCL, which prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with us for a period of three yearsafter the date of the transaction in which the person acquired in excess of 15% of our outstanding voting stock, unless the merger or combination is approvedin a prescribed manner.Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any, is the only sole sourceof gain for an investment in our common stock.We have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future earnings, if any, to finance the growth anddevelopment of our business. In addition, the terms of any future debt agreements may preclude us from paying dividends. As a result, capital appreciation, ifany, of our common stock will be the sole source of gain for an investor for the foreseeable future.68Our certificate of incorporation provides that the Court of Chancery of the State of Delaware is the exclusive forum for certain litigation that may beinitiated by our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for such disputes with us or our directors,officers or employees.Our certificate of incorporation provides that the Court of Chancery of the State of Delaware is the exclusive forum for (i) any derivative action or proceedingbrought on our behalf, (ii) any action asserting a claim for breach of a fiduciary duty owed by any of our directors, officers or other employees to us or ourstockholders, (iii) any action asserting a claim arising pursuant to any provision of the DGCL, our certificate of incorporation or our bylaws or (iv) any actionasserting a claim governed by the internal affairs doctrine. The choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forumthat it finds favorable for disputes with us or our directors, officers or other employees, which may discourage such lawsuits against us and our directors,officers and other employees. Alternatively, if a court were to find the choice of forum provision contained in our certificate of incorporation to beinapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions.Item 1B.Unresolved Staff Comments.None.Item 2.Properties.We lease our corporate headquarters, which consists of approximately 16,000 square feet in Cambridge, Massachusetts. The lease for our corporateheadquarters has an initial term of approximately 4 years that expires in February 2022. In addition, we lease our primary laboratory space, which consists of9,500 square feet in Cambridge, Massachusetts, under a lease with an initial term of five years that expires in April 2023 and includes an option to extend forone additional two-year term. In addition, we lease smaller laboratory and office space.Item 3.Legal Proceedings.On March 27, 2018, James Watkins, a purported stockholder of ours, filed a putative class action complaint alleging violations of the federalsecurities laws, in the United States District Court for the District of Massachusetts (Case No. 18-10587), against us, Ilan Ganot, our Chief Executive Officer,Jennifer Ziolkowski, our Chief Financial Officer, and the underwriters in our initial public offering, J.P. Morgan Securities LLC, Goldman Sachs & Co. LLC,Leerink Partners, LLC, Nomura Securities Co., LLC and Chardan Capital Markets LLC. The plaintiff in this suit claims to represent purchasers of our commonstock during the period from January 25, 2018 to March 14, 2018 and seeks unspecified damages arising out of the alleged failure to disclose risks associatedwith toxicity and potential for adverse events related to our lead product candidate. On May 29, 2018, the plaintiff, Mr. Watkins, and Ashish Bhandari,another purported stockholder, filed separate motions each seeking his appointment as lead plaintiff and approval of his selected lead counsel. On June 5,2018, Mr. Watkins withdrew his motion. On August 14, 2018, Mr. Bhandari withdrew his motion. On October 16, 2018, Mr. Watkins voluntarily dismissedhis claims without prejudice to his ability to participate in any putative class action as an absent class member.On March 28, 2018, Robert Lowinger, a purported stockholder of ours, filed a putative class action complaint alleging violations of the federalsecurities laws, in the Business Litigation Section of the Superior Court of the Commonwealth of Massachusetts (Civil Action No. 1884-00984), against us,Ilan Ganot, Jennifer Ziolkowski, our directors and certain of the underwriters in our initial public offering. The plaintiff in this suit claims to representpurchasers of our common stock in or traceable to our January 25, 2018 initial public offering and seeks unspecified damages arising out of the allegedfailure to disclose risks associated with toxicity and potential for adverse events related to our lead product candidate. On April 30, 2018, all defendantsincluding us moved to stay the proceedings in favor of the prior-filed federal court securities class action. The plaintiff filed his opposition to this motion onMay 14, 2018, and defendants filed a reply in support of their motion on May 24, 2018. After oral argument on June 13, 2018, the court issued an order onJune 22, 2018 allowing the motion to stay and directing the parties to advise the court of the status of the federal court action every six months. On December21, 2018, the parties filed a joint status report informing the court of the voluntary dismissal of the federal actions and of plaintiff’s intent to move to vacatethe stay. The court has scheduled a status conference for June 24, 2019.While we believe that we have meritorious defenses to the allegations made in this complaint, it is not currently possible to assess whether or not theoutcome of this suit may have a material adverse effect on our business, financial condition, results of operations or prospects.69In addition, we may be involved in various other legal proceedings arising out of our operations. We are not currently a party to any such other legalproceedings that, in the opinion of our management, are likely to have a material adverse effect on our business, financial condition, results of operations orprospects. Regardless of outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resourcesand other factors.Item 4.Mine Safety Disclosures.Not applicable.70PART IIItem 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.Market InformationOur common stock has been publicly traded on the Nasdaq Global Select Market under the symbol “SLDB” since January 26, 2018 in connectionwith our initial public offering. Prior to that date, there was no established public trading market for our common stock.The following graph compares the performance of our common stock to The Nasdaq Composite Index and to The Nasdaq Biotechnology Index fromJanuary 26, 2018 (the first date that shares of our common stock were publicly traded) through December 31, 2018. The comparison assumes $100 wasinvested after the market closed on January 26, 2018 in our common stock and in each of the foregoing indices, and it assumes reinvestment of dividends, ifany. The stock price performance included in this graph is not necessarily indicative of future stock price performance.COMPARISON OF CUMULATIVE TOTAL RETURNAmong The Nasdaq Composite Index, The Nasdaq Biotechnology Index and Solid Biosciences Inc. HoldersAs of February 15, 2019, we had approximately 86 holders of record of our common stock. This number does not include beneficial owners whoseshares were held in street name. The actual number of holders of our common stock is greater than this number of record holders and includes stockholderswho are beneficial owners, but whose shares are held in street name by brokers or held by other nominees. This number of holders of record also does notinclude stockholders whose shares may be held in trust by other entities.Information about our Equity Compensation PlansInformation about our equity compensation plans is incorporated herein by reference to the section entitled “Securities authorized for issuance underequity compensation plans” in Item 12 of Part III of this Annual Report on Form 10-K.Purchase of Equity SecuritiesWe did not purchase any of our registered equity securities during the period covered by this Annual Report on Form 10-K.71Recent Sales of Unregistered SecuritiesWe did not sell any securities, during the year ended December 31, 2018 that were not registered under the Securities Act of 1933, as amended, or theSecurities Act, and that have not otherwise been described in a Quarterly Report on Form 10-Q.Use of Proceeds from Initial Public OfferingOn January 30, 2018, we closed our initial public offering, in which we issued and sold 8,984,375 shares of common stock, including 1,171,875shares of our common stock issued upon the exercise in full of the underwriters’ over-allotment option, at a public offering price of $16.00 per share. Theaggregate gross proceeds to us from our initial public offering were approximately $143.8 million. All of the shares of common stock issued and sold in ourinitial public offering were registered under the Securities Act pursuant to a registration statement on Form S-1 (Registration No. 333-222357), which wasdeclared effective by the SEC on January 25, 2018 and a registration statement on Form S-1 MEF (Registration No. 333-222705) filed pursuant to Rule462(b) of the Securities Act. J.P. Morgan Securities LLC, Goldman Sachs & Co. LLC and Leerink Partners LLC were joint book-running managers for theinitial public offering. The offering commenced on January 25, 2018 and did not terminate until the sale of all of the shares offered. The aggregate netproceeds to us were approximately $129.1 million, after deducting underwriting discounts and commissions and offering expenses payable by us ofapproximately $14.7 million.Except as set forth below, no offering expenses were paid directly or indirectly to any of our directors or officers (or their associates) or personsowning ten percent or more of any class of our equity securities or to any other affiliates, JPMC Strategic Investments II Corporation, or JPMC, owned inexcess of 10% of our issued and outstanding common stock immediately prior to our initial public offering, and JPMC is an affiliate of J.P. Morgan SecuritiesLLC, which was a book running manager in our initial public offering. In addition, Mr. Robert Huffines, one of our directors, is an employee of J.P. MorganSecurities LLC.There has been no material change in our planned use of the net proceeds from the offering as described in our final prospectus filed with the SEC onJanuary 29, 2018 pursuant to Rule 424(b) under the Securities Act. We have been using and plan to continue to use the net offering proceeds to fundresearch, development and clinical trial expenses, and the remainder for general and administrative expenses and other general corporate purposes.Item 6.Selected Financial Data.The statement of operations data for the years ended December 31, 2018, 2017 and 2016 and the balance sheet data as of December 31, 2018 and2017 are derived from our audited consolidated financial statements included elsewhere in this Annual Report on Form 10-K. The statement of operationsdata for the year ended December 31, 2015 and the selected balance sheet data as of December 31, 2016 and 2015 is derived from our audited consolidatedfinancial statements that are not included in this Annual Report on Form 10-K.72Our historical results are not necessarily indicative of results that should be expected in any future period. The following selected financial datashould be read in conjunction with the section of this report entitled “Management’s Discussion and Analysis of Financial Condition and Results ofOperations” and our financial statements and the related notes included elsewhere in this Annual Report on Form 10-K. Year ended December 31, (in thousands, except shares and per share data) 2018 2017 2016 2015 Consolidated statements of operations data: Revenue $- $- $- $- Operating expenses: Research and development 57,965 39,905 20,116 4,192 General and administrative 17,722 14,952 5,460 2,372 Total operating expenses 75,687 54,857 25,576 6,564 Loss from operations (75,687) (54,857) (25,576) (6,564)Other income (expense): Revaluation of preferred unit tranche rights - 459 1,163 (103)Interest and Other income 889 1,220 640 3 Total other income (expense), net 889 1,679 1,803 (100)Net loss $(74,798) $(53,178) $(23,773) $(6,664)Net loss attributable to Solid Biosciences Inc. $(74,798) $(52,118) $(21,539) $(6,377)Net loss attributable to common stockholders $(74,798) $(39,317) $(17,230) $(6,445)Net loss per share attributable to common stockholders, basic and diluted (1) $(2.25) $(2.88) $(10.14) $(7.61)Weighted average common stock outstanding, basic and diluted (1) 33,262,597 13,649,485 1,698,904 846,569 As of December 31, (in thousands) 2018 2017 2016 2015 Consolidated balance sheet data: Cash, cash equivalents and available-for-sale securities $122,464 $69,094 $37,658 $55,387 Working capital (2) 116,158 59,387 33,099 41,772 Total assets 139,597 76,193 40,636 55,696 Capital lease obligations, net of current portion 859 - - - Redeemable preferred units - 124,179 71,649 61,697 Accumulated deficit (199,056) (124,258) (84,941) (67,711)Total equity/(deficit) 125,183 (59,257) (37,886) (19,925) (1)See Note 15 to our consolidated financial statements in this Annual Report on Form 10-K for details on the calculation of basic and diluted net lossper share attributable to common stockholders.(2)We define working capital as current assets less current liabilities.73Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations.The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our financialstatements and related notes appearing elsewhere in this Annual Report on Form 10-K. Some of the information contained in this discussion and analysis orset forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the “Risk Factors” section of thisAnnual Report on Form 10-K, our actual results could differ materially from the results described, in or implied, by these forward-looking statements.OverviewOur mission is to cure Duchenne muscular dystrophy, or DMD, a genetic muscle-wasting disease predominantly affecting boys, with symptoms thatusually manifest between three and five years of age. DMD is a progressive, irreversible and ultimately fatal disease that affects approximately one in every3,500 to 5,000 live male births and has an estimated prevalence of 10,000 to 15,000 cases in the United States alone. DMD is caused by mutations in thedystrophin gene, which result in the absence or near-absence of dystrophin protein. Dystrophin protein works to strengthen muscle fibers and protect themfrom daily wear and tear. Without functioning dystrophin and certain associated proteins, muscles suffer excessive damage from normal daily activities andare unable to regenerate, leading to the build-up of fibrotic, or scar, and fat tissue. There is no cure for DMD and, for the vast majority of patients, there are nosatisfactory symptomatic or disease-modifying treatments. Our lead product candidate, SGT-001, is a gene transfer under development to restore functionaldystrophin protein expression in patients’ muscles. Based on our preclinical program that included multiple animal species of different phenotypes andgenetic variations, we believe the mechanism of action of SGT-001, if our clinical trials prove to be successful, has the potential to slow or even halt theprogression of DMD, regardless of the type of genetic mutation or stage of the disease.Since our inception, we have devoted substantial resources to identifying and developing SGT-001 and our other product candidates, developing ourmanufacturing processes, organizing and staffing our company and providing general and administrative support for these operations. We have incurredsignificant losses every year since our inception. We do not have any products approved for sale. To date, we have not generated any revenue. Our ability toeventually generate any product revenue sufficient to achieve profitability will depend on the successful development, approval and eventualcommercialization of SGT-001 and our other product candidates. If successfully developed and approved, we intend to commercialize SGT-001 in the UnitedStates and European Union and may enter into licensing agreements or strategic collaborations in other markets. If we generate product sales or enter intolicensing agreements or strategic collaborations, we expect that any revenue we generate will fluctuate from quarter to quarter and year to year as a result ofthe timing and amount of any product sales, license fees, milestone payments and other payments. If we fail to complete the development of SGT-001 and ourother product candidates in a timely manner or obtain regulatory approval of them, our ability to generate future revenue, and our results of operations andfinancial position, would be materially adversely affected.SGT-001 has been granted Rare Pediatric Disease Designation, or RPDD, and Fast Track Designation, in the United States and Orphan DrugDesignations in both the United States and European Union. The safety and efficacy of SGT-001 are currently being evaluated in a Phase I/II clinical trialcalled IGNITE DMD.Due to our significant research and development expenditure, licensing and patent investment, and general administrative costs associated with ouroperations, we have generated substantial operating losses in each period since our inception. Our net losses were $74.8 million, $53.2 million and$23.8 million for the years ended December 31, 2018, 2017 and 2016, respectively. As of December 31, 2018, we had an accumulated deficit of $199.1million. We expect to incur significant expenses and increasing operating losses for the foreseeable future.As we seek to develop and commercialize SGT-001 and our other product candidates, we anticipate that our expenses will increase significantly andthat we will need substantial additional funding to support our continuing operations. Until such time as we can generate significant revenue from productsales, if ever, we expect to finance our operations through a combination of public or private equity financings, debt financings or other sources, which mayinclude licensing agreements or strategic collaborations. We may be unable to raise additional funds or enter into such agreements or arrangements whenneeded on favorable terms, if at all. If we fail to raise capital or enter into such agreements as and when needed, we may have to significantly delay, scale backor discontinue the development or commercialization of SGT-001 or our other product candidates.74Because of the numerous risks and uncertainties associated with product development, we are unable to predict the timing or amount of increasedexpenses or determine when or if we will be able to achieve or maintain profitability. Even if we are able to generate revenue from product sales, we may notbecome profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue ouroperations at planned levels and be forced to reduce or terminate our operations.On January 30, 2018, we completed our initial public offering in which we sold 8,984,375 shares of our common stock, including shares of ourcommon stock issued upon the exercise in full of the underwriters’ over-allotment option, at a public offering price of $16.00 per share, resulting in netproceeds of $129.1 million, after deducting underwriting discounts and commissions and offering expenses.As of December 31, 2018, we had cash, cash equivalents and available-for-sale securities of $122.5 million. We believe that our cash, cashequivalents and available-for-sale securities as of December 31, 2018 will enable us to fund our operating expenses and capital expenditure requirementsthrough the first quarter of 2020. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resourcessooner than we currently anticipate.Corporate conversionWe operated as a Delaware limited liability company under the name Solid Biosciences, LLC until immediately prior to the effectiveness of ourregistration statement on Form S-1 on January 25, 2018, at which time we converted into a Delaware corporation pursuant to a statutory conversion andchanged our name to Solid Biosciences Inc. In addition, immediately following the statutory conversion, entities formed solely for the purpose of holdingmembership interests in our limited liability company were merged with and into us. We refer to the corporate conversion and the mergers, collectively as theCorporate Conversion. As a result of the Corporate Conversion, the holders of the Series 1 and 2 Senior Preferred and Junior Preferred Units and Series A, B, Cand D Common Units of Solid Biosciences, LLC became holders of common stock of Solid Biosciences Inc.The consolidated financial statements included elsewhere in this Annual Report on Form 10-K are those of Solid Biosciences Inc. and its subsidiaries.Merger and recapitalizationWe historically owned 100% of the voting units of our wholly owned subsidiary, Solid GT, LLC, or Solid GT, and the results of Solid GT are includedin our consolidated financial statements. Solid GT was organized in Delaware in August 2014 and was engaged in the business of developing disease-modifying interventions for DMD through gene therapy. In November 2015, Solid GT issued voting units to new investors, which decreased our votingownership in Solid GT to 77%. We consolidated the results of Solid GT as we owned a majority voting interest in Solid GT and we directed the activities ofSolid GT.Net loss attributable to non-controlling interests in our consolidated statement of operations and comprehensive loss consists of the portion of the netincome or loss of Solid GT that is not allocated to us. Changes in the amount of net loss attributable to non-controlling interests are directly impacted bychanges in the net income or loss of Solid GT. On March 29, 2017, we merged the operations of Solid GT into the company and Solid GT ceased to exist as aseparate legal entity. As a result, for periods subsequent to March 29, 2017, we no longer report any non-controlling interests related to Solid GT.Financial operations overviewRevenueWe have not generated any revenue to date and do not expect to generate any revenue from the sale of our products for the next few years, if ever. Ifour development efforts for SGT-001 or our other product candidates are successful and result in marketing approval or if we enter into collaboration orlicense agreements with third parties, we may generate revenue in the future from a combination of product sales or payments from those collaboration orlicense agreements.75Operating expensesWe classify our operating expenses into two categories: research and development, and general and administrative expenses. Personnel costs,including salaries, benefits, bonuses and equity-based compensation expense, comprise a significant component of each of these expense categories. Weallocate expenses associated with personnel costs based on the nature of work associated with these resources.Research and development expensesResearch and development expenses consist primarily of costs incurred for our research activities, including our discovery efforts, and thedevelopment of SGT-001 and our other product candidates and include: •expenses incurred under agreements with third parties, including CROs, that conduct research and preclinical activities on our behalf, as well asCMOs, that manufacture SGT-001 and our other product candidates for use in our preclinical studies and clinical trials; •salaries, benefits and other related costs, including equity-based compensation expense, for personnel engaged in research and developmentfunctions; •costs of outside consultants, engaged to assist in our research and development activities, including their fees, equity-based compensation andrelated travel expenses; •costs of laboratory supplies and acquiring, developing and manufacturing preclinical study and clinical trial materials; •costs incurred in seeking regulatory approval of SGT-001 and our other product candidates; •expenses incurred under our intellectual property licenses; and •facility-related research and development expenses, which include direct depreciation costs and allocated expenses for rent and maintenance offacilities and other operating costs.We expense research and development expenses as incurred. We recognize costs for certain development activities, such as preclinical research anddevelopment and clinical trial costs, based on an evaluation of the progress to completion of specific tasks using information and data provided to us by ourvendors, collaborators and third-party service providers. Payments for these activities are based on the terms of the individual agreements, which may differfrom the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses.We typically use our employee and infrastructure resources across our product candidates. We track outsourced development costs and milestonepayments made under our licensing arrangements by product candidates, but we do not allocate personnel costs, license payments made under our licensingarrangements or other internal costs to product candidates on a program-specific basis. These costs are included in unallocated research and developmentexpenses in the table below.The following table summarizes our research and development expenses by product candidates for the respective periods: Year ended December 31, 2018 2017 2016 SGT-001 $29,033 $24,674 $13,891 Other product candidates 3,506 1,619 1,021 Unallocated research and development expenses 25,426 13,612 5,204 Total research and development expenses $57,965 $39,905 $20,116 76We cannot determine with certainty the duration, costs and timing of clinical trials of SGT-001 and our other product candidates or if, when or to whatextent we will generate revenue from the commercialization and sale of any our product candidates for which we obtain marketing approval or our otherresearch and development expenses. We may never succeed in obtaining marketing approval for any of our product candidates. The duration, costs andtiming of clinical trials and development of our product candidates will depend on a variety of factors, including: •the scope, rate of progress, expense and results of any clinical trials of SGT-001 or other product candidates and other research and developmentactivities that we may conduct; •the imposition of regulatory restrictions on clinical trials, including full and partial clinical holds and the time and activities required to lift anysuch holds; •uncertainties in clinical trial design and patient enrollment or drop out or discontinuation rates; •significant and changing government regulation and regulatory guidance; •potential additional studies or clinical trials requested by regulatory agencies; •the timing and receipt of any marketing approvals; and •the expense of filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights.Research and development activities are central to our business model. Product candidates in later stages of clinical development generally havehigher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials.We expect that our research and development expenses will continue to increase for the foreseeable future as we proceed with clinical trials for SGT-001,initiate clinical trials for product candidates other than SGT-001 and continue to identify and develop additional product candidates.General and administrative expensesGeneral and administrative expenses consist primarily of salaries and other related costs, including equity-based compensation, for personnel in ourexecutive, finance, business development and administrative functions. General and administrative expenses also include legal fees relating to patent andcorporate matters, professional fees for accounting, auditing, tax and consulting services, insurance costs, travel expenses, and facility-related expenses,which include direct depreciation costs and allocated expenses for rent and maintenance of office facilities and other operating costs.We expect that our general and administrative expenses will increase in the future as we increase our general and administrative personnel headcountto support our research and development activities and activities related to the potential commercialization of SGT-001 and our other product candidate. Wealso expect to continue to incur increased expenses associated with being a public company, including costs of accounting, audit, legal, regulatory and tax-related services associated with maintaining compliance with exchange listing and SEC requirements, director and officer insurance costs and investor andpublic relations costs.Other income (expense)Revaluation of preferred unit tranche rightsIncluded in the terms of the Redeemable Preferred Unit Purchase Agreement was a right, which we refer to as the Redeemable Preferred Tranche Right,granted to the holders of the Redeemable Preferred Units issued in December 2013. The Redeemable Preferred Tranche Right obligated the holders topurchase, and provided the holders with the right to purchase, additional redeemable preferred units under certain circumstances. The Redeemable PreferredTranche Right was transferrable by the investors.The terms of the Series 1 Senior Preferred Unit Purchase Agreement, as amended on September 1, 2017, also contained a right, which we refer to as theSeries 1 Tranche Right. The Series 1 Tranche Right obligated the holders of the Series 1 Senior Preferred Units to purchase 1,973,430 Series 2 SeniorPreferred Units at a purchase price of $12.67 per unit in the event we achieved certain preclinical milestones. In addition, the holders of a majority of theSeries 1 Senior Preferred Units had the right to require the holders of the Series 1 Senior Preferred Units to purchase the Series 2 Senior Preferred Units at anytime prior to December 1, 2017. The Series 1 Tranche Right was subject to certain transfer rights.77We concluded that the Redeemable Preferred Tranche Right and the Series 1 Tranche Right, together the Tranche Rights, met the definition of afreestanding financial instrument as the Tranche Rights were legally detachable and separately exercisable from the Redeemable Preferred Units and theSeries 1 Senior Preferred Units. Therefore, we allocated the net proceeds between the Tranche Rights and the Redeemable Preferred Units or the Series 1Senior Preferred Units. The Tranche Rights were initially recorded at fair value and were re-measured at fair value each reporting period. Changes in the fairmarket value were recognized as a component of other income (expense), net, in the consolidated statements of operations.In October 2016, the Redeemable Preferred Tranche Right was settled with the closing of the Redeemable Preferred Unit financing. In October 2017,the Series 1 Tranche Right was settled in connection with the closing of the Series 2 Senior Preferred Financing.Interest incomeInterest income consists of interest income earned on our cash, cash equivalents and available-for-sale securities.Other incomeWe have received funding from charitable organizations, which is not considered to be an ongoing major or central part of our business. The amountsreceived are recorded as other income as services are performed and research expenses are incurred in the consolidated statements of operations.Income taxesFrom our inception in 2013 until January 25, 2018, we were organized as a Delaware limited liability company for federal and state income taxpurposes and treated as a partnership for U.S. income tax purposes. As such, we were not viewed as a taxpaying entity in any jurisdiction and did not require aprovision for income taxes. Each member of our company was responsible for the tax liability, if any, related to its proportionate share of our taxable income.As a result of the Corporate Conversion, we are now treated as a corporation for U.S. income tax purposes and thus are subject to U.S. federal, state andlocal income taxes and are taxed at the prevailing corporate tax rates. Among other things, we expect to generate net operating losses at the corporatelevel. We account for income taxes using an asset and liability approach, which requires recognition of deferred tax assets and liabilities for the expectedfuture tax consequences of events that have been recognized in the consolidated financial statements, but have not been reflected in taxable income. Avaluation allowance is established to reduce deferred tax assets to their estimated realizable value.We account for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of taxbenefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by thetaxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit torecognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of beingrealized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that areconsidered appropriate as well as the related net interest and penalties.Critical accounting policies and use of estimatesOur management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, whichhave been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financialstatements and related disclosures requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expensesand the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trendsand events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments aboutthe carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis.Our actual results may differ from these estimates.While our significant accounting policies are described in more detail in the notes to our consolidated financial statements appearing at the end ofthis Annual Report on Form 10-K, we believe that the following accounting policies are those most critical to the judgments and estimates used in thepreparation of our consolidated financial statements.78Accrued research and development expensesAs part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses.This process involves reviewing open contract and purchase orders, communicating with our personnel to identify services that have been performed on ourbehalf and estimating the level of service performed and the associated costs incurred for the services when we have not yet been invoiced or otherwisenotified of the actual costs. The majority of our service providers invoice us in arrears for services performed, on a pre-determined schedule or whencontractual milestones are met; however, some require advanced payments. We make estimates of our accrued expenses as of each balance sheet date in ourconsolidated financial statements based on facts and circumstances known to us at that time. Examples of estimated accrued research and developmentexpenses include fees paid to: •CROs in connection with performing research activities on our behalf and conducting clinical trials and preclinical studies on our behalf; •vendors in connection with preclinical development activities; •vendors related to product manufacturing and development and distribution of clinical and preclinical supplies; and •third parties under our intellectual property licenses.We base our expenses related to preclinical studies and clinical trials on our estimates of the services received and efforts expended pursuant toquotes and contracts with multiple CROs that conduct and manage preclinical studies and clinical trials on our behalf. The financial terms of theseagreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which paymentsmade to our vendors will exceed the level of services provided and result in a prepayment of the expense. In accruing fees, we estimate the time period overwhich services will be performed, and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effortvaries from our estimate, we adjust the accrual or amount of prepaid expense accordingly. Although we do not expect our estimates to be materially differentfrom amounts actually incurred, our understanding of the status and timing of services performed relative to the actual status and timing of services performedmay vary and may result in us reporting amounts that are too high or too low in any particular period. To date, we have not made any material adjustments toour prior estimates of accrued research and development expenses.Equity-based compensationIn connection with the completion of our initial public offering, we adopted the 2018 Omnibus Incentive Plan, which provides for the issuance ofshare-based awards, including options to purchase common stock. The 2018 Omnibus Incentive Plan provides for the awarding of up to 5,001,000 shares ofcommon stock for equity awards.We measure all stock options and other stock-based awards granted to employees and directors based on the fair value on the date of the grant andrecognize compensation expense of those awards, over the requisite service period, which is generally the vesting period of the respective award. Forfeituresare accounted for as they occur. We apply the straight-line method of expense recognition to all awards with only service-based vesting conditions. We havenot issued any awards with performance-based vesting conditions.For stock-based awards granted to non-employees, compensation expense is recognized over the period during which services are rendered by suchnon-employees until completed. At the end of each financial reporting period prior to the completion of the service, the fair value of these awards isremeasured using the then-current fair value of our common stock and updated assumption inputs in the Black-Scholes option-pricing model.The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. We historically have been aprivate company and lack company-specific historical and implied volatility information. Therefore, we estimate our expected stock volatility based on thehistorical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as we have adequate historical data regardingthe volatility of our own traded stock price. For options with service-based vesting conditions, the expected term of our stock options has been determinedutilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal tothe contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant ofthe award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that we have never paid cashdividends and do not expect to pay any cash dividends in the foreseeable future, if ever.79Results of operationsComparison of the years ended December 31, 2018 and 2017The following table summarizes our results of operations for the years ended December 31, 2018 and 2017: Years ended December 31, Increase 2018 2017 (decrease) (in thousands) Revenue $- $- $- Operating expenses: Research and development 57,965 39,905 18,060 General and administrative 17,722 14,952 2,770 Total operating expenses 75,687 54,857 20,830 Loss from operations (75,687) (54,857) (20,830)Other income (expense): Revaluation of preferred unit tranche rights - 459 (459)Interest income 619 219 400 Other income 270 1,001 (731)Total other income (expense) 889 1,679 (790)Net loss $(74,798) $(53,178) $(21,620) Research and development expenses Years ended December 31, Increase 2018 2017 (decrease) (in thousands) SGT-001 $29,033 $24,674 $4,359 Other product candidates 3,506 1,619 1,887 Unallocated research and development expenses 25,426 13,612 11,814 Total research and development expenses $57,965 $39,905 $18,060 Research and development expenses for the year ended December 31, 2018 were $58.0 million, compared to $39.9 million for the year endedDecember 31, 2017. The increase of $18.1 million in research and development costs was due to unallocated research and development costs of $11.8million primarily due to personnel and facility related expenses, including costs incurred to operate the new lab facility, a net $4.4 million increase in costsrelated to our lead product candidate SGT-001 driven by higher clinical development and manufacturing activities of $6.7 million offset by a $2.3 millionreduction in preclinical costs, and a $1.9 million increase in costs related to our other product candidates. General and administrative expensesGeneral and administrative expenses were $17.7 million for the year ended December 31, 2018, compared to $15.0 million for the year endedDecember 31, 2017. The increase of $2.7 million was driven by personnel and facility related expenses of $3.1 million as well as higher professional servicesand other corporate expenses of $1.9 million associated with being a public company, partially offset by a decrease in equity-based compensation of$2.3 million. The reduction in equity-based compensation of $2.3 million was primarily due to a charge associated with the exchange of certain of our vestedcommon units in connection with the recapitalization of Solid Biosciences, LLC and our merger with Solid GT on March 29, 2017. Revaluation of preferred unit tranche rightsWe issued the Series 1 Tranche Right on March 29, 2017 and it was settled in October 2017 in connection with the Series 2 senior preferred unitfinancing. The revaluation of the Series 1 Tranche Right resulted in a gain of $0.5 million in the year ended December 31, 2017 due to the settlement of thetranche right.80Interest incomeInterest income was $0.6 million and $0.2 million for the years ended December 31, 2018 and 2017 respectively. The increase in interest income wasdue to an increase in available-for-sale securities in our portfolio.Other incomeOther income for the year ended December 31, 2018 was $0.3 million compared to $1.0 million for the year ended December 31, 2017. The decreaseof $0.7 million was due a reduction of income from charitable organizations. We do not expect these contributions to significantly increase in future periods. Comparison of the years ended December 31, 2017 and 2016The following table summarizes our results of operations for the years ended December 31, 2017 and 2016: Years ended December 31, Increase 2017 2016 (decrease) (in thousands) Revenue $- $- $- Operating expenses: Research and development 39,905 20,116 19,789 General and administrative 14,952 5,460 9,492 Total operating expenses 54,857 25,576 29,281 Loss from operations (54,857) (25,576) (29,281)Other income (expense): Revaluation of preferred unit tranche rights 459 1,163 (704)Interest income 219 369 (150)Other income 1,001 271 730 Total other income (expense) 1,679 1,803 (124)Net loss $(53,178) $(23,773) $(29,405)Research and development expenses Years ended December 31, Increase 2017 2016 (decrease) (in thousands) SGT-001 $24,674 $13,891 $10,783 Other product candidates 1,619 1,021 598 Unallocated research and development expenses 13,612 5,204 8,408 Total research and development expenses $39,905 $20,116 $19,789Research and development expenses for the year ended December 31, 2017 were $39.9 million, compared to $20.1 million for the year endedDecember 31, 2016. The increase of $19.8 million in research and development costs was due to a $10.8 million increase in clinical and preclinical researchand manufacturing costs related to our lead product candidate SGT-001, $0.6 million increase in costs related to our other product candidates and $8.4million increase in unallocated research and development costs due primarily to increased compensation and headcount.General and administrative expensesGeneral and administrative expenses were $15.0 million for the year ended December 31, 2017, compared to $5.5 million for the year endedDecember 31, 2016. The increase of $9.5 million was primarily due to in an increase in equity-based compensation of $3.9 million, an increase of$2.9 million in professional fees related to our initial public offering, an increase of $2.1 million in personnel-related expenses and an increase of$0.6 million in other corporate expenses. The increase in equity-based compensation of $3.9 million during the year ended December 31, 2017 was primarilydue to a charge associated with the exchange of certain of our vested common units in connection with the recapitalization of our company and our mergerwith Solid GT on March 29, 2017. 81Revaluation of preferred unit tranche rightsThe revaluation of the Redeemable Preferred Tranche Right resulted in a gain of $1.2 million for the year ended December 31, 2016 due to a decreasein the fair value of the preferred units. We issued the Series 1 Tranche Right on March 29, 2017 and it was settled in October 2017 in connection with theSeries 2 senior preferred unit financing. The revaluation of the Series 1 Tranche Right resulted in a gain of $0.5 million in the year ended December 31, 2017due to the settlement of the tranche right.Interest incomeInterest income remained consistent at $0.2 million and $0.4 million for the years ended December 31, 2017 and 2016, respectively.Other incomeOther income for the year ended December 31, 2017 was $1.0 million compared to $0.3 million for the year ended December 31, 2016. The increaseof $0.7 million was due to income from charitable organizations. We do not expect these contributions to significantly increase in future periods. Liquidity and capital resourcesSources of liquidityTo date, we have financed our operations primarily through private placements of preferred units and our initial public offering. Through December31, 2018, we raised an aggregate of $144.6 million of gross proceeds from our sales of preferred units prior to the completion of our initial public offering andan aggregate of $129.1 million of net proceeds from the sale of our common stock after deducting underwriting discounts and commission and offeringexpenses in our initial public offering.We completed our initial public offering on January 30, 2018, in which we sold 8,984,375 shares of common stock, including the underwriters’ over-allotment option, at a public offering price of $16.00 per share, resulting in net proceeds of $129.1 million. As of December 31, 2018, we had cash, cashequivalents and available-for-sale securities of $122.5 million and had no debt outstanding.Cash flowsThe following table summarizes our sources and uses of cash for each of the periods presented: Year ended December 31, 2018 2017 2016 (in thousands) Cash used in operating activities $(70,197) $(43,224) $(20,120)Cash (used in) provided by investing activities (26,762) 10,448 (4,052)Cash provided by financing activities 131,507 77,078 3,420 Net increase (decrease) in cash and cash equivalents $34,548 $44,302 $(20,752) Operating activitiesDuring the year ended December 31, 2018, operating activities used $70.2 million of cash, primarily resulting from our net loss of $74.8 million andcash used in changes in our operating assets and liabilities of $2.8 million offset by non-cash charges of $7.4 million due primarily to equity-basedcompensation of $6.0 million and depreciation expense of $1.6 million. Net cash used in changes in our operating assets and liabilities consisted primarily ofan increase in prepaid expenses and other assets of $4.9 million which was primarily due to an increase in prepayments related to research and developmentactivities. Net cash used in changes in our operating assets and liabilities also included a decrease in accounts payable of $1.6 million due to the timing ofpayments. These changes were offset by an increase in accrued expenses and other liabilities of $2.9 million as well as proceeds received from our landlordfor tenant improvements related to the buildout of our lab space of $0.8 million.82During the year ended December 31, 2017, operating activities used $43.2 million of cash, primarily resulting from our net loss of $53.2 million offsetby net non-cash charges of $5.5 million due primarily to equity-based compensation of $5.3 million, which included $3.7 million associated with theexchange of Series A common units into Series B and D common units, and cash provided by changes in our operating assets and liabilities of $4.4 million.Net cash provided by changes in our operating assets and liabilities during the year ended December 31, 2017 consisted of a decrease in prepaid expensesand other current assets of $0.8 million due to the timing of prepaid research and development expense payments and net increase in accounts payable andaccrued expenses of $3.6 million due to the timing of payments and the increase in the overall activity of the company. During the year ended December 31, 2016, operating activities used $20.1 million of cash, primarily resulting from our net loss of $23.8 million offsetby non-cash charges of $0.9 million and cash provided by changes in our operating assets and liabilities of $2.8 million. Non-cash charges of $0.9 millionrepresented equity-based compensation expense of $1.5 million and amortization of premiums on available-for-sale securities of $0.5 million, offset by$1.1 million of gains on the revaluation of our Redeemable Preferred Tranche Right due to a decrease in the fair value of the underlying preferred units forthe year ended December 31, 2016. Net cash provided by changes in our operating assets and liabilities during the year ended December 31, 2016 consistedof an increase of $4.8 million in accounts payable, accrued expenses and other current liabilities, partially offset by a $2.0 million increase in prepaidexpenses and other current assets. The increase in accounts payable, accrued expenses and other current liabilities was largely due to an increase ofpreclinical trial-related expenses. The increase in prepaid expenses and other current assets was primarily due to the payment of preclinical activities inadvance of the related research and development.Investing activitiesDuring the year ended December 31, 2018, investing activities used $26.8 million of cash, consisting primarily of net purchases of investments aswell as the acquisition of property and equipment.During the year ended December 31, 2017, investing activities provided $10.4 million of cash, consisting primarily of the net proceeds on the saleand maturity of available-for-sale securities partially offset by purchases of property and equipment.During the year ended December 31, 2016, investing activities used $4.1 million of cash, consisting primarily of net purchases of investments and toa lesser extent the acquisition of property and equipment.Financing activitiesDuring the year ended December 31, 2018, net cash provided by financing activities was $131.5 million, primarily due to the net proceeds from ourinitial public offering.During the year ended December 31, 2017, net cash provided by financing activities was $77.1 million, primarily due to the net proceeds from oursale of Series 1 and 2 Senior Preferred Units of $24.5 million and $55.0 million, respectively, partially offset by payments made in connection with our initialpublic offering.During the year ended December 31, 2016, net cash provided by financing activities was $3.4 million, due to the proceeds from our sale ofRedeemable Preferred Units.Funding requirementsWe expect our expenses to increase substantially in connection with our ongoing development activities related to SGT-001. In addition, we expectto incur additional costs associated with operating as a public company. We expect that our expenses will increase substantially if and as we: •continue to enroll patients in IGNITE DMD and continue clinical development of SGT-001; •move other current or future product candidates into clinical trials; •continue research and preclinical development of our other product candidate, Anti-LTBP4; •seek to identify additional product candidates; •seek marketing approvals for our product candidates that successfully complete clinical trials, if any;83 •establish a sales, marketing and distribution infrastructure to commercialize any products for which we may obtain marketing approval; •arrange for manufacture of larger quantities of our product candidates for clinical development and potential commercialization; •maintain, expand, protect and enforce our intellectual property portfolio; •hire and retain additional clinical, quality control and scientific personnel; •build out new facilities or expand existing facilities to support our activities; •acquire or in-license other drugs, technologies and intellectual property; and •add operational, financial and management information systems and personnel.On January 30, 2018, we completed our initial public offering in which we sold 8,984,375 shares of common stock, including shares of common stockissued upon the exercise in full of the underwriters’ over-allotment option, at a public offering price of $16.00 per share, resulting in net proceeds of $129.1million, after deducting underwriting discounts and commissions and offering expenses.As of December 31, 2018, we had cash, cash equivalents and available-for-sale securities of $122.5 million. We believe that our cash, cashequivalents and available-for-sale securities as of December 31, 2018, will enable us to fund our operating expenses and capital expenditure requirementsthrough the first quarter of 2020. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resourcessooner than we currently anticipate.Because of the numerous risks and uncertainties associated with the development of SGT-001 and other product candidates and programs andbecause the extent to which we may enter collaborations with third parties for development of our product candidates is unknown, we are unable to estimatethe timing and amounts of increased capital outlays and operating expenses associated with completing the research and development of our productcandidates. Our future capital requirements will depend on many factors, including: •the progress and results of IGNITE DMD and future clinical trials of SGT-001 and our other product candidates; •the costs, timing and outcome of regulatory review of SGT-001 and our other product candidates; •the scope, progress, results and costs of discovery, laboratory testing, manufacturing, preclinical development and clinical trials for otherproduct candidates that we may pursue in the future, if any; •the costs associated with our manufacturing process development and evaluation of third-party manufacturers; •whether we decide to construct and validate our own manufacturing facility and the associated costs; •revenue, if any, received from commercial sale of SGT-001 or other product candidates, should any of our product candidates receive marketingapproval; •the costs of preparing, filing and prosecuting patent applications, maintaining, defending and enforcing our intellectual property rights anddefending intellectual property-related claims; •the outcome of any lawsuits filed against us; •the terms of our current and any future license agreements and collaborations; and •the extent to which we acquire or in-license other product candidates, technologies and intellectual property.We intend to supply our clinical development program for SGT-001 with drug product produced at a cGMP compliant facility located at one of ourCDMO partners. We intend to establish the capability and capacity to supply SGT-001 at commercial scale from multiple sources, including potentiallybuilding our own GMP facility to ensure redundancy and reliability. We expect that such a facility would require capital expenditures of between $60.0million to $75.0 million to commence operations. We expect to finalize plans to potentially build our own GMP facility after we have additional data fromIGNITE DMD.Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertainprocess that takes years to complete, and we may never generate the necessary data or results84required to obtain marketing approval for any product candidates or generate revenue from the sale of any products for which we may obtain marketingapproval. In addition, our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be derived from salesof products that we do not expect to be commercially available for many years, if ever. Accordingly, we will need to obtain substantial additional funds toachieve our business objectives.Adequate additional funds may not be available to us on acceptable terms, or at all. We do not currently have any committed external source of funds.To the extent that we raise additional capital through the sale of equity securities, our existing stockholders’ ownership interest may be diluted. Any debt orpreferred equity financing, if available, may involve agreements that include restrictive covenants that may limit our ability to take specific actions, such asincurring additional debt, making capital expenditures or declaring dividends, which could adversely impact our ability to conduct our business, and mayrequire the issuance of warrants, which could potentially dilute existing stockholders’ ownership interests.If we raise additional funds through licensing agreements and strategic collaborations with third parties, we may have to relinquish valuable rights toour technology, future revenue streams, research programs, or product candidates or grant licenses on terms that may not be favorable to us. If we are unableto raise additional funds, we may be required to delay, limit, reduce and/or terminate development of our product candidates or any future commercializationefforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.Contractual obligations and commitmentsThe following table summarizes our contractual obligations at December 31, 2018 and the effects that such obligations are expected to have on ourliquidity and cash flows in future periods: Payments due by period (in thousands) Total Less Than1 Year 1 - 3Years 3 - 5Years More Than5 Years Operating lease commitments (1) $7,308 $1,934 $4,073 $1,301 $- Capital lease commitments (2) $1,313 $276 $553 $484 $- Total $8,621 $2,210 $4,626 $1,785 $- (1)Represents minimum payments due for our leases of office and laboratory space in Cambridge, Massachusetts.In January 2018, we executed a lease agreement for lab space in Cambridge, Massachusetts. The lease consists of approximately 9,500 square feetwith an initial term of five years with the option to extend the term for one additional two-year term. The future minimum rent commitment for theinitial five-year term is approximately $3.4 million. In addition to rent, the lease requires us to pay additional amounts for taxes, insurance,maintenance and other operating expenses.In January 2018, we executed a lease agreement for office space in Cambridge, Massachusetts. The lease will serve as our corporate headquarters andconsists of approximately 16,000 square feet. The term of the lease runs through February 2022. The future minimum rent commitment for the leaseterm is approximately $3.9 million. In addition to rent, the lease requires us to pay additional amounts for taxes, insurance, maintenance and otheroperating expenses.(2)Represents minimum payments due for our lease of lab equipment which is in use in our lab facility in Cambridge, Massachusetts.In November 2018, we executed a capital lease financing agreement for lab equipment. The future minimum lease commitment for the four-year termis approximately $1.3 million. Under various agreements with third-party licensors, we have agreed to make milestone payments and pay royalties to third parties based on specificmilestones. We have not included any such contingent payment obligations in the table above as the amount, timing and likelihood of such payments arenot known. See “Business—Strategic partnerships and collaborations/licenses.”We enter into contracts in the normal course of business with CROs and CMOs for clinical trials, preclinical research studies and testing,manufacturing and other services and products for operating purposes. These contracts do not contain any minimum purchase commitments and arecancelable by us upon prior notice of 30 days and, as a result, are not included in the table of contractual obligations above.85Off-balance sheet arrangementsWe did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules andregulations of the SEC.Recently issued accounting pronouncementsWe have reviewed all recently issued standards and have determined that, other than as disclosed in Note 2 to our consolidated financial statementsappearing at the end of this Annual Report on Form 10-K, such standards will not have a material impact on our consolidated financial statements or do nototherwise apply to our operations.Emerging growth company statusThe JOBS Act permits an emerging growth company such as us to take advantage of an extended transition period to comply with new or revisedaccounting standards applicable to public companies until those standards would otherwise apply to private companies. We have irrevocably elected to optout of this provision and, as a result, we will comply with new or revised accounting standards when they are required to be adopted by public companies thatare not emerging growth companies.Item 7A.Quantitative and Qualitative Disclosures About Market Risk.Interest Rate RiskWe are exposed to market risk related to changes in interest rates. As of December 31, 2018, our available-for-sale securities consisted of corporatebond securities and U.S. government agency securities that have contractual maturities of one year or less. Our primary exposure to market risk is interestincome sensitivity, which is affected by changes in the general level of U.S. interest rates. However, because of the short-term nature of our portfolio, animmediate 10% change in market interest rates would not have a material impact on the fair market value of our investment portfolio or on our financialposition or results of operations.Inflation RiskWe do not believe that inflation had a material effect on our business, financial condition or results of operations in the last three years.Item 8.Financial Statements and Supplementary Data.The information required by this Item 8 is included at the end of this Annual Report on Form 10-K beginning on page F-1.Item 9.Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.Not applicable. Item 9A.Controls and Procedures.Evaluation of Disclosure Controls and ProceduresOur management, with the participation of our principal executive officer and principal financial officer, evaluated the effectiveness of our disclosurecontrols and procedures as of December 31, 2018. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under theSecurities Exchange Act of 1934, as amended, or the Exchange Act, means controls and other procedures of a company that are designed to ensure thatinformation required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized andreported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls andprocedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act isaccumulated and communicated to its management, including its principal executive and principal financial officers, or persons performing similar functions,as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how welldesigned and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluatingthe cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of December 31, 2018,our principal executive officer and principal financial officer86concluded that, as of such date, our disclosure controls and procedures were not effective, due to the material weaknesses described below.Management’s Annual Report on Internal Control over Financial ReportingOur management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rules 13a-15(f) and15d-15(f) under the Exchange Act. Our internal control over financial reporting is a process designed to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accountingprinciples. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Projections of anyevaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degreeof compliance with the policies or procedures may deteriorate.A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonablepossibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.In connection with the preparation of our consolidated financial statements as of and for the years ended December 31, 2016 and 2015, we identifiedmaterial weaknesses in our internal control over financial reporting. The material weaknesses we identified were as follows: •We did not design or maintain an effective control environment commensurate with our financial reporting requirements. We lacked a sufficientnumber of professionals with an appropriate level of accounting knowledge, training and experience to appropriately analyze, record anddisclose accounting matters timely and accurately. Additionally, the limited personnel resulted in our inability to consistently establishappropriate authorities and responsibilities in pursuit of our financial reporting objectives, as demonstrated by, among other things, ourinsufficient segregation of duties in our finance and accounting functions. This material weakness contributed to the additional materialweaknesses detailed below. •We did not design and maintain formal accounting policies, procedures and controls to achieve complete, accurate and timely financialaccounting, reporting and disclosures, including controls over the preparation and review of account reconciliations and journal entries.Additionally, we did not design and maintain controls over the appropriate cut-off, classification and presentation of accounts and disclosuresin the financial statements. •We did not design and maintain formal accounting policies, processes and controls to analyze, account for and disclose complex transactions.Specifically, we did not design and maintain controls to analyze, account for and disclose complex transactions, including variable interestentities, preferred units, the preferred unit tranche right and equity-based compensation.These material weaknesses resulted in a restatement of our previously issued 2015 annual consolidated financial statements and adjustments to our2016 annual consolidated financial statements, which were recorded prior to their issuance. Additionally, these material weaknesses could result in amisstatement of our accounts or disclosures that would result in a material misstatement of the annual or interim consolidated financial statements that wouldnot be prevented or detected.Under the supervision and with the participation of our management, including our principal executive officer and principal financial officer, weconducted an evaluation of the effectiveness of our internal control over financial reporting based on the framework described in Internal Control –Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on our evaluation under thatframework, our management concluded that our internal control over financial reporting was not effective as of December 31, 2018 due to the materialweaknesses described above.This Annual Report on Form 10-K does not include an attestation report of our independent registered public accounting firm due to a transitionperiod established by rules of the SEC for “emerging growth companies”. Remediation ActivitiesManagement has been actively engaged in remediating the above described material weaknesses. The following remedial actions have been takenduring the year ended December 31, 2018: •hired additional full-time accounting resources and financial planning and analysis resources with appropriate levels of experience, including anew Assistant Controller and Senior Accountant, and reallocated responsibilities87 across the accounting organization to ensure that the appropriate level of knowledge and experience is applied based on risk and complexity oftransactions and tasks under review; •strengthened our internal policies, processes and reviews, including substantial completion of the formal documentation thereof; •implemented a financial close policy and monitoring program, including the formation of a disclosure committee comprised of members of oursenior management team, financial management and representatives from our accounting and legal departments to review and approve SECfilings and investor communications, the results of which are discussed with the audit committee quarterly; and •engaged a professional accounting services firm to help us assess and commence documentation of our internal controls for complying with theSarbanes-Oxley Act.The process of implementing an effective financial reporting system is a continuous effort that requires us to anticipate and react to changes in ourbusiness and the economic and regulatory environments and to expend significant resources to maintain a financial reporting system that is adequate tosatisfy our reporting obligations. As we continue to evaluate and take actions to improve our internal control over financial reporting, we may take additionalactions to address control deficiencies or modify certain of the remediation measures described above.While significant progress has been made to enhance our internal control over financial reporting, we are still in the process of implementing,documenting and testing these processes, procedures and controls. Additional time is required to complete implementation and to assess and ensure thesustainability of these procedures. We believe the above actions will be effective in remediating the material weaknesses described above and we willcontinue to devote significant time and attention to these remedial efforts. However, the material weaknesses cannot be considered remediated until theapplicable remedial controls operate for a sufficient period of time and management has concluded, through testing, that these controls are operatingeffectively.Changes in Internal Control over Financial ReportingThe items described in “Remediation Activities” above are considered a change in our internal control over financial reporting (as defined in Rules13a-15(f) and 15d-15(f) of the Exchange Act) during the fourth quarter of 2018 that has materially affected, or is reasonably likely to materially affect, ourinternal control over financial reporting. Item 9B.Other Information.Not applicable.88PART IIIItem 10.Directors, Executive Officers and Corporate Governance.Set forth below are the names, ages and positions of our current executive officers and directors as of February 15, 2019. Name Age Position(s) heldExecutive Officers Ilan Ganot 45 Co-founder, President, Chief Executive Officer and DirectorAlvaro Amorrortu 47 Chief Operating OfficerLynette Herscha 47 Chief Legal Officer and SecretaryCarl Morris, Ph.D. 49 Chief Scientific OfficerJoel Schneider, Ph.D. 34 Chief Technology Officer and Head of Exploratory Research and DevelopmentJorge A. Quiroz, M.D. 49 Chief Medical OfficerJennifer Ziolkowski 44 Chief Financial Officer and TreasurerNon-Employee Directors Andrey Zarur, Ph.D. 48 Co-founder and Chairman of the Board of DirectorsMatthew Arnold 49 DirectorMartin Freed, M.D., F.A.C.P. 58 DirectorRobert Huffines 53 DirectorAdam Koppel, M.D., Ph.D. 49 DirectorSukumar Nagendran, M.D. 53 DirectorRajeev Shah 41 DirectorAdam Stone 39 DirectorLynne Sullivan 52 DirectorExecutive officersIlan Ganot is one of our co-founders and has served as our Chief Executive Officer and as a member of our board of directors since our inception in2013. Mr. Ganot has served as our President since June 2018. Previously, Mr. Ganot served as an investment banker at JPMorgan Chase & Co., a leadingglobal financial services firm, from September 2011 to September 2013. From October 2008 to August 2011, Mr. Ganot served as a banker at NomuraSecurities Co., Ltd., a securities and investment banking company, and from September 2003 to September 2008, at Lehman Brothers, a global financialservices firm. Mr. Ganot received his M.B.A. from London Business School and holds law and business degrees from the Interdisciplinary Center in Herzliya,Israel. Mr. Ganot also practiced corporate law in Israel and was a Captain in the Israeli Defense Forces. He is qualified to serve on our board of directorsbecause of his personal dedication to improving treatments available for DMD patients and his extensive leadership experience.Alvaro Amorrortu has served as our Chief Operating Officer since January 2017. Mr. Amorrortu served as our Senior Vice President of Operations fromNovember 2015 to December 2016. Prior to joining us, he served as Vice President of Consulting for IMS Health (now IQVIA), a healthcare oriented servicesand technology company, from July 2015 to November 2015 and Vice President of Campbell Alliance (now InVentiv Health Consulting), a managementconsulting firm serving the pharmaceutical and biotech industry, from July 2012 to June 2015. He was at the Monitor Group (now Monitor Deloitte), amanagement consulting firm, from April 2003 to May 2012 where he held various positions, including Associate Partner. From 1995 to 2000, Mr. Amorrortugained significant experience in project engineering and managing food-processing manufacturing facilities through various positions at Molinos Rio de laPlata and Trigalia (subsidiaries of Bunge Group and Cargill, respectively). Mr. Amorrortu received his M.B.A. from The Wharton School of the University ofPennsylvania and received an M.S. from the Instituto Tecnologico de Buenos Aires, Argentina.Carl Morris, Ph.D. has served as our Chief Scientific Officer since June 2017, and previously served as our Senior Vice President of Research andDevelopment from September 2015 to June 2017. Prior to joining us, Dr. Morris held various leadership positions within Pfizer Inc.’s, or Pfizer’s, RareDisease Research Unit from January 2010 to August 2015, including serving as a Senior Director, Director and Senior Principal Scientist. Prior to Pfizer,Dr. Morris held various positions within the Tissue Repair unit at Wyeth Pharmaceuticals, Inc., a pharmaceutical company acquired by Pfizer. Dr. Morris wasan Assistant Professor at Boston University School of Medicine and a founding faculty member of the Muscle and Aging Research Unit. He is also co-founderand a member of the board of directors of Breed Nutrition Inc. Dr. Morris holds a B.A. in Biology from Franklin Pierce College and a Ph.D. in Physiologyfrom UCLA.89Lynette Herscha has served as our Chief Legal Officer and Secretary since January 2019. Prior to joining us, she served as General Counsel, Secretaryand a member of the Executive Team at Concert Pharmaceuticals, Inc., a public biopharmaceutical company, from 2017 to 2018 and its Vice President andAssistant Secretary Legal from 2014 to 2017. Before joining Concert Pharmaceuticals, Ms. Herscha held various senior legal positions at MomentaPharmaceuticals, Inc., a public biotechnology company, from 2006 to 2014 and Phase Forward, Inc., a public technology company, from 2000 to 2006. Shebegan her career at the law offices of Fullbright & Jaworski. Ms. Herscha holds a J.D. from Boston University School of Law and a B.A. from BostonUniversity.Joel Schneider, Ph.D. has served as our Chief Technology Officer and Head of Exploratory Research and Development since June 2017. Dr. Schneideralso served as an Analyst from March 2014 to March 2015, a Director from March 2015 to January 2017 and our Vice President of Research andDevelopment from January 2017 to June 2017. Prior to joining us, Dr. Schneider completed a postdoctoral fellowship at Harvard University in theDepartment of Stem Cell and Regenerative Biology from January 2013 to 2014. He holds a Ph.D. in Cell Biology and Molecular Medicine from RutgersUniversity and a B.A. in Biology from Brandeis University.Jorge A. Quiroz, M.D. has served as our Chief Medical Officer since January 2016. Prior to joining us, Dr. Quiroz served as the Head ofNeurodevelopment & Psychiatry, Translational Medicine Neurosciences at F. Hoffmann-La Roche AG, a multinational healthcare company, from 2014 to2015 and, prior to that, as Head of Psychiatry from 2012 to 2014 and Translational Medicine Leader from 2009 to 2011 at Hoffmann-La Roche. From 2007 to2009, he served as the Director of Johnson & Johnson’s Pharmaceutical Research & Development LLC and from 2005 to 2007 he served as its AssociateDirector. Dr. Quiroz holds a medical degree from the Pontifical Catholic University of Chile and he completed his medical training as a Research Fellow atthe Laboratory of Molecular Pathophysiology, Mood and Anxiety Disorders Program, at the NIH in Bethesda, Maryland from February 2001 to May 2005.He is board certified in Psychiatry by the National Commission for Certification of Medical Specialties. He also holds an M.B.A. dual degree from ColumbiaUniversity and the London Business School.Jennifer Ziolkowski has served as our Chief Financial Officer and Treasurer since May 2017. Prior to joining us, she served as the Head of SalesOperations, North America for Philips Healthcare, a healthcare company, from 2014 to 2017 and as its Senior Director of Finance, North America from 2012to 2014. Ms. Ziolkowski served as Controller of Medical Consumables and Sensors from 2010 to 2012, Director of Finance of Imaging Systems from 2008 to2010, Senior Director of Finance and Corporate Controller from 2007 to 2008 at TransMedics, Inc., a medical device company, and held various finance andcorporate development leadership positions at Cytyc Corporation, a medical technology company, from 2001 to 2007. From 1996 to 2001, Ms. Ziolkowskigained significant experience at PricewaterhouseCoopers LLP where she served as a Senior Transaction Services Consultant and as Audit Senior and Staff inthe Boston Technology Group. Ms. Ziolkowski holds a B.S. in Accounting from Boston College and is a Certified Public Accountant.Non-employee directorsAndrey Zarur, Ph.D. is one of our co-founders and has served as the Chairman of our board of directors since our inception in 2013. Dr. Zarur co-founded GreenLight Biosciences Inc., a biotechnology company, in August 2008, and currently serves as its Chairman and Chief Executive Officer. FromJanuary 2006 to August 2014, he served as Managing General Partner of Kodiak Venture Partners, a venture capital firm. Dr. Zarur also serves as a member ofthe board of directors for a number of private companies. Dr. Zarur holds an M.S. and a Ph.D. from Massachusetts Institute of Technology and anundergraduate degree from Universidad Nacional Autónoma de México. Mr. Zarur is qualified to serve on our board of directors based on his over 20 years ofexperience in leading companies from clinical-stage drug development to global commercialization.Matthew Arnold is a founding member of Solid and has served as a member of our board of directors since our inception in 2013. A former energyexecutive, since 2009, Mr. Arnold has been actively working with startup businesses in the United Kingdom and Europe, primarily in the technology andclean tech sectors. He holds an M.S. from the University of Virginia and a B.A. from Duke University. Mr. Arnold is qualified to serve on our board ofdirectors because of his extensive management and board experience with startup companies and his background in finance.Martin Freed, M.D., F.A.C.P. has served as a member of our board of directors since June 2018. Dr. Freed has served as an independent consultant toseveral private pharmaceutical, biotechnology, and healthcare companies, specializing in clinical and general pharmaceutical development and clinical andregulatory strategy since February 2015. He co-founded and served as chief medical officer of Civitas Therapeutics, Inc., a biopharmaceutical companyacquired by Acorda Therapeutics, Inc., or Acorda, from December 2010 to October 2014, and as senior vice president, clinical development of90Acorda from October 2014 through January 2015. Dr. Freed spent nearly 14 years at GlaxoSmithKline and its predecessor, SmithKline BeechamPharmaceuticals or SmithKline Beecham, where he served numerous roles including vice president, clinical development and medical affairs in themetabolism therapeutic area. Dr. Freed currently serves on the board of directors of Dicerna Pharmaceuticals, Inc. Dr. Freed has been Board Certified inInternal Medicine, Nephrology and Clinical Pharmacology. He performed his internal medicine residency at Temple University Hospital and nephrologyfellowship at Yale-New Haven Hospital. A Fellow of the American College of Physicians, Dr. Freed received a B.S. with distinction in biology from theUniversity of Delaware and an M.D. from Pennsylvania State University’s College of Medicine. Dr. Freed is qualified to serve on our board of directorsbecause of his extensive leadership experience, his public company board experience and his experience working in the healthcare sector.Robert Huffines has served as a member of our board of directors since December 2013. Mr. Huffines joined J.P. Morgan, a leading global financialservices firm, in 1991 and currently serves as the Global Chairman of Investment Banking, a position he has held since February 2017. Throughout his careerat J.P. Morgan, Mr. Huffines has held various leadership positions, including serving as Co-Head of the Global Healthcare Investment Banking Group from2002 to 2010 and Vice Chairman from 2011 to January 2017. Mr. Huffines received an M.B.A. from the University of Virginia and a B.A. from the Universityof North Carolina. Mr. Huffines is qualified to serve on our board of directors based on his over 25 years of experience advising healthcare companies and hisleadership experience.Adam Koppel, M.D., Ph.D. has served as a member of our board of directors since October 2017. Dr. Koppel rejoined Bain Capital, a global investmentfirm, in 2016 as a Managing Director of Bain Capital Life Sciences. He initially joined Bain Capital Public Equity in 2003 where he was a leader within thehealthcare sector until mid-2014. During the period from mid-2014 to mid-2016, Dr. Koppel worked at Biogen Inc., or Biogen, a biotechnology company,where he served as EVP of Corporate Development and Chief Strategy Officer. Prior to joining Bain Capital in 2003, Dr. Koppel was an Associate Principal atMcKinsey & Co., a management consulting firm, where he served a variety of healthcare companies. Dr. Koppel currently serves on the board of directors ofAptinyx Inc. and Dicerna Pharmaceuticals, Inc., both public biotechnology companies. Previously, Dr. Koppel served of the board of directors of Trevena Inc.and PTC Therapeutics, Inc. Dr. Koppel also serves as a member of the board of directors for a number of private companies. Dr. Koppel received an M.D. andPh.D. in Neuroscience from the University of Pennsylvania School of Medicine. He also received an M.B.A. from The Wharton School at the University ofPennsylvania, where he was a Palmer Scholar. He graduated magna cum laude from Harvard University with an A.B. and A.M. in History and Science.Dr. Koppel is qualified to serve on our board of directors because of his extensive leadership experience, his public company board experience and hisexperience working in the healthcare sector.Sukumar Nagendran, M.D., has served as a member of our board of directors since September 2018. Dr. Nagendran was most recently the ChiefMedical Officer & Senior Vice President of AveXis Inc., a clinical-stage gene therapy company, or AveXis, from September 2015 to July 2018, prior to thecompany’s acquisition by Novartis. Prior to AveXis, Dr. Nagendran was Vice President of Medical Affairs of Quest Diagnostics from March 2013 toSeptember 2015. Prior to Quest Diagnostics, Dr. Nagendran held key leadership positions at Pfizer, Novartis, Daiichi Sankyo, and ReataPharmaceuticals. Prior to moving to the biotech industry, Dr. Nagendran practiced internal medicine, with a focus on diabetes and cardiovascular disease. Heis a Mayo Alumni Laureate and founding member of the Robert Wood Johnson Legacy Society. He is also the sponsor for the Fonseca-Nagendran Scholaraward at the American Diabetes Association to enhance research in minority populations. Dr. Nagendran received his undergraduate degree in Biochemistryfrom Rutgers University and his M.D. from Rutgers Medical School and trained in Internal Medicine at Mayo Clinic, Rochester. Dr. Nagendran is qualifiedto serve on our board of directors because of his extensive leadership experience and his experience working in the healthcare sector.Rajeev Shah has served as a member of our board of directors since March 2017. Mr. Shah is a Managing Director and Portfolio Manager at RACapital Management, LLC, or RA Capital, an investment management company. Prior to joining RA Capital in 2004, Mr. Shah was a Senior Project Leader atAltus Pharmaceuticals Inc., a spin-off of Vertex Pharmaceuticals Inc., from 2001 to 2004. Mr. Shah is currently a member of the board of directors of RaPharmaceuticals, Inc., Kala Pharmaceuticals Inc., Eidos Therapeutics, Inc. and KalVista Pharmaceuticals, Inc., all of which are public biopharmaceuticalcompanies. Mr. Shah also serves as a member of the board of directors for a number of private companies. Mr. Shah holds a B.A. in Chemistry from CornellUniversity. Mr. Shah is qualified to serve on our board of directors because of his extensive leadership experience, his public company board experience andhis experience investing in life science companies.Adam Stone has served as a member of our board of directors since November 2015. Mr. Stone is currently the Chief Investment Officer of PerceptiveAdvisors, a life science focused hedge fund, where he has worked since May 2006.91Mr. Stone received a B.A. from Princeton University. Mr. Stone is qualified to serve on our board of directors because of his extensive experience developingearly-stage biotech and health care companies.Lynne Sullivan has served as a member of our board of directors since November 2015. Ms. Sullivan is currently the Chief Financial Officer forCompass Therapeutics, LLC, a biotechnology company, or Compass, where she has worked since December 2018. Prior to Compass, Ms. Sullivan served asBiogen’s Senior Vice President of Finance from 2016 to December 2018, where she also served as Vice President of Tax and Corporate Finance from February2015 to March 2016 and Vice President of Tax from April 2008 to February 2015. Ms. Sullivan is currently a member of the board of directors of resTORbio,Inc., a public biopharmaceutical company. She received an M.S. in Taxation from Bentley University and a B.S.B.A. from Suffolk University. Ms. Sullivanwas a Certified Public Account for over 20 years. Ms. Sullivan is qualified to serve on our board of directors because of her extensive experience in publicaccounting and financial expertise and her experience working in the healthcare sector.Section 16(a) beneficial ownership reporting complianceSection 16(a) of the Exchange Act requires our directors and executive officers and holders of more than 10% of our common stock to file with theSEC initial reports of ownership and reports of changes in ownership of our common stock and other equity securities. These Section 16 reporting persons arerequired by SEC regulation to furnish us with copies of all Section 16(a) forms they file.Based solely on a review of reports furnished to us, or written representations from reporting persons, we believe all directors, executive officers, and10% owners timely filed all reports regarding transactions in our securities required to be filed for the fiscal year ended December 31, 2018 by Section 16(a)under the Exchange Act, with the exception of a Form 3/A filed by Dr. Zarur on February 1, 2019 to correct the number of shares of common stock that hebeneficially owned indirectly at the time of filing the original Form 3 on January 25, 2018.Audit CommitteeOur board of directors has established an audit committee, which operates under a charter that has been approved by our board of directors and that isavailable on the Investor Relations portion of our website, www.solidbio.com. Our audit committee consists of Ms. Sullivan, Mr. Arnold and Dr. Koppel, withMs. Sullivan serving as chair of the audit committee. Our board of directors has determined that each of these individuals meets the independencerequirements of the Sarbanes-Oxley Act, Rule 10A-3 under the Exchange Act, and the applicable listing standards of Nasdaq. Each member of our auditcommittee can read and understand fundamental financial statements in accordance with Nasdaq audit committee requirements. In arriving at thisdetermination, the board has examined each audit committee member’s employment and other experience. Our board of directors has determined thatMs. Sullivan qualifies as an audit committee financial expert within the meaning of SEC regulations and meets the financial sophistication requirements ofthe Nasdaq listing rules. In making this determination, our board has considered Ms. Sullivan’s formal education and previous and current experience infinancial roles. Both our independent registered public accounting firm and management periodically meet privately with our audit committee.The functions of our audit committee include, among other things: •evaluating the performance, independence and qualifications of our independent auditors and determining whether to retain our existingindependent auditors or engage new independent auditors; •reviewing and approving the engagement of our independent auditors to perform audit services and any permissible non-audit services; •monitoring the rotation of partners of our independent auditors on our engagement team as required by law; •prior to engagement of any independent auditor, and at least annually thereafter, reviewing relationships that may reasonably be thought to bearon their independence, and assessing and otherwise taking the appropriate action to oversee the independence of our independent auditor; •reviewing our annual and quarterly financial statements and reports, including the disclosures contained under the caption “Management’sDiscussion and Analysis of Financial Condition and Results of Operations,” and discussing the statements and reports with our independentauditors and management;92 •reviewing with our independent auditors and management any significant issues that arise regarding accounting principles and financialstatement presentation and matters concerning the scope, adequacy and effectiveness of our financial controls; •reviewing with management and our auditors any earnings announcements and other public announcements regarding material financialdevelopments; •establishing procedures for the receipt, retention and treatment of complaints received by us regarding financial controls, accounting or auditingmatters and other matters; •preparing the audit committee report that the SEC requires in our annual proxy statement; •reviewing and providing oversight of any related-person transactions in accordance with our related-person transaction policy and reviewingand monitoring compliance with legal and regulatory requirements, including our code of business conduct and ethics; •reviewing our major financial risk exposures, including the guidelines and policies to govern the process by which risk assessment and riskmanagement is implemented; •reviewing on a periodic basis our investment policy; and •reviewing and evaluating on an annual basis the performance of the audit committee and the audit committee charter.Our board of directors has determined that the composition and functioning of our audit committee complies with all applicable requirements of theSarbanes-Oxley Act, and all applicable SEC and Nasdaq rules and regulations.Code of business conduct and ethicsWe have adopted a Code of Business Conduct and Ethics, or the Code of Conduct, that applies to our directors, executive officers and employees,including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. TheCode of Conduct is available on the Investor Relations portion of our website, www.solidbio.com. The nominating and corporate governance committee ofour board of directors is responsible for overseeing the Code of Conduct and must approve any waivers of the Code of Conduct for employees, executiveofficers and directors. In addition, we intend to post on our website all disclosures that are required by law or the listing standards of Nasdaq concerning anyamendments to, or waivers of, any provision of the Code of Conduct.Item 11.Executive Compensation.Compensation of our Named Executive OfficersThe following information describes the material elements of compensation awarded to, earned by or paid to each of our named executive officers, orthe Named Executive Officers. The Named Executive Officers for the year ended December 31, 2018 are: •Ilan Ganot, our Chief Executive Officer; •Alvaro Amorrortu, our Chief Operating Officer; and •Carl Morris. Ph.D., our Chief Scientific Officer.93Summary Compensation Table for Fiscal Year 2018The following table contains information about the compensation paid to or earned by each of our Named Executive Officers during the most recentlycompleted fiscal year. Name and Principal Position Year Salary($) Bonus($) (1) Option Awards($) (2) Total ($) Ilan Ganot, President and Chief Executive Officer 2018 450,000 247,500 5,286,270 5,983,770 2017 400,000 200,000 - 600,000 Alvaro Amorrortu, Chief Operating Officer 2018 330,000 132,000 2,380,736 2,842,736 Carl Morris, Ph.D. Chief Scientific Officer 2018 320,000 128,000 3,604,209 4,052,209 (1)Represents annual discretionary bonuses paid to the Named Executive Officers in respect of performance during the fiscal year ended December 31,2018.(2)The amount in this column represents the aggregate grant date fair value of the award as computed in accordance with Financial AccountingStandard Board Accounting Standards Codification Topic 718. The assumptions used in calculating the grant date fair value of the award reported inthis column are set forth in Note 12 to our audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.Narrative to Summary Compensation TableBase Salary. In 2018, we paid our Named Executive Officers base salaries as follows: Mr. Ganot: $450,000; Mr. Amorrortu: $330,000; and Dr. Morris:$320,000. For 2019, our board of directors increased base salary amounts for our Named Executive Officers as follows: Mr. Ganot: $520,000; Mr. Amorrortu:$400,000; and Dr. Morris: $380,000.We use base salaries to recognize the experience, skills, knowledge and responsibilities required of all our employees, including our NamedExecutive Officers. None of our Named Executive Officers is currently party to an employment agreement or other agreement or arrangement that provides forautomatic or scheduled increases in base salary.Annual Bonus. Our board of directors may, in its discretion, award bonuses to our Named Executive Officers from time to time. Our employmentagreements with our Named Executive Officers provide that they will be eligible for annual performance-based bonuses up to a specified percentage of theirsalary, subject to approval by our board of directors. Performance-based bonuses, which are calculated as a percentage of base salary, are designed to motivateour employees to achieve annual goals based on our strategic, financial and operating performance objectives. From time to time, our board of directors hasapproved discretionary annual cash bonuses to our Named Executive Officers with respect to their prior year performance.With respect to 2018, our board of directors awarded discretionary bonuses of $247,500, $132,000 and $128,000 to Mr. Ganot, Mr. Amorrortu andDr. Morris, respectively.Equity Incentives. Although we do not have a formal policy with respect to the grant of equity incentive awards to our executive officers, or anyformal equity ownership guidelines applicable to them, we believe that equity grants provide our executives with a strong link to our long-term performance,create an ownership culture and help to align the interests of our executives and our stockholders. In addition, we believe that equity grants with a time-basedvesting feature promote executive retention because this feature incents our executive officers to remain in our employment during the vesting period.Accordingly, our board of directors periodically reviews the equity incentive compensation of our Named Executive Officers and from time to time may grantequity incentive awards to them in the form of stock options.In February 2018, we granted options to purchase 134,657 and 203,858 shares of our common stock to Mr. Amorrortu and Dr. Morris, respectively,and in July 2018, we granted an option to purchase 193,000 shares of our common stock to Mr. Ganot. These options vest in equal annual installments over aterm of four years from the date of grant. Our employees and executives are eligible to receive stock options and other stock-based awards pursuant to our 2018 Omnibus Incentive Plan, or the2018 Plan.We use stock options to compensate our executive officers in the form of initial grants in connection with the commencement of employment andalso at various times, often but not necessarily annually, if we have performed as94expected or better than expected. None of our executive officers is currently party to an employment agreement that provides for automatic award of stockoptions. We have granted stock options to our executive officers with time-based vesting. The options that we have granted to our executive officerstypically become exercisable as to 25% of the shares underlying the option on the first anniversary of the grant date and as to an additional 25% of theoriginal number of shares underlying the option annually thereafter. Vesting rights cease upon termination of employment and exercise rights cease shortlyafter termination, except that vesting is fully accelerated upon certain terminations in connection with a change of control and exercisability is extended inthe case of death or disability. Prior to the exercise of an option, the holder has no rights as a stockholder with respect to the shares subject to such option,including no voting rights and no right to receive dividends or dividend equivalents.The exercise price of all stock options granted after the closing of our initial public offering is equal to the fair market value of shares of our commonstock on the date of grant, which is determined by reference to the closing market price of our common stock on the date of grant.Employment AgreementsWe have entered into employment agreements with each of our Named Executive Officers. The employment agreements set forth the terms of theNamed Executive Officers’ compensation, including their base salary, and annual performance bonus opportunity. In addition, the employment agreementsprovide that, subject to eligibility requirements under the plan documents governing such programs and our policies, the Named Executive Officers areentitled, on the same basis as our other employees, to participate in and receive benefits under, any medical, vision and dental insurance policy maintainedby us and we will pay, consistent with our then-current employee benefit policy, a portion of the cost of the premiums for any such insurance policy in whichthe Named Executive Officer elects to participate. Each Named Executive Officer will also be eligible to receive paid vacation time, sick time, and Companyholidays consistent with our policies as then in effect from time to time and equity awards at such times and on such terms and conditions as the board ofdirectors may determine. Each Named Executive Officer’s employment is at will.Employment Agreement with Ilan GanotOn January 25, 2019, we entered into an employment agreement with Mr. Ganot, our President and Chief Executive Officer, which employmentagreement amended and restated the terms of his existing agreement (with the exception of the restrictive covenant provisions contained therein).Pursuant to his employment agreement, Mr. Ganot is entitled to an annual base salary of $520,000, effective as of January 1, 2019, which base salarywill be reviewed by the board of directors from time to time and is subject to change in the discretion of the board of directors. Mr. Ganot is also eligible toearn an annual performance bonus, with a target bonus amount equal to up to 55% of his base salary, based upon the board’s assessment of his performanceand the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s), or acombination of cash and equity.Mr. Ganot will remain bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant to therestrictive covenants in his existing employment agreement, which provisions shall remain in full force and effect. Under these restrictive covenants, he hasagreed not to compete with us during his employment and for a period of one year after the termination of his employment (provided that he is not restrictedfrom promoting treatments for, or endeavoring to cure, DMD), not to solicit our employees, consultants, or actual or prospective customers or businessrelations during his employment and for a period of one year after the termination of his employment, and to protect our confidential and proprietaryinformation indefinitely.Mr. Ganot’s employment agreement and his employment may be terminated: (1) upon his death or at our election due to his “disability”; (2) at ourelection, with or without “cause”; and (3) at his election, with or without “good reason” (as such terms are defined in his employment agreement).In the event of the termination of Mr. Ganot’s employment by us without cause, or by Mr. Ganot for good reason, prior to or more than twelve monthsfollowing a “change in control” (as defined in his employment agreement), Mr. Ganot is entitled to receive his base salary that has accrued and to which he isentitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including the terminationdate, unreimbursed business expenses for which expenses he has timely submitted appropriate documentation, and other amounts or benefits to which he isentitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as95the Ganot Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, Mr. Ganot is entitled to (1)continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 12 months and (2) provided he is eligible for andtimely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation of nondiscriminationrequirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive thesame type of coverage, for a period of up to 12 months following his date of termination.In the event of the termination of Mr. Ganot’s employment by us without cause, or by Mr. Ganot for good reason, within twelve months following achange in control, he is entitled to receive the Ganot Accrued Obligations. In addition, subject to his execution and nonrevocation of a release of claims inour favor, he is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 18 months, (2) providedhe is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result in the violation ofnondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employeeswho receive the same type of coverage, for a period of up to 18 months following his date of termination, (3) a lump sum payment equal to 150% of his targetbonus for the year in which his employment is terminated or, if higher, his target bonus immediately prior to the change in control and (4) full vestingacceleration of any then-unvested equity awards that vest based solely based on the passage of time held by Mr. Ganot, such that any such equity awards heldby him become fully exercisable or non-forfeitable as of the termination date.If Mr. Ganot’s employment is terminated for any other reason, including as a result of his death or disability, for cause, or voluntarily by him withoutgood reason, our obligations under the employment agreement cease immediately, and he is only entitled to receive the Ganot Accrued Obligations.Employment Agreement with Alvaro AmorrortuOn January 25, 2019, we entered into an employment agreement with Mr. Amorrortu, our Chief Operating Officer, which employment agreementamended and restated the terms of his existing agreement (with the exception of the restrictive covenant provisions contained therein).Pursuant to his employment agreement, Mr. Amorrortu is entitled to an annual base salary of $400,000, effective as of January 1, 2019, which basesalary will be reviewed by the board of directors from time to time and is subject to change in the discretion of the board of directors. Mr. Amorrortu is alsoeligible to earn an annual performance bonus, with a target bonus amount equal to up to 40% of his base salary, based upon the board’s assessment of hisperformance and the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s),or a combination of cash and equity.Mr. Amorrortu will remain bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant tothe restrictive covenants in his existing employment agreement, which provisions shall remain in full force and effect. Under these restrictive covenants, hehas agreed not to compete with us during his employment and for a period of one year after the termination of his employment, not to solicit our employees,consultants, or actual or prospective customers or business relations during his employment and for a period of one year after the termination of hisemployment, and to protect our confidential and proprietary information indefinitely.Mr. Amorrortu’s employment agreement and his employment may be terminated: (1) upon his death or at our election due to his “disability”; (2) atour election, with or without “cause”; and (3) at his election, with or without “good reason” (as such terms are defined in his employment agreement).In the event of the termination of Mr. Amorrortu’s employment by us without cause, or by Mr. Amorrortu for good reason, prior to or more than twelvemonths following a “change in control” (as defined in his employment agreement), Mr. Amorrortu is entitled to receive his base salary that has accrued and towhich he is entitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including thetermination date, unreimbursed business expenses for which expenses he has timely submitted appropriate documentation, and other amounts or benefits towhich he is entitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as the Amorrortu AccruedObligations. In addition, subject to his execution and nonrevocation of a release of claims in our favor, Mr. Amorrortu is entitled to (1) continued payment ofhis base salary, in accordance with our regular payroll procedures, for a period of 12 months and (2) provided he is eligible for and timely elects to continuereceiving group medical insurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of96applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated, active employees who receive the same type ofcoverage, for a period of up to 12 months following his date of termination. In the event of the termination of Mr. Amorrortu’s employment by us without cause, or by Mr. Amorrortu for good reason, within twelve monthsfollowing a change in control, he is entitled to receive the Amorrortu Accrued Obligations. In addition, subject to his execution and nonrevocation of arelease of claims in our favor, he is entitled to (1) continued payment of his base salary, in accordance with our regular payroll procedures, for a period of 12months, (2) provided he is eligible for and timely elects to continue receiving group medical insurance under COBRA and the payments would not result inthe violation of nondiscrimination requirements of applicable law, payment by us of the portion of health coverage premiums we pay for similarly-situated,active employees who receive the same type of coverage, for a period of up to 12 months following his date of termination, (3) a lump sum payment equal to100% of his target bonus for the year in which his employment is terminated or, if higher, his target bonus immediately prior to the change in control and (4)full vesting acceleration of any then-unvested equity awards that vest based solely based on the passage of time held by Mr. Amorrortu, such that any suchequity awards held by him become fully exercisable or non-forfeitable as of the termination date.If Mr. Amorrortu’s employment is terminated for any other reason, including as a result of his death or disability, for cause, or voluntarily by himwithout good reason, our obligations under the employment agreement cease immediately, and he is only entitled to receive the Amorrortu AccruedObligations.Employment Agreement with Carl MorrisOn January 25, 2019, we entered into an employment agreement with Dr. Morris, our Chief Scientific Officer, which employment agreement amendedand restated the terms of his existing agreement (with the exception of the restrictive covenant provisions contained therein).Pursuant to his employment agreement, Dr. Morris is entitled to an annual base salary of $380,000, effective as of January 1, 2019, which base salarywill be reviewed by the board of directors from time to time and is subject to change in the discretion of the board of directors. Dr. Morris is also eligible toearn an annual performance bonus, with a target bonus amount equal to up to 40% of his base salary, based upon the board’s assessment of his performanceand the Company’s attainment of targeted goals as set by the board in its sole discretion. The bonus may be in the form of cash, equity award(s), or acombination of cash and equity.Dr. Morris will remain bound by proprietary rights, non-disclosure, developments, non-competition and non-solicitation obligations pursuant to therestrictive covenants in his existing employment agreement, which provisions shall remain in full force and effect. Under these restrictive covenants, he hasagreed not to compete with us during his employment and for a period of one year after the termination of his employment, not to solicit our employees,consultants, or actual or prospective customers or business relations during his employment and for a period of one year after the termination of hisemployment, and to protect our confidential and proprietary information indefinitely.Dr. Morris’s employment agreement and his employment may be terminated: (1) upon his death or at our election due to his “disability”; (2) at ourelection, with or without “cause”; and (3) at his election, with or without “good reason” (as such terms are defined in his employment agreement).In the event of the termination of Dr. Morris’s employment by us without cause, or by Dr. Morris for good reason, prior to or more than twelve monthsfollowing a “change in control” (as defined in his employment agreement), Dr. Morris is entitled to receive his base salary that has accrued and to which he isentitled as of the termination date, to the extent consistent with Company policy, accrued but unused paid time off through and including the terminationdate, unreimbursed business expenses for which expenses he has timely submitted appropriate documentation, and other amounts or benefits to which he isentitled in accordance with the terms of the benefit plans then-sponsored by us, which we refer to collectively as the Morris Accrued Obligations. In addition,subject to his execution and nonrevocation of a release of claims in our favor, Dr. Morris is entitled to (1) continued payment of his base salary, in accordancewith our regular payroll procedures, for a period of 12 months and (2) provided he is eligible for and timely elects to continue receiving group medicalinsurance under COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of theportion of health coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 monthsfollowing his date of termination. In the event of the termination of Dr. Morris’s employment by us without cause, or by Dr. Morris for good reason, within twelve months following achange in control, he is entitled to receive the Morris Accrued Obligations. In addition,97subject to his execution and nonrevocation of a release of claims in our favor, he is entitled to (1) continued payment of his base salary, in accordance withour regular payroll procedures, for a period of 12 months, (2) provided he is eligible for and timely elects to continue receiving group medical insuranceunder COBRA and the payments would not result in the violation of nondiscrimination requirements of applicable law, payment by us of the portion ofhealth coverage premiums we pay for similarly-situated, active employees who receive the same type of coverage, for a period of up to 12 months followinghis date of termination, (3) a lump sum payment equal to 100% of his target bonus for the year in which his employment is terminated or, if higher, his targetbonus immediately prior to the change in control and (4) full vesting acceleration of any then-unvested equity awards that vest based solely based on thepassage of time held by Dr. Morris, such that any such equity awards held by him become fully exercisable or non-forfeitable as of the termination date.If Dr. Morris’s employment is terminated for any other reason, including as a result of his death or disability, for cause, or voluntarily by him withoutgood reason, our obligations under the employment agreement cease immediately, and he is only entitled to receive the Morris Accrued Obligations.2018 Outstanding Equity Awards at Fiscal Year-EndThe following table sets forth information regarding equity awards held by our Named Executive Officers as of December 31, 2018. Option Awards Stock Awards Name Number of securitiesunderlying unexercisedoptions (#) exercisable Number of securitiesunderlying unexercisedoptions (#) unexercisable Optionexerciseprice ($) Option expirationdate Numberof shares ofstock thathave notvested (#) Market value ofshares of stockthat have notvested ($) (9) Ilan Ganot - 193,000 (1) 37.89 July 25, 2028 Alvaro Amorrortu - 134,657 (2) 26.23 February 14, 2028 8,824 (3) 236,483 23,760 (4) 636,768 13,243 (5) 354,912 19,268 (6) 516,382 Carl Morris - 203,858 (2) 26.23 February 14, 2028 17,280 (7) 463,104 26,514 (8) 710,575 (1)This option was granted on July 25, 2018 under the 2018 Plan and is subject to vesting in equal annual installments over four years from the vestingstart date through and including July 25, 2022.(2)This option was granted on February 14, 2018 under the 2018 Plan and is subject to vesting in equal annual installments over four years from thevesting start date through and including February 14, 2022.(3)Consists of restricted stock awards granted under our Solid Biosciences, LLC Amended and Restated Equity Incentive Plan. The grant was made onNovember 30, 2015, vested as to 25% on the first anniversary of the vesting start date and is subject to equal monthly vesting installments thereafterthrough and including November 30, 2019.(4)Consists of restricted stock awards granted pursuant to the Solid GT, LLC limited liability agreement adopted by the members of such company. Thegrant was made on November 30, 2015, vested as to 25% on the first anniversary of the vesting start date and is subject to equal monthly vestinginstallments thereafter through and including November 30, 2019.(5)Consists of restricted stock awards granted under our Solid Biosciences, LLC Amended and Restated Equity Incentive Plan. The grant was made onSeptember 12, 2017, vested as to 25% on the first anniversary of the vesting start date and is subject to equal monthly vesting installments thereafterthrough and including September 12, 2021.(6)Consists of restricted stock awards granted under our Solid Biosciences, LLC Amended and Restated Equity Incentive Plan. The grant was made onDecember 17, 2017, vested as to 25% on the first anniversary of the vesting start date and is subject to equal monthly vesting installments thereafterthrough and including January 30, 2022.(7)Consists of restricted stock awards granted under our Solid Biosciences, LLC Amended and Restated Equity Incentive Plan. The grant was made onSeptember 1, 2015 and is subject to vesting in equal annual installments over four years from the vesting start date through and including September1, 2019.(8)Consists of restricted stock awards granted under our Solid Biosciences, LLC Amended and Restated Equity Incentive Plan. The grant was made onMarch 30, 2017, vested as to 25% on the first anniversary of the vesting start date and is subject to equal semi-annual vesting installments thereafterthrough and including March 30, 2021.(9)Calculated based on the closing market price of our common stock on December 31, 2018.98On January 23, 2019, we granted a stock option to Mr. Ganot for the right to buy 155,000 shares of our common stock, a stock option toMr. Amorrortu for the right to buy 60,000 shares of our common stock and a stock option to Dr. Morris for the right to buy 60,000 shares of our commonstock. The options have an exercise price of $22.93 per share, vest in four equal installments beginning on January 23, 2020 and expire on January 23, 2029.Equity Incentive PlansSolid Biosciences, LLC Amended and Restated Equity Incentive PlanPrior to the closing of our initial public offering, Solid Biosciences, LLC maintained its Amended and Restated Equity Incentive Plan, or the ExistingPlan, under which Solid Biosciences, LLC granted Series D Common Units to its employees, consultants and other service providers. The Existing Plan wasfrozen in connection with our initial public offering. No further awards will be granted under the Existing Plan, but awards granted prior to the freeze datewill continue in accordance with their terms and the terms of the Existing Plan.2018 Omnibus Incentive PlanPrior to our initial public offering, the board of managers of Solid Biosciences, LLC adopted the Solid Biosciences Inc. 2018 Omnibus Incentive Plan,or 2018 Plan, contingent upon the consummation of our initial public offering. The unitholders of Solid Biosciences, LLC approved the 2018 Plancontingent upon the consummation of our initial public offering.The material terms of the 2018 Plan are summarized below. The following summary is qualified in its entirety by reference to the complete text of the2018 Plan, a copy of which was filed as Exhibit 99.1 to our registration statement on Form S-8 filed with the SEC on January 29, 2018, and is incorporatedherein by reference.Administration of the planThe board of managers of Solid Biosciences, LLC appointed the compensation committee of our board of directors as the committee under the 2018Plan with the authority to administer the 2018 Plan. We refer to our board of directors or compensation committee, as applicable, as the Administrator. TheAdministrator is authorized to grant awards to eligible employees, consultants and non-employee directors.Number of authorized shares and award limitsThe aggregate number of our shares of common stock that may be issued or used for reference purposes under the 2018 Plan may not exceed5,001,000 shares (subject to adjustment as described below). Our shares of common stock that are subject to awards will be counted against the overall limitas one share for every share granted or covered by an award. If any award is cancelled, expires or terminates unexercised for any reason, the shares covered bysuch award will again be available for the grant of awards under the 2018 Plan, except that any shares that are not issued as the result of a net exercise orsettlement or that are used to pay any exercise price or tax withholding obligation will not be available for the grant of awards. Shares of common stock thatwe repurchase on the open market with the proceeds of an option exercise price also will not be available for the grant of awards. Awards that may be settledsolely in cash will not be deemed to use any shares.The maximum number of our shares of common stock that may be granted pursuant to awards under the 2018 Plan during any fiscal year to any non-employee director is 1,000,200 shares. The foregoing individual participant limit is cumulative; that is, to the extent that shares of common stock that may begranted to an individual in a fiscal year are not granted, the number of shares of common stock that may be granted to such individual is increased in thesubsequent fiscal years during the term of the 2018 Plan until used.The Administrator will, in accordance with the terms of the 2018 Plan, make appropriate adjustments to the above aggregate and individual limits(other than cash limitations), to the number and/or kind of shares or other property (including cash) underlying awards and to the purchase price of sharesunderlying awards, in each case, to reflect any change in our capital structure or business by reason of any stock split, reverse stock split, stock dividend,combination or reclassification of shares, any recapitalization, merger, consolidation, spin off, split off, reorganization or any partial or complete liquidation,any sale or transfer of all or part of our assets or business, or any other corporate transaction or event that would be considered an “equity restructuring”within the meaning of Financial Accounting Standards Board Accounting Standards Codification Topic 718. In addition, the Administrator may take similaraction with respect to other extraordinary events.99Eligibility and participationAll of our current and prospective employees and consultants, as well as our non-employee directors, are eligible to be granted non-qualified stockoptions, restricted stock, performance-based cash awards and other stock-based awards under the 2018 Plan. Only our and our subsidiaries’ employees areeligible to be granted incentive stock options, or ISOs, under the 2018 Plan. Eligibility for awards under the 2018 Plan is determined by the Administrator inits discretion. In addition, each member of our board of directors who is not an employee of the company or any of our affiliates is expected to be eligible toreceive awards under the 2018 Plan.Types of awardsStock options. The 2018 Plan authorizes the Administrator to grant ISOs to eligible employees and non-qualified stock options to purchase shares toemployees, consultants, prospective employees, prospective consultants and non-employee directors. The Administrator will determine the number of sharesof common stock subject to each option, the term of each option, the exercise price (which may not be less than the fair market value of the shares of commonstock at the time of grant, or 110% of fair market value in the case of ISOs granted to 10% stockholders), the vesting schedule and the other terms andconditions of each option. Options will be exercisable at such times and subject to such terms as are determined by the Administrator at the time of grant. Themaximum term of options under the 2018 Plan is ten years (or five years in the case of ISOs granted to 10% stockholders). Upon the exercise of an option, theparticipant must make payment of the full exercise price (a) in cash or by check, bank draft or money order; (b) solely to the extent permitted by law andauthorized by the Administrator, through the delivery of irrevocable instructions to a broker, reasonably acceptable to us, to promptly deliver to us anamount equal to the aggregate exercise price; or (c) on such other terms and conditions as may be acceptable to the Administrator (including, withoutlimitation, the relinquishment of options or by payment in full or in part in the form of shares of common stock).Restricted stock. The 2018 Plan authorizes the Administrator to grant restricted stock. Recipients of restricted stock will be required to enter into anagreement with us subjecting the restricted stock to transfer and other restrictions and providing the criteria or dates on which such awards vest and suchrestrictions lapse. The restrictions on restricted stock may lapse and the awards may vest over time, based on performance criteria or other factors, asdetermined by the Administrator at the time of grant. Except as otherwise determined by the Administrator, a holder of restricted stock has all of the attendantrights of a stockholder including the right to receive dividends, if any, subject to and conditioned upon vesting and restrictions lapsing on the underlyingrestricted stock, the right to vote shares and, subject to and conditioned upon the vesting and restrictions lapsing for the underlying shares, the right to tendersuch shares. However, the Administrator may in its discretion provide at the time of grant that the right to receive dividends on restricted stock will not besubject to the vesting or lapsing of the restrictions on the restricted stock.Other stock-based awards. The 2018 Plan authorizes the Administrator to grant awards of shares of common stock and other awards that are valued inwhole or in part by reference to, or are payable in or otherwise based on, shares of common stock, including, but not limited to, shares of common stockawarded purely as a bonus and not subject to any restrictions or conditions; shares of common stock in payment of the amounts due under an incentive orperformance plan sponsored or maintained by us or an affiliate; stock appreciation rights; stock equivalent units; restricted stock units; performance awardsentitling participants to receive a number of shares of common stock (or cash in an equivalent value) or a fixed dollar amount, payable in cash, stock or acombination of both, with respect to a designated performance period; or awards valued by reference to book value of our shares of common stock. In general,other stock-based awards that are denominated in shares of common stock will include the right to receive dividends, if any, subject to and conditioned uponvesting and restrictions lapsing on the underlying award, but the Administrator may in its discretion provide at the time of grant that the right to receivedividends on a stock-denominated award will not be subject to the vesting or lapsing of the restrictions on the performance award.Performance-based cash awards. The 2018 Plan authorizes the Administrator to grant cash awards that are payable or otherwise based on theattainment of pre-established performance goals during a performance period. These performance goals will be based on the attainment of a certain targetlevel of, or a specified increase in (or decrease where noted), criteria selected by the Administrator.Such performance goals may be based upon the attainment of specified levels of company, affiliate, subsidiary, division, other operational unit,business segment or administrative department performance relative to the performance of other companies. The Administrator may designate additionalbusiness criteria on which the performance goals may be based or adjust, modify or amend those criteria. Unless the Administrator determines otherwise, theAdministrator will disregard and exclude the impact of special, unusual or non-recurring items, events, occurrences or circumstances; discontinued100operations or the disposal of a business; the operations of any business that we acquire during the fiscal year or other applicable performance period; or achange in accounting standards required by generally accepted accounting principles or changes in applicable law or regulations.Effect of certain transactions; Change in controlIn the event of a change in control, as defined in the 2018 Plan, except as otherwise provided by the Administrator, unvested awards will not vest.Instead, the Administrator may, in its sole discretion, provide that outstanding awards will be: assumed and continued; purchased based on the price per sharepaid in the change in control transaction (less, in the case of options and stock appreciation rights, or SARs, the exercise price), as adjusted by theAdministrator for any contingent purchase price, escrow obligations, indemnification obligations or other adjustments to the purchase price; and/or in thecase of stock options or other stock-based appreciation awards where the change in control price is less than the applicable exercise price, cancelled.However, the Administrator may in its sole discretion provide for the acceleration of vesting and lapse of restrictions of an award at any time including inconnection with a change in control.Non-transferability of awardsExcept as the Administrator may permit, at the time of grant or thereafter, awards granted under the 2018 Plan are generally not transferable by aparticipant other than by will or the laws of descent and distribution. Shares of common stock acquired by a permissible transferee will continue to be subjectto the terms of the 2018 Plan and the applicable award agreement.TermAwards under the 2018 Plan may not be made after December 18, 2027, but awards granted prior to such date may extend beyond that date.Amendment and terminationSubject to the rules referred to in the balance of this paragraph, our board of directors or the Administrator (to the extent permitted by law) may at anytime amend, in whole or in part, any or all of the provisions of the 2018 Plan, or suspend or terminate it entirely, retroactively or otherwise. Except as requiredto comply with applicable law, no such amendment, suspension or termination may reduce the rights of a participant with respect to awards previouslygranted without the consent of such participant. In addition, without the approval of stockholders, no amendment may be made that would: increase theaggregate number of shares of common stock that may be issued under the 2018 Plan; increase the maximum individual participant share limitations for afiscal year or year of a performance period; change the classification of individuals eligible to receive awards under the 2018 Plan; extend the maximum termof any option; reduce the exercise price of any option or SAR or cancel any outstanding “in-the-money” option or SAR in exchange for cash; substitute anyoption or SAR in exchange for an option or SAR (or similar other award) with a lower exercise price; alter the performance goals; or require stockholderapproval in order for the 2018 Plan to continue to comply with Section 162(m) or Section 422 of the Internal Revenue Code of 1986, as amended, or theCode.Registration of sharesOn January 29, 2018, we filed a registration statement on Form S-8 under the Securities Act of 1933, as amended, or the Securities Act, to register thefull number of shares of common stock that will be available for issuance under the 2018 Plan, as described in the section titled “Number of authorized sharesand award limits” above.Non-employee director compensationDuring 2018, we did not provide any compensation to Mr. Ganot, our President and Chief Executive Officer, for his service as a member of our board.Mr. Ganot’s compensation as an executive officer is set forth above under “Executive Compensation-2018 Summary Compensation Table.”Non-employee director compensation is set by our board of directors at the recommendation of our compensation committee. In 2018, thecompensation committee retained Radford, an AON Hewitt company, to assist in assessing our non-employee director compensation program and providerecommendations in order to establish the compensation program.101Under our current director compensation program, we pay our non-employee directors a cash retainer for their service on the board of directors and fortheir service on each committee of which the director is a member. The chairs of each committee receive higher retainers for such service. These fees arepayable in arrears in equal semi-annual installments not later than the 15th business day following the end of the second and fourth calendar quarters,provided that the amount of such payment will be prorated for any portion of such semi-annual period that the director is not serving on the board, on suchcommittee or in such position, and no fee shall be payable in respect of any period prior to the completion of our initial public offering. The fees paid to non-employee directors for their service on the board of directors and for their service on each committee of the board of directors of which the director is amember are as follows: Committee Member AnnualFee ChairpersonIncremental AnnualFee Board of Directors $35,000 $35,000 Audit Committee 7,500 7,500 Clinical Committee 7,500 7,500 Compensation Committee 5,000 5,000 Nominating and Governance Committee 4,000 4,000 In his role as chairman of the board, Dr. Zarur was paid cash compensation for fiscal year 2018 in the amount of $225,000 and, pursuant to our directorcompensation program described above, will be paid cash compensation of $70,000 in the aggregate annually starting in fiscal year 2019. The compensationarrangements we have with Dr. Zarur for his services to us as a consultant are described below in Item 13, “Certain Relationships and Related Transactions,and Director Independence – Other arrangements.”We also reimburse our non-employee directors for reasonable out-of-pocket business expenses incurred in connection with the performance of theirduties as directors, including travel expenses in connection with their attendance in person at our board of director and committee meetings.In addition, under our current director compensation program, each new non-employee director elected to our board of directors receives an option topurchase 20,000 shares of our common stock under our 2018 Plan. Each of these options vest in equal annual installments over a three-year period measuredfrom the date of grant, subject to the director’s continued service as a director. Further, on the date of our annual meeting of stockholders, each non-employeedirector that has served on our board of directors for at least six months prior to such annual meeting receives an option to purchase 10,000 shares of ourcommon stock under our 2018 Plan. Each of these options vest in full on the earlier to occur of the one-year anniversary of the grant date and immediatelyprior to our first annual meeting of stockholders occurring after the grant date, subject to the director’s continued service as a director. All options granted toour non-employee directors under our director compensation program will be issued at exercise prices equal to the fair market value of our common stock onthe date of grant and will become exercisable in full in the event of a change in control.This program is intended to provide compensation for our non-employee directors in a manner that enables us to attract and retain outstandingdirector candidates and reflects the substantial time commitment necessary to oversee our affairs. We also seek to align the interests of our directors and ourstockholders, and we have chosen to do so by compensating our non-employee directors with a mix of cash and equity-based compensation.102The table below shows the compensation paid to our non-employee directors during 2018. Name FeesEarned orPaid inCash ($) OptionAwards($) (1)(2) All OtherCompensation($) Total ($) Andrey Zarur, Ph.D. 225,000 165,200 (3) - 390,200 Gilad Hayeem (4) - - - - Matthew Arnold 37,752 183,385 (5) - 221,137 Martin Freed, M.D., F.A.C.P. 21,403 377,020 (6) - 398,423 Robert Huffines 32,219 183,385 (5) - 215,604 Adam Koppel, M.D., Ph.D. 48,719 183,385 (5) - 232,104 Sukumar Nagendran, M.D. 11,034 393,461 (7) - 404,495 Rajeev Shah 39,760 183,385 (5) - 223,145 Adam Stone 44,186 183,385 (5) - 227,571 Lynne Sullivan 49,710 183,385 (5) - 233,095 (1)The amount in this column represents the aggregate grant date fair value of the award as computed in accordance with Financial AccountingStandard Board Accounting Standards Codification Topic 718. The assumptions used in calculating the grant date fair value of the award reported inthis column are set forth in Note 12 to our audited consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K.(2)As of December 31, 2018, our non-employee directors, or former directors in the case of Mr. Hayeem, held options to purchase shares of our commonstock as follows: Dr. Zarur: 10,000 shares; Mr. Arnold: 10,000 shares; Dr. Freed: 20,000 shares; Mr. Huffines: 10,000 shares; Dr. Koppel: 10,000shares; Mr. Hayeem: 0 shares; Dr. Nagendran: 20,000 shares; Mr. Shah: 10,000 shares; Mr. Stone: 10,000 shares; and Ms. Sullivan: 10,000 shares. Asof December 31, 2018, our non-employee directors, or former directors in the case of Mr. Hayeem, held stock awards as follows: Dr. Zarur: 709,924shares, including shares held directly and indirectly and Mr. Hayeem: 3,542,746 shares.(3)Consists of an option to purchase 10,000 shares of our common stock granted on December 13, 2018.(4)Mr. Hayeem resigned from his roles as president and as a member of our board in June 2018.(5)Consists of (i) an option to purchase 1,835 shares of our common stock granted on July 25, 2018 and (ii) an option to purchase 8,165 shares of ourcommon stock granted on December 13, 2018.(6)Consists of (i) an option to purchase 3,669 shares of our common stock granted on July 25, 2018 and (ii) an option to purchase 16,331 shares of ourcommon stock granted on December 13, 2018.(7)Consists of (i) an option to purchase 2,760 shares of our common stock granted on September 12, 2018 and (ii) an option to purchase 17,240 shares ofour common stock granted on December 13, 2018.Compensation committee interlocks and insider participationNone of the current members of our compensation committee has ever been an executive officer or employee of ours. None of our executive officerscurrently serves, or has served during the last completed fiscal year, on the compensation committee or board of directors of any other entity that has one ormore executive officers serving as a member of our board of directors or compensation committee.Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.Security Ownership of Certain Beneficial Owners and ManagementThe following table sets forth information regarding the beneficial ownership of our common stock as of February 15, 2019 by (i) each person whomwe know to beneficially own more than 5% of our outstanding common stock (a “5% stockholder”), (ii) each director, (iii) each Named Executive Officer and(iv) all current directors and executive officers as a group. Unless otherwise indicated, the address of each executive officer and director is c/o SolidBiosciences, 141 Portland Street, Fifth Floor, Cambridge, MA 02139.The number of shares of common stock “beneficially owned” by each stockholder is determined under rules issued by the SEC regarding thebeneficial ownership of securities. This information is not necessarily indicative of beneficial ownership for any other purpose. Under these rules, beneficialownership of shares of our common stock includes (1) any shares as to which the person or entity has sole or shared voting power or investment power and(2) any shares as to which the person or entity has the right to acquire beneficial ownership within 60 days after February 15, 2019. The percentage ofbeneficial ownership in the table below is based on 35,422,915 shares of common stock deemed to be outstanding as of February 15, 2019.103Unless otherwise indicated below, and subject to community property laws where applicable, to our knowledge, all persons named in the table havesole voting and investment power with respect to their shares of common stock. Name of Beneficial Owner Number ofSharesBeneficiallyOwned Percentage ofSharesBeneficiallyOwned 5% Stockholders: Perceptive Life Sciences Master Fund LTD (1) 3,927,222 11.09%Gilad Hayeem (2) 3,542,746 10.00%Boxer Capital, LLC (3) 3,498,272 9.88%Entities affiliated with RA Capital Management, LLC (4) 2,689,444 7.59%BCLS SB Investco, LP (5) 1,989,444 5.62%Biogen New Ventures Inc. (6) 1,772,464 5.00%Named Executive Officers and Directors: Ilan Ganot (7) 1,393,040 3.93%Alvaro Amorrortu (8) 187,410 * Carl Morris, Ph.D. (9) 162,509 * Andrey Zarur, Ph.D. (10) 709,294 2.00%Matthew Arnold 3,386,293 9.56%Martin Freed, M.D., F.A.C.P. - * Robert Huffines - * Adam Koppel, M.D., Ph.D. (11) 1,989,444 5.62%Sukumar Nagendran, M.D. 2,000 * Rajeev Shah (4) 2,689,444 7.59%Adam Stone (12) - * Lynne Sullivan - * All current directors and executive officers as a group (16 persons) (13) 11,096,779 31.20% *Less than one percent.(1)Consists of shares held by Perceptive Life Sciences Master Fund LTD, or the Master Fund. Perceptive Advisors LLC is the investment manager toMaster Fund and may be deemed to beneficially own the securities directly held by the Master Fund. Joseph Edelman is the managing member ofPerceptive Advisors LLC. Perceptive Advisors LLC and Mr. Edelman may be deemed to beneficially own the shares held by the Master Fund. Theaddress of Perceptive is 51 Astor Place, 10th Floor, New York, NY 10003. Perceptive reports that it holds shared voting power and shared dispositivepower with respect to all shares held by it. Based on information set forth in a Schedule 13G filed with the SEC on February 14, 2019.(2)All shares are held by DTMG Limited (“DTMG”), which is owned and controlled by Gilad Hayeem. Mr. Hayeem and DTMG report that they holdshared voting power and shared dispositive power with respect to all shares held. The address for Mr. Hayeem and DTMG is c/o Hunton AndrewsKurth LLP, Attn: Eric Markus, 2200 Pennsylvania Avenue, NW, Washington, DC 20037. In connection with estate planning activities, Mr. Hayeemsold units of the Company equivalent to approximately 353,050 shares to a sub-trust of an employee-benefit trust established by a former employer ofMr. Hayeem. Such sub-trust has as its beneficiaries Mr. Hayeem and his family. Because Mr. Hayeem does not exercise investment or voting control ofthe shares held by such sub-trust, such shares do not appear in the table above. Based on information set forth in a Schedule 13G filed with the SECon February 14, 2019 and on information provided to us by Mr. Hayeem(3)Boxer Capital LLC and Boxer Management Inc. beneficially own 3,498,272 shares, and they report that they hold shared voting power and shareddispositive power with respect to these shares. Braslyn Ltd beneficially owns 11,488 shares and reports that it holds shared voting power and shareddispositive power with respect to these shares. Joe Lewis beneficially owns 3,509,760 shares and reports that he holds shared voting power and shareddispositive power with respect to these shares. MVA Investors, LLC beneficially owns 30,210 shares and reports that it holds sole voting power andsole dispositive power with respect to these shares. Braslyn, Boxer Capital, Boxer Management, Joe Lewis and MVA Investors may be deemed tobeneficially own 3,539,970 shares. The address of Boxer Capital LLC and MVA Investors, LLC is 11682 El Camino Real, Suite 320, San Diego, CA92130. The address of Boxer Management, Braslyn and Joe Lewis is Cay House, EP Taylor Drive N7776, Lyford Cay, New Providence, Bahamas.Based on information set forth in a Schedule 13G filed with the SEC on February 14, 2019.104(4)Consists of (a) 1,368,981 shares held by RA Capital Healthcare Fund, L.P. (“RA Capital Fund”), (b) 320,463 shares held by Blackwell Partners LLC—Series A (“Blackwell”) and (c) 1,000,000 shares that RA Capital Fund and Blackwell purchased in connection with the closing of our initial publicoffering. RA Capital Management, LLC (“RA Capital”) is the general partner of RA Capital Fund and the investment manager to Blackwell.Investment decisions with respect to the shares held by RA Capital Fund and Blackwell are made by a portfolio management team at RA Capital ofwhich Rajeev Shah, a member of our board of directors, is a member. Mr. Shah disclaims beneficial ownership of all shares held by RA Capital Fundand Blackwell, except to the extent of his pecuniary interest therein. The address for each of RA Capital Fund, Blackwell, and RA Capital is c/o 20Park Plaza, Suite 1200, Boston, MA 02116. Entities affiliated with RA Capital report that they hold shared voting power and shared dispositive powerwith respect to all shares held by them.(5)Consists of shares held by BCLS SB Investco, LP (“BCLS”),. The governance, investment strategy and decision-making process with respect toinvestments held by BCLS is directed by Bain Capital Life Sciences Investors, LLC, whose managers are Jeffrey Schwartz and Adam Koppel, amember of our board of directors. As a result, each of Bain Capital Life Sciences Investors, LLC, Mr. Schwartz and Dr. Koppel may be deemed to sharevoting and dispositive power over the shares held by BCLS. The address of BCLS is c/o Bain Capital Life Sciences, LP, 200 Clarendon Street,Boston, Massachusetts 02116.(6)Consists of shares held by Biogen New Ventures Inc. and Biogen Inc. The address of Biogen New Ventures Inc. and Biogen Inc. is 225 Binney Street,Cambridge, MA 02142. Biogen New Ventures Inc. and Biogen Inc. report that they hold shared voting power and shared dispositive power withrespect to all shares held. Based on information set forth in a Schedule 13G filed with the SEC on February 14, 2019.(7)Consists of (a) 1,041,495 shares held by Mr. Ganot as an individual, (b) 60,631 shares held by Mr. Ganot and Ms. Ganot as joint tenants with right ofsurvivorship and (c) 290,914 shares held by Mr. Adam Ganot and Ms. Ganot, as trustees for the Ilan Ganot 2017 Irrevocable Trust.(8)Consists of (a) 167,046 shares of common stock owned by Mr. Amorrortu and (b) 33,664 shares of common stock underlying options held by Mr.Amorrortu that are exercisable as of February 15, 2019 or will become exercisable within 60 days after such date.(9)Consists of (a) 111,545 shares of common stock owned by Dr. Morris and (b) 50,964 shares of common stock underlying options held by Dr. Morristhat are exercisable as of February 15, 2019 or will become exercisable within 60 days after such date.(10)Consists of (a) 691,105 shares held by Mr. Zarur as an individual and (b) 18,189 shares held by Mr. Zarur’s wife.(11)Consists of shares held by BCLS. Dr. Koppel is a manager of Bain Capital Life Sciences Investors, LLC and as a result, by virtue of the relationshipsdescribed in footnote (5) above, may be deemed to share beneficial ownership of the shares held by BCLS. The address of Dr. Koppel is c/o BainCapital Life Sciences, LP, 200 Clarendon Street, Boston, Massachusetts 02116.(12)Mr. Stone is Chief Investment Officer of Perceptive Advisors LLC. Mr. Stone disclaims beneficial ownership of the shares held by Perceptive. Theaddress of Mr. Stone is 51 Astor Place, 10th Floor, New York, NY 10003.(13)Includes 139,525 shares of common stock underlying options that are exercisable as of February 15, 2019 or will become exercisable within 60 daysafter such date.Securities Authorized for Issuance under Equity Compensation PlansThe following table provides information about our equity compensation plans as of December 31, 2018. Plan Category (a)Number ofsecuritiesto be issued uponthe exercise ofoutstandingoptions,warrants andrights (b)Weighted-averageexercise priceof outstandingoptions,warrantsand rights (c)Number of securitiesremaining availablefor future issuanceunder equitycompensation plans(excluding securitiesreflected in column(a)) Equity compensation plans approved by security holders 1,153,198 $28.73 3,847,802 Equity compensation plans not approved by security holders - - - Total 1,153,198 $28.73 3,847,802 105Item 13.Certain Relationships and Related Transactions, and Director Independence.In addition to the executive officer and director compensation arrangements discussed above under “Compensation of our executive officers anddirectors,” we describe transactions since January 1, 2018 to which we have been or will be a participant, in which the amount involved in the transactionexceeds or will exceed $120,000 and in which any of our directors, executive officers or beneficial holders of more than 5% of any class of our capital stock,or 5% Security Holders, or any immediate family member of, or person sharing the household with, any of these individuals, had or will have a direct orindirect material interest.Limited liability company agreement of Solid Biosciences, LLCSolid Biosciences, LLC was party to a limited liability company agreement, or the LLC Agreement with its members that terminated upon theCorporate Conversion. Under the terms of the LLC Agreement, Series A Common Unit holders were entitled to designate two individuals to serve on ourboard of managers. Pursuant to this provision, the two board appointees were Mssrs. Arnold and Huffines. Mr. Huffines is an employee of J.P. MorganSecurities LLC, a participating underwriter in our initial public offering. An affiliate of J.P. Morgan Securities LLC owned in excess of 10% of our issued andoutstanding common stock immediately prior to our initial public offering. See “Underwriting—Conflicts of Interest” in our prospectus filed with the SECfiled on January 29, 2018 for a description of services that the underwriters provided to us in connection with our initial public offering.Corporate conversionIn connection with our Corporate Conversion, Solid Biosciences, LLC unitholders received 26,498,559 shares of common stock for all units heldimmediately prior to the Corporate Conversion. The existing units held by our executive officers, directors and 5% Security Holders were converted on thesame basis as all other holders of such units.As result of the Corporate Conversion, the holders of Series A Common Units of Solid Biosciences, LLC became holders of shares of our commonstock.Amended and restated registration rights agreementWe are party to an Amended and Restated Registration Rights Agreement, or the Registration Rights Agreement, dated March 29, 2017, with certainof our stockholders, or the Investors, which includes our 5% Security Holders and entities affiliated with certain of our directors. The Registration RightsAgreement provides the Investors the right, subject to certain conditions, to demand that we file a registration statement or to request that their shares becovered by a registration statement that we are otherwise filing.Participation in initial public offeringIn our initial public offering, certain of our 5% stockholders and their affiliates purchased an aggregate of 2,300,000 shares of our common stock.Each of those purchases was made through the underwriters at the initial public offering price of $16.00 per share. The following table sets forth the aggregatenumber of shares of our common stock that these 5% stockholders and their affiliates purchased in our initial public offering: Purchaser (1) Shares ofcommon stock Totalpurchase price RA Capital Management LLC 1,000,000 $16,000,000 Perceptive Advisors LLC 1,000,000 $16,000,000 BCLS SB Investco, LP 300,000 $4,800,000 (1)See “Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters” for more information about theshares held by the below identified entities.Other arrangementsWe employ Annie Ganot, one of our Co-Founders and the wife of Ilan Ganot, as Director, Patient Advocacy. Mr. Ganot is our CEO and a member ofour board of directors. Ms. Ganot receives an annual salary and bonus payments of less than $200,000.106In respect of his services as a consultant to us for the three years ended December 31, 2018, on January 2, 2019, we granted Dr. Zarur an option topurchase 100,000 shares of our common stock. In respect of his services as a consultant to us for the year ending December 31, 2019, (i) on January 2, 2019,we granted Dr. Zarur an option to purchase 10,000 shares of our common stock, and (ii) we will pay him $100,000.Indemnification agreementsWe entered into agreements to indemnify our directors and executive officers in connection with our initial public offering. These agreements requireus, among other things, to indemnify these individuals for certain expenses (including attorneys’ fees), judgments, fines and settlement amounts reasonablyincurred by such persons in any action or proceeding, including any action by or in our right, on account of any services undertaken by any such person onbehalf of our company or that person’s status as a member of our board of directors to the maximum extent allowed under Delaware law.Policy for approval of related-person transactionsWe have adopted a written related-person transaction policy that sets forth our procedures for the identification, review, consideration and approval orratification of any transaction, arrangement or relationship in which we are a participant, the amount involved exceeds $120,000 and one of our executiveofficers, directors, director nominees or 5% stockholders (or their immediate family members), each of whom we refer to as a “related person,” has a direct orindirect material interest.If a related person proposes to enter into such a transaction, arrangement or relationship, which we refer to as a “related-person transaction,” therelated person must report the proposed related-person transaction to our general counsel. The policy calls for the proposed related-person transaction to bereviewed by and if deemed appropriate approved by, the audit committee of our board of directors. Whenever practicable, the reporting, review and approvalwill occur prior to entry into the transaction. If advance review and approval is not practicable, the audit committee will review and, in its discretion, mayratify the related-person transaction. The policy also permits the chair of the audit committee to review, and if deemed appropriate approve, proposed related-person transactions that arise between audit committee meetings, subject to ratification by the audit committee at its next meeting. Any related-persontransactions that are ongoing in nature will be reviewed annually.A related-person transaction reviewed under the policy will be considered approved or ratified if it is authorized by the audit committee after fulldisclosure of the related person’s interest in the transaction. As appropriate for the circumstances, the committee will review and consider: •the related person’s interest in the related-person transaction; •the approximate dollar amount involved in the related-person transaction; •the approximate dollar amount of the related person’s interest in the transaction without regard to the amount of any profit or loss; •whether the transaction was undertaken in the ordinary course of our business; •whether the terms of the transaction are no less favorable to us than terms that could have been reached with an unrelated third party; •the purpose of, and the potential benefits to us of, the related-person transaction; and •any other information regarding the related-person transaction or the related person in the context of the proposed transaction that would bematerial to investors in light of the circumstances of the particular transaction.The audit committee may approve or ratify the transaction only if the audit committee determines that, under all of the circumstances, the transactionis not inconsistent with our best interests. The audit committee may impose any conditions on the related-person transaction that it deems appropriate.The policy provides that transactions involving compensation of executive officers will be reviewed and approved by the compensation committee ofour board of directors in the manner specified in its charter.107Director independenceApplicable Nasdaq rules require a majority of a listed company’s board of directors to be comprised of independent directors within one year oflisting. In addition, Nasdaq rules require that, subject to specified exceptions, each member of a listed company’s audit, compensation and nominating andcorporate governance committees be independent under the Exchange Act. Audit committee members also satisfy independence criteria set forth inRule 10A-3 under the Exchange Act and compensation committee members must also satisfy the independence criteria set forth in Rule 10C-1 under theExchange Act. The Nasdaq independence definition includes a series of objective tests, such as that the director is not, and has not been for at least threeyears, one of our employees and that neither the director nor any of his or her family members has engaged in various types of business dealings with us. Inaddition, under applicable Nasdaq rules, a director will only qualify as an “independent director” if, in the opinion of the listed company’s board of directors,that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. Inorder to be considered independent for purposes of Rule 10A-3, a member of an audit committee of a listed company may not, other than in his or hercapacity as a member of the audit committee, the board of directors, or any other board committee, accept, directly or indirectly, any consulting, advisory, orother compensatory fee from the listed company or any of its subsidiaries or otherwise be an affiliated person of the listed company or any of its subsidiaries.In order to be considered independent for purposes of Rule 10C-1, the board must consider, for each member of a compensation committee of a listedcompany, all factors specifically relevant to determining whether a director has a relationship to such company which is material to that director’s ability tobe independent from management in connection with the duties of a compensation committee member, including, but not limited to: (1) the source ofcompensation of the director, including any consulting advisory or other compensatory fee paid by such company to the director; and (2) whether thedirector is affiliated with the company or any of its subsidiaries or affiliates.Our board of directors has determined that all members of the board of directors, except Ilan Ganot and Andrey Zarur, are independent directors, asdefined under applicable Nasdaq rules. In making such determination, our board of directors considered the relationships that each such non-employeedirector has with our Company and all other facts and circumstances that our board of directors deemed relevant in determining his or her independence,including the beneficial ownership of our common stock by each non-employee director. Our board of directors previously made a determination that GiladHayeem, who served as a member of our board of directors until June 2018, was not an independent director.Our board of directors has determined that the composition of our committees currently complies with all applicable independence requirements ofNasdaq and the rules and regulations of the SEC.Item 14.Principal Accounting Fees and Services.The following table represents aggregate fees billed to us by PwC for the fiscal years ended December 31, 2018 and 2017: 2018 2017 Audit fees $698,300 $1,234,500 Audit-related fees 20,000 - Tax fees 75,158 131,727 All other fees 2,756 1,800 Total $796,214 $1,368,027 The services rendered by PwC in connection with the fees presented above were as follows:Audit FeesAudit fees consist of amounts for professional services rendered for audit and quarterly reviews of our financial statements and review of ourregistration statement on Form S-1.Audit-Related FeesAudit-related fees consist of amounts for professional services rendered related to the implementation of an accounting standard in the year prior to itsadoption.108Tax FeesTax fees consist of fees for professional services related to tax compliance and consultations.All other feesAll other fees include license fees for web-based accounting research tools.Pre-approval policiesThe audit committee has not adopted policies and procedures for the pre-approval of audit and non-audit services rendered by our independentregistered public accounting firm and, consequently, all audit and non-audit services are pre-approved by the whole audit committee or the chair of the auditcommittee.109PART IVItem 15.Exhibits, Financial Statement Schedules.(1) Financial Statements: PageReport of Independent Registered Public Accounting FirmF-1Consolidated Balance Sheets at December 31, 2018 and 2017F-2Consolidated Statements of Operations for the Years Ended December 31, 2018, 2017 and 2016F-3Consolidated Statements of Comprehensive Loss for the Years Ended December 31, 2018, 2017 and 2016F-4Consolidated Statements of Preferred Units and Stockholders’/Members’ Equity/(Deficit) for the Years Ended December 31, 2018, 2017 and 2016F-5Consolidated Statements of Cash Flows for the Years Ended December 31, 2018, 2017 and 2016F-6Notes to Consolidated Financial StatementsF-7(2) Financial Statement Schedules:All financial statement schedules have been omitted because they are not applicable, not required or the information required is shown in thefinancial statements or the notes thereto.(3) Exhibits. The following is a list of exhibits filed as part of this Annual Report on Form 10-K.110 ExhibitNumber Description 2.1Agreement and Plan of Merger, dated March 29, 2017, by and between Solid Biosciences, LLC and Solid GT, LLC (incorporated by referenceto Exhibit 2.1 to the Registration Statement on Form S-1 filed on December 29, 2017). 2.2Plan of Conversion, dated January 25, 2018 (incorporated by reference to Exhibit 2.2 to the Annual Report on Form 10-K filed on March 29,2018). 2.3Agreement and Plan of Merger, dated January 25, 2018, by and among Solid Biosciences Inc., Bain Capital Life Sciences Fund, L.P., BCIP LifeSciences Associates, LP, BCLS Solid Bio, Inc., Foresite Capital Fund III, L.P. and FC Fund III Solid Holdings, Inc. (incorporated by reference toExhibit 2.3 to the Annual Report on Form 10-K filed on March 29, 2018). 3.1Certificate of Incorporation of Solid Biosciences Inc. (incorporated by reference to Exhibit 4.1 to the Registration Statement on Form S-8 filedon January 29, 2018). 3.2Bylaws of Solid Biosciences Inc. (incorporated by reference to Exhibit 4.2 to the Registration Statement on Form S-8 filed on January 29,2018). 4.1Specimen Common Stock Certificate (incorporated by reference to Exhibit 4.1 to the Registration Statement on Form S-1 filed on December29, 2017).10.1†Amended and Restated Registration Rights Agreement dated March 29, 2017 by and among Solid Biosciences, LLC and certain investors(incorporated by reference to Exhibit 10.17 to the Registration Statement on Form S-1 on December 29, 2017).10.2*†Employment Agreement, dated as of January 25, 2019, by and between Solid Biosciences Inc. and Ilan Ganot.10.3*†Employment Agreement, dated as of January 25, 2019, by and between Solid Biosciences Inc. and Alvaro Amorrortu10.4*†Employment Agreement, dated as of January 25, 2019, by and between Solid Biosciences Inc. and Carl Morris. Ph.D.10.5†Solid Biosciences, LLC Amended and Restated Equity Incentive Plan and form of unit restriction agreement (incorporated by reference toExhibit 10.7 to the Annual Report on Form 10-K filed on March 29, 2018).10.6†Solid Biosciences Inc. 2018 Omnibus Incentive Plan (incorporated by reference to Exhibit 99.1 to the Registration Statement on Form S-8 filedon January 29, 2018).10.7*†Form of Incentive Stock Option Agreement under 2018 Omnibus Incentive Plan.10.8*†Form of Nonqualified Stock Option Agreement under 2018 Omnibus Incentive Plan.10.9†Form of Restricted Stock Agreement under 2018 Omnibus Incentive Plan (incorporated by reference to Exhibit 10.9 to the RegistrationStatement on Form S-1 filed on December 29, 2017).10.10#Exclusive Patent License Agreement, dated as of October 16, 2015, by and between Solid GT, LLC and the University of Washington(incorporated by reference to Exhibit 10.10 to the Registration Statement on Form S-1 filed on December 29, 2017).10.11#Patent License Agreement, dated as of March 10, 2016, by and between Solid GT, LLC and the Regents of the University of Michigan(incorporated by reference to Exhibit 10.11 to Amendment No. 1 to the Registration Statement on Form S-1 filed on January 16, 2018).10.12#License Agreement, dated as of October 15, 2015, by and between Solid GT, LLC and The Curators of the University of Missouri (incorporatedby reference to Exhibit 10.12 to Amendment No. 1 to the Registration Statement on Form S-1 filed on January 16, 2018).10.13#Cell Line License Agreement, dated as of November 20, 2016, by and between Solid Biosciences, LLC and Life Technologies Corporation(incorporated by reference to Exhibit 10.13 to Amendment No. 1 to the Registration Statement on Form S-1 filed on January 16, 2018).10.14#License Agreement, dated as of June 23, 2016, by and between Solid GT, LLC and the President and Fellows of Harvard College (incorporatedby reference to Exhibit 10.14 to the Registration Statement on Form S-1 filed on December 29, 2017).10.15#License Agreement, dated as of August 3, 2017, by and between Solid Biosciences, LLC and the President and Fellows of Harvard College(incorporated by reference to Exhibit 10.15 to the Registration Statement on Form S-1 filed on December 29, 2017).11110.16First Amendment to Patent License Agreement, dated as of March 15, 2017, by and between Solid GT, LLC and the Regents of the Universityof Michigan (incorporated by reference to Exhibit 10.16 to Amendment No. 1 to the Registration Statement on Form S-1 filed on January 16,2018).10.17Form of Indemnification Agreement for Directors and Officers (incorporated by reference to Exhibit 10.16 to the Registration Statement onForm S-1 filed on December 29, 2017).10.18Sublease, dated as of January 30, 2018, by and between Solid Biosciences, LLC and Twitter, Inc. (incorporated by reference to Exhibit 10.20 tothe Annual Report on Form 10-K filed on March 29, 2018).10.19Lease Agreement, dated as of December 22, 2017, by and between Solid Biosciences, LLC and ARE-MA Region No. 59, LLC (incorporated byreference to Exhibit 10.21 to the Annual Report on Form 10-K filed on March 29, 2018).10.20*†Summary of Non-Employee Director Compensation Program. 21.1*Subsidiaries of Solid Biosciences Inc.23.1*Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm.31.1*Certification of Chief Executive Officer of the Registrant Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.31.2*Certification of Chief Financial Officer of the Registrant Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.32.1**Certification of Chief Executive Officer of the Registrant Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of theSarbanes-Oxley Act of 2002.32.2**Certification of Chief Financial Officer of the Registrant Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of theSarbanes-Oxley Act of 2002. *Filed herewith.**Furnished herewith.†Indicates management contract or compensatory plan.#Confidential treatment has been granted as to certain portions, which portions the Registrant has omitted and filed separately with the SEC.Item 16.Form 10-K Summary.Not applicable.112SIGNATURESPursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Report tobe signed on its behalf by the undersigned, thereunto duly authorized. SOLID BIOSCIENCES INC. Date: March 13, 2019 By: /s/ Ilan Ganot Ilan GanotPresident, Chief Executive Officer and Director(Principal Executive Officer) Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Report has been signed below by the following persons onbehalf of the Registrant in the capacities and on the dates indicated. /s/ Ilan Ganot Ilan GanotPresident, Chief Executive Officer and Director(Principal Executive Officer)March 13, 2019 /s/ Jennifer Ziolkowski Jennifer Ziolkowski Chief Financial Officer(Principal Financial and Accounting Officer)March 13, 2019 /s/ Andrey Zarur, Ph.D. Andrey Zarur, Ph.D. Chairman of the BoardMarch 13, 2019 /s/ Matthew Arnold Matthew ArnoldDirectorMarch 13, 2019 /s/ Martin Freed Martin Freed Director March 13, 2019 /s/ Robert Huffines Robert Huffines DirectorMarch 13, 2019 /s/ Adam Koppel Adam Koppel, M.D., Ph.D.DirectorMarch 13, 2019 /s/ Sukumar Nagendran Sukumar Nagendran Director March 13, 2019 /s/ Rajeev Shah Rajeev Shah DirectorMarch 13, 2019 /s/ Adam Stone Adam Stone DirectorMarch 13, 2019 /s/ Lynne Sullivan Lynne SullivanDirectorMarch 13, 2019 113Report of Independent Registered Public Accounting Firm To the Board of Directors and Stockholders ofSolid Biosciences Inc.: Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of Solid Biosciences Inc. and its subsidiaries (the “Company”) as of December 31, 2018 and2017, and the related consolidated statements of operations, of comprehensive loss, of preferred units and stockholders’/members’ equity (deficit) and of cashflows for each of the three years in the period ended December 31, 2018, including the related notes (collectively referred to as the “consolidated financialstatements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as ofDecember 31, 2018 and 2017, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2018 inconformity with accounting principles generally accepted in the United States of America. Substantial Doubt about the Company’s Ability to Continue as a Going Concern The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a going concern. As discussed inNote 1 to the consolidated financial statements, the Company has incurred losses and negative cash flows from operations since inception, that raisesubstantial doubt about its ability to continue as a going concern. Management’s plans in regard to these matters are also described in Note 1. Theconsolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Basis for Opinion These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’sconsolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board(United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and theapplicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits of these consolidated financial statements in accordance with the standards of the PCAOB. Those standards require that we plan andperform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error orfraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits weare required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness ofthe Company's internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud,and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosuresin the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management,as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion. /s/ PricewaterhouseCoopers LLPBoston, MassachusettsMarch 13, 2019 We have served as the Company’s auditor since 2017.F-1SOLID BIOSCIENCES INC.CONSOLIDATED BALANCE SHEETS(In thousands, except share and per share data) December 31, 2018 2017 Assets Current assets: Cash and cash equivalents $86,366 $52,080 Available-for-sale securities 36,098 17,014 Prepaid expenses and other current assets 6,175 1,499 Restricted cash - 65 Total current assets 128,639 70,658 Property and equipment, net 10,422 2,429 Other non-current assets 209 - Restricted cash 327 - Deferred offering costs - 3,106 Total assets $139,597 $76,193 Liabilities, Preferred Units and Stockholders' / Members' Equity / (Deficit) Current liabilities: Accounts payable $3,691 $5,066 Accrued expenses 8,235 5,972 Current portion of capital lease obligations 173 - Other current liabilities 382 233 Total current liabilities 12,481 11,271 Capital lease obligations, net of current portion 859 - Other non-current liabilities 1,074 - Total liabilities 14,414 11,271 Commitments and Contingencies (Note 13) Series 2 Senior Preferred Units, no units authorized at December 31, 2018 and 4,886,000 units authorized at December 31, 2017; no units issued and outstanding at December 31, 2018 and 4,886,000 units issued and outstanding at December 31, 2017 - 55,002 Series 1 Senior Preferred Units, no units authorized at December 31, 2018 and 2,500,000 units authorized at December 31, 2017; no units issued and outstanding at December 31, 2018 and 2,500,000 units issued and outstanding at December 31, 2017 - 25,000 Junior Preferred Units, no units authorized at December 31, 2018 and 4,414,356 units authorized at December 31, 2017; no units issued and outstanding at December 31, 2018 and 4,414,356 units issued and outstanding at December 31, 2017 - 44,177 Stockholders’ / Members’ Equity / (Deficit): Series A, B, C and D Common Units, no units authorized at December 31, 2018 and 20,189,509 units authorized at December 31, 2017; no units issued and outstanding at December 31, 2018 and 19,438,552 units issued and outstanding at December 31, 2017 - 65,014 Preferred stock, $0.001 par value; 10,000,000 shares authorized at December 31, 2018 and no shares authorized at December 31, 2017; no shares issued and outstanding at December 31, 2018 and December 31, 2017 - - Common stock, $0.001 par value; 300,000,000 shares authorized at December 31, 2018 and no shares authorized at December 31, 2017; 35,432,460 shares issued and outstanding at December 31, 2018 and no shares issued and outstanding at December 31, 2017 35 - Additional Paid-in Capital 324,209 Accumulated other comprehensive loss (5) (13)Accumulated deficit (199,056) (124,258)Total stockholders'/members’ equity/(deficit) 125,183 (59,257)Total liabilities, preferred units and stockholders'/members’ equity $139,597 $76,193 The accompanying notes are an integral part of these consolidated financial statements.F-2SOLID BIOSCIENCES INC.CONSOLIDATED STATEMENTS OF OPERATIONS(In thousands, except share and per share data) Year Ended December 31, 2018 2017 2016 Revenue $- $- $- Operating expenses: Research and development 57,965 39,905 20,116 General and administrative 17,722 14,952 5,460 Total operating expenses 75,687 54,857 25,576 Loss from operations (75,687) (54,857) (25,576)Other income (expense): Revaluation of preferred unit tranche rights - 459 1,163 Interest income 619 219 369 Other income 270 1,001 271 Total other income (expense), net 889 1,679 1,803 Net loss $(74,798) $(53,178) $(23,773)Net loss attributable to non-controlling interest - (1,060) (2,234)Net loss attributable to Solid Biosciences Inc. $(74,798) $(52,118) $(21,539)Decretion (accretion) of preferred units to redemption value - (959) 4,309 Redemption of preferred units - 15,685 - Redemption of redeemable interest from non-controlling interest in Solid GT - (1,925) - Net loss attributable to common stockholders $(74,798) $(39,317) $(17,230)Net loss per share attributable to common stockholders, basic and diluted $(2.25) $(2.88) $(10.14)Weighted average common stock outstanding, basic and diluted 33,262,597 13,649,485 1,698,904 The accompanying notes are an integral part of these consolidated financial statements.F-3SOLID BIOSCIENCES INC.CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS(In thousands) Year Ended December 31, 2018 2017 2016 Net loss $(74,798) $(53,178) $(23,773)Other comprehensive loss: Unrealized gain (loss) on available-for-sale securities 8 (36) 33 Comprehensive loss (74,790) (53,214) (23,740)Comprehensive loss attributable to non-controlling interest - (1,060) (2,234)Comprehensive loss attributable to Solid Biosciences Inc. $(74,790) $(52,154) $(21,506) The accompanying notes are an integral part of these consolidated financial statements. F-4SOLID BIOSCIENCES INC.CONSOLIDATED STATEMENTS OF PREFERRED UNITS AND STOCKHOLDERS’/MEMBERS’ EQUITY/(DEFICIT)(In thousands except for share data) RedeemablePreferredUnits Amount Series 2SeniorPreferredUnits Amount Series 1SeniorPreferredUnits Amount JuniorPreferredUnits Amount SeriesA, B, Cand DCommonUnits Amount CommonStock Amount Additionalpaidin capital Accumulatedothercomprehensiveincome (loss) AccumulatedDeficit TotalMembers’/Stockholders’Equity(Deficit) Non-controllingInterest TotalEquity(Deficit) Balance atDecember 31,2016 17,100,000 $71,649 - - - - - - 5,123,917 $558 - - - $23 $(84,941)$(84,360)$46,474 $(37,886)Issuance ofSeries 1seniorpreferredunits, net of issuancecosts of $500and trancheright of $459 - - - - 2,500,000 $24,041 - - - - - - - - - - - - Accretion ofSeries 1seniorpreferredunits to redemptionvalue - - - - - 959 - - - - - - - - (959) (959) - (959)Redemptionof preferredunits - (15,685) - - - - - - - - - - - - 15,685 15,685 - 15,685 Equity-basedcompensation - - - - - - - - - 5,030 - - - - - 5,030 300 5,330 Net loss - - - - - - - - - - - - - - (52,118) (52,118) (1,060) (53,178)Issuance ofSeries Bcommon unitsin exchangefor Series Acommon units - - - - - - - - (1,301,520) - - - - - - - - - Issuance ofSeries Dcommon unitsin exchangefor Series Acommon units - - - - - - - - (160,954) - - - - - - - - - Issuance ofSeries Acommon unitsin exchangeforredeemablepreferredunits (17,100,000) (55,964) - - - - - - 12,219,299 55,964 - - - - - 55,964 - 55,964 Issuance ofjuniorpreferredunits in redemptionof Class Dnon-controlling interest inSolid GT - - - - - - 4,414,356 $44,177 - - - - - - (1,925) (1,925) (42,252) (44,177)Issuance ofSeries Ccommon unitsin exchangefor Class Bnon-controlling interest inSolid GT - - - - - - - - 1,635,916 2,053 - - - - - 2,053 (2,053) - Issuance ofSeries Dcommon unitsin exchangefor Class Cnon-controlling interest inSolid GT - - - - - - - - 1,083,205 1,409 - - - - - 1,409 (1,409) - Issuance ofSeries Dcommon units - - - - - - - - 838,689 - - - - - - - - - Issuance ofSeries 2seniorpreferredunits, 4,886,000 $55,002 Unrealizedloss onavailable forsalesecurities - - - - - - - - - - - - - (36) - (36) - (36)Balance atDecember 31,2017 - - 4,886,000 $55,002 2,500,000 $25,000 4,414,356 $44,177 19,438,552 $65,014 - $- $- $(13)$(124,258)$(59,257) - $(59,257)Conversionof units intoshares ofcommon stock - - (4,886,000) (55,002) (2,500,000) (25,000) (4,414,356) (44,177) (19,429,620) (65,180) 26,498,559 26 189,333 - - 124,179 - 124,179 Issuance ofcommonstock uponinitial public offering,net ofissuancecosts of$4,592 - - - - - - - - - - 8,984,375 $9 129,087 - - 129,096 - 129,096 Equity-basedcompensation - - - - - - - - - 166 5,789 - - 5,955 - 5,955 Net loss - - - - - - - - - - - (74,798) (74,798) - (74,798)Repurchaseof commonunits/ sharesof commonstock - - - - - - - - (8,932) - (50,474) - - - - - - - Unrealizedgain onavailable forsalesecurities - - - - - - - - - - - - $- 8 - 8 - 8 Balance atDecember 31,2018 - - - $- - - - $- - $- 35,432,460 $35 $324,209 $(5)$(199,056)$125,183 $- $125,183 The accompanying notes are an integral part of these consolidated financial statements. F-5SOLID BIOSCIENCES INC.CONSOLIDATED STATEMENTS OF CASH FLOWS(In thousands) Year Ended December 31, 2018 2017 2016 Cash flows from operating activities: Net loss $(74,798) $(53,178) $(23,773)Adjustments to reconcile net loss to net cash used in operating activities: Amortization of (discount)/premium on available-for-sale securities (90) 206 505 Equity-based compensation expense 5,955 5,330 1,470 Depreciation expense 1,566 448 56 (Gain) / loss on sale of property and equipment 4 - - Loss (gain) from revaluation of preferred unit tranche right - (459) (1,163)Changes in operating assets and liabilities: Proceeds from landlord lease incentive for tenant improvements 823 - - Prepaid expenses and other current assets (4,930) 815 (2,005)Accounts payable (1,610) 1,579 2,213 Accrued expenses and other current liabilities 2,883 2,035 2,577 Net cash used in operating activities (70,197) (43,224) (20,120)Cash flows from investing activities: Purchases of property and equipment (7,776) (2,276) (392)Proceeds from sales and maturities of available for sale securities 25,335 31,621 22,035 Purchases of available for sale securities (44,321) (18,897) (25,695)Net cash (used in) provided by investing activities (26,762) 10,448 (4,052)Cash flows from financing activities: Proceeds from issuance of Series 1 Senior preferred units - 24,500 - Proceeds from issuance of Series 2 Senior preferred units - 55,002 - Payment of deferred offering costs (2,168) (2,424) - Proceeds from issuance of redeemable preferred units - - 3,420 Proceeds from initial public offering of common stock, net of commissions and underwriting discounts 133,688 - - Principal payments under capital lease obligation (13) - - Net cash provided by financing activities 131,507 77,078 3,420 Net increase (decrease) in cash, cash equivalents and restricted cash 34,548 44,302 (20,752)Cash, cash equivalents, and restricted cash at beginning of period 52,145 7,843 28,595 Cash, cash equivalents, and restricted cash at end of period $86,693 $52,145 $7,843 Supplemental disclosure of non-cash investing and financing activities: Conversion of Series A, B, C and D common units into shares of common stock $65,180 - - Conversion of Series 2 Senior Preferred units into shares of common stock $55,002 - - Conversion of Series 1 Senior Preferred units into shares of common stock $25,000 - - Conversion of Junior Preferred units into shares of common stock $44,177 - - Reclassification of preferred unit tranche liability to preferred units upon settlement - - 10,841 Decretion (accretion) to redemption value for redeemable preferred units - $(959) $4,309 Redemption of preferred units - $15,685 - Redemption of redeemable interest from non-controlling interest in Solid GT - $(1,925) - Deferred offering costs included in accounts payable and accrued expenses - $682 $47 Property and equipment included in accounts payable and accruals $952 $265 $116 Property and equipment acquired through a capital lease $1,023 - - Issuance of Series D common units in exchange for Series A common units - $638 - Issuance of Series A common units in exchange for Redeemable preferred units - $55,964 - Issuance of Junior preferred units upon redemption of Class D non-controlling interest in Solid GT - $44,177 - Issuance of Series C common units in exchange for Class B non-controlling interest in Solid GT - $2,053 - Issuance of Series D common units in exchange for Class C non-controlling interest in Solid GT - $1,409 - The accompanying notes are an integral part of these consolidated financial statements.F-6 SOLID BIOSCIENCES INC.NOTES TO CONSOLIDATED FINANCIAL STATEMENTS(Amounts in thousands, except share and per share data)1. Nature of the Business and Basis of PresentationNature of BusinessSolid Biosciences Inc. was organized in March 2013 under the name SOLID Ventures Management, LLC. In October 2013, the company changed its name toSolid Ventures, LLC and in June 2015, the company changed its name to Solid Biosciences, LLC. The company operated as a Delaware limited liabilitycompany under the name Solid Biosciences, LLC until immediately prior to the effectiveness of its registration statement on Form S-1 on January 25, 2018,at which time it completed a statutory corporate conversion into a Delaware corporation (the “Corporate Conversion”) and changed its name to SolidBiosciences Inc. (the “Company”) In addition, entities formed solely for the purpose of holding membership interests in the Company’s limited liabilitycompany were merged with and into the Company. As a result of the Corporate Conversion, all of the Series 1 and 2 Senior Preferred, Junior Preferred Units,Series A, B, C and D Common Units of Solid Biosciences, LLC converted into shares of common stock of Solid Biosciences Inc. on a one for 0.8485 basisand all of the unit holders of Solid Biosciences, LLC became holders of common stock of Solid Biosciences Inc.The Company’s mission is to cure Duchenne muscular dystrophy (“DMD”), a genetic muscle-wasting disease predominantly affecting boys. It is caused bymutations in the dystrophin gene, which result in the absence or near-absence of dystrophin protein. Dystrophin protein works to strengthen muscle fibersand protect them from daily wear and tear. Without functioning dystrophin and certain associated proteins, muscles suffer excessive damage from normaldaily activities and are unable to regenerate, leading to the build-up of fibrotic, or scar, and fat tissue. The Company’s lead product candidate, SGT-001, is agene transfer under development to restore functional dystrophin protein expression in patients’ muscles. SGT-001 has been granted Rare Pediatric DiseaseDesignation and Fast Track in the United States and Orphan Drug Designations in both the United States and European Union. The Company filed anInvestigational New Drug application (“IND”) in September 2017 and initiated a Phase I/II for SGT-001 in the United States during the fourth quarter of2017, which is called IGNITE DMD.The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to,development by competitors of new technological innovations, dependence on licenses, protection of proprietary technology, dependence on key personnel,compliance with government regulations and the need to obtain additional financing to fund operations. Product candidates currently under developmentwill require significant additional research and development efforts, including extensive pre-clinical studies and clinical trials and regulatory approval, priorto commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance andreporting capabilities.The Company’s product candidates are in development. There can be no assurance that the Company’s research and development will be successfullycompleted, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary governmentregulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it isuncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change intechnology and substantial competition from, among others, other pharmaceutical and biotechnology companies. In addition, the Company is dependentupon the services of its employees, partners and consultants.Initial Public Offering in January 2018On January 30, 2018, the Company completed its initial public offering with the sale of 8,984,375 shares of common stock, including shares of commonstock issued upon the exercise in full of the underwriters’ over-allotment option, at a public offering price of $16.00 per share, resulting in net proceeds of$129,096, after deducting underwriting discounts and commissions and offering expenses.LiquidityThe accompanying consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and whichcontemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. Through December 31, 2018, theCompany has funded its operations primarily with proceeds from the sale of redeemable preferred units and member units and its recently completed initialpublic offering. In accordance with ASC 205-40, Going Concern, the Company has evaluated whether there are conditions and events, considered in the aggregate, that raisesubstantial doubt about the Company’s ability to continue as a going concern withinF-7one year after the date the financial statements are issued. As of December 31, 2018, the Company had an accumulated deficit of $199,056. During the yearended December 31, 2018, the Company incurred a net loss of $74,798 and used $70,197 of cash in operations. The Company expects to continue togenerate operating losses in the foreseeable future. The Company currently expects that its cash, cash equivalents and available-for-sale securities of$122,464 will be sufficient to fund its operating expenses and capital requirements, based upon its current operating plan, into early 2020. In accordance with the requirements of ASC 205-40, the Company determined that there is substantial doubt about the Company’s ability to continue as agoing concern within twelve months of the issuance date of these financial statements. The financial statements do not include any adjustments that mightresult from the outcome of this uncertainty. Although the Company has been successful in raising capital in the past, there is no assurance that it will besuccessful in obtaining such additional financing on terms acceptable to the Company, if at all, nor is it considered probable under the accounting standards.As such, under the requirements of ASC 205-40, management may not consider the potential for future capital raises or management plans to reduce costs thatare not considered probable in its assessment of the Company’s ability to meet its obligations for the next twelve months. If the Company is unable to obtainfunding, the Company would be forced to delay, reduce or eliminate some or all of its research and development programs, pre-clinical and clinical testing orcommercialization efforts, which could adversely affect its business prospects. Merger and Recapitalization in March 2017The Company had historically owned 100% of the voting units of its wholly owned subsidiary, Solid GT, LLC (“Solid GT”), and the results of Solid GT wereincluded in the Company’s consolidated financial statements. In November 2015, Solid GT issued voting units to new investors which decreased theCompany’s voting ownership in Solid GT to 77%. The Company continued to consolidate the results of Solid GT into its financial statements as theCompany owned a majority voting interest in Solid GT and directed the activities of Solid GT. However, because the Company controlled but owned lessthan 100% of Solid GT, the Company recorded a non-controlling ownership interest at its fair value at inception and recognizes the net loss or profitattributable to non-controlling interests in the consolidated statements of operations based on a profit and loss sharing arrangement between the Companyand the non-controlling interests. The Company also presented the change in equity related to equity-based compensation issued to Solid GT employees bySolid GT, in non-controlling interest. See Note 12, Equity-Based Compensation, for additional information.On March 29, 2017, the Company merged the operations of Solid GT into the Company and Solid GT ceased to exist as a legal entity. See Note 3, Mergerand Recapitalization, for additional information.The proportionate share of the loss attributed to the non-controlling interest amounted to $0, $1,060 and $2,234, for the years ended December 31, 2018,2017 and 2016, respectively.There was no non-controlling interest at December 31, 2018 and 2017. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States ofAmerica (“GAAP”). The accompanying consolidated financial statements include the accounts of Solid Biosciences Inc. and its wholly owned or controlledsubsidiaries. All intercompany accounts and transactions have been eliminated.2. Summary of Significant Accounting PoliciesUse of EstimatesThe preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates, judgments andassumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidatedfinancial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidatedfinancial statements include, but are not limited to, the recognition of research and development expenses and equity-based compensation. Estimates areperiodically reviewed in light of changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they becomeknown. Actual results could differ from the Company’s estimates.Cash EquivalentsThe Company considers all short-term, highly liquid investments with original maturities of 90 days or less at acquisition date to be cash equivalents.F-8Restricted CashThe Company held restricted cash of $327 in separate restricted bank accounts as security deposits for the leases of the Company’s facilities as ofDecember 31, 2018. The Company has included the restricted cash of $327 as a non-current asset as of December 31, 2018.The Company held restricted cash of $65 in a separate restricted bank account as a security deposit for the lease of the Company’s facility as of December 31,2017. The Company has included the restricted cash of $65 as a current asset as of December 31, 2017.Available-for-Sale SecuritiesAvailable-for-sale securities consist of investments with original maturities greater than 90 days at acquisition date. The Company has classified itsinvestments with maturities beyond one year as short term, based on their highly liquid nature and because such available-for-sale securities represent theinvestment of cash that is available for current operations.The Company classifies all of its investments as available-for-sale securities. The Company’s investments are measured and reported at fair value usingquoted prices in active markets for similar securities. Unrealized gains and losses on available-for-sale debt securities are reported as a separate component ofstockholders’/members’ equity/(deficit). The cost of debt securities sold is determined on a specific identification basis, and realized gains and losses areincluded in other income (expense) within the consolidated statement of operations. If any adjustment to fair value reflects a decline in the value of theinvestment that the Company considers to be “other than temporary,” the Company reduces the investment to fair value through a charge to the consolidatedstatement of operations. No such adjustments were necessary during the periods presented.Concentration of Credit Risk and of Significant SuppliersFinancial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and available-for-salesecurities. Periodically, the Company maintains deposits in accredited financial institutions in excess of federally insured limits. The Company maintainseach of its cash, cash equivalents and available-for-sale securities balances with high-quality and accredited financial institutions and accordingly, suchfunds are not exposed to significant credit risk. The Company does not believe that it is subject to unusual credit risk beyond the normal credit riskassociated with commercial banking relationships.The Company is dependent on third-party manufacturers to supply products for research and development activities of its programs, including clinical andpre-clinical testing. These programs could be adversely affected by a significant interruption in the supply of such drug substance products.Fair Value MeasurementsCertain assets and liabilities are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid totransfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participantson the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservableinputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, ofwhich the first two are considered observable and the last is considered unobservable: •Level 1—Quoted prices in active markets for identical assets or liabilities. •Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quotedprices in markets that are not active for identical or similar assets or liabilities or other inputs that are observable or can be corroborated byobservable market data. •Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of theassets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.The Company’s cash equivalents and available-for-sale securities are carried at fair value, determined according to the fair value hierarchy described above.See Note 4, Fair Value of Financial Assets and Liabilities, for additional information. TheF-9carrying values of the Company’s accounts payable and accrued expenses and other current liabilities approximate their fair value due to the short-termnature of these liabilities.Deferred Offering CostsThe Company capitalizes certain legal and other third-party fees that are directly associated with in-process equity financings as deferred offering costs untilsuch financings are consummated. After consummation of the equity financing, these costs are recorded as a reduction of the proceeds generated as a result ofthe offering. Should the planned equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expense inthe consolidated statements of operations. Deferred offering costs amounted to $0 at December 31, 2018 and $3,106 at December 31, 2017.Property and EquipmentProperty and equipment are stated at cost less accumulated depreciation. Depreciation expense is recognized using the straight-line method over the usefullife of the asset. Laboratory equipment is depreciated over five years. Computer equipment is depreciated over three years. Computer software is depreciatedover two years. Furniture and office equipment are depreciated over five years. Leasehold improvements are amortized over the shorter of the lease term or theestimated useful life of the related asset. Expenditures for repairs and maintenance of assets are charged to expense as incurred. Upon retirement or sale, thecost and related accumulated depreciation of assets disposed of are removed from the accounts and any resulting gain or loss is included in loss fromoperations. Equipment under capital lease is stated at fair value at the inception of the lease less accumulated depreciation. Equipment held under capitallease is depreciated over the remaining lease term or the estimated useful life of the equipment.Impairment of Long-Lived AssetsLong-lived assets, comprised of property and equipment, to be held and used are tested for recoverability whenever events or changes in businesscircumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to performan impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends andsignificant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, theCompany compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value.An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carryingamount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discountedcash flows. To date, the Company has not recorded any impairment losses or disposals on long-lived assets.Research and Development CostsResearch and development costs are expensed as incurred. Research and development expenses include salaries, equity-based compensation and benefits ofemployees, third-party license fees and other operational costs related to the Company’s research and development activities, including allocated facility-related expenses and external costs of outside vendors engaged to conduct both pre-clinical studies and clinical trials. Non-refundable pre-payments forgoods or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized asexpense as the goods or services are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered or theservices rendered.Research Contract Costs and AccrualsThe Company has entered into various research and development contracts with research institutions and other companies. These agreements are generallycancelable, and related payments are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoingresearch costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion ofevents, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reportingperiod. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from theactual costs.F-10Patent CostsAll patent-related costs incurred for filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of theexpenditure. Amounts incurred are classified as general and administrative expenses.Equity-Based CompensationIn connection with the completion of the Company’s initial public offering, the Company adopted the 2018 Omnibus Incentive Plan, which provides for theissuance of share-based awards, including options to purchase common stock. The 2018 Omnibus Incentive Plan provides for the awarding of up to5,001,000 shares of common stock for equity awards.The Company measures all stock options and other stock-based awards granted to employees and directors based on the fair value on the date of the grantand recognizes compensation expense of those awards, over the requisite service period, which is generally the vesting period of the respective award.Forfeitures are accounted for as they occur. The Company applies the straight-line method of expense recognition to all awards with only service-basedvesting conditions. The Company has not issued any awards with performance-based vesting conditions.For stock-based awards granted to non-employees, compensation expense is recognized over the period during which services are rendered by such non-employees until completed. At the end of each financial reporting period prior to the completion of the service, the fair value of these awards is remeasuredusing the then-current fair value of the Company’s common stock and updated assumption inputs in the Black-Scholes option-pricing model.The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The Company historically has beena private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on thehistorical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding thevolatility of its own traded stock price. For options with service-based vesting conditions, the expected term of the Company’s stock options has beendetermined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effectat the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that theCompany has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.The Company classifies stock-based compensation expense in its consolidated statement of operations and comprehensive loss in the same manner in whichthe award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.Income TaxesIncome taxes are accounted for under the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized forthe future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respectivetax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporarydifferences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in theperiod that includes the enactment date. The Company records valuation allowances to reduce deferred income tax assets to the amount that is more likelythan not to be realized. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not morelikely than not that a position will be sustained, no amount of benefit attributable to the position is recognized. The tax benefit to be recognized of any taxposition that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized uponresolution of the contingency.Prior to January 25, 2018, the Company had not been subject to U.S. federal income taxes as the Company was organized as a limited liability company. Assuch, the taxable income or loss was passed through to and included in the tax returns of the members. Since January 25, 2018, the Company’s income hassince been subject to U.S. federal, state, local, and foreign income taxes and taxed at the prevailing corporate tax rates.Segment DataThe Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company’ssingular focus is on developing treatments through gene therapy and other means for patients with DMD. All of the Company’s tangible assets are held in theUnited States.F-11Comprehensive LossComprehensive loss includes net loss, as well as other changes in stockholders’/members’ equity/(deficit) that result from transactions and economic eventsother than those with members. The Company’s only element of other comprehensive income (loss) in all periods presented was unrealized gains (losses)from available-for-sale securities.Net Loss per ShareThe Company follows the two-class method when computing net loss per share, as the Company has issued shares that meet the definition of participatingsecurities. The two-class method determines net loss per share for each class of common and participating securities according to dividends declared oraccumulated and participation rights in undistributed earnings. The two-class method requires income available to common stockholders for the period to beallocated between common and participating securities based upon their respective rights to receive dividends as if all income for the period had beendistributed.Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weightedaverage number of shares of common stock outstanding for the period. Diluted net loss attributable to common stockholders is computed by adjusting netloss attributable to common stockholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per shareattributable to common stockholders is computed by dividing the diluted net loss attributable to common stockholders by the weighted average number ofshares of common stock outstanding for the period, including potential dilutive shares of common stock assuming the dilutive effect of common stockequivalents.The Company’s preferred stock contractually entitles the holders of such shares to participate in dividends but does not contractually require the holders ofsuch shares to participate in losses of the Company. Accordingly, in periods in which the Company reports a net loss, such losses are not allocated to suchparticipating securities. In periods in which the Company reports a net loss attributable to common stockholders, diluted net loss per share attributable tocommon stockholders is the same as basic net loss per share attributable to common stockholders, since dilutive shares of common stock are not assumed tohave been issued if their effect is anti-dilutive. Funding from Charitable OrganizationsThe Company has received funding from charitable organizations to perform research and development services to identify therapies for people with DMD.The amounts received are recognized as services are performed and research expenses are incurred. These are included in other income in the consolidatedstatements of operations as the arrangement between the Company and the charitable organizations are not part of the Company’s on-going, major or centraloperations. Any amount received in advance of services performed is recorded in other current liabilities in the consolidated balance sheets if the services areexpected to be performed within the next twelve months.The Company recognized other income of $270, $1,001 and $271 for the years ended December 31, 2018, 2017 and 2016, respectively, which is included inthe consolidated statements of operations.ContingenciesLoss contingency provisions are recorded if the potential loss from any claim, asserted or unasserted, or legal proceeding, is considered probable and theamount can be reasonably estimated or a range of loss can be determined. These accruals represent the Company’s best estimate of probable loss. Disclosurealso is provided when it is reasonably possible that a loss will be incurred or when it is reasonably possible that the amount of a loss will exceed the recordedprovision. The Company reviews the status of each significant matter and assesses its potential financial exposure. Significant judgment is required in boththe determination of probability and the determination as to whether an exposure is reasonably estimable. Because of uncertainties related to these matters,accruals are based only on the best information available at the time. As additional information becomes available, the Company reassesses the potentialliability related to pending claims and may change its estimates. These changes in the estimates of the potential liabilities could have a material impact onthe Company’s consolidated results of operations and financial position.F-12Recently Adopted Accounting PronouncementsIn May 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-09, Compensation—StockCompensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”). ASC 2017-09 provides guidance about which changes to the terms orconditions of a share-based payment award require an entity to apply modification accounting in Topic 718. The Company adopted this standard in the firstquarter of 2018 and its adoption did not have any impact on the Company’s consolidated financial statements.In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (“ASU 2016-18”), which requires that amounts generally described as restrictedcash and restricted cash equivalents should be included with cash and cash equivalents. The Company adopted this standard in the first quarter of 2018 andits adoption resulted in the inclusion of restricted cash in total cash and cash equivalents in the determination of changes in cash and cash equivalents in theCompany’s consolidated statements of cash flows. The presentation of restricted cash on the consolidated balance sheet remains the same.A reconciliation of the amounts from the cash flow statement to the balance sheet is as follows: December 312018 December 312017 December 312016 Cash and cash equivalents as presented on balance sheet $86,366 $52,080 $7,678 Restricted cash, current, as presented on balance sheet - 65 165 Restricted cash, non-current, as presented on balance sheet 327 - - Cash and cash equivalents and restricted cash as presented on cash flow statement $86,693 $52,145 $7,843 In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU2016-15”). ASU 2016-15 reduces diversity in practice by providing guidance on the classification of certain cash receipts and payments in the statement ofcash flows. ASU 2016-15 clarifies that when cash receipts and cash payments have aspects of more than one class of cash flows and cannot be separated,classification will depend on the predominant source or use. ASU 2016-15 is effective on a retrospective basis. The Company adopted this standard in thefirst quarter of 2018 and the adoption of this standard did not have a material impact on the Company’s consolidated statements of cash flows.Recently Issued Accounting PronouncementsIn February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”), which sets out the principles for the recognition, measurement,presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach,classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. Thisclassification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease,respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of theirclassification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. ASU 2016-02 supersedesthe previous leases standard, ASC 840, Leases. The standard is effective for public entities for annual periods beginning after December 15, 2018 and forinterim periods within those fiscal years. The Company will adopt the new leasing standards on January 1, 2019, using a modified retrospective transition approach to be applied to leases existing asof, or entered into after, January 1, 2019. The Company has reviewed the existing lease contract and the impact of the new leasing standards on theconsolidated results of operations, financial position and disclosures. Upon adoption of the new leasing standards, the Company expects to recognize a leaseliability and related right of-use asset on the consolidated balance sheet within a range of approximately $4.5 million to $6.0 million. The impact of adoptionof the new leasing standards will have an immaterial impact to the consolidated statements of income.In August 2018 the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirementsfor Fair Value Measurement. This new standard modifies certain disclosure requirements on fair value measurements. This new standard will be effective forthe Company on January 1, 2020. The Company does not expect that the adoption of this new standard will have a material impact on the disclosures. F-133. Merger and RecapitalizationOn March 29, 2017, the Company completed a series of transactions, which included the issuance of Series 1 Senior Preferred Units pursuant to the SeniorPreferred Unit Purchase Agreement (the “Senior Preferred Unit Purchase Agreement”) and the merger of Solid GT into the Company pursuant to the mergeragreement between the Company and Solid GT (the “Merger Agreement”), collectively referred to as the “Merger and Recapitalization.” As part of theMerger and Recapitalization, the Company (a) issued 2,500,000 Series 1 Senior Preferred Units to new investors at $10.00 per unit resulting in gross proceedsto the Company of $25,000, (b) merged operations of Solid GT into the Company, effected through the exchange of Solid GT units held by non-controllinginterests of the Company into new classes of the Company units, and (c) exchanged existing Redeemable Preferred Units and Series A Common Units of theCompany into new units. The details of each component of the Merger and Recapitalization are as follows: (a)Issuance of Series 1 Senior Preferred UnitsPursuant to the Senior Preferred Unit Purchase Agreement, the Company issued 2,500,000 Series 1 Senior Preferred Units to new investors at $10.00 per unitresulting in gross proceeds to the Company of $25,000.See Note 10, Redeemable Preferred Units, Series 2 and Series 1 Senior Preferred Units and Junior Preferred Units , for additional information. (b)Merger of Solid GT into the CompanyPrior to the Merger and Recapitalization, the Company issued Class B Non-Voting and Class D Voting Units of Solid GT to holders which represent non-controlling interests of the Company. On March 29, 2017, in connection with the Merger and Recapitalization, the non-controlling interests were eliminatedas follows: •50,000 Class B Non-Voting Units of Solid GT (“Solid GT Class B Units”) were exchanged for 1,635,916 Series C Common Units of theCompany; and •134,920 Class D Voting Units of Solid GT (“Solid GT Class D Units”) were exchanged for 4,414,356 Junior Preferred Units of the Company.In addition, the Class C Non-Voting Units of Solid GT (“Solid GT Class C Restricted Units”) were exchanged for Series D Common Units of the Company.The Solid GT Class C Restricted Units were held by employees and consultants of Solid GT. See Note 12, Equity-Based Compensation, for additionalinformation.Since there was no change in control in connection with the Solid GT merger, the exchange of Solid GT Class B Units, Class C Restricted Units and Class DUnits was accounted for as an equity transaction. In addition, because Solid GT Class D Units represented preferred units with preference over the otherclasses of Solid GT Units, the difference between the carrying value of the Solid GT Class D Units and the fair value of Junior Preferred Units was recorded asa deemed dividend in members’ deficit, which impacts net loss attributable to common unitholders. See Note 15, Net Loss per Unit, for additionalinformation. (c)Exchange of the Company’s existing Redeemable Preferred Units and Series A Common UnitsIn connection with the Merger and Recapitalization, the Company exchanged its existing Redeemable Preferred Units and Series A Common Units asfollows: •17,100,000 Redeemable Preferred Units of the Company were exchanged for 12,219,299 Series A Common Units of the Company. See Note10, Redeemable Preferred Units, Series 2 and Series 1 Senior Preferred Units and Junior Preferred Units, for additional information. •4,560,000 Series A Common Units of the Company were exchanged for 3,258,480 Series B Common Units of the Company. See Note 11,Members’ Deficit, for additional information. •563,917 Series A Common Units of the Company were exchanged for 402,963 Series D Common Units of the Company. See Note 11,Members’ Deficit, for additional information.F-14The table below displays the pre-merger and post-merger capitalization structure of the Company: Pre-Merger and Recapitalization Post-Merger and Recapitalization Entity Class Issued Entity Class Issued Company Redeemable Preferred 17,100,000 Company Series A Common 12,219,299 Company Series A Common (Founders) 4,560,000 Company Series B Common 3,258,480 Company Series A Common (Others) 563,917 Company Series D Common 402,963 Solid GT Class A Voting 450,000 Ceased to exist Solid GT Class B Non-Voting 50,000 Company Series C Common 1,635,916 Solid GT Class C Non-Voting 33,107 Company Series D Common 1,083,205 Solid GT Class D Voting 134,920 Company Junior Preferred 4,414,356 Company(Total) Common Units (Series A) 5,123,917 Company(Total) Common Units(Series A, B, C and D) 18,599,863 4. Fair Value of Financial Assets and LiabilitiesThe following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis and indicate the levelof the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of December 31, 2018 Using: Level 1 Level 2 Level 3 Total Assets: Cash equivalents $- $54,423 $- $54,423 Available for sale securities - 36,098 - $36,098 $- $90,521 $- $90,521 Fair Value Measurements as of December 31, 2017 Using: Level 1 Level 2 Level 3 Total Assets: Available for sale securities $- $17,014 $- $17,014 As of December 31, 2018 and 2017, the fair values of the Company’s available-for-sale securities were determined using level two inputs. At December 31,2018 the portfolio consisted of U.S. government agency securities, corporate bond securities and commercial paper. At December 31, 2017, the portfolioconsisted of U.S. government agency securities and corporate bond securities. During the years ended December 31, 2018 and 2017, there were no transfersbetween Level 1, Level 2 and Level 3.The fair value of the Company’s cash, restricted cash, accounts payable, and accrued expenses and other current liabilities approximate their carrying valuedue to their short-term maturities.5. Available-for-Sale SecuritiesAs of December 31, 2018 and 2017, the fair value of available-for-sale debt securities by type of security was as follows: December 31, 2018 AmortizedCost GrossUnrealizedGain GrossUnrealizedLoss FairValue Investments: U.S. government agency securities $13,543 - $(2) $13,541 Corporate bond securities 12,860 2 (5) $12,857 Commercial paper 9,700 - - $9,700 $36,103 $2 $(7) $36,098 F-15 December 31, 2017 AmortizedCost GrossUnrealizedGain GrossUnrealizedLoss FairValue Investments: U.S. government agency securities $9,473 $- $(7) $9,466 Corporate bond securities 7,554 - (6) 7,548 $17,027 $- $(13) $17,014 The estimated fair value and amortized cost of the Company’s available-for-sale securities by contractual maturity are summarized as follows: December 31, 2017 December 31, 2018 AmortizedCost FairValue AmortizedCost FairValue Due in one year or less $17,027 $17,014 $36,103 $36,098 Total available-for-sale securities $17,027 $17,014 $36,103 $36,098 The average maturity of the Company’s available-for-sale securities as of December 31, 2018 and 2017 and was approximately 0.3 years and 0.4 years,respectively.6. Prepaid Expenses and Other Current AssetsPrepaid expenses and other current assets consist of the following: December 31, 2018 2017 Prepaid research and development expenses $4,365 $951 Prepaid expenses and other assets 1,810 548 $6,175 $1,499 7. Property and EquipmentProperty and equipment consists of the following: December 31, 2018 2017 Furniture and fixtures $187 $61 Laboratory equipment 5,998 2,338 Leasehold improvements 4,585 68 Computer equipment 166 77 Computer software 123 23 Construction in process 1,351 366 12,410 2,933 Less accumulated depreciation 1,988 504 $10,422 $2,429 Depreciation expense was $1,566, $448 and $56 for the years ended December 31, 2018, 2017, and 2016 respectively.F-168. Accrued ExpensesAccrued expenses and other current liabilities consist of the following: December 31,2018 December 31,2017 Accrued research and development $3,529 $1,855 Accrued compensation 3,534 2,033 Accrued other 1,172 2,084 $8,235 $5,972 9. Preferred Unit Tranche RightsIncluded in the terms of the Redeemable Preferred Unit Purchase Agreement and the Series 1 Senior Preferred Unit Purchase Agreement were Tranche Rightswhich obligated the investors to purchase additional preferred units under certain conditions. The Tranche Rights also provided the investors with the rightto purchase these additional units. The Company concluded that the Tranche Rights met the definition of a freestanding financial instrument as the TrancheRights were legally detachable and separately exercisable from the Redeemable Preferred Units and the Series 1 Senior Preferred Units. Therefore, theCompany allocated the net proceeds to each Tranche Right and the Redeemable Preferred Units or the Series 1 Senior Preferred Units based on the fair valueat the date of issuance with the remaining proceeds being allocated to the Redeemable Preferred Units or Series 1 Senior Preferred Units.Through the final settlement date in October 2016, the Company estimated the fair value of the Redeemable Preferred Unit Tranche Right based on theprobability of closing the tranches and the estimated future value of the Redeemable Preferred Units. The Redeemable Preferred Unit Tranche Right wasrecorded as a liability as the purchase price of the additional Redeemable Preferred Units was less than the estimated fair value of the Redeemable PreferredUnits at the expected settlement date. Upon settlement, the Redeemable Preferred Unit Tranche Right was reclassified to Redeemable Preferred Units. InOctober 2016, the Redeemable Preferred Unit Tranche Right was settled and no Redeemable Preferred Unit Tranche Right was outstanding subsequent toOctober 2016.The estimated fair value of the Series 1 Senior Preferred Unit Tranche Right was determined using a probability-weighted present value model thatconsidered the probability of closing the tranche through achievement of the preclinical milestones, estimated to be 50% on the date of issue and theestimated future value of Series 1 Senior Preferred Units at closing. The Company converted future values to present value using a discount rate appropriatefor probability adjusted cash flows. The estimates were based, in part, on subjective assumptions. Changes to these assumptions can have a significant impacton the fair value of the Series 1 Senior Preferred Unit Tranche Right. The Series 1 Tranche Right was settled in connection with the closing of the Series 2Senior Preferred Unit financing on October 26, 2017.A roll-forward of each tranche right is as follows: RedeemablePreferred UnitTranche Right Series 1 SeniorPreferred UnitTranche Right Balance at December 31, 2015 $12,004 $- Change in fair value (1,163) - Reclassification to preferred units (10,841) - Balance at December 31, 2016 - - Issuance - 459 Change in fair value - (459)Balance at December 31, 2017 - - Issuance - - Change in fair value - - Balance at December 31, 2018 $- $- F-1710. Redeemable Preferred Units, Series 2 and Series 1 Senior Preferred Units and Junior Preferred UnitsRedeemable Preferred UnitsThe Company has issued redeemable preferred units (“Redeemable Preferred Units”). The Redeemable Preferred Units are classified outside of members’deficit because the units contain redemption features that are not solely within the control of the Company.In December 2013, the Company issued 3,420,000 Redeemable Preferred Units at an issuance price of $1.00 per unit for proceeds of $3,420. In December 2014, the Company issued 3,420,000 Redeemable Preferred Units at an issuance price of $1.00 per unit for proceeds of $3,420.In October 2015, the Company issued 6,840,000 Redeemable Preferred Units at an issuance price of $1.00 per unit for proceeds of $6,840.In November and December 2016, the Company issued an aggregate of 3,420,000 Redeemable Preferred Units at $1.00 per unit for proceeds of$3,420.On March 29, 2017, the Redeemable Preferred Units were exchanged to Series A Common Units. See Note 3, Merger and Recapitalization, for additionalinformation. The Redeemable Preferred Units, which are carried at fair value due to their fair value redemption feature, were remeasured for a final time totheir redemption value on March 29, 2017 and then were reclassified to members’ deficit.Redeemable Preferred Units consisted of the following: Authorized Issued andOutstanding CarryingValue LiquidationPreference At December 31, 2016 60,000,000 17,100,000 $71,649 $55,746 At December 31, 2017 - - $- $- At December 31, 2018 - - $- $- The holders of the Redeemable Preferred Units had the following rights and preferences:Tranche RightThe Redeemable Preferred Unit Tranche Right obligated the holders to purchase, and provided the holders with the right to purchase, additional RedeemablePreferred Units, under certain circumstances. The Redeemable Preferred unitholders purchased these additional units in 2016 and 2015. In October 2016, theRedeemable Preferred Unit Tranche Right was settled with the closing of the Redeemable Preferred Unit financing. See Note 9, Preferred Unit TrancheRights, for additional information.RedemptionThe Redeemable Preferred Units were redeemable on or after December 27, 2022 at the option of the Redeemable Preferred unitholder. The RedeemablePreferred Units were redeemable at the fair market value on the redemption date.ConversionThe Redeemable Preferred Units had no conversion rights.Voting RightsThe holders of Redeemable Preferred Units were entitled to vote as a single class with the holders of the Series A Common Units on certain matters, includingthe election of managers, with each Redeemable Preferred Unit and Series A Common Unit carrying one vote per unit.F-18DistributionsThe Company’s Board of Managers had authority to determine the amount, if any, of proceeds available for distribution to the unitholders. Prior to theconversion of the Redeemable Preferred Units on March 29, 2017, such proceeds were to be distributed in accordance with the following order of priority: •First, to the holders of Redeemable Preferred Units, pro rata in proportion to the remaining amount to be distributed to each such holder, untileach such holder has received distributions in an amount equal to the cumulative capital contributions since inception in respect of theRedeemable Preferred Units. •Thereafter, to all Redeemable Preferred Unitholders, Series A Common Units held by the Company’s founders, Series A Common Units issued tonon-founders between December 27, 2013 and December 26, 2014, and vested Series A Restricted Common Unitholders issued subsequent toDecember 26, 2014 pro rata in proportion to their percentage interest at the time of distribution.No distributions were made in 2018, 2017 or 2016.LiquidationIn the event of any liquidation, dissolution, or winding-up of the Company, the assets of the Company would have been distributed in accordance with thesame order of priority that applied to distributions.Series 2 Senior Preferred UnitsOn October 26, 2017, the Company completed the sale of 4,886,000 Series 2 Senior Preferred Units at a price of $11.26 per unit resulting in net proceeds of$55,002.Series 2 Senior Preferred Units consist of the following: Authorized Issued andOutstanding CarryingValue LiquidationPreference Common UnitsIssuable UponConversion At December 31, 2017 4,886,000 4,886,000 $55,002 $55,002 4,886,000 At December 31, 2018 - - $- $- -Series 1 Senior Preferred UnitsOn March 29, 2017, the Company issued 2,500,000 Series 1 Senior Preferred Units at an issuance price of $10.00 per unit for proceeds of $25,000. See Note3, Merger and Recapitalization, for additional information.Series 1 Senior Preferred Units consist of the following: Authorized Issued andOutstanding CarryingValue LiquidationPreference Common UnitsIssuable UponConversion At December 31, 2017 2,500,000 2,500,000 $25,000 $25,000 2,500,000 At December 31, 2018 - - - - -Junior Preferred UnitsOn March 29, 2017, 134,920 Solid GT Class D Units were exchanged for 4,414,356 Junior Preferred Units of the Company. See Note 3, Merger andRecapitalization, for additional information.F-19Junior Preferred Units consisted of the following: Authorized Issued andOutstanding CarryingValue LiquidationPreference At December 31, 2017 4,414,356 4,414,356 $44,177 $42,500 At December 31, 2018 - - $- $- The holders of the Series 1 and Series 2 Senior Preferred Units and Junior Preferred Units had the following rights and preferences:Tranche RightThe holders of Series 1 Senior Preferred Units were obligated to purchase 1,973,430 Series 2 Senior Preferred Units at $12.67 per unit for gross proceeds of$25,000 in the event the Company achieves certain pre-clinical milestones. In addition, the holders of a majority of the Series 1 Senior Preferred Units hadthe right to require the holders of the Series 1 Senior Preferred Units to purchase the Series 2 Senior Preferred Units at any time prior to September 1, 2017,which in August 2017, was extended to December 1, 2017. The Series 1 Tranche Right was subject to certain transfer rights. See Note 9, Preferred UnitTranche Rights, for additional information. The Series 1 Tranche Right was settled in connection with the closing of the Series 2 Senior Preferred Unitfinancing on October 26, 2017.RedemptionThe Series 1 and Series 2 Senior Preferred Units were redeemable on or after March 29, 2022 at the option of the holder at a redemption price equal to theoriginal purchase price of $10.00 and $11.26 per unit, respectively, plus any declared but unpaid distributions. The Company presented Series 1 and Series 2Senior Preferred Units outside of permanent equity since the redemption of Series 1 and Series 2 Senior Preferred Units was outside the control of theCompany.The consent of the Junior Preferred unitholders along with Series 1 and Series 2 Senior Preferred unitholders could have effected a deemed liquidation event.Therefore, the Company presented the Junior Preferred Units outside of permanent equity.Voting RightsThe holders of the Series 1 and Series 2 Senior Preferred Units and Junior Preferred Units were entitled to vote together, and not as separate classes, with eachSeries 1 and Series 2 Senior Preferred Unit, Junior Preferred Unit, Series A Common Unit and Series B Common Unit carrying one vote per unit.Subject to maintaining certain ownership levels, the Series 1 and Series 2 Senior Preferred unitholders as a class were entitled to elect two of the nine boardmembers while such units were outstanding. The Junior Preferred unitholders as a class are entitled to elect two of the nine board members while such unitswere outstanding.DividendsThe holders of Series 1 and Series 2 Senior Preferred Units were entitled to an 8% annual dividend based on the Series 1 and Series 2 Senior Preferred Unitissuance price of $10.00 and $11.26 per unit, respectively, when and if declared by the Board of Managers. No dividends were declared or paid to Series 1 orSeries 2 Senior Preferred unitholders.The holders of the Junior Preferred Units were entitled to an 8% annual dividend based on the Junior Preferred Unit issuance price of $9.63 per unit, when andif declared by the Board of Managers. No dividends were declared or paid to Junior Preferred unitholders.F-20DistributionsThe Company’s Board of Managers had authority to determine the amount, if any, of proceeds available for distribution. Such proceeds were to be distributedin accordance with the following order of priority: •First, the Series 2 Senior Preferred unitholders were entitled to an amount distributed, on a pro rata basis, equal to the Series 2 Senior PreferredUnit price of $11.26 per unit and any declared but unpaid Series 2 Senior Preferred dividends. •Second, the Series 1 Senior Preferred and the Junior Preferred unitholders were entitled to an amount distributed, on a pro rata basis, equal to theSeries 1 Senior Preferred Unit price of $10.00 per unit and any declared but unpaid Series 1 Senior Preferred dividends and the Junior PreferredUnit price of $9.63 per unit and any declared but unpaid Junior Preferred dividends, respectively. •Third, the Series A, B, C and D Common unitholders were entitled to an amount distributed, on a pro rata basis, subject to certain limitations,until the cumulative amount distributed with respect to one Series A Common Unit, Series B Common Unit, Series C Common Unit and vestedSeries D Common Unit equaled the cumulative amount distributed to one Junior Preferred Unit. •Fourth, the Junior Preferred unitholders and the Series A, B, C and vested D Common unitholders were entitled to an amount distributed on a prorata basis, subject to certain limitations, until the cumulative amount distributed with respect to one Junior Preferred Unit, Series A CommonUnit, Series B Common Unit, Series C Common Unit and vested Series D Common Unit equaled the cumulative amount distributed to oneSeries 1 Senior Preferred Unit. •Fifth, the Series 1 and Series 2 Senior Preferred, the Junior Preferred and the Series A, B, C and vested D Common unitholders were entitled toparticipate on a pro rata basis in cumulative distributions, subject to certain limitations, in the remaining proceeds available for distribution.As a result of the issuance of the Series 2 Senior Preferred Units on October 26, 2017, the Series 2 Senior Preferred unitholders were entitled to cumulativeamounts distributed equal to the amount paid per unit for the Series 2 Senior Preferred Units and any declared but unpaid Series 2 Senior Preferred cumulativedividends, prior to and with priority over any distributions to any other unitholders. In addition, upon the issuance of the Senior Series 2 Preferred units, theholders of the Junior Preferred Units no longer shared pro rata in the order of distributions with the Senior Series 1 Preferred unitholders and were subordinateto distributions made to Series 1 Senior Preferred unitholders.No distributions were made during the years ended December 31, 2018 and 2017.LiquidationIn the event of any liquidation, dissolution, or winding-up of the Company, the assets of the Company would have been distributed in accordance with thesame order of priority that applied to distributions.Corporate ConversionImmediately prior to the effectiveness of the Company’s registration statement on Form S-1, which occurred on January 25, 2018, the Company completedthe Corporate Conversion whereby all the Series 1 and Series 2 Senior Preferred, Junior Preferred Units converted into shares of common stock.F-2111. Members’ DeficitSeries A, B, C and D Common UnitsSeries A, B, C and D Common Units consisted of the following: December 31, 2018 Authorized Issued andOutstanding CarryingValue Series A Common Units - - $- Series B Common Units - - - Series C Common Units - - - Series D Common Units - - - - - $- December 31, 2017 Authorized Issued andOutstanding CarryingValue Series A Common Units 12,219,299 12,219,299 $55,964 Series B Common Units 3,258,480 3,258,480 3,613 Series C Common Units 1,635,916 1,635,916 2,053 Series D Common Units 3,075,814 2,324,857 3,384 20,189,509 19,438,552 $65,014 December 31, 2016 Authorized Issued andOutstanding CarryingValue Series A Common Units 20,000,000 5,123,917 $558 Series A Common UnitsFounders Series A Common UnitsOn December 27, 2013, the Company issued 4,560,000 restricted Series A Common Units to its founders with time-based vesting conditions. Unvested unitsof Series A Common Units may not be sold or transferred by the holder. These restrictions lapse according to the time-based vesting conditions of each award.At December 31, 2016 and 2015, 3,420,000 and 2,280,000 restricted Series A Common Units were vested, respectively. The aggregated intrinsic value of therestricted Series A Common Units that vested during the year ended December 31, 2016 was $3,306. There were no restricted Series A Common Units thatvested during the years ended December 31, 2017 and 2018.On March 29, 2017, in connection with the Merger and Recapitalization, the 4,560,000 founders’ restricted Series A Common Units were exchanged for3,258,480 restricted Series B Common Units. All restricted Series B Common Units continued to vest pursuant to the original vesting terms under therestricted Series A Common Units agreements and the Company continued to recognize compensation expense over the related service period.In addition, in connection with the exchange of the founders’ restricted Series A Common Units into restricted Series B Common Units, the Companyrecognized $2,710 of equity based compensation expense for vested units, which represents the incremental fair value of the units before and after the Mergerand Recapitalization. The Company has recorded the additional compensation expense in the amount of $904 over the remaining vesting period of the SeriesB Common Units during the year ended December 31, 2017.Non-Founder Series A Common UnitsIn March and November 2014, the Company issued 169,667 restricted Series A Common Units at a per unit value of $2.59 to certain employees andconsultants.In September and November 2015, the Company issued 305,000 restricted Series A Common Units at per unit values between $2.39 and $2.65 to certainemployees.F-22In May and September 2016, the Company issued 60,000 restricted Series A Common Units at per unit values between $2.03 and $2.14 to certain employees.In December 2016, the Company issued 48,000 restricted Series A Common Units at a per unit value of $2.25 to certain employees.On March 29, 2017, in connection with the Merger and Recapitalization, 563,917 non-founder restricted Series A Common Units were exchanged for402,963 restricted Series D Common Units. All restricted Series D Common Units will continue to vest pursuant to their original vesting period, which wasgenerally four years, under the restricted Series A Common Units agreement, and the Company will continue to recognize compensation expense over therelated service period.In addition, in connection with the exchange of the non-founders’ restricted Series A Common Units into restricted Series D Common Units, the Companyrecognized $140 of equity-based compensation expense for vested units, which represents the incremental fair value of the units before and after the Mergerand Recapitalization. The Company will record additional compensation expense in the amount of $115 over the remaining vesting period of the Series DCommon units of which $48 and $54 were recognized during the years ended December 31, 2017 and 2018, respectively.The holders of the Series A, B, C and D Common Units were entitled to the following rights and priorities:Voting RightsHolders of Series A and B Common Units had the right to one vote per unit held by such member. The Series A Common unitholders as a class were entitledto elect two of the eight board members while such units are outstanding. The Series B Common unitholders as a class were entitled to elect three of the eightboard members while such units are outstanding.Holders of Series C and D Common Units did not have the right to vote for the election of board members.RedemptionThe Series A, B, C and D Common Units were not redeemable.Distributions and Liquidation PreferenceThe holders of the Series A, B, C and D Common Units were entitled to participate in distributions after preferential distributions were made to the Series 1and Series 2 Senior Preferred and Junior Preferred unitholders as follows: •The Series A, B, C and D Common unitholders were entitled to participate in distributions on a pro rata basis, subject to certain limitations,until the cumulative amount distributed with respect to one Series A Common Unit, Series B Common Unit, Series C Common Unit and vestedSeries D Common Unit equaled the cumulative amount distributed to one Junior Preferred Unit. •The Junior Preferred unitholders and the Series A, B, C and D Common unitholders were entitled to participate in distributions on a pro ratabasis, subject to certain limitations, until the cumulative amount distributed with respect to one Junior Preferred Unit, Series A Common Unit,Series B Common Unit, Series C Common Unit and vested Series D Common Unit equaled the cumulative amount distributed to one Series 1Senior Preferred Unit. •The Series 1 Senior Preferred, Junior Preferred unitholders and the Series A, B, C and D Common unitholders were entitled to participate indistributions on a pro rata basis, subject to certain limitations, until the cumulative amount distributed with respect to one Series 1 SeniorPreferred Unit, Junior Preferred Unit, Series A Common Unit, Series B Common Unit, Series C Common Unit and vested Series D CommonUnit equaled the cumulative amount distributed to one Series 2 Senior Preferred Unit. •All unitholders were entitled to participate on a pro rata basis in cumulative distributions, subject to certain limitations, in the remainingproceeds available for distribution.No distributions were made to the Series A, B, C or D Common unitholders during the years ended December 31, 2018, 2017 and 2016.F-23Corporate ConversionImmediately prior to the effectiveness of the Company’s registration statement on Form S-1, which occurred on January 25, 2018, the Company completedthe Corporate Conversion whereby all the Series A, B, C, and D Common Units converted into shares of common stock.12. Equity-Based Compensation2018 Omnibus Incentive PlanIn connection with the closing of the Company’s initial public offering, the board of directors and stockholders approved the 2018 Omnibus Incentive Plan,which provides for the reservation of 5,001,000 shares of common stock for equity awards.The following table summarizes the Company’s stock option activity for the year ended December, 31 2018: Number ofOptions WeightedAverageExercisePrice Outstanding at December 31, 2017 - $- Granted 1,185,207 28.51 Forfeitures (32,009) 20.80 Outstanding at December 31, 2018 1,153,198 28.73 Vested and expected to vest as of December 31, 2018 1,153,198 28.73 Exercisable at December 31, 2018 - $- At December 31, 2018, the Company had an aggregate of $19,528 of unrecognized equity-based compensation cost related to stock options outstanding.Stock options outstanding as well as options vested and expected to vest are expected to be recognized over a weighted average period of 3.2 years and havean intrinsic value of $2,260 as of December 31, 2018. The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions noted in thefollowing table: Year EndedDecember 31,2018Expected volatility 73.8% - 86.4%Expected dividends 0.0%Expected term (in years) 5.25 - 6.25Risk-free rate 2.6% - 3.1% The weighted average fair value of options to purchase shares of common stock granted during the year ended December 31, 2018 was $19.94.F-24Restricted Common StockIn connection with the Company’s Corporate Conversion on January 25, 2018, all restricted Series B and D common units were converted to restricted sharesof common stock. The following table summarizes the Company’s unvested restricted shares of common stock activity for the year ended December 31,2018: Units Weighted-AverageGrant DateFair Value Unvested restricted Series D Common Units at December 31, 2017 1,404,265 $4.83 Vested units prior to Corporate Conversion (66,019) 3.46 Forfeited units prior to Corporate Conversion (8,932) 2.99 Unvested Series D Common Units at January 25, 2018 prior to Corporate Conversion 1,329,314 4.91 Conversion to restricted shares of common stock upon Corporate Conversion 1,128,182 5.79 Vested shares of Common Stock (334,144) 4.51 Forfeited (50,474) 4.99 Unvested restricted Series D Common Units at December 31, 2018 743,564 $6.40 The aggregate intrinsic value of restricted common units that vested during the years ended December 31, 2018, 2017, and 2016 were $8,721, $3,358, and$351 respectively. At December 31, 2018, the Company had an aggregate of $4,466 of unrecognized equity-based compensation related restricted shares of common stock,which is expected to be recognized over a weighted average period of 1.3 years. The Company recorded equity-based compensation expense related to all of its share and unit-based awards to employees and non-employees in thefollowing captions within its consolidated statements of operations for the years ended December 31, 2018, 2017 and 2016 Year Ended December 31, 2018 2017 2016 Research and development expenses $4,180 $1,206 $1,262 General and administrative expenses $1,775 $4,124 $208 $5,955 $5,330 $1,470 13. Commitments and ContingenciesOperating LeaseIn January 2018, the Company executed a lease agreement for lab space in Cambridge, Massachusetts. The lease consists of approximately 9,500 square feetwith an initial term of five years with the option to extend the term for one additional two year term. The future minimum rent commitment for the initial five-year term is approximately $3,387. In addition to rent, the lease requires the Company to pay additional amounts for taxes, insurance, maintenance and otheroperating expenses.In January 2018, the Company executed a lease agreement for office space in Cambridge, Massachusetts. The space serves as the Company’s corporateheadquarters and consists of approximately 16,000 square feet. The term of the lease runs through February 2022. The future minimum rent commitment forthe lease term is approximately $3,922. In addition to rent, the lease requires the Company to pay additional amounts for taxes, insurance, maintenance andother operating expenses.F-25During the years ended December 31, 2018, 2017 and 2016, the Company recognized $2,524, $1,301 and $270, respectively, of rental expense related tooffice and laboratory space.Future minimum lease payments for these operating leases as of December 31, 2018 amounted to $7,309. Capital LeaseIn November 2018, the Company entered into a 48-month capital lease for certain lab equipment to be used at its facility in Cambridge Massachusetts. Thefuture minimum lease commitment for the lease term is approximately $1,313. At December 31, 2018 the Company expects to make the following fixed and non-cancelable payments related to its operating and capital leasecommitments: Year Ending December 31, 2019 $2,210 2020 2,293 2021 2,332 2022 1,508 2023 278 Thereafter - Total $8,621 Letter of CreditThe Company had outstanding letters of credit in the amounts of $327 and $65 at December 31, 2018 and 2017, respectively, which were required as acondition of the Company’s office and laboratory leases.Indemnification AgreementsIn the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and otherparties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringementclaims made by third parties. In addition, the Company has entered into indemnification agreements with its executive officers and members of its board ofdirectors that require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service asexecutive officers or directors. The maximum potential amount of future payments the Company could be required to make under these indemnificationagreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnification arrangements.The Company does not believe that the outcome of any claims under indemnification arrangements will have a material effect on its financial position,results of operations or cash flows, and it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31,2018 and 2017.ContingenciesIn the first quarter of 2017, the Company terminated the development, manufacturing and testing agreement (the “Agreement”) it had entered into in January2016 with a third-party. The Company and the third-party were in dispute regarding the remaining amounts owed by the Company to the third-party underthe Agreement. The Company settled the matter in April 2018 for $1,320.Legal ProceedingsOn March 27, 2018, a purported stockholder of the Company, filed a putative class action complaint alleging violations of the federal securities laws, in theUnited States District Court for the District of Massachusetts (Case No. 18-10587), against the Company and certain of the Company’s current executiveofficers and underwriters in the Company’s initial public offering. The plaintiff claims to represent purchasers of the Company’s common stock during theperiod from January 25, 2018 to March 14, 2018 and seeks unspecified damages arising out of the alleged failure to disclose risks associated with toxicityand potential for adverse events related to the Company’s lead product candidate. On May 29, 2018, the plaintiff and another purported stockholder filedseparate motions each seeking his appointment as lead plaintiff and approval of his selected leadF-26counsel. On June 5, 2018, the plaintiff withdrew his motion. On August 14, 2018, the other purported stockholder withdrew his motion. On October 16, 2018,the plaintiff voluntarily dismissed his claims without prejudice to his ability to participate in any putative class actions as an absent class member.On March 28, 2018, a purported stockholder of the Company, filed a putative class action complaint alleging violations of the federal securities laws, in theBusiness Litigation Section of the Superior Court of the Commonwealth of Massachusetts (Civil Action No. 1884-00984), against the Company, Ilan Ganot,Jennifer Ziolkowski, the Company’s directors and certain of the underwriters in the Company’s initial public offering. The plaintiff in this suit claims torepresent purchasers of the Company’s common stock in or traceable to the Company’s January 25, 2018 initial public offering and seeks unspecifieddamages arising out of the alleged failure to disclose risks associated with toxicity and potential for adverse events related to the Company’s lead productcandidate. On April 30, 2018, all defendants including the Company moved to stay the proceedings in favor of the prior-filed federal court securities classaction. The plaintiff filed his opposition to this motion on May 14, 2018, and defendants filed a reply in support of their motion on May 24, 2018. After oralargument on June 13, 2018, the court issued an order on June 22, 2018 allowing the motion to stay and directing the parties to advise the court of the statusof the federal court action every six months. On December 21, 2018, the parties filed a joint status report informing the court of the voluntary dismissal of thefederal actions and of plaintiff’s intent to move to vacate the stay. The court has scheduled a status conference for June 24, 2019.While the Company is vigorously defending against all claims asserted, this litigation could result in substantial costs to the Company and a diversion of theCompany’s management’s attention and resources, which could harm its business. In addition, the uncertainty of the pending lawsuit or potential filing ofadditional lawsuits could lead to more volatility and a reduction in the Company’s stock price. Given the early stage of the litigation, at this time theCompany is unable to reasonably estimate possible losses or form a judgment that an unfavorable outcome is either probable or remote. It is not currentlypossible to assess whether or not the outcome of these proceedings may have a material adverse effect on the Company. 14. License AgreementsUniversity of Washington License AgreementIn 2015, the Company entered into a license agreement with the University of Washington, acting through UW CoMotion, under which the Companyobtained an exclusive, royalty-bearing, sublicensable, worldwide license under a patent application owned by the University of Washington relating to novelmicro-dystrophins and all patents claiming priority to such patent to develop, manufacture, and commercialize products for use in the treatment of DMD andrelated disease indications caused by a lack of functional dystrophin. The Company has the right to grant sublicenses to third parties contingent upon writtenapproval by the University of Washington prior to executing such sublicense, which approval may not be unreasonably withheld.In consideration for the rights granted by the agreement, the Company paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2015. The Company is required to reimburse the University of Washington for costs incurred in applying for, prosecuting andmaintaining patents and pay up to an aggregate of approximately $1 million upon the achievement of certain milestones. In October 2017, the first milestonewas achieved under this agreement. The milestone payment was recorded as a research and development expense in the fourth quarter of 2017. There were nomilestones achieved during the years ended December 31, 2018 and 2016. The Company must also pay royalties of a low single digit percentage of futuresales by the Company and its sublicensees of products developed under the licensed patent rights. In addition, the Company must pay an annualmaintenance fee until certain milestones are achieved, at which time a minimum annual royalty requirement will replace such maintenance fee and will applyto the Company and its sublicensees.The license agreement remains in effect until the expiration of the last-to-expire patent licensed under the agreement. The Company may terminate theagreement at any time upon providing sixty days’ written notice to the University of Washington. The University of Washington may terminate theagreement upon the Company’s uncured, material breach of the agreement or if the Company enters into an insolvency-related event.The Company recorded research and development expense in the amount of $47, $135, and $0 for the years ended December 31, 2018, 2017 and 2016,respectively, under the agreement.F-27The University of Missouri License AgreementIn 2015, the Company entered into a license agreement with the Curators of the University of Missouri (the “University of Missouri”), a public corporation ofMissouri, under which the Company obtained an exclusive, royalty-bearing, sublicensable, worldwide license under certain patent and patent applicationsowned by the University of Missouri relating to a novel synthetic microdystrophin gene to make, sell and distribute products for use in the treatment of DMDand related disease indications resulting from a lack of functional dystrophin.In consideration for the rights granted by the agreement, the Company paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2015. The Company is required to reimburse the University of Missouri for costs incurred in applying for, prosecuting andmaintaining the licensed patents and pay up to an aggregate of approximately $1 million upon the achievement of certain milestones for each productdeveloped based on the licensed patents. In October 2017, the first milestone was achieved under this agreement. The milestone payment was recorded as aresearch and development expense in the fourth quarter of 2017. There were no milestones achieved during the years ended December 31, 2018 and 2016.The Company must pay a royalty of a low single digit percentage of future sales or by its sublicensees of products developed using the licensed patents. Inaddition, the Company must pay an annual maintenance fee until certain milestones are achieved, after which time a minimum annual royalty will replacesuch maintenance fee.Under the agreement, the Company granted the University of Missouri a non-exclusive, royalty-free, irrevocable, paid-up license, with the right to grantsublicenses to non-profit, academic, educational or governmental institutions, to practice and use improvements made by the Company using the licensedpatent rights, solely for non-commercial research purposes.The license agreement remains in effect until the expiration of the last-to-expire patent or the abandonment of the last to be abandoned patent applicationlicensed under the agreement. The University of Missouri may terminate the agreement, or render the license granted thereunder non-exclusive, in individualcountries if the Company’s sublicensees fail to achieve certain milestones. The Company may terminate the license agreement at any time upon providingsix months’ written notice to the University of Missouri and paying a termination fee. Each of the University of Missouri and the Company may alsoterminate the agreement for an uncured default or breach of the agreement by the other party. The Company’s ability to cure such breach only applies to thefirst two notices of such breach provided by the University of Missouri, and thereafter, the University of Missouri may terminate the agreement for theCompany’s default or breach of the agreement upon thirty days’ written notice without an opportunity to cure such default or breach.The Company recorded research and development expense in the amount of $10, $11, and $0 for the years ended December 31, 2018, 2017 and 2016,respectively, under the agreement.The University of Michigan License AgreementIn 2016, the Company entered into a license agreement with the Regents of the University of Michigan, (the “University of Michigan”), a constitutionalcorporation of Michigan, under which the Company obtained an exclusive, royalty-bearing, sublicensable, worldwide license to make, sell and distributeproducts under certain patents owned by the University of Michigan related to microdystrophin and utrophin spectrin-like nucleic acid sequences for any usethat, but for this agreement, would comprise an infringement of a valid claim included in the licensed patent rights.In consideration for the rights granted by the agreement, the Company paid a one-time license fee and a separate fee to cover past patent prosecution costs,which the Company recorded as a research and development expense in 2016. The Company is required to reimburse the University of Michigan for costsincurred in applying for, prosecuting and maintaining patents, and pay up to an aggregate of approximately $1 million upon the achievement of certainmilestones. There were no milestones achieved during the years ended December 31, 2018, 2017 and 2016. The Company must also pay a royalty of a lowsingle digit percentage on future sales by the Company or its sublicensees of products developed using the licensed rights, with a minimum annual royaltyafter certain milestones are achieved. In addition, the Company must pay an annual maintenance fee in any year in which the minimum annual royalty is notreached.Under the agreement, the University of Michigan reserves for itself and its affiliates the right to use the licensed rights for non-commercial research, publicservice, internal and educational purposes and the right to grant the same limited non-commercial rights to other non-profit research institutions.F-28The license agreement remains in effect until the expiration of the last-to-expire patent licensed under the agreement. The University of Michigan mayterminate the agreement upon the Company’s uncured material breach of the agreement, including failure to make required payments under the agreement orto achieve certain milestones, or if the Company becomes insolvent or bankrupt. The Company may terminate the license agreement at any time uponproviding sixty days’ written notice to the University of Michigan.The Company recorded and research and development expense in the amount of $35, $4 and $145 for the years ended December 31, 2018, 2017 and 2016,respectively, under the agreement.Harvard College License AgreementsIn 2016, the Company entered into a license agreement with the President and Fellows of Harvard College, (“Harvard College”), under which the Companyobtained a non-exclusive, royalty-bearing, sublicensable, worldwide license to use certain intellectual property owned by Harvard College to develop,manufacture, and commercialize products for use in the treatment of DMD.In consideration for the rights granted by the agreement, the Company paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2016. The Company is required to pay an annual license maintenance fee until certain milestones are achieved, after which time theannual maintenance fee will increase annually. Such annual maintenance fee will further increase if the Company grants certain rights to a sublicensee orstrategic partner with whom the Company collaborates on the development and commercialization of licensed products. The annual maintenance fee iscreditable against royalty payments. The Company also must pay a milestone payment within thirty days after achieving certain milestones. There were nomilestones achieved during the years ended December 31, 2018, 2017 and 2016. The Company must pay a royalty of a low single digit percentage on futuresales by the Company or its sublicensees of products developed using the licensed technology.The license agreement remains in effect for an initial term of fifteen years, with automatic three-year renewal periods thereafter unless one of the partiesprovides notice of non-renewal. The Company may terminate the license agreement at any time upon providing sixty days’ written notice to HarvardCollege. Harvard College may terminate the agreement in the event the Company becomes bankrupt or insolvent. Both Harvard College and the Companymay also terminate the agreement for an uncured material breach of the agreement by the other party.The Company recorded research and development expense in the amount of $20, $45 and $45 for the years ended December 31, 2018, 2017 and 2016,respectively, under the agreement.In August 2017, the Company entered into another license agreement with Harvard College, under which the Company obtained a non-exclusive, royalty-bearing, sublicensable, worldwide license to use certain intellectual property owned by Harvard College to develop, manufacture, and commercializeproducts for use in the treatment of DMD.In consideration for the rights granted by the agreement, the Company paid a one-time, non-refundable license fee, which was recorded as a research anddevelopment expense in 2017. The Company is required to pay an annual license maintenance fee until certain milestones are achieved, after which time theannual maintenance fee will increase annually. Such annual maintenance fee will further increase if the Company grants certain rights to a sublicensee orstrategic partner with whom the Company collaborates on the development and commercialization of licensed products. The annual maintenance fee iscreditable against royalty payments. The Company also must pay a milestone payment within thirty days after achieving certain milestones. There were nomilestones achieved during the years ended December 31, 2018 and 2017. The Company must pay a royalty of a low single digit percentage on future salesby the Company or its sublicensees of products developed using the licensed technology.The license agreement remains in effect for an initial term of fifteen years, with automatic three-year renewal periods thereafter unless one of the partiesprovides notice of non-renewal. The Company may terminate the license agreement at any time upon providing sixty days’ written notice to HarvardCollege. Harvard College may terminate the agreement in the event the Company becomes bankrupt or insolvent. Both Harvard College and the Companymay also terminate the agreement for an uncured material breach of the agreement by the other party.The Company recorded research and development expense in the amount of $5 and $23 for the years ended December 31, 2018 and 2017, respectively, underthe agreement.F-29Other License AgreementsIn 2016, the Company entered into a license agreement with Life Technologies Corporation, (“Life Technologies”). In consideration for obtaining a non-exclusive, royalty-free, worldwide license to use certain technologies and associated know-how to develop product candidates, the Company paid a one-time, non-refundable license fee. This fee was recorded as a research and development expense in 2016. The license agreement will remain effective inperpetuity unless earlier terminated. Life Technologies has the right to terminate the agreement upon the Company’s material, uncured breach of theagreement or in the event that it determines that continued performance of the agreement may violate any laws. The Company is obligated to diligentlypursue regulatory approval necessary for the development, manufacture and sale of the licensed products. The Company has the right to terminate theagreement at any time upon providing thirty days’ written notice to Life Technologies.15. Net Loss per ShareBasic and diluted net loss per share attributable to common stockholders were calculated as follows:The numerator for basic and diluted net loss per share attributable to common stockholders is as follows: Year Ended December 31, 2018 2017 2016 Net loss $(74,798) $(53,178) $(23,773)Net loss attributable to non-controlling interest - (1,060) (2,234)Net loss attributable to Solid Biosciences Inc. $(74,798) $(52,118) $(21,539)Decretion (accretion) of preferred units to redemption value - (959) 4,309 Redemption of preferred units - 15,685 - Redemption of redeemable interest from non-controlling interest in Solid GT - (1,925) - Net loss attributable to common stockholders $(74,798) $(39,317) $(17,230) The denominator is as follows: Year Ended December 31 2018 2017 2016 Weighted average common stock outstanding, basic and diluted 33,262,597 13,649,485 1,698,904 Net loss per share attributable to common stockholders, basic and diluted is as follows: Year Ended December 31, 2018 2017 2016 Net loss per share attributable to common stockholders, basic and diluted $(2.25) $(2.88) $(10.14) The following potential common stock equivalents, presented based on amounts outstanding at each period end, were excluded from the calculation ofdiluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: Year Ended December 31, 2018 2017 2016 Options to purchase shares of common stock 1,153,198 - - Unvested shares of common stock 743,564 - - Series A common units - - 1,104,391 Series B common units - - - Series D common units - 1,404,265 - 1,896,762 1,404,265 1,104,391F-30 16. Income TaxesThe Company recorded no tax benefit for the year ended December 31, 2018 for the net operating losses incurred due to its uncertainty of realizing a benefitfrom those items. The Company was not subject to federal and state income taxes for the year ended December 31, 2017 as it was organized as a limitedliability company which was taxed as a partnership for U.S. tax purposes.A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations as of December 31, 2018 is as follows: December 31, 2018 Income tax computed at federal statutory tax rate 21.0%State taxes, net of federal benefit 5.5%Permanent differences (0.8)%Tax credits 9.2%Loss taxed as a partnership (1.7)%Conversion to a C-Corporation 0.5%Other (0.1)%Valuation allowance (33.6)% 0.0% The Company established deferred tax assets and liabilities on identified book to tax temporary differences as of the date of conversion to a C-corporation.Deferred income taxes reflect the net tax effects of these temporary differences between the carrying amounts of assets and liabilities for financial reportingpurposes and the amounts used for income tax purposes. Significant components of the Company’s net deferred tax assets as of December 31, 2018 are asfollows: December 31 2018 Deferred tax assets: Tax loss carryforwards $16,417 Tax credit carryforwards 6,903 Deferred expenses 372 Accrued expenses 935 Stock Compensation 856 Other 177 Total deferred tax assets 25,660 Depreciation (406)Valuation allowance (25,254)Net deferred taxes $- As of December 31, 2018, the Company has federal net operating loss carryforwards of $59,357 and tax credits of $6,349 which may be used to offset futurefederal income and tax liability, respectively. In addition, the Company has state net operating loss carryforwards of approximately $59,453 and tax creditsof $702 which may be used to offset future state income and tax liability, respectively. The Company’s ability to utilize these federal and state carryforwardsmay be limited in the future if the Company experiences an ownership change pursuant to Internal Revenue Code Section 382. Ownership changes, asdefined in the Internal Revenue Code, including those resulting from the issuance of common stock in connection with the Company’s public offerings, maylimit the amount of net operating loss and tax credit carryforwards that can be utilized to offset future taxable income or tax liability. The Company has notconducted a study to assess whether a change of control has occurred or whether there have been multiple changes of control since inception due to thesignificant complexity and cost associated with such a study. If the Company has experienced a change of control, as defined by Section 382, at any timesince inception, utilization of the net operating loss carryforwards or research and development tax credit carryforwards would be subject to an annuallimitation under Section 382. Any limitation may result in expiration of a portion of the netF-31operating loss carryforwards or research and development tax credit carryforwards before utilization. Further, until a study is completed and any limitation isknown, no amounts are being presented as an uncertain tax position.A valuation allowance is recorded against deferred tax assets if it is more likely than not that some or all of the deferred tax assets will not be realized. TheCompany has evaluated the positive and negative evidence bearing upon the realizability of the deferred tax assets. The Company concluded, in accordancewith the applicable accounting standards, that it is more likely than not that the Company will not realize the benefit of its deferred tax assets. Accordingly,the Company has recorded a full valuation allowance against its deferred tax assets. The Company had approximately $25,254 in valuation allowancesrecorded against its deferred tax assets as of December 31, 2018.The Company files tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subjectto examination by federal and state jurisdictions, where applicable. There are currently no pending income tax examinations. The Company’s C-Corporation2018 tax year is open under statute. Any tax credit or net operating loss carryforward can be adjusted in future periods after the respective year of generation’sstatute of limitation has closed.As of December 31, 2018, the Company did not have unrecognized tax benefits. The Company recognizes interest and penalties related to income taxes as acomponent of income tax expense. As of December 31, 2018, no interest and penalties have been recorded. 17. Retirement PlanThe Company has a defined contribution savings plan under Section 401(k) of the Internal Revenue Code. The plan covers substantially all employees whomeet minimum age and service requirements and allows participants to defer a portion of their annual compensation on a pretax basis. Companycontributions to the plan may be made at the discretion of the Company’s board of managers. The Company made no contributions to the plan during theyears ended December 31, 2016, 2017 and 2018. 18. Selected Quarterly Financial Information (Unaudited)Selected quarterly results from operations for the years ended December 31, 2018 and 2017 are as follows: 2018 Quarter Ended March 31 June 30 September 30 December 31 (in thousands, except for per share data) Revenues $- $- $- $- Operating expenses 15,973 18,178 19,150 22,386 Loss from operations (15,973) (18,178) (19,150) (22,386)Net loss (15,877) (17,980) (19,020) (21,921)Net loss attributable to Solid Biosciences Inc. (15,877) (17,980) (19,020) (21,921)Net loss attributable to common stockholders (15,877) (17,980) (19,020) (21,921)Net loss per share attributable to common stockholders $(0.54) $(0.52) $(0.55) $(0.63) 2017 Quarter Ended March 31 June 30 September 30 December 31 (in thousands, except for per unit data) Revenues $- $- $- $- Operating expenses 14,113 11,887 13,696 15,161 Loss from operations (14,113) (11,887) (13,696) (15,161)Net loss (13,875) (11,311) (13,505) (14,487)Net loss attributable to Solid Biosciences, LLC (12,815) (11,311) (13,505) (14,487)Net loss attributable to common unitholders (14) (11,311) (13,505) (14,487)Net loss per unit attributable to common unitholders $(0.01) $(0.66) $(0.79) $(0.84) F-32Exhibit 10.2EMPLOYMENT AGREEMENTTHIS EMPLOYMENT AGREEMENT (the “Agreement”), is made as of January 25, 2019 by and between SolidBiosciences Inc. (the “Company”), and Ilan Ganot (the “Executive”) (together, the “Parties”).RECITALSWHEREAS, the Company desires to continue to employ the Executive as its Chief Executive Officer; andWHEREAS, the Company and the Executive are party to an employment agreement dated December 20, 2013 (the“Existing Agreement”) and desire to amend and restate the Existing Agreement with the exception of Sections 3-9 of the ExistingAgreement (the “Restrictive Covenant Provisions”), which shall not be so amended or restated and shall remain in full force and effect;andWHEREAS, the Executive has agreed to continue employment with the Company on the terms and conditions set forth inthis Agreement;NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements of the Partiesherein contained, the Parties hereto agree as follows:1. Agreement. This Agreement shall be effective as of the date first set forth above (the “Effective Date”). Following the EffectiveDate, the Executive shall continue to be an employee of the Company until such employment relationship is terminated in accordancewith Section 6 hereof (the “Term of Employment”).2. Position. During the Term of Employment, the Executive shall serve as the Chief Executive Officer of the Company, working outof the Company’s office in Cambridge, Massachusetts, and travelling as reasonably required by the Executive’s job duties.3. Scope of Employment. During the Term of Employment, the Executive shall be responsible for the performance of those dutiesconsistent with the Executive’s position as Chief Executive Officer. The Executive shall report to the Company’s board of directors(the “Board”) and shall perform and discharge faithfully, diligently, and to the best of the Executive’s ability, the Executive’s dutiesand responsibilities hereunder. The Executive shall devote substantially all of the Executive’s business time, loyalty, attention andefforts to the business and affairs of the Company and its affiliates. Membership on boards of directors of any other companies orcommunity, charitable or industry organizations will be permitted only with the express approval of the Board. The Executive agrees toabide by the rules, regulations, instructions, personnel practices and policies of the Company and any changes therein that may beadopted from time to time by the Company.4. Compensation. As full compensation for all services rendered by the Executive to the Company and any affiliate thereof, during theTerm of Employment, the Company will provide to the Executive the following:  (a) Base Salary. Effective as of January 1, 2019, the Executive shall receive a base salary at the annualized rate of$520,000.00 (the “Base Salary”). The Executive’s Base Salary shall be paid in equal installments in accordance with the Company’sregularly established payroll procedures. The Executive’s Base Salary will be reviewed from time to time by the Board and is subjectto change in the discretion of the Board.(b) Annual Discretionary Bonus. Effective as of January 1, 2019, the Executive will be eligible to earn an annualperformance bonus of up to 55% of the Executive’s Base Salary (the “Target Bonus”), based upon the Board’s assessment of theExecutive’s performance and the Company’s attainment of targeted goals as set by the Board in its sole discretion. The Board maydetermine to provide the bonus in the form of cash, equity award(s), or a combination of cash and equity. Following the close of eachcalendar year, the Board will determine whether the Executive has earned a performance bonus, and the amount of any performancebonus, based on the set criteria. No amount of the annual bonus is guaranteed, and the Executive must be an employee in goodstanding on the date of payment in order to be eligible for any annual bonus, except as specifically set forth below. The Executive’sbonus eligibility will be reviewed from time to time by the Board and is subject to change in the discretion of the Board.(c) Equity Award. The Executive will be eligible to receive equity awards, if any, at such times and on such terms andconditions as the Board shall, in its sole discretion, determine.(d) Paid Time Off. The Executive shall receive paid vacation time plus sick time, consistent with the Company’s policies asin effect from time to time. In addition, the Executive shall receive paid time off for Company holidays which are set annually and inaccordance with Company policy.(e) Benefits. Subject to eligibility requirements and the Company’s polices, the Executive shall have the right, on the samebasis as other employees of the Company, to participate in, and to receive benefits under, any medical, vision and dental insurancepolicy maintained by the Company and the Company shall pay a portion of the cost of the premiums for such medical, vision anddental insurance that is consistent with the Company’s then current employee benefit policy if the Executive elects to participate insuch plans.(f) Withholdings. All compensation payable to the Executive shall be subject to applicable taxes and withholdings.5. Expenses. The Executive will be reimbursed for his actual, necessary and reasonable business expense pursuant to Company policy,subject to the provisions of Section 3 of Exhibit A attached hereto.6. Employment Termination. This Agreement and the employment of the Executive shall terminate upon the occurrence of any of thefollowing:(a) Upon the death of the Executive or at the election of the Company due to the Executive’s “Disability”. As used in thisAgreement, the term “Disability” shall mean a physical or mental illness or disability that prevents the Executive from performing theduties of the Executive’s position for a period of more than any three consecutive months or for periods aggregating more than twenty-six weeks during any twelve-month period. The Company shall  determine in good faith and in its sole discretion whether the Executive is unable to perform the services provided for herein.(b) At the election of the Company, with or without “Cause” (as defined below), immediately upon written notice by theCompany to the Executive. As used in this Agreement, “Cause” shall mean a finding by the Board that the Executive: (i)performed his duties, in the good faith opinion of the Board, in a grossly negligent or reckless manner or withwillful malfeasance; (ii)exhibited habitual drunkenness or engaged in substance abuse; (iii)committed any material violation of any state or federal law relating to the workplace environment (including,without limitation, laws relating to sexual harassment or age, sex or other prohibited discrimination) or anymaterial violation of any material Company policy; (iv)willfully failed or refused to perform in the usual manner at the usual time those duties which he regularly androutinely performed in connection with the business of the Company or such other duties reasonably related to thecapacity in which the Executive is employed hereunder which may be assigned to the Executive by the Board,which failure or refusal continues for a period of more than seven (7) days after written notice thereof has beenprovided to the Executive by the Board, such notice to set forth in reasonable detail the nature of such failure orrefusal; (v)performed any material action when specifically and reasonably instructed not to do so by the Board; (vi)committed any fraud or used or appropriated for his personal use or benefit any funds, properties or opportunitiesof the Company not authorized by the Board to be so used or appropriated; or (vii)was convicted of, or pled guilty or “no contest” to, any felony or any other crime related to the Executive’semployment or involving moral turpitude.(c) At the election of the Executive, with or without “Good Reason” (as defined below), immediately upon written notice bythe Executive to the Company (subject, if it is with Good Reason, to the timing provisions set forth in the definition of Good Reason).As used in this Agreement, “Good Reason” shall mean (without the Executive’s consent): (i)a material diminution in the nature or scope of Executive’s duties, responsibilities, or authority; (ii)a material diminution of the Executive’s base compensation; (iii)the Company’s requiring Executive to relocate Executive’s primary office more than fifty (50) miles from theExecutive’s then-current primary office; or  (iv)any material breach of this Agreement by the Company not otherwise covered by this paragraph; provided, however, that in each case, the Company shall have a period of not less than thirty (30) days to cure any act constitutingGood Reason following Executive’s delivery to the Company of written notice within sixty (60) days of the action or omissionconstituting Good Reason and that the Executive actually terminates employment within thirty (30) days following the expiration of theCompany’s cure period.7. Effect of Termination.(a) All Terminations Other Than by the Company Without Cause or by the Executive With Good Reason. If the Executive’semployment is terminated under any circumstances other than a Qualifying Termination (as defined below) (including a voluntarytermination by the Executive without Good Reason pursuant to Section 6(c), a termination by the Company for Cause pursuant toSection 6(b) or due to the Executive’s death or Disability pursuant to Section 6(a)), the Company’s obligations under this Agreementshall immediately cease and the Executive shall only be entitled to receive (i) the Base Salary that has accrued and to which theExecutive is entitled as of the effective date of such termination and to the extent consistent with general Company policy, accrued butunused paid time off through and including the effective date of such termination, to be paid in accordance with the Company’sestablished payroll procedure and applicable law but no later than the next regularly scheduled pay period, (ii) unreimbursed businessexpenses for which expenses the Executive has timely submitted appropriate documentation in accordance with Section 5 hereof, and(iii) any amounts or benefits to which the Executive is then entitled under the terms of the benefit plans then-sponsored by theCompany in accordance with their terms (and not accelerated to the extent acceleration does not satisfy Section 409A of the InternalRevenue Code of 1986, as amended, (the “Code”) (the payments described in this sentence, the “Accrued Obligations”).(b) Termination by the Company Without Cause or by the Executive With Good Reason Prior to or More Than TwelveMonths Following a Change in Control. If the Executive’s employment is terminated by the Company without Cause pursuant toSection 6(b) or by the Executive with Good Reason pursuant to Section 6(c) (in either case, a “Qualifying Termination”) prior to ormore than twelve (12) months following a Change in Control (as defined below), the Executive shall be entitled to the AccruedObligations. In addition, and subject to Exhibit A and the conditions of Section 7(d), the Company shall: (i) continue to pay to theExecutive, in accordance with the Company’s regularly established payroll procedures, the Executive’s Base Salary for a period oftwelve (12) months and (ii) provided the Executive is eligible for and timely elects to continue receiving group medical insurancepursuant to the “COBRA” law, continue to pay (but in no event longer than twelve (12) months following the Executive’s terminationdate) the share of the premium for health coverage that is paid by the Company for active and similarly-situated employees who receivethe same type of coverage, unless the Company’s provision of such COBRA payments will violate the nondiscrimination requirementsof applicable law, in which case this benefit will not apply (collectively, the “Severance Benefits”).  (c) Termination by the Company Without Cause or by the Executive With Good Reason Within Twelve Months Following aChange in Control. If a Qualifying Termination occurs within twelve (12) months following a Change in Control, then the Executiveshall be entitled to the Accrued Obligations. In addition, and subject to Exhibit A and the conditions of Section 7(d), the Companyshall: (i) continue to pay to the Executive, in accordance with the Company’s regularly established payroll procedures, the Executive’sBase Salary for a period of eighteen (18) months; (ii) pay to the Executive, in a single lump sum on the Payment Date (as definedbelow) an amount equal to 150% of the Executive’s Target Bonus for the year in which termination occurs or the Executive’s TargetBonus immediately prior to the Change in Control, if higher, (iii) provided the Executive is eligible for and timely elects to continuereceiving group medical insurance pursuant to the “COBRA” law, continue to pay (but in no event longer than eighteen (18) monthsfollowing the Executive’s termination date) the share of the premium for health coverage that is paid by the Company for active andsimilarly-situated employees who receive the same type of coverage, unless the Company’s provision of such COBRA payments willviolate the nondiscrimination requirements of applicable law, in which case this benefit will not apply, and (iv) provide that the vestingof the Executive’s then-unvested equity awards that vest based solely on the passage of time shall be accelerated, such that all thenunvested time-based equity awards shall vest and become fully exercisable or non-forfeitable as of the termination date (collectively,the “Change in Control Severance Benefits”).(d) Severance and Release of Claims Agreement. As a condition of the Executive’s receipt of the Severance Benefits or theChange in Control Severance Benefits, as applicable, the Executive must execute and deliver to the Company a severance and releaseof claims agreement in a form to be provided by the Company (the “Severance Agreement”), which Severance Agreement mustbecome irrevocable within 60 days following the date of the Executive’s termination of employment (or such shorter period as may bedirected by the Company). The Severance Benefits or the Change in Control Severance Benefits, as applicable, will be paid orcommence to be paid in the first regular payroll beginning after the Severance Agreement becomes effective, provided that if theforegoing 60 day period (or shorter period as may be directed by the Company) would end in a calendar year subsequent to the year inwhich the Executive’s employment ends, the Severance Benefits or Change in Control Severance Benefits, as applicable, will not bepaid or begin to be paid before the first payroll of the subsequent calendar year (the date the Severance Benefits or Change in ControlSeverance Benefits, as applicable, commence pursuant to this sentence, the “Payment Date”).(e) Change in Control Definition. For purposes of this Agreement, “Change in Control” shall mean the occurrence of any ofthe following events, provided that such event or occurrence constitutes a change in the ownership or effective control of theCompany, or a change in the ownership of a substantial portion of the assets of the Company, as defined in Treasury Regulation §§1.409A-3(i)(5)(v), (vi) and (vii): (i) the acquisition by an individual, entity or group (within the meaning of Section 13(d)(3) or 14(d)(2)of the Securities Exchange Act of 1934 (the “Exchange Act”)) (a “Person”) of beneficial ownership of any capital stock of theCompany if, after such acquisition, such Person beneficially owns (within the meaning of Rule 13d-3 under the Exchange Act) fiftypercent (50%) or more of either (x) the then-outstanding shares of common stock of the Company (the “Outstanding CompanyCommon Stock”) or (y) the combined voting power of the then-outstanding securities of the Company entitled to vote generally in theelection of directors (the “Outstanding Company Voting Securities”); provided,  however, that for purposes of this subsection (i), the following acquisitions shall not constitute a Change in Control: (1) any acquisitiondirectly from the Company or (2) any acquisition by any entity pursuant to a Business Combination (as defined below) which complieswith clauses (x) and (y) of subsection (iii) of this definition; or (ii) a change in the composition of the Board that results in theContinuing Directors (as defined below) no longer constituting a majority of the Board (or, if applicable, the Board of Directors of asuccessor corporation to the Company), where the term “Continuing Director” means at any date a member of the Board (x) who wasa member of the Board on the Effective Date or (y) who was nominated or elected subsequent to such date by at least a majority of thedirectors who were Continuing Directors at the time of such nomination or election or whose election to the Board was recommendedor endorsed by at least a majority of the directors who were Continuing Directors at the time of such nomination or election; provided,however, that there shall be excluded from this clause (y) any individual whose initial assumption of office occurred as a result of anactual or threatened election contest with respect to the election or removal of directors or other actual or threatened solicitation ofproxies or consents, by or on behalf of a person other than the Board; or (iii) the consummation of a merger, consolidation,reorganization, recapitalization or share exchange involving the Company, or a sale or other disposition of all or substantially all of theassets of the Company (a “Business Combination”), unless, immediately following such Business Combination, each of the followingtwo (2) conditions is satisfied: (x) all or substantially all of the individuals and entities who were the beneficial owners of theOutstanding Company Common Stock and Outstanding Company Voting Securities immediately prior to such Business Combinationbeneficially own, directly or indirectly, more than fifty percent (50%) of the then-outstanding shares of common stock and thecombined voting power of the then-outstanding securities entitled to vote generally in the election of directors, respectively, of theresulting or acquiring corporation in such Business Combination (which shall include, without limitation, a corporation which as aresult of such transaction owns the Company or substantially all of the Company’s assets either directly or through one (1) or moresubsidiaries) (such resulting or acquiring corporation is referred to herein as the “Acquiring Corporation”) in substantially the sameproportions as their ownership of the Outstanding Company Common Stock and Outstanding Company Voting Securities,respectively, immediately prior to such Business Combination and (y) no Person (excluding any employee benefit plan (or related trust)maintained or sponsored by the Company or by the Acquiring Corporation) beneficially owns, directly or indirectly, fifty percent(50%) or more of the then-outstanding shares of common stock of the Acquiring Corporation, or of the combined voting power of thethen-outstanding securities of such corporation entitled to vote generally in the election of directors (except to the extent that suchownership existed prior to the Business Combination); or (iv) the liquidation or dissolution of the Company.8. Modified Section 280G Cutback. Notwithstanding any other provision of this Agreement, except as set forth in Section 8(b), in theevent that the Company undergoes a “Change in Ownership or Control” (as defined below), the following provisions shall apply:(a) The Company shall not be obligated to provide to the Executive any portion of any “Contingent CompensationPayments” (as defined below) that the Executive would otherwise be entitled to receive to the extent necessary to eliminate any“excess parachute payments” (as defined in Section 280G(b)(1) of the Code) for the Executive. For purposes of this Section 8, theContingent Compensation Payments so eliminated shall be referred to as the “Eliminated  Payments” and the aggregate amount (determined in accordance with Treasury Regulation Section 1.280G-1, Q/A-30 or any successorprovision) of the Contingent Compensation Payments so eliminated shall be referred to as the “Eliminated Amount.”(b) Notwithstanding the provisions of Section 8(a), no such reduction in Contingent Compensation Payments shall be madeif (1) the Eliminated Amount (computed without regard to this sentence) exceeds (2) 100% of the aggregate present value (determinedin accordance with Treasury Regulation Section 1.280G-1, Q/A-31 and Q/A-32 or any successor provisions) of the amount of anyadditional taxes that would be incurred by the Executive if the Eliminated Payments (determined without regard to this sentence) werepaid to the Executive (including state and federal income taxes on the Eliminated Payments, the excise tax imposed by Section 4999 ofthe Code payable with respect to all of the Contingent Compensation Payments in excess of the Executive’s “base amount” (as definedin Section 280G(b)(3) of the Code), and any withholding taxes). The override of such reduction in Contingent CompensationPayments pursuant to this Section 8(b) shall be referred to as a “Section 8(b) Override.” For purpose of this paragraph, if any federalor state income taxes would be attributable to the receipt of any Eliminated Payment, the amount of such taxes shall be computed bymultiplying the amount of the Eliminated Payment by the maximum combined federal and state income tax rate provided by law.(c) For purposes of this Section 8 the following terms shall have the following respective meanings:(i) “Change in Ownership or Control” shall mean a change in the ownership or effective control of the Companyor in the ownership of a substantial portion of the assets of the Company determined in accordance with Section 280G(b)(2)of the Code.(ii) “Contingent Compensation Payment” shall mean any payment (or benefit) in the nature of compensation thatis made or made available (under this Agreement or otherwise) to or for the benefit of a “disqualified individual” (as definedin Section 280G(c) of the Code) and that is contingent (within the meaning of Section 280G(b)(2)(A)(i) of the Code) on aChange in Ownership or Control of the Company.(d) Any payments or other benefits otherwise due to the Executive following a Change in Ownership or Control that couldreasonably be characterized (as determined by the Company) as Contingent Compensation Payments (the “Potential Payments”) shallnot be made until the dates provided for in this Section 8(d). Within thirty (30) days after each date on which the Executive firstbecomes entitled to receive (whether or not then due) a Contingent Compensation Payment relating to such Change in Ownership orControl, the Company shall determine and notify the Executive (with reasonable detail regarding the basis for its determinations) (1)which Potential Payments constitute Contingent Compensation Payments, (2) the Eliminated Amount and (3) whether the Section 8(b)Override is applicable. Within thirty (30) days after delivery of such notice to the Executive, the Executive shall deliver a response tothe Company (the “Executive Response”) stating either (A) that the Executive agrees with the Company’s determination pursuant tothe preceding sentence or (B) that the Executive disagrees with such determination, in which case the Executive shall set forth (x)which Potential Payments should be characterized as Contingent Compensation Payments, (y) the Eliminated Amount, and (z) whetherthe Section  8(b) Override is applicable. In the event that the Executive fails to deliver an Executive Response on or before the required date, theCompany’s initial determination shall be final. If the Executive states in the Executive Response that the Executive agrees with theCompany’s determination, the Company shall make the Potential Payments to the Executive within three (3) business days followingdelivery to the Company of the Executive Response (except for any Potential Payments which are not due to be made until after suchdate, which Potential Payments shall be made on the date on which they are due). If the Executive states in the Executive Responsethat the Executive disagree with the Company’s determination, then, for a period of sixty (60) days following delivery of the ExecutiveResponse, the Executive and the Company shall use good faith efforts to resolve such dispute. If such dispute is not resolved withinsuch 60-day period, such dispute shall be settled exclusively by arbitration in Cambridge, Massachusetts, in accordance with the rulesof the American Arbitration Association then in effect. Judgment may be entered on the arbitrator’s award in any court havingjurisdiction. The Company shall, within three (3) business days following delivery to the Company of the Executive Response, maketo the Executive those Potential Payments as to which there is no dispute between the Company and the Executive regarding whetherthey should be made (except for any such Potential Payments which are not due to be made until after such date, which PotentialPayments shall be made on the date on which they are due). The balance of the Potential Payments shall be made within three (3)business days following the resolution of such dispute. (e) The Contingent Compensation Payments to be treated as Eliminated Payments shall be determined by the Company bydetermining the “Contingent Compensation Payment Ratio” (as defined below) for each Contingent Compensation Payment and thenreducing the Contingent Compensation Payments in order beginning with the Contingent Compensation Payment with the highestContingent Compensation Payment Ratio. For Contingent Compensation Payments with the same Contingent Compensation PaymentRatio, such Contingent Compensation Payment shall be reduced based on the time of payment of such Contingent CompensationPayments with amounts having later payment dates being reduced first. For Contingent Compensation Payments with the sameContingent Compensation Payment Ratio and the same time of payment, such Contingent Compensation Payments shall be reducedon a pro rata basis (but not below zero) prior to reducing Contingent Compensation Payment with a lower Contingent CompensationPayment Ratio. The term “Contingent Compensation Payment Ratio” shall mean a fraction the numerator of which is the value of theapplicable Contingent Compensation Payment that must be taken into account by the Executive for purposes of Section 4999(a) of theCode, and the denominator of which is the actual amount to be received by the Executive in respect of the applicable ContingentCompensation Payment. For example, in the case of an equity grant that is treated as contingent on the Change in Ownership orControl because the time at which the payment is made or the payment vests is accelerated, the denominator shall be determined byreference to the fair market value of the equity at the acceleration date, and not in accordance with the methodology for determining thevalue of accelerated payments set forth in Treasury Regulation Section 1.280G-1 Q/A-24(b) or (c)).(f) The provisions of this Section 8 are intended to apply to any and all payments or benefits available to the Executive underthis Agreement or any other agreement or plan under which the Executive receives Contingent Compensation Payments.  9. Absence of Restrictions. The Executive represents and warrants that the Executive is not bound by any employment contracts,restrictive covenants or other restrictions that prevent the Executive from entering into employment with, or carrying out theExecutive’s responsibilities for, the Company, or which are in any way inconsistent with any of the terms of this Agreement.10. Notice. Any notice delivered under this Agreement shall be deemed duly delivered three (3) business days after it is sent byregistered or certified mail, return receipt requested, postage prepaid, one (1) business day after it is sent for next-business day deliveryvia a reputable nationwide overnight courier service, or immediately upon hand delivery, in each case to the address of the recipient setforth below.To Executive:At the address set forth in the Executive’s personnel fileTo Company:Solid Biosciences Inc.141 Portland StreetFifth FloorCambridge, MA 02139 Either Party may change the address to which notices are to be delivered by giving notice of such change to the other Party in themanner set forth in this Section 10.11. Applicable Law; Jury Trial Waiver. This Agreement shall be governed by and construed in accordance with the laws of the Stateof Delaware (without reference to the conflict of laws provisions thereof). Any action, suit or other legal proceeding arising under orrelating to any provision of this Agreement shall be commenced only in a court of the State of Delaware (or, if appropriate, a federalcourt located within the State of Delaware), and the Company and the Executive each consents to the jurisdiction of such a court. TheCompany and the Executive each hereby irrevocably waives any right to a trial by jury in any action, suit or other legal proceedingarising under or relating to any provision of this Agreement.12. Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of both Parties and their respectivesuccessors and assigns, including any corporation with which or into which the Company may be merged or which may succeed to itsassets or business; provided, however, that the obligations of the Executive are personal and shall not be assigned by the Executive.13. At-Will Employment. During the Term of Employment, the Executive will continue to be an at-will employee of the Company,which means that, notwithstanding any other provision set forth herein, the employment relationship can be terminated by either Partyfor any reason, at any time, with or without prior notice and with or without Cause.14. Acknowledgment. The Executive states and represents that the Executive has had an opportunity to fully discuss and review theterms of this Agreement with an attorney. The Executive further states and represents that the Executive has carefully read thisAgreement,  understands the contents herein, freely and voluntarily assents to all of the terms and conditions hereof, and signs the Executive’s nameof the Executive’s own free act.15. No Oral Modification, Waiver, Cancellation or Discharge. This Agreement may be amended or modified only by a writteninstrument executed by both the Company and the Executive. No delay or omission by the Company in exercising any right under thisAgreement shall operate as a waiver of that or any other right. A waiver or consent given by the Company on any one occasion shallbe effective only in that instance and shall not be construed as a bar to or waiver of any right on any other occasion.16. Captions and Pronouns. The captions of the sections of this Agreement are for convenience of reference only and in no waydefine, limit or affect the scope or substance of any section of this Agreement. Whenever the context may require, any pronouns usedin this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular forms of nouns and pronounsshall include the plural, and vice versa.17. Interpretation. The Parties agree that this Agreement will be construed without regard to any presumption or rule requiringconstruction or interpretation against the drafting Party. References in this Agreement to “include” or “including” should be read asthough they said “without limitation” or equivalent forms. References in this Agreement to the “Board” shall include any authorizedcommittee thereof.18. Severability. Each provision of this Agreement must be interpreted in such manner as to be effective and valid under applicablelaw, but if any provision of this Agreement is held to be prohibited by or invalid under applicable law, such provision will beineffective only to the extent of such prohibition or invalidity, without invalidating the remainder of such provision or the remainingprovisions of this Agreement. Moreover, if a court of competent jurisdiction determines any of the provisions contained in thisAgreement to be unenforceable because the provision is excessively broad in scope, whether as to duration, activity, geographicapplication, subject or otherwise, it will be construed, by limiting or reducing it to the extent legally permitted, so as to be enforceableto the extent compatible with then applicable law to achieve the intent of the Parties.19. Entire Agreement. This Agreement constitutes the entire agreement between the Parties and supersedes all prior agreements andunderstandings, whether written or oral, relating to the subject matter of this Agreement, provided that, for the avoidance of doubt, theRestrictive Covenant Provisions are not amended hereby and remain in full force and effect. [Signatures on Page Following]  IN WITNESS WHEREOF, the Parties hereto have executed this Agreement as of the day and year set forth above. SOLID BIOSCIENCES INC. By: /s/ Jennifer Ziolkowski Name: Jennifer Ziolkowski Title: Chief Financial Officer EXECUTIVE: /s/ Ilan GanotIlan Ganot  EXHIBIT APayments Subject to Section 409A1.Subject to this Exhibit A, any severance payments that may be due under the Agreement shall begin only upon thedate of the Executive’s “separation from service” (determined as set forth below) which occurs on or after the termination of theExecutive’s employment. The following rules shall apply with respect to distribution of the severance payments, if any, to be providedto the Executive under the Agreement, as applicable: (a)It is intended that each installment of the severance payments provided under the Agreement shall betreated as a separate “payment” for purposes of Section 409A of the Internal Revenue Code (“Section 409A”). Neither theCompany nor the Executive shall have the right to accelerate or defer the delivery of any such payments except to the extentspecifically permitted or required by Section 409A. (b)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is not a“specified employee” (within the meaning of Section 409A), then each installment of the severance payments shall be madeon the dates and terms set forth in the letter agreement. (c)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is a“specified employee” (within the meaning of Section 409A), then: (i)Each installment of the severance payments due under the Agreement that, in accordance with the dates andterms set forth herein, will in all circumstances, regardless of when the Executive’s separation from serviceoccurs, be paid within the short-term deferral period (as defined under Section 409A) shall be treated as ashort-term deferral within the meaning of Treasury Regulation Section 1.409A-1(b)(4) to the maximumextent permissible under Section 409A and shall be paid on the dates and terms set forth in the Agreement;and (ii)Each installment of the severance payments due under the Agreement that is not described in this Exhibit A,Section 1(c)(i) and that would, absent this subsection, be paid within the six-month period following theExecutive’s “separation from service” from the Company shall not be paid until the date that is six monthsand one day after such separation from service (or, if earlier, the Executive’s death), with any suchinstallments that are required to be delayed being accumulated during the six-month period and paid in alump sum on the date that is six months and one day following the Executive’s separation from service andany subsequent installments, if any, being paid in accordance with the dates and terms set forth herein;provided, however, that the preceding provisions of this sentence shall not apply to any installment ofpayments if and to the maximum extent that that such installment is deemed to be paid under a separationpay plan that does not provide for a deferral of compensation by reason of the application of  Treasury Regulation 1.409A-1(b)(9)(iii) (relating to separation pay upon an involuntary separation fromservice). Any installments that qualify for the exception under Treasury Regulation Section 1.409A-1(b)(9)(iii) must be paid no later than the last day of the Executive’s second taxable year following the taxable yearin which the separation from service occurs. 2.The determination of whether and when the Executive’s separation from service from the Company has occurredshall be made and in a manner consistent with, and based on the presumptions set forth in, Treasury Regulation Section 1.409A-1(h). Solely for purposes of Section 2 of this Exhibit A, “Company” shall include all persons with whom the Company would beconsidered a single employer under Section 414(b) and 414(c) of the Code. 3.All reimbursements and in-kind benefits provided under the Agreement shall be made or provided in accordancewith the requirements of Section 409A to the extent that such reimbursements or in-kind benefits are subject to Section 409A,including, where applicable, the requirements that (i) any reimbursement is for expenses incurred during the Executive’s lifetime (orduring a shorter period of time specified in the Agreement), (ii) the amount of expenses eligible for reimbursement during a calendaryear may not affect the expenses eligible for reimbursement in any other calendar year, (iii) the reimbursement of an eligible expensewill be made on or before the last day of the calendar year following the year in which the expense is incurred and (iv) the right toreimbursement is not subject to set off or liquidation or exchange for any other benefit. 4.The Company makes no representation or warranty and shall have no liability to the Executive or to any otherperson if any of the provisions of the Agreement (including this Exhibit A) are determined to constitute deferred compensation subjectto Section 409A but that do not satisfy an exemption from, or the conditions of, that section. 5.The Agreement is intended to comply with, or be exempt from, Section 409A and shall be interpreted accordingly. [Remainder of page intentionally left blank.] Exhibit 10.3EMPLOYMENT AGREEMENTTHIS EMPLOYMENT AGREEMENT (the “Agreement”), is made as of January 25, 2019 by and between SolidBiosciences Inc. (the “Company”), and Alvaro Amorrortu (the “Executive”) (together, the “Parties”).RECITALSWHEREAS, the Company desires to continue to employ the Executive as its Chief Operating Officer; andWHEREAS, the Company and the Executive are party to a letter agreement dated November 6, 2015 (the “ExistingAgreement”) and desire to amend and restate the Existing Agreement with the exception of Exhibit A, as amended, attached to theExisting Agreement (the “Restrictive Covenant Agreement”), which shall not be so amended or restated and shall remain in full forceand effect; andWHEREAS, the Executive has agreed to continue employment with the Company on the terms and conditions set forth inthis Agreement;NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements of the Partiesherein contained, the Parties hereto agree as follows:1. Agreement. This Agreement shall be effective as of the date first set forth above (the “Effective Date”). Following the EffectiveDate, the Executive shall continue to be an employee of the Company until such employment relationship is terminated in accordancewith Section 6 hereof (the “Term of Employment”).2. Position. During the Term of Employment, the Executive shall serve as the Chief Operating Officer of the Company, working outof the Company’s office in Cambridge, Massachusetts, and travelling as reasonably required by the Executive’s job duties.3. Scope of Employment. During the Term of Employment, the Executive shall be responsible for the performance of those dutiesconsistent with the Executive’s position as Chief Operating Officer. The Executive shall report to the Chief Executive Officer of theCompany and/or the Company’s board of directors (the “Board”) and shall perform and discharge faithfully, diligently, and to the bestof the Executive’s ability, the Executive’s duties and responsibilities hereunder. The Executive shall devote substantially all of theExecutive’s business time, loyalty, attention and efforts to the business and affairs of the Company and its affiliates. Membership onboards of directors of up to two other companies or community, charitable or industry organizations will be permitted only with theexpress approval of the Chief Executive Officer, provided that such activities do not create a conflict of interest or otherwise interferewith the Executive’s performance of the Executive’s duties hereunder. Membership on boards of directors of any other companies orcommunity, charitable or industry organizations will be permitted only with the express approval of the Board. The Executive agrees toabide by the rules, regulations, instructions, personnel practices and policies of the Company and any changes therein that may beadopted from time to time by the Company.  4. Compensation. As full compensation for all services rendered by the Executive to the Company and any affiliate thereof, during theTerm of Employment, the Company will provide to the Executive the following:(a) Base Salary. Effective as of January 1, 2019, the Executive shall receive a base salary at the annualized rate of$400,000.00 (the “Base Salary”). The Executive’s Base Salary shall be paid in equal installments in accordance with the Company’sregularly established payroll procedures. The Executive’s Base Salary will be reviewed from time to time by the Board and is subjectto change in the discretion of the Board.(b) Annual Discretionary Bonus. Effective as of January 1, 2019, the Executive will be eligible to earn an annualperformance bonus of up to 40% of the Executive’s Base Salary (the “Target Bonus”), based upon the Board’s assessment of theExecutive’s performance and the Company’s attainment of targeted goals as set by the Board in its sole discretion. The Board maydetermine to provide the bonus in the form of cash, equity award(s), or a combination of cash and equity. Following the close of eachcalendar year, the Board will determine whether the Executive has earned a performance bonus, and the amount of any performancebonus, based on the set criteria. No amount of the annual bonus is guaranteed, and the Executive must be an employee in goodstanding on the date of payment in order to be eligible for any annual bonus, except as specifically set forth below. The Executive’sbonus eligibility will be reviewed from time to time by the Board and is subject to change in the discretion of the Board.(c) Equity Award. The Executive will be eligible to receive equity awards, if any, at such times and on such terms andconditions as the Board shall, in its sole discretion, determine.(d) Paid Time Off. The Executive shall receive paid vacation time plus sick time, consistent with the Company’s policies asin effect from time to time. In addition, the Executive shall receive paid time off for Company holidays which are set annually and inaccordance with Company policy.(e) Benefits. Subject to eligibility requirements and the Company’s polices, the Executive shall have the right, on the samebasis as other employees of the Company, to participate in, and to receive benefits under, any medical, vision and dental insurancepolicy maintained by the Company and the Company shall pay a portion of the cost of the premiums for such medical, vision anddental insurance that is consistent with the Company’s then current employee benefit policy if the Executive elects to participate insuch plans.(f) Withholdings. All compensation payable to the Executive shall be subject to applicable taxes and withholdings.5. Expenses. The Executive will be reimbursed for his actual, necessary and reasonable business expense pursuant to Company policy,subject to the provisions of Section 3 of Exhibit A attached hereto. ActiveUS 171349162 6. Employment Termination. This Agreement and the employment of the Executive shall terminate upon the occurrence of any of thefollowing:(a) Upon the death of the Executive or at the election of the Company due to the Executive’s “Disability”. As used in thisAgreement, the term “Disability” shall mean a physical or mental illness or disability that prevents the Executive from performing theduties of the Executive’s position for a period of more than any three consecutive months or for periods aggregating more than twenty-six weeks during any twelve-month period. The Company shall determine in good faith and in its sole discretion whether theExecutive is unable to perform the services provided for herein.(b) At the election of the Company, with or without “Cause” (as defined below), immediately upon written notice by theCompany to the Executive. As used in this Agreement, “Cause” shall mean a finding by the Company’s Chief Executive Officer or theBoard that the Executive: (i)performed his duties, in the good faith opinion of the Company’s Chief Executive Officer or the Board, in agrossly negligent or reckless manner or with willful malfeasance; (ii)exhibited habitual drunkenness or engaged in substance abuse; (iii)committed any material violation of any state or federal law relating to the workplace environment (including,without limitation, laws relating to sexual harassment or age, sex or other prohibited discrimination) or anymaterial violation of any material Company policy; (iv)willfully failed or refused to perform in the usual manner at the usual time those duties which he regularly androutinely performed in connection with the business of the Company or such other duties reasonably related to thecapacity in which the Executive is employed hereunder which may be assigned to the Executive by theCompany’s Chief Executive Officer or the Board, which failure or refusal continues for a period of more thanseven (7) days after written notice thereof has been provided to the Executive by the Company’s Chief ExecutiveOfficer or the Board, such notice to set forth in reasonable detail the nature of such failure or refusal; (v)performed any material action when specifically and reasonably instructed not to do so by the Company’s ChiefExecutive Officer or the Board; (vi)committed any fraud or used or appropriated for his personal use or benefit any funds, properties or opportunitiesof the Company not authorized by the Company’s Chief Executive Officer or the Board to be so used orappropriated; or (vii)was convicted of, or pled guilty or “no contest” to, any felony or any other crime related to the Executive’semployment or involving moral turpitude. ActiveUS 171349162 (c) At the election of the Executive, with or without “Good Reason” (as defined below), immediately upon written notice bythe Executive to the Company (subject, if it is with Good Reason, to the timing provisions set forth in the definition of Good Reason).As used in this Agreement, “Good Reason” shall mean (without the Executive’s consent): (i)a material diminution in the nature or scope of Executive’s duties, responsibilities, or authority; (ii)a material diminution of the Executive’s base compensation; (iii)the Company’s requiring Executive to relocate Executive’s primary office more than fifty (50) miles from theExecutive’s then-current primary office; or (iv)any material breach of this Agreement by the Company not otherwise covered by this paragraph; provided, however, that in each case, the Company shall have a period of not less than thirty (30) days to cure any act constitutingGood Reason following Executive’s delivery to the Company of written notice within sixty (60) days of the action or omissionconstituting Good Reason and that the Executive actually terminates employment within thirty (30) days following the expiration of theCompany’s cure period.7. Effect of Termination.(a) All Terminations Other Than by the Company Without Cause or by the Executive With Good Reason. If the Executive’semployment is terminated under any circumstances other than a Qualifying Termination (as defined below) (including a voluntarytermination by the Executive without Good Reason pursuant to Section 6(c), a termination by the Company for Cause pursuant toSection 6(b) or due to the Executive’s death or Disability pursuant to Section 6(a)), the Company’s obligations under this Agreementshall immediately cease and the Executive shall only be entitled to receive (i) the Base Salary that has accrued and to which theExecutive is entitled as of the effective date of such termination and to the extent consistent with general Company policy, accrued butunused paid time off through and including the effective date of such termination, to be paid in accordance with the Company’sestablished payroll procedure and applicable law but no later than the next regularly scheduled pay period, (ii) unreimbursed businessexpenses for which expenses the Executive has timely submitted appropriate documentation in accordance with Section 5 hereof, and(iii) any amounts or benefits to which the Executive is then entitled under the terms of the benefit plans then-sponsored by theCompany in accordance with their terms (and not accelerated to the extent acceleration does not satisfy Section 409A of the InternalRevenue Code of 1986, as amended, (the “Code”) (the payments described in this sentence, the “Accrued Obligations”).(b) Termination by the Company Without Cause or by the Executive With Good Reason Prior to or More Than TwelveMonths Following a Change in Control. If the Executive’s employment is terminated by the Company without Cause pursuant toSection 6(b) or by the Executive with Good Reason pursuant to Section 6(c) (in either case, a “Qualifying Termination”) prior to ormore than twelve (12) months following a Change in Control (as defined below), the Executive shall be entitled to the AccruedObligations. In addition, and ActiveUS 171349162 subject to Exhibit A and the conditions of Section 7(d), the Company shall: (i) continue to pay to the Executive, in accordance with theCompany’s regularly established payroll procedures, the Executive’s Base Salary for a period of twelve (12) months and (ii) providedthe Executive is eligible for and timely elects to continue receiving group medical insurance pursuant to the “COBRA” law, continueto pay (but in no event longer than twelve (12) months following the Executive’s termination date) the share of the premium for healthcoverage that is paid by the Company for active and similarly-situated employees who receive the same type of coverage, unless theCompany’s provision of such COBRA payments will violate the nondiscrimination requirements of applicable law, in which case thisbenefit will not apply (collectively, the “Severance Benefits”).(c) Termination by the Company Without Cause or by the Executive With Good Reason Within Twelve Months Following aChange in Control. If a Qualifying Termination occurs within twelve (12) months following a Change in Control, then the Executiveshall be entitled to the Accrued Obligations. In addition, and subject to Exhibit A and the conditions of Section 7(d), the Companyshall: (i) continue to pay to the Executive, in accordance with the Company’s regularly established payroll procedures, the Executive’sBase Salary for a period of twelve (12) months; (ii) pay to the Executive, in a single lump sum on the Payment Date (as defined below)an amount equal to 100% of the Executive’s Target Bonus for the year in which termination occurs or the Executive’s Target Bonusimmediately prior to the Change in Control, if higher, (iii) provided the Executive is eligible for and timely elects to continue receivinggroup medical insurance pursuant to the “COBRA” law, continue to pay (but in no event longer than twelve (12) months following theExecutive’s termination date) the share of the premium for health coverage that is paid by the Company for active and similarly-situated employees who receive the same type of coverage, unless the Company’s provision of such COBRA payments will violate thenondiscrimination requirements of applicable law, in which case this benefit will not apply, and (iv) provide that the vesting of theExecutive’s then-unvested equity awards that vest based solely on the passage of time shall be accelerated, such that all then unvestedtime-based equity awards shall vest and become fully exercisable or non-forfeitable as of the termination date (collectively, the“Change in Control Severance Benefits”). Notwithstanding the foregoing, any outstanding shares of the Company’s common stockheld by the Executive that are subject to vesting pursuant to a restricted stock agreement with the Company as of the Effective Date,shall vest, to the extent they are then unvested, in full upon a Change in Control.(d) Severance and Release of Claims Agreement. As a condition of the Executive’s receipt of the Severance Benefits or theChange in Control Severance Benefits, as applicable, the Executive must execute and deliver to the Company a severance and releaseof claims agreement in a form to be provided by the Company (the “Severance Agreement”), which Severance Agreement mustbecome irrevocable within 60 days following the date of the Executive’s termination of employment (or such shorter period as may bedirected by the Company). The Severance Benefits or the Change in Control Severance Benefits, as applicable, will be paid orcommence to be paid in the first regular payroll beginning after the Severance Agreement becomes effective, provided that if theforegoing 60 day period (or shorter period as may be directed by the Company) would end in a calendar year subsequent to the year inwhich the Executive’s employment ends, the Severance Benefits or Change in Control Severance Benefits, as applicable, will not bepaid or begin to be paid before the first payroll of the subsequent ActiveUS 171349162 calendar year (the date the Severance Benefits or Change in Control Severance Benefits, as applicable, commence pursuant to thissentence, the “Payment Date”).(e) Change in Control Definition. For purposes of this Agreement, “Change in Control” shall mean the occurrence of any ofthe following events, provided that such event or occurrence constitutes a change in the ownership or effective control of theCompany, or a change in the ownership of a substantial portion of the assets of the Company, as defined in Treasury Regulation §§1.409A-3(i)(5)(v), (vi) and (vii): (i) the acquisition by an individual, entity or group (within the meaning of Section 13(d)(3) or 14(d)(2)of the Securities Exchange Act of 1934 (the “Exchange Act”)) (a “Person”) of beneficial ownership of any capital stock of theCompany if, after such acquisition, such Person beneficially owns (within the meaning of Rule 13d-3 under the Exchange Act) fiftypercent (50%) or more of either (x) the then-outstanding shares of common stock of the Company (the “Outstanding CompanyCommon Stock”) or (y) the combined voting power of the then-outstanding securities of the Company entitled to vote generally in theelection of directors (the “Outstanding Company Voting Securities”); provided, however, that for purposes of this subsection (i), thefollowing acquisitions shall not constitute a Change in Control: (1) any acquisition directly from the Company or (2) any acquisition byany entity pursuant to a Business Combination (as defined below) which complies with clauses (x) and (y) of subsection (iii) of thisdefinition; or (ii) a change in the composition of the Board that results in the Continuing Directors (as defined below) no longerconstituting a majority of the Board (or, if applicable, the Board of Directors of a successor corporation to the Company), where theterm “Continuing Director” means at any date a member of the Board (x) who was a member of the Board on the Effective Date or (y)who was nominated or elected subsequent to such date by at least a majority of the directors who were Continuing Directors at the timeof such nomination or election or whose election to the Board was recommended or endorsed by at least a majority of the directorswho were Continuing Directors at the time of such nomination or election; provided, however, that there shall be excluded from thisclause (y) any individual whose initial assumption of office occurred as a result of an actual or threatened election contest with respectto the election or removal of directors or other actual or threatened solicitation of proxies or consents, by or on behalf of a person otherthan the Board; or (iii) the consummation of a merger, consolidation, reorganization, recapitalization or share exchange involving theCompany, or a sale or other disposition of all or substantially all of the assets of the Company (a “Business Combination”), unless,immediately following such Business Combination, each of the following two (2) conditions is satisfied: (x) all or substantially all ofthe individuals and entities who were the beneficial owners of the Outstanding Company Common Stock and Outstanding CompanyVoting Securities immediately prior to such Business Combination beneficially own, directly or indirectly, more than fifty percent(50%) of the then-outstanding shares of common stock and the combined voting power of the then-outstanding securities entitled tovote generally in the election of directors, respectively, of the resulting or acquiring corporation in such Business Combination (whichshall include, without limitation, a corporation which as a result of such transaction owns the Company or substantially all of theCompany’s assets either directly or through one (1) or more subsidiaries) (such resulting or acquiring corporation is referred to hereinas the “Acquiring Corporation”) in substantially the same proportions as their ownership of the Outstanding Company Common Stockand Outstanding Company Voting Securities, respectively, immediately prior to such Business Combination and (y) no Person(excluding any employee benefit plan (or related trust) maintained or sponsored by the Company or by the Acquiring Corporation)beneficially owns, directly or indirectly, fifty ActiveUS 171349162 percent (50%) or more of the then-outstanding shares of common stock of the Acquiring Corporation, or of the combined voting powerof the then-outstanding securities of such corporation entitled to vote generally in the election of directors (except to the extent that suchownership existed prior to the Business Combination); or (iv) the liquidation or dissolution of the Company.8. Modified Section 280G Cutback. Notwithstanding any other provision of this Agreement, except as set forth in Section 8(b), in theevent that the Company undergoes a “Change in Ownership or Control” (as defined below), the following provisions shall apply:(a) The Company shall not be obligated to provide to the Executive any portion of any “Contingent CompensationPayments” (as defined below) that the Executive would otherwise be entitled to receive to the extent necessary to eliminate any“excess parachute payments” (as defined in Section 280G(b)(1) of the Code) for the Executive. For purposes of this Section 8, theContingent Compensation Payments so eliminated shall be referred to as the “Eliminated Payments” and the aggregate amount(determined in accordance with Treasury Regulation Section 1.280G-1, Q/A-30 or any successor provision) of the ContingentCompensation Payments so eliminated shall be referred to as the “Eliminated Amount.”(b) Notwithstanding the provisions of Section 8(a), no such reduction in Contingent Compensation Payments shall be madeif (1) the Eliminated Amount (computed without regard to this sentence) exceeds (2) 100% of the aggregate present value (determinedin accordance with Treasury Regulation Section 1.280G-1, Q/A-31 and Q/A-32 or any successor provisions) of the amount of anyadditional taxes that would be incurred by the Executive if the Eliminated Payments (determined without regard to this sentence) werepaid to the Executive (including state and federal income taxes on the Eliminated Payments, the excise tax imposed by Section 4999 ofthe Code payable with respect to all of the Contingent Compensation Payments in excess of the Executive’s “base amount” (as definedin Section 280G(b)(3) of the Code), and any withholding taxes). The override of such reduction in Contingent CompensationPayments pursuant to this Section 8(b) shall be referred to as a “Section 8(b) Override.” For purpose of this paragraph, if any federalor state income taxes would be attributable to the receipt of any Eliminated Payment, the amount of such taxes shall be computed bymultiplying the amount of the Eliminated Payment by the maximum combined federal and state income tax rate provided by law.(c) For purposes of this Section 8 the following terms shall have the following respective meanings:(i) “Change in Ownership or Control” shall mean a change in the ownership or effective control of the Companyor in the ownership of a substantial portion of the assets of the Company determined in accordance with Section 280G(b)(2)of the Code.(ii) “Contingent Compensation Payment” shall mean any payment (or benefit) in the nature of compensation thatis made or made available (under this Agreement or otherwise) to or for the benefit of a “disqualified individual” (as definedin Section 280G(c) of the Code) and that is contingent (within the meaning of Section 280G(b)(2)(A)(i) of the Code) on aChange in Ownership or Control of the Company. ActiveUS 171349162 (d) Any payments or other benefits otherwise due to the Executive following a Change in Ownership or Control that couldreasonably be characterized (as determined by the Company) as Contingent Compensation Payments (the “Potential Payments”) shallnot be made until the dates provided for in this Section 8(d). Within thirty (30) days after each date on which the Executive firstbecomes entitled to receive (whether or not then due) a Contingent Compensation Payment relating to such Change in Ownership orControl, the Company shall determine and notify the Executive (with reasonable detail regarding the basis for its determinations) (1)which Potential Payments constitute Contingent Compensation Payments, (2) the Eliminated Amount and (3) whether the Section 8(b)Override is applicable. Within thirty (30) days after delivery of such notice to the Executive, the Executive shall deliver a response tothe Company (the “Executive Response”) stating either (A) that the Executive agrees with the Company’s determination pursuant tothe preceding sentence or (B) that the Executive disagrees with such determination, in which case the Executive shall set forth (x)which Potential Payments should be characterized as Contingent Compensation Payments, (y) the Eliminated Amount, and (z) whetherthe Section 8(b) Override is applicable. In the event that the Executive fails to deliver an Executive Response on or before the requireddate, the Company’s initial determination shall be final. If the Executive states in the Executive Response that the Executive agreeswith the Company’s determination, the Company shall make the Potential Payments to the Executive within three (3) business daysfollowing delivery to the Company of the Executive Response (except for any Potential Payments which are not due to be made untilafter such date, which Potential Payments shall be made on the date on which they are due). If the Executive states in the ExecutiveResponse that the Executive disagree with the Company’s determination, then, for a period of sixty (60) days following delivery of theExecutive Response, the Executive and the Company shall use good faith efforts to resolve such dispute. If such dispute is notresolved within such 60-day period, such dispute shall be settled exclusively by arbitration in Cambridge, Massachusetts, in accordancewith the rules of the American Arbitration Association then in effect. Judgment may be entered on the arbitrator’s award in any courthaving jurisdiction. The Company shall, within three (3) business days following delivery to the Company of the Executive Response,make to the Executive those Potential Payments as to which there is no dispute between the Company and the Executive regardingwhether they should be made (except for any such Potential Payments which are not due to be made until after such date, whichPotential Payments shall be made on the date on which they are due). The balance of the Potential Payments shall be made withinthree (3) business days following the resolution of such dispute. (e) The Contingent Compensation Payments to be treated as Eliminated Payments shall be determined by the Company bydetermining the “Contingent Compensation Payment Ratio” (as defined below) for each Contingent Compensation Payment and thenreducing the Contingent Compensation Payments in order beginning with the Contingent Compensation Payment with the highestContingent Compensation Payment Ratio. For Contingent Compensation Payments with the same Contingent Compensation PaymentRatio, such Contingent Compensation Payment shall be reduced based on the time of payment of such Contingent CompensationPayments with amounts having later payment dates being reduced first. For Contingent Compensation Payments with the sameContingent Compensation Payment Ratio and the same time of payment, such Contingent Compensation Payments shall be reducedon a pro rata basis (but not below zero) prior to reducing Contingent Compensation Payment with a lower Contingent CompensationPayment Ratio. The term “Contingent Compensation Payment Ratio” ActiveUS 171349162 shall mean a fraction the numerator of which is the value of the applicable Contingent Compensation Payment that must be taken intoaccount by the Executive for purposes of Section 4999(a) of the Code, and the denominator of which is the actual amount to bereceived by the Executive in respect of the applicable Contingent Compensation Payment. For example, in the case of an equity grantthat is treated as contingent on the Change in Ownership or Control because the time at which the payment is made or the paymentvests is accelerated, the denominator shall be determined by reference to the fair market value of the equity at the acceleration date, andnot in accordance with the methodology for determining the value of accelerated payments set forth in Treasury Regulation Section1.280G-1 Q/A-24(b) or (c)).(f) The provisions of this Section 8 are intended to apply to any and all payments or benefits available to the Executive underthis Agreement or any other agreement or plan under which the Executive receives Contingent Compensation Payments.9. Absence of Restrictions. The Executive represents and warrants that the Executive is not bound by any employment contracts,restrictive covenants or other restrictions that prevent the Executive from entering into employment with, or carrying out theExecutive’s responsibilities for, the Company, or which are in any way inconsistent with any of the terms of this Agreement.10. Notice. Any notice delivered under this Agreement shall be deemed duly delivered three (3) business days after it is sent byregistered or certified mail, return receipt requested, postage prepaid, one (1) business day after it is sent for next-business day deliveryvia a reputable nationwide overnight courier service, or immediately upon hand delivery, in each case to the address of the recipient setforth below.To Executive:At the address set forth in the Executive’s personnel fileTo Company:Solid Biosciences Inc.141 Portland StreetFifth FloorCambridge, MA 02139 Either Party may change the address to which notices are to be delivered by giving notice of such change to the other Party in themanner set forth in this Section 10.11. Applicable Law; Jury Trial Waiver. This Agreement shall be governed by and construed in accordance with the laws of the Stateof Delaware (without reference to the conflict of laws provisions thereof). Any action, suit or other legal proceeding arising under orrelating to any provision of this Agreement shall be commenced only in a court of the State of Delaware (or, if appropriate, a federalcourt located within the State of Delaware), and the Company and the Executive each consents to the jurisdiction of such a court. TheCompany and the Executive each hereby irrevocably waives any right to a trial by jury in any action, suit or other legal proceedingarising under or relating to any provision of this Agreement.12. Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of both Parties and their respectivesuccessors and assigns, including any corporation with which or ActiveUS 171349162 into which the Company may be merged or which may succeed to its assets or business; provided, however, that the obligations of theExecutive are personal and shall not be assigned by the Executive.13. At-Will Employment. During the Term of Employment, the Executive will continue to be an at-will employee of the Company,which means that, notwithstanding any other provision set forth herein, the employment relationship can be terminated by either Partyfor any reason, at any time, with or without prior notice and with or without Cause.14. Acknowledgment. The Executive states and represents that the Executive has had an opportunity to fully discuss and review theterms of this Agreement with an attorney. The Executive further states and represents that the Executive has carefully read thisAgreement, understands the contents herein, freely and voluntarily assents to all of the terms and conditions hereof, and signs theExecutive’s name of the Executive’s own free act.15. No Oral Modification, Waiver, Cancellation or Discharge. This Agreement may be amended or modified only by a writteninstrument executed by both the Company and the Executive. No delay or omission by the Company in exercising any right under thisAgreement shall operate as a waiver of that or any other right. A waiver or consent given by the Company on any one occasion shallbe effective only in that instance and shall not be construed as a bar to or waiver of any right on any other occasion.16. Captions and Pronouns. The captions of the sections of this Agreement are for convenience of reference only and in no waydefine, limit or affect the scope or substance of any section of this Agreement. Whenever the context may require, any pronouns usedin this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular forms of nouns and pronounsshall include the plural, and vice versa.17. Interpretation. The Parties agree that this Agreement will be construed without regard to any presumption or rule requiringconstruction or interpretation against the drafting Party. References in this Agreement to “include” or “including” should be read asthough they said “without limitation” or equivalent forms. References in this Agreement to the “Board” shall include any authorizedcommittee thereof.18. Severability. Each provision of this Agreement must be interpreted in such manner as to be effective and valid under applicablelaw, but if any provision of this Agreement is held to be prohibited by or invalid under applicable law, such provision will beineffective only to the extent of such prohibition or invalidity, without invalidating the remainder of such provision or the remainingprovisions of this Agreement. Moreover, if a court of competent jurisdiction determines any of the provisions contained in thisAgreement to be unenforceable because the provision is excessively broad in scope, whether as to duration, activity, geographicapplication, subject or otherwise, it will be construed, by limiting or reducing it to the extent legally permitted, so as to be enforceableto the extent compatible with then applicable law to achieve the intent of the Parties.19. Entire Agreement. This Agreement constitutes the entire agreement between the Parties and supersedes all prior agreements andunderstandings, whether written or oral, relating to the subject matter of this Agreement, provided that, for the avoidance of doubt, theRestrictive Covenant Agreement is not amended hereby and remains in full force and effect. [Signatures on Page Following] ActiveUS 171349162 IN WITNESS WHEREOF, the Parties hereto have executed this Agreement as of the day and year set forth above. SOLID BIOSCIENCES INC. By:/s/ Ilan Ganot Name:Ilan Ganot Title:CEO EXECUTIVE: /s/ Alvaro AmorrortuAlvaro Amorrortu ActiveUS 171349162 EXHIBIT APayments Subject to Section 409A1.Subject to this Exhibit A, any severance payments that may be due under the Agreement shall begin only upon thedate of the Executive’s “separation from service” (determined as set forth below) which occurs on or after the termination of theExecutive’s employment. The following rules shall apply with respect to distribution of the severance payments, if any, to be providedto the Executive under the Agreement, as applicable: (a)It is intended that each installment of the severance payments provided under the Agreement shall betreated as a separate “payment” for purposes of Section 409A of the Internal Revenue Code (“Section 409A”). Neither theCompany nor the Executive shall have the right to accelerate or defer the delivery of any such payments except to the extentspecifically permitted or required by Section 409A. (b)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is not a“specified employee” (within the meaning of Section 409A), then each installment of the severance payments shall be madeon the dates and terms set forth in the letter agreement. (c)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is a“specified employee” (within the meaning of Section 409A), then: (i)Each installment of the severance payments due under the Agreement that, in accordance with the dates andterms set forth herein, will in all circumstances, regardless of when the Executive’s separation from serviceoccurs, be paid within the short-term deferral period (as defined under Section 409A) shall be treated as ashort-term deferral within the meaning of Treasury Regulation Section 1.409A-1(b)(4) to the maximumextent permissible under Section 409A and shall be paid on the dates and terms set forth in the Agreement;and (ii)Each installment of the severance payments due under the Agreement that is not described in this Exhibit A,Section 1(c)(i) and that would, absent this subsection, be paid within the six-month period following theExecutive’s “separation from service” from the Company shall not be paid until the date that is six monthsand one day after such separation from service (or, if earlier, the Executive’s death), with any suchinstallments that are required to be delayed being accumulated during the six-month period and paid in alump sum on the date that is six months and one day following the Executive’s separation from service andany subsequent installments, if any, being paid in accordance with the dates and terms set forth herein;provided, however, that the preceding provisions of this sentence shall not apply to any installment ofpayments if and to the maximum extent that that such installment is deemed to be paid under a separationpay plan that does not ActiveUS 171349162 provide for a deferral of compensation by reason of the application of Treasury Regulation 1.409A-1(b)(9)(iii) (relating to separation pay upon an involuntary separation from service). Any installments that qualifyfor the exception under Treasury Regulation Section 1.409A-1(b)(9)(iii) must be paid no later than the lastday of the Executive’s second taxable year following the taxable year in which the separation from serviceoccurs. 2.The determination of whether and when the Executive’s separation from service from the Company has occurredshall be made and in a manner consistent with, and based on the presumptions set forth in, Treasury Regulation Section 1.409A-1(h). Solely for purposes of Section 2 of this Exhibit A, “Company” shall include all persons with whom the Company would beconsidered a single employer under Section 414(b) and 414(c) of the Code. 3.All reimbursements and in-kind benefits provided under the Agreement shall be made or provided in accordancewith the requirements of Section 409A to the extent that such reimbursements or in-kind benefits are subject to Section 409A,including, where applicable, the requirements that (i) any reimbursement is for expenses incurred during the Executive’s lifetime (orduring a shorter period of time specified in the Agreement), (ii) the amount of expenses eligible for reimbursement during a calendaryear may not affect the expenses eligible for reimbursement in any other calendar year, (iii) the reimbursement of an eligible expensewill be made on or before the last day of the calendar year following the year in which the expense is incurred and (iv) the right toreimbursement is not subject to set off or liquidation or exchange for any other benefit. 4.The Company makes no representation or warranty and shall have no liability to the Executive or to any otherperson if any of the provisions of the Agreement (including this Exhibit A) are determined to constitute deferred compensation subjectto Section 409A but that do not satisfy an exemption from, or the conditions of, that section. 5.The Agreement is intended to comply with, or be exempt from, Section 409A and shall be interpreted accordingly. [Remainder of page intentionally left blank.] ActiveUS 171349162Exhibit 10.4EMPLOYMENT AGREEMENTTHIS EMPLOYMENT AGREEMENT (the “Agreement”), is made as of January 25, 2019 by and between SolidBiosciences Inc. (the “Company”), and Dr. Carl Morris (the “Executive”) (together, the “Parties”).RECITALSWHEREAS, the Company desires to continue to employ the Executive as its Chief Scientific Officer; andWHEREAS, the Company and the Executive are party to a letter agreement dated August 10, 2015 (the “ExistingAgreement”) and desire to amend and restate the Existing Agreement with the exception of Exhibit A, as amended, attached to theExisting Agreement (the “Restrictive Covenant Agreement”), which shall not be so amended or restated and shall remain in full forceand effect; andWHEREAS, the Executive has agreed to continue employment with the Company on the terms and conditions set forth inthis Agreement;NOW, THEREFORE, in consideration of the foregoing and of the respective covenants and agreements of the Partiesherein contained, the Parties hereto agree as follows:1. Agreement. This Agreement shall be effective as of the date first set forth above (the “Effective Date”). Following the EffectiveDate, the Executive shall continue to be an employee of the Company until such employment relationship is terminated in accordancewith Section 6 hereof (the “Term of Employment”).2. Position. During the Term of Employment, the Executive shall serve as the Chief Scientific Officer of the Company, working out ofthe Company’s office in Cambridge, Massachusetts, and travelling as reasonably required by the Executive’s job duties.3. Scope of Employment. During the Term of Employment, the Executive shall be responsible for the performance of those dutiesconsistent with the Executive’s position as Chief Scientific Officer. The Executive shall report to the Chief Executive Officer of theCompany and/or the Company’s board of directors (the “Board”) and shall perform and discharge faithfully, diligently, and to the bestof the Executive’s ability, the Executive’s duties and responsibilities hereunder. The Executive shall devote substantially all of theExecutive’s business time, loyalty, attention and efforts to the business and affairs of the Company and its affiliates. Membership onboards of directors of up to two other companies or community, charitable or industry organizations will be permitted only with theexpress approval of the Chief Executive Officer, provided that such activities do not create a conflict of interest or otherwise interferewith the Executive’s performance of the Executive’s duties hereunder. Membership on boards of directors of any other companies orcommunity, charitable or industry organizations will be permitted only with the express approval of the Board. The Executive agrees toabide by the rules, regulations, instructions, personnel practices and policies of the Company and any changes therein that may beadopted from time to time by the Company.  4. Compensation. As full compensation for all services rendered by the Executive to the Company and any affiliate thereof, during theTerm of Employment, the Company will provide to the Executive the following:(a) Base Salary. Effective as of January 1, 2019, the Executive shall receive a base salary at the annualized rate of$380,000.00 (the “Base Salary”). The Executive’s Base Salary shall be paid in equal installments in accordance with the Company’sregularly established payroll procedures. The Executive’s Base Salary will be reviewed from time to time by the Board and is subjectto change in the discretion of the Board.(b) Annual Discretionary Bonus. Effective as of January 1, 2019, the Executive will be eligible to earn an annualperformance bonus of up to 40% of the Executive’s Base Salary (the “Target Bonus”), based upon the Board’s assessment of theExecutive’s performance and the Company’s attainment of targeted goals as set by the Board in its sole discretion. The Board maydetermine to provide the bonus in the form of cash, equity award(s), or a combination of cash and equity. Following the close of eachcalendar year, the Board will determine whether the Executive has earned a performance bonus, and the amount of any performancebonus, based on the set criteria. No amount of the annual bonus is guaranteed, and the Executive must be an employee in goodstanding on the date of payment in order to be eligible for any annual bonus, except as specifically set forth below. The Executive’sbonus eligibility will be reviewed from time to time by the Board and is subject to change in the discretion of the Board.(c) Equity Award. The Executive will be eligible to receive equity awards, if any, at such times and on such terms andconditions as the Board shall, in its sole discretion, determine.(d) Paid Time Off. The Executive shall receive paid vacation time plus sick time, consistent with the Company’s policies asin effect from time to time. In addition, the Executive shall receive paid time off for Company holidays which are set annually and inaccordance with Company policy.(e) Benefits. Subject to eligibility requirements and the Company’s polices, the Executive shall have the right, on the samebasis as other employees of the Company, to participate in, and to receive benefits under, any medical, vision and dental insurancepolicy maintained by the Company and the Company shall pay a portion of the cost of the premiums for such medical, vision anddental insurance that is consistent with the Company’s then current employee benefit policy if the Executive elects to participate insuch plans.(f) Withholdings. All compensation payable to the Executive shall be subject to applicable taxes and withholdings.5. Expenses. The Executive will be reimbursed for his actual, necessary and reasonable business expense pursuant to Company policy,subject to the provisions of Section 3 of Exhibit A attached hereto.6. Employment Termination. This Agreement and the employment of the Executive shall terminate upon the occurrence of any of thefollowing: ActiveUS 171352047 (a) Upon the death of the Executive or at the election of the Company due to the Executive’s “Disability”. As used in thisAgreement, the term “Disability” shall mean a physical or mental illness or disability that prevents the Executive from performing theduties of the Executive’s position for a period of more than any three consecutive months or for periods aggregating more than twenty-six weeks during any twelve-month period. The Company shall determine in good faith and in its sole discretion whether theExecutive is unable to perform the services provided for herein.(b) At the election of the Company, with or without “Cause” (as defined below), immediately upon written notice by theCompany to the Executive. As used in this Agreement, “Cause” shall mean a finding by the Company’s Chief Executive Officer or theBoard that the Executive: (i)performed his duties, in the good faith opinion of the Company’s Chief Executive Officer or the Board, in agrossly negligent or reckless manner or with willful malfeasance; (ii)exhibited habitual drunkenness or engaged in substance abuse; (iii)committed any material violation of any state or federal law relating to the workplace environment (including,without limitation, laws relating to sexual harassment or age, sex or other prohibited discrimination) or anymaterial violation of any material Company policy; (iv)willfully failed or refused to perform in the usual manner at the usual time those duties which he regularly androutinely performed in connection with the business of the Company or such other duties reasonably related to thecapacity in which the Executive is employed hereunder which may be assigned to the Executive by theCompany’s Chief Executive Officer or the Board, which failure or refusal continues for a period of more thanseven (7) days after written notice thereof has been provided to the Executive by the Company’s Chief ExecutiveOfficer or the Board, such notice to set forth in reasonable detail the nature of such failure or refusal; (v)performed any material action when specifically and reasonably instructed not to do so by the Company’s ChiefExecutive Officer or the Board; (vi)committed any fraud or used or appropriated for his personal use or benefit any funds, properties or opportunitiesof the Company not authorized by the Company’s Chief Executive Officer or the Board to be so used orappropriated; or (vii)was convicted of, or pled guilty or “no contest” to, any felony or any other crime related to the Executive’semployment or involving moral turpitude.(c) At the election of the Executive, with or without “Good Reason” (as defined below), immediately upon written notice bythe Executive to the Company (subject, if it is with Good Reason, to the timing provisions set forth in the definition of Good Reason).As used in this Agreement, “Good Reason” shall mean (without the Executive’s consent): ActiveUS 171352047 (i)a material diminution in the nature or scope of Executive’s duties, responsibilities, or authority; (ii)a material diminution of the Executive’s base compensation; (iii)the Company’s requiring Executive to relocate Executive’s primary office more than fifty (50) miles from theExecutive’s then-current primary office; or (iv)any material breach of this Agreement by the Company not otherwise covered by this paragraph; provided, however, that in each case, the Company shall have a period of not less than thirty (30) days to cure any act constitutingGood Reason following Executive’s delivery to the Company of written notice within sixty (60) days of the action or omissionconstituting Good Reason and that the Executive actually terminates employment within thirty (30) days following the expiration of theCompany’s cure period.7. Effect of Termination.(a) All Terminations Other Than by the Company Without Cause or by the Executive With Good Reason. If the Executive’semployment is terminated under any circumstances other than a Qualifying Termination (as defined below) (including a voluntarytermination by the Executive without Good Reason pursuant to Section 6(c), a termination by the Company for Cause pursuant toSection 6(b) or due to the Executive’s death or Disability pursuant to Section 6(a)), the Company’s obligations under this Agreementshall immediately cease and the Executive shall only be entitled to receive (i) the Base Salary that has accrued and to which theExecutive is entitled as of the effective date of such termination and to the extent consistent with general Company policy, accrued butunused paid time off through and including the effective date of such termination, to be paid in accordance with the Company’sestablished payroll procedure and applicable law but no later than the next regularly scheduled pay period, (ii) unreimbursed businessexpenses for which expenses the Executive has timely submitted appropriate documentation in accordance with Section 5 hereof, and(iii) any amounts or benefits to which the Executive is then entitled under the terms of the benefit plans then-sponsored by theCompany in accordance with their terms (and not accelerated to the extent acceleration does not satisfy Section 409A of the InternalRevenue Code of 1986, as amended, (the “Code”) (the payments described in this sentence, the “Accrued Obligations”).(b) Termination by the Company Without Cause or by the Executive With Good Reason Prior to or More Than TwelveMonths Following a Change in Control. If the Executive’s employment is terminated by the Company without Cause pursuant toSection 6(b) or by the Executive with Good Reason pursuant to Section 6(c) (in either case, a “Qualifying Termination”) prior to ormore than twelve (12) months following a Change in Control (as defined below), the Executive shall be entitled to the AccruedObligations. In addition, and subject to Exhibit A and the conditions of Section 7(d), the Company shall: (i) continue to pay to theExecutive, in accordance with the Company’s regularly established payroll procedures, the Executive’s Base Salary for a period oftwelve (12) months and (ii) provided the Executive is eligible for and timely elects to continue receiving group medical insurancepursuant to the ActiveUS 171352047 “COBRA” law, continue to pay (but in no event longer than twelve (12) months following the Executive’s termination date) the shareof the premium for health coverage that is paid by the Company for active and similarly-situated employees who receive the same typeof coverage, unless the Company’s provision of such COBRA payments will violate the nondiscrimination requirements of applicablelaw, in which case this benefit will not apply (collectively, the “Severance Benefits”).(c) Termination by the Company Without Cause or by the Executive With Good Reason Within Twelve Months Following aChange in Control. If a Qualifying Termination occurs within twelve (12) months following a Change in Control, then the Executiveshall be entitled to the Accrued Obligations. In addition, and subject to Exhibit A and the conditions of Section 7(d), the Companyshall: (i) continue to pay to the Executive, in accordance with the Company’s regularly established payroll procedures, the Executive’sBase Salary for a period of twelve (12) months; (ii) pay to the Executive, in a single lump sum on the Payment Date (as defined below)an amount equal to 100% of the Executive’s Target Bonus for the year in which termination occurs or the Executive’s Target Bonusimmediately prior to the Change in Control, if higher, (iii) provided the Executive is eligible for and timely elects to continue receivinggroup medical insurance pursuant to the “COBRA” law, continue to pay (but in no event longer than twelve (12) months following theExecutive’s termination date) the share of the premium for health coverage that is paid by the Company for active and similarly-situated employees who receive the same type of coverage, unless the Company’s provision of such COBRA payments will violate thenondiscrimination requirements of applicable law, in which case this benefit will not apply, and (iv) provide that the vesting of theExecutive’s then-unvested equity awards that vest based solely on the passage of time shall be accelerated, such that all then unvestedtime-based equity awards shall vest and become fully exercisable or non-forfeitable as of the termination date (collectively, the“Change in Control Severance Benefits”).(d) Severance and Release of Claims Agreement. As a condition of the Executive’s receipt of the Severance Benefits or theChange in Control Severance Benefits, as applicable, the Executive must execute and deliver to the Company a severance and releaseof claims agreement in a form to be provided by the Company (the “Severance Agreement”), which Severance Agreement mustbecome irrevocable within 60 days following the date of the Executive’s termination of employment (or such shorter period as may bedirected by the Company). The Severance Benefits or the Change in Control Severance Benefits, as applicable, will be paid orcommence to be paid in the first regular payroll beginning after the Severance Agreement becomes effective, provided that if theforegoing 60 day period (or shorter period as may be directed by the Company) would end in a calendar year subsequent to the year inwhich the Executive’s employment ends, the Severance Benefits or Change in Control Severance Benefits, as applicable, will not bepaid or begin to be paid before the first payroll of the subsequent calendar year (the date the Severance Benefits or Change in ControlSeverance Benefits, as applicable, commence pursuant to this sentence, the “Payment Date”).(e) Change in Control Definition. For purposes of this Agreement, “Change in Control” shall mean the occurrence of any ofthe following events, provided that such event or occurrence constitutes a change in the ownership or effective control of theCompany, or a change in the ownership of a substantial portion of the assets of the Company, as defined in Treasury Regulation §§1.409A-3(i)(5)(v), (vi) and (vii): (i) the acquisition by an individual, entity or ActiveUS 171352047 group (within the meaning of Section 13(d)(3) or 14(d)(2) of the Securities Exchange Act of 1934 (the “Exchange Act”)) (a “Person”)of beneficial ownership of any capital stock of the Company if, after such acquisition, such Person beneficially owns (within themeaning of Rule 13d-3 under the Exchange Act) fifty percent (50%) or more of either (x) the then-outstanding shares of common stockof the Company (the “Outstanding Company Common Stock”) or (y) the combined voting power of the then-outstanding securities ofthe Company entitled to vote generally in the election of directors (the “Outstanding Company Voting Securities”); provided, however,that for purposes of this subsection (i), the following acquisitions shall not constitute a Change in Control: (1) any acquisition directlyfrom the Company or (2) any acquisition by any entity pursuant to a Business Combination (as defined below) which complies withclauses (x) and (y) of subsection (iii) of this definition; or (ii) a change in the composition of the Board that results in the ContinuingDirectors (as defined below) no longer constituting a majority of the Board (or, if applicable, the Board of Directors of a successorcorporation to the Company), where the term “Continuing Director” means at any date a member of the Board (x) who was a memberof the Board on the Effective Date or (y) who was nominated or elected subsequent to such date by at least a majority of the directorswho were Continuing Directors at the time of such nomination or election or whose election to the Board was recommended orendorsed by at least a majority of the directors who were Continuing Directors at the time of such nomination or election; provided,however, that there shall be excluded from this clause (y) any individual whose initial assumption of office occurred as a result of anactual or threatened election contest with respect to the election or removal of directors or other actual or threatened solicitation ofproxies or consents, by or on behalf of a person other than the Board; or (iii) the consummation of a merger, consolidation,reorganization, recapitalization or share exchange involving the Company, or a sale or other disposition of all or substantially all of theassets of the Company (a “Business Combination”), unless, immediately following such Business Combination, each of the followingtwo (2) conditions is satisfied: (x) all or substantially all of the individuals and entities who were the beneficial owners of theOutstanding Company Common Stock and Outstanding Company Voting Securities immediately prior to such Business Combinationbeneficially own, directly or indirectly, more than fifty percent (50%) of the then-outstanding shares of common stock and thecombined voting power of the then-outstanding securities entitled to vote generally in the election of directors, respectively, of theresulting or acquiring corporation in such Business Combination (which shall include, without limitation, a corporation which as aresult of such transaction owns the Company or substantially all of the Company’s assets either directly or through one (1) or moresubsidiaries) (such resulting or acquiring corporation is referred to herein as the “Acquiring Corporation”) in substantially the sameproportions as their ownership of the Outstanding Company Common Stock and Outstanding Company Voting Securities,respectively, immediately prior to such Business Combination and (y) no Person (excluding any employee benefit plan (or related trust)maintained or sponsored by the Company or by the Acquiring Corporation) beneficially owns, directly or indirectly, fifty percent(50%) or more of the then-outstanding shares of common stock of the Acquiring Corporation, or of the combined voting power of thethen-outstanding securities of such corporation entitled to vote generally in the election of directors (except to the extent that suchownership existed prior to the Business Combination); or (iv) the liquidation or dissolution of the Company. ActiveUS 171352047 8. Modified Section 280G Cutback. Notwithstanding any other provision of this Agreement, except as set forth in Section 8(b), in theevent that the Company undergoes a “Change in Ownership or Control” (as defined below), the following provisions shall apply:(a) The Company shall not be obligated to provide to the Executive any portion of any “Contingent CompensationPayments” (as defined below) that the Executive would otherwise be entitled to receive to the extent necessary to eliminate any“excess parachute payments” (as defined in Section 280G(b)(1) of the Code) for the Executive. For purposes of this Section 8, theContingent Compensation Payments so eliminated shall be referred to as the “Eliminated Payments” and the aggregate amount(determined in accordance with Treasury Regulation Section 1.280G-1, Q/A-30 or any successor provision) of the ContingentCompensation Payments so eliminated shall be referred to as the “Eliminated Amount.”(b) Notwithstanding the provisions of Section 8(a), no such reduction in Contingent Compensation Payments shall be madeif (1) the Eliminated Amount (computed without regard to this sentence) exceeds (2) 100% of the aggregate present value (determinedin accordance with Treasury Regulation Section 1.280G-1, Q/A-31 and Q/A-32 or any successor provisions) of the amount of anyadditional taxes that would be incurred by the Executive if the Eliminated Payments (determined without regard to this sentence) werepaid to the Executive (including state and federal income taxes on the Eliminated Payments, the excise tax imposed by Section 4999 ofthe Code payable with respect to all of the Contingent Compensation Payments in excess of the Executive’s “base amount” (as definedin Section 280G(b)(3) of the Code), and any withholding taxes). The override of such reduction in Contingent CompensationPayments pursuant to this Section 8(b) shall be referred to as a “Section 8(b) Override.” For purpose of this paragraph, if any federalor state income taxes would be attributable to the receipt of any Eliminated Payment, the amount of such taxes shall be computed bymultiplying the amount of the Eliminated Payment by the maximum combined federal and state income tax rate provided by law.(c) For purposes of this Section 8 the following terms shall have the following respective meanings:(i) “Change in Ownership or Control” shall mean a change in the ownership or effective control of the Companyor in the ownership of a substantial portion of the assets of the Company determined in accordance with Section 280G(b)(2)of the Code.(ii) “Contingent Compensation Payment” shall mean any payment (or benefit) in the nature of compensation thatis made or made available (under this Agreement or otherwise) to or for the benefit of a “disqualified individual” (as definedin Section 280G(c) of the Code) and that is contingent (within the meaning of Section 280G(b)(2)(A)(i) of the Code) on aChange in Ownership or Control of the Company.(d) Any payments or other benefits otherwise due to the Executive following a Change in Ownership or Control that couldreasonably be characterized (as determined by the Company) as Contingent Compensation Payments (the “Potential Payments”) shallnot be made until the dates provided for in this Section 8(d). Within thirty (30) days after each date on which the Executive firstbecomes entitled to receive (whether or not then due) a Contingent Compensation Payment ActiveUS 171352047 relating to such Change in Ownership or Control, the Company shall determine and notify the Executive (with reasonable detailregarding the basis for its determinations) (1) which Potential Payments constitute Contingent Compensation Payments, (2) theEliminated Amount and (3) whether the Section 8(b) Override is applicable. Within thirty (30) days after delivery of such notice to theExecutive, the Executive shall deliver a response to the Company (the “Executive Response”) stating either (A) that the Executiveagrees with the Company’s determination pursuant to the preceding sentence or (B) that the Executive disagrees with suchdetermination, in which case the Executive shall set forth (x) which Potential Payments should be characterized as ContingentCompensation Payments, (y) the Eliminated Amount, and (z) whether the Section 8(b) Override is applicable. In the event that theExecutive fails to deliver an Executive Response on or before the required date, the Company’s initial determination shall be final. Ifthe Executive states in the Executive Response that the Executive agrees with the Company’s determination, the Company shall makethe Potential Payments to the Executive within three (3) business days following delivery to the Company of the Executive Response(except for any Potential Payments which are not due to be made until after such date, which Potential Payments shall be made on thedate on which they are due). If the Executive states in the Executive Response that the Executive disagree with the Company’sdetermination, then, for a period of sixty (60) days following delivery of the Executive Response, the Executive and the Companyshall use good faith efforts to resolve such dispute. If such dispute is not resolved within such 60-day period, such dispute shall besettled exclusively by arbitration in Cambridge, Massachusetts, in accordance with the rules of the American Arbitration Associationthen in effect. Judgment may be entered on the arbitrator’s award in any court having jurisdiction. The Company shall, within three(3) business days following delivery to the Company of the Executive Response, make to the Executive those Potential Payments as towhich there is no dispute between the Company and the Executive regarding whether they should be made (except for any suchPotential Payments which are not due to be made until after such date, which Potential Payments shall be made on the date on whichthey are due). The balance of the Potential Payments shall be made within three (3) business days following the resolution of suchdispute. (e) The Contingent Compensation Payments to be treated as Eliminated Payments shall be determined by the Company bydetermining the “Contingent Compensation Payment Ratio” (as defined below) for each Contingent Compensation Payment and thenreducing the Contingent Compensation Payments in order beginning with the Contingent Compensation Payment with the highestContingent Compensation Payment Ratio. For Contingent Compensation Payments with the same Contingent Compensation PaymentRatio, such Contingent Compensation Payment shall be reduced based on the time of payment of such Contingent CompensationPayments with amounts having later payment dates being reduced first. For Contingent Compensation Payments with the sameContingent Compensation Payment Ratio and the same time of payment, such Contingent Compensation Payments shall be reducedon a pro rata basis (but not below zero) prior to reducing Contingent Compensation Payment with a lower Contingent CompensationPayment Ratio. The term “Contingent Compensation Payment Ratio” shall mean a fraction the numerator of which is the value of theapplicable Contingent Compensation Payment that must be taken into account by the Executive for purposes of Section 4999(a) of theCode, and the denominator of which is the actual amount to be received by the Executive in respect of the applicable ContingentCompensation Payment. For example, in the case of an equity grant that is treated as contingent on the Change in Ownership orControl ActiveUS 171352047 because the time at which the payment is made or the payment vests is accelerated, the denominator shall be determined by reference tothe fair market value of the equity at the acceleration date, and not in accordance with the methodology for determining the value ofaccelerated payments set forth in Treasury Regulation Section 1.280G-1 Q/A-24(b) or (c)).(f) The provisions of this Section 8 are intended to apply to any and all payments or benefits available to the Executive underthis Agreement or any other agreement or plan under which the Executive receives Contingent Compensation Payments.9. Absence of Restrictions. The Executive represents and warrants that the Executive is not bound by any employment contracts,restrictive covenants or other restrictions that prevent the Executive from entering into employment with, or carrying out theExecutive’s responsibilities for, the Company, or which are in any way inconsistent with any of the terms of this Agreement.10. Notice. Any notice delivered under this Agreement shall be deemed duly delivered three (3) business days after it is sent byregistered or certified mail, return receipt requested, postage prepaid, one (1) business day after it is sent for next-business day deliveryvia a reputable nationwide overnight courier service, or immediately upon hand delivery, in each case to the address of the recipient setforth below.To Executive:At the address set forth in the Executive’s personnel fileTo Company:Solid Biosciences Inc.141 Portland StreetFifth FloorCambridge, MA 02139 Either Party may change the address to which notices are to be delivered by giving notice of such change to the other Party in themanner set forth in this Section 10.11. Applicable Law; Jury Trial Waiver. This Agreement shall be governed by and construed in accordance with the laws of the Stateof Delaware (without reference to the conflict of laws provisions thereof). Any action, suit or other legal proceeding arising under orrelating to any provision of this Agreement shall be commenced only in a court of the State of Delaware (or, if appropriate, a federalcourt located within the State of Delaware), and the Company and the Executive each consents to the jurisdiction of such a court. TheCompany and the Executive each hereby irrevocably waives any right to a trial by jury in any action, suit or other legal proceedingarising under or relating to any provision of this Agreement.12. Successors and Assigns. This Agreement shall be binding upon and inure to the benefit of both Parties and their respectivesuccessors and assigns, including any corporation with which or into which the Company may be merged or which may succeed to itsassets or business; provided, however, that the obligations of the Executive are personal and shall not be assigned by the Executive. ActiveUS 171352047 13. At-Will Employment. During the Term of Employment, the Executive will continue to be an at-will employee of the Company,which means that, notwithstanding any other provision set forth herein, the employment relationship can be terminated by either Partyfor any reason, at any time, with or without prior notice and with or without Cause.14. Acknowledgment. The Executive states and represents that the Executive has had an opportunity to fully discuss and review theterms of this Agreement with an attorney. The Executive further states and represents that the Executive has carefully read thisAgreement, understands the contents herein, freely and voluntarily assents to all of the terms and conditions hereof, and signs theExecutive’s name of the Executive’s own free act.15. No Oral Modification, Waiver, Cancellation or Discharge. This Agreement may be amended or modified only by a writteninstrument executed by both the Company and the Executive. No delay or omission by the Company in exercising any right under thisAgreement shall operate as a waiver of that or any other right. A waiver or consent given by the Company on any one occasion shallbe effective only in that instance and shall not be construed as a bar to or waiver of any right on any other occasion.16. Captions and Pronouns. The captions of the sections of this Agreement are for convenience of reference only and in no waydefine, limit or affect the scope or substance of any section of this Agreement. Whenever the context may require, any pronouns usedin this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular forms of nouns and pronounsshall include the plural, and vice versa.17. Interpretation. The Parties agree that this Agreement will be construed without regard to any presumption or rule requiringconstruction or interpretation against the drafting Party. References in this Agreement to “include” or “including” should be read asthough they said “without limitation” or equivalent forms. References in this Agreement to the “Board” shall include any authorizedcommittee thereof.18. Severability. Each provision of this Agreement must be interpreted in such manner as to be effective and valid under applicablelaw, but if any provision of this Agreement is held to be prohibited by or invalid under applicable law, such provision will beineffective only to the extent of such prohibition or invalidity, without invalidating the remainder of such provision or the remainingprovisions of this Agreement. Moreover, if a court of competent jurisdiction determines any of the provisions contained in thisAgreement to be unenforceable because the provision is excessively broad in scope, whether as to duration, activity, geographicapplication, subject or otherwise, it will be construed, by limiting or reducing it to the extent legally permitted, so as to be enforceableto the extent compatible with then applicable law to achieve the intent of the Parties.19. Entire Agreement. This Agreement constitutes the entire agreement between the Parties and supersedes all prior agreements andunderstandings, whether written or oral, relating to the subject matter of this Agreement, provided that, for the avoidance of doubt, theRestrictive Covenant Agreement is not amended hereby and remains in full force and effect. [Signatures on Page Following] ActiveUS 171352047 IN WITNESS WHEREOF, the Parties hereto have executed this Agreement as of the day and year set forth above. SOLID BIOSCIENCES INC. By: /s/ Ilan Ganot Name: Ilan Ganot Title: CEO EXECUTIVE: /s/ Carl MorrisDr. Carl Morris ActiveUS 171352047 EXHIBIT APayments Subject to Section 409A1.Subject to this Exhibit A, any severance payments that may be due under the Agreement shall begin only upon thedate of the Executive’s “separation from service” (determined as set forth below) which occurs on or after the termination of theExecutive’s employment. The following rules shall apply with respect to distribution of the severance payments, if any, to be providedto the Executive under the Agreement, as applicable: (a)It is intended that each installment of the severance payments provided under the Agreement shall betreated as a separate “payment” for purposes of Section 409A of the Internal Revenue Code (“Section 409A”). Neither theCompany nor the Executive shall have the right to accelerate or defer the delivery of any such payments except to the extentspecifically permitted or required by Section 409A. (b)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is not a“specified employee” (within the meaning of Section 409A), then each installment of the severance payments shall be madeon the dates and terms set forth in the letter agreement. (c)If, as of the date of the Executive’s “separation from service” from the Company, the Executive is a“specified employee” (within the meaning of Section 409A), then: (i)Each installment of the severance payments due under the Agreement that, in accordance with the dates andterms set forth herein, will in all circumstances, regardless of when the Executive’s separation from serviceoccurs, be paid within the short-term deferral period (as defined under Section 409A) shall be treated as ashort-term deferral within the meaning of Treasury Regulation Section 1.409A-1(b)(4) to the maximumextent permissible under Section 409A and shall be paid on the dates and terms set forth in the Agreement;and (ii)Each installment of the severance payments due under the Agreement that is not described in this Exhibit A,Section 1(c)(i) and that would, absent this subsection, be paid within the six-month period following theExecutive’s “separation from service” from the Company shall not be paid until the date that is six monthsand one day after such separation from service (or, if earlier, the Executive’s death), with any suchinstallments that are required to be delayed being accumulated during the six-month period and paid in alump sum on the date that is six months and one day following the Executive’s separation from service andany subsequent installments, if any, being paid in accordance with the dates and terms set forth herein;provided, however, that the preceding provisions of this sentence shall not apply to any installment ofpayments if and to the maximum extent that that such installment is deemed to be paid under a separationpay plan that does not ActiveUS 171352047 provide for a deferral of compensation by reason of the application of Treasury Regulation 1.409A-1(b)(9)(iii) (relating to separation pay upon an involuntary separation from service). Any installments that qualifyfor the exception under Treasury Regulation Section 1.409A-1(b)(9)(iii) must be paid no later than the lastday of the Executive’s second taxable year following the taxable year in which the separation from serviceoccurs. 2.The determination of whether and when the Executive’s separation from service from the Company has occurredshall be made and in a manner consistent with, and based on the presumptions set forth in, Treasury Regulation Section 1.409A-1(h). Solely for purposes of Section 2 of this Exhibit A, “Company” shall include all persons with whom the Company would beconsidered a single employer under Section 414(b) and 414(c) of the Code. 3.All reimbursements and in-kind benefits provided under the Agreement shall be made or provided in accordancewith the requirements of Section 409A to the extent that such reimbursements or in-kind benefits are subject to Section 409A,including, where applicable, the requirements that (i) any reimbursement is for expenses incurred during the Executive’s lifetime (orduring a shorter period of time specified in the Agreement), (ii) the amount of expenses eligible for reimbursement during a calendaryear may not affect the expenses eligible for reimbursement in any other calendar year, (iii) the reimbursement of an eligible expensewill be made on or before the last day of the calendar year following the year in which the expense is incurred and (iv) the right toreimbursement is not subject to set off or liquidation or exchange for any other benefit. 4.The Company makes no representation or warranty and shall have no liability to the Executive or to any otherperson if any of the provisions of the Agreement (including this Exhibit A) are determined to constitute deferred compensation subjectto Section 409A but that do not satisfy an exemption from, or the conditions of, that section. 5.The Agreement is intended to comply with, or be exempt from, Section 409A and shall be interpreted accordingly. [Remainder of page intentionally left blank.] ActiveUS 171352047Exhibit 10.7Solid Biosciences Inc.2018 Omnibus Incentive PlanIncentive Stock Option Agreement Participant: _________________________Grant Date: _________________________Per Share Exercise Price: $_____Number of Shares of Common Stock subject to this Option: _____________________ * * * * * * * * * * * * *This Incentive Stock Option Award Agreement (this “Agreement”), dated as of the Grant Date specified above, isentered into by and between Solid Biosciences Inc., a Delaware corporation, (the “Company”) and the Participant specified above,pursuant to the Solid Biosciences Inc. 2018 Omnibus Incentive Plan, as in effect and as amended from time to time (the “Plan”),which is administered by the Committee; andWhereas, it has been determined that it would be in the best interests of the Company to grant the incentive stock optionprovided for herein to the Participant.Now, therefore, in consideration of the mutual covenants and promises hereinafter set forth and for other good and valuableconsideration, the parties hereto hereby mutually covenant and agree as follows:1.Incorporation by Reference; Plan Document Receipt. This Agreement is subject in all respects to the terms andprovisions of the Plan (including, without limitation, any amendments thereto adopted at any time and from time to time unless suchamendments are expressly intended not to apply to the award provided hereunder), all of which terms and provisions are made a part ofand incorporated in this Agreement as if they were each expressly set forth herein. Any capitalized term not defined in this Agreementshall have the same meaning as is ascribed thereto in the Plan. The Participant hereby acknowledges receipt of a true copy of the Planand that the Participant has read the Plan carefully and fully understands its content. In the event of any conflict between the terms ofthis Agreement and the terms of the Plan, the terms of the Plan shall control.2.Grant of Option. The Company hereby grants to the Participant, as of the Grant Date specified above, anincentive stock option (this “Option”) to acquire from the Company at the Per Share Exercise Price specified above, the aggregatenumber of shares of Common Stock specified above (the “Option Shares”). Except as otherwise provided by the Plan, the Participantagrees and understands that nothing contained in this Agreement provides, or is intended to  provide, the Participant with any protection against potential future dilution of the Participant’s interest in the Company for any reason.The Participant shall have no rights as a stockholder with respect to any shares of Common Stock covered by this Option unless anduntil the Participant has become the holder of record of the shares of Common Stock, and no adjustments shall be made for dividendsin cash or other property, distributions, or other rights in respect of any such shares, except as otherwise specifically provided for in thePlan or this Agreement.3.Tax Matters. The Option granted hereby is intended to qualify as an “incentive stock option” under Section 422of the Code. Notwithstanding the foregoing, the Option will not qualify as an “incentive stock option,” among other events, (a) if theParticipant disposes of the Option Shares at any time during the two-year period following the date of this Agreement or the one-yearperiod following the date of any exercise of the Option; (b) except in the event of the Participant’s death or Disability, if the Participantis not employed by the Company, a Parent, or a Subsidiary at all times during the period beginning on the date of this Agreement andending on the day that is three months before the date of any exercise of the Option; or (c) to the extent the aggregate fair market valueof the Common Stock subject to “incentive stock options” held by the Participant that become exercisable for the first time in anycalendar year (under all plans of the Company, a Parent, or a Subsidiary) exceeds $100,000. For purposes of clause (c) above, the “fairmarket value” of the Common Stock shall be determined as of the Grant Date. To the extent that the Option does not qualify as an“incentive stock option,” it shall not affect the validity of the Option and shall constitute a separate non-qualified stock option. In theevent that the Participant disposes of the Option Shares within either two years following the Grant Date or one year following the dateof exercise of the Option, the Participant must deliver to the Company, within seven days following such disposition, a written noticespecifying the date on which such shares were disposed of, the number of shares of Common Stock so disposed, and, if suchdisposition was by a sale or exchange, the amount of consideration received.4.Vesting; Detrimental Activity; Expiration.(a)Vesting. The Option subject to this grant shall become vested in accordance with the vesting scheduleabove. All vesting of the Option granted hereunder shall occur only on the appropriate vesting date specified above, subject to theParticipant’s continued service with the Company or any of its Subsidiaries through each applicable vesting date. There shall be noproportionate or partial vesting in the periods before each vesting date.(b)Effect of Detrimental Activity. The provisions of Section 6.3(c)(ii) of the Plan regarding DetrimentalActivity shall apply to the Option. The Participant acknowledges and agrees that the restrictions herein and in the Plan regardingDetrimental Activity are necessary for the protection of the business and goodwill of the Company and its Affiliates, and areconsidered by the Participant to be reasonable for such purposes. Without intending to limit the legal or equitable remedies available inthe Plan and in this Agreement, the Participant acknowledges that engaging in Detrimental Activity will cause the Company and itsAffiliates material irreparable injury for which there is no adequate remedy at law, that it will not be possible to measure damages forsuch injuries precisely and that, in the event of such activity or threat thereof, the Company shall be entitled, in addition to the remediesprovided under the Plan, to obtain from any court of competent jurisdiction a temporary restraining order or a preliminary or permanentinjunction restraining the Participant from engaging in Detrimental Activity or such other relief as may be2 required to specifically enforce any of the covenants in the Plan and this Agreement without the necessity of posting a bond, and in thecase of a temporary restraining order or a preliminary injunction, without having to prove special damages.(c)Expiration. The term of the Option shall be until the tenth anniversary of the Grant Date, after whichtime it shall expire (such tenth anniversary date, the “Expiration Date”), subject to earlier termination in the event of the Participant’sTermination as specified in the Plan and this Agreement. Upon the Expiration Date, the Option (whether vested or not) shallautomatically be cancelled for no consideration, shall no longer be exercisable, and shall cease to be outstanding. 5.Termination. Subject to the terms of the Plan and this Agreement, the Option, to the extent vested at the time ofthe Participant’s Termination, shall remain exercisable as follows:(a)Termination due to Death or Disability. In the event of the Participant’s Termination by reason of deathor Disability, the vested portion of this Option shall remain exercisable until the earlier of (i) one year from the date of suchTermination, and (ii) the Expiration Date.(b)Termination Without Cause. In the event of the Participant’s involuntary Termination by the Companywithout Cause, the vested portion of this Option shall remain exercisable until the earlier of (i) ninety days from the date of suchTermination, and (ii) the Expiration Date.(c)Voluntary Termination. In the event of the Participant’s voluntary Termination, the vested portion ofthis Option shall remain exercisable until the earlier of (i) thirty days from the date of such Termination, and (ii) the Expiration Date.(d)Termination for Cause. In the event of the Participant’s Termination by the Company for Cause (or inthe event of a voluntary Termination by the Participant after the occurrence of an event that would be grounds for a Termination forCause), the Option granted hereunder (whether or not vested) shall terminate and expire upon such Termination.(e)Treatment of Unvested Option upon Termination. Any portion of this Option that is not vested as of thedate of the Participant’s Termination for any reason shall terminate and expire as of the date of such Termination.6.Method of Exercise and Payment. Subject to Section 9 hereof, to the extent that the Option has become vestedand exercisable with respect to a number of shares of Common Stock as provided herein, the Option may thereafter be exercised by theParticipant, in whole or in part, at any time or from time to time before the expiration of the Option as provided herein and inaccordance with Section 6.3 of the Plan, including, without limitation, by the delivery of any form of exercise notice as may berequired by the Committee and payment in full of the Per Share Exercise Price multiplied by the number of shares of Common Stockunderlying the portion of the Option exercised.3 7.Non-transferability. The Option, and any rights and interests with respect thereto, issued under this Agreementand the Plan shall not, prior to vesting, be sold, exchanged, Transferred, assigned, or otherwise disposed of in any way by theParticipant (or any beneficiary(ies) of the Participant), other than by testamentary disposition by the Participant or the laws of descentand distribution. Any attempt to sell, exchange, Transfer, assign, pledge, encumber, or otherwise dispose of or hypothecate in any waythe Option, or the levy of any execution, attachment, or similar legal process upon the Option, contrary to the terms and provisions ofthis Agreement and/or the Plan shall be null and void and without legal force or effect.8.Governing Law. All questions concerning the construction, validity, and interpretation of this Agreement shall begoverned by and construed in accordance with the internal laws of the State of Delaware without giving effect to its principles ofconflicts of laws.9.Withholding of Tax. The Company or any Affiliate shall have the power and the right to deduct or withhold,require the Participant to remit to the Company or such Affiliate, or make any other arrangements as it considers appropriate to ensurethat it has received an amount sufficient to satisfy any federal, state, local, and foreign taxes of any kind (including, but not limited to,the Participant’s FICA and SDI obligations) that the Company, in its sole discretion, deems necessary to be withheld or remitted tocomply with the Code and/or any other applicable law, rule, or regulation with respect to the Option and, if the Participant fails to doso, the Company may otherwise refuse to issue or Transfer any shares of Common Stock otherwise required to be issued pursuant tothis Agreement.10.Recoupment Policy. The Participant acknowledges and agrees that this Option (including any shares ofCommon Stock issued upon exercise thereof) shall be subject to the terms and provisions of any “clawback” or recoupment policy thatmay be adopted by the Company or its Affiliates from time to time or as may be required by any applicable law (including, withoutlimitation, the Dodd-Frank Wall Street Reform and Consumer Protection Act and implementing rules and regulations thereunder).11.Notices. Any notice or communication given hereunder shall be in writing and shall be deemed to have been dulygiven: (i) when delivered in person; (ii) two days after being sent by United States mail; or (iii) on the first business day following thedate of deposit if delivered by a nationally recognized overnight delivery service, in each case, to the appropriate party at the addressset forth below (or such other address as the party may from time to time specify):If to the Company, to:Solid Biosciences Inc. Attention: Chief Executive Officerwith a copy (which shall not constitute notice) to:Proskauer Rose LLP4 Eleven Times SquareNew York, NY 10036-8299Attention: Julie M. Allen, Esq.If to the Participant, to the address on file with the Company.12.No Right to Employment. Nothing in this Agreement shall affect the right of the Company or any of itsAffiliates to terminate the Participant’s employment at any time, with or without Cause, or shall be deemed to create any rights toemployment or continued employment. The rights and obligations arising under this Agreement are not intended to and do not affectthe Participant’s employment relationship that otherwise exists between the Participant and the Company or any of its Affiliates,whether such employment relationship is at will or defined by an employment contract. Moreover, this Agreement is not intended toand does not amend any existing employment contract between the Participant and the Company or any of its Affiliates; to the extentthere is a conflict between this Agreement and such an employment contract, the employment contract shall govern and take priority.13.Data Protection. By executing this Agreement, the Participant hereby consents to the holding and processing ofpersonal information provided by the Participant to the Company, any Affiliate thereof, trustee, or third party service provider, for allpurposes relating to the operation of the Plan. These include, but are not limited to: (i) administering and maintaining Participantrecords; (ii) providing information to the Company, its Affiliates, trustees of any employee benefit trust, registrars, brokers, or third-party administrators of the Plan; (iii) providing information to future purchasers or merger partners of the Company or any Affiliatethereof, or the business in which the Participant works; and (iv) transferring information about the Participant to any country or territorythat may not provide the same protection for the information as the Participant’s home country.14.Market Stand-Off. If requested by the Company, any Affiliate, or a lead underwriter of any public offering ofthe shares of Common Stock (a “Lead Underwriter”), the Participant shall irrevocably agree, and by execution of this Agreementshall irrevocably be deemed to have agreed, not to sell, contract to sell, grant any option to purchase, transfer the economic risk ofownership in, make any short sale of, pledge, or otherwise Transfer or dispose of, any interest in any shares of Common Stock or anysecurities convertible into, derivative of, or exchangeable or exercisable for shares of Common Stock, or any other rights to purchase oracquire shares of Common Stock (except shares of Common Stock included in such public offering or acquired on the public marketafter such offering) during such period of time following the effective date of a registration statement of the Company filed under theSecurities Act that a Lead Underwriter shall specify (the “Lock-up Period”). The Participant hereby further agrees to sign suchdocuments as may be requested by a Lead Underwriter, the Company, or any Affiliate to effect the foregoing and agree that theCompany or an Affiliate may impose stop transfer instructions with respect to shares of Common Stock acquired pursuant to anAward until the end of such Lock-up Period.5 15.Compliance with Laws. The issuance of this Option (and the shares of Common Stock upon exercise of thisOption) pursuant to this Agreement shall be subject to, and shall comply with, any applicable requirements of any foreign and U.S.federal and state securities laws, rules, and regulations (including, without limitation, the provisions of the Securities Act, the ExchangeAct, and in each case any respective rules and regulations promulgated thereunder) and any other law or regulation applicable thereto.The Company shall not be obligated to issue this Option or any of the shares of Common Stock pursuant to this Agreement if any suchissuance would violate any such requirements.16.Section 409A. Notwithstanding anything herein or in the Plan to the contrary, the Option is intended to beexempt from the applicable requirements of Section 409A and shall be limited, construed, and interpreted in accordance with suchintent.17.Binding Agreement; Assignment. This Agreement shall inure to the benefit of, be binding upon, and beenforceable by the Company and its successors and assigns. The Participant shall not assign any part of this Agreement without theprior express written consent of the Company.18.Headings. The titles and headings of the various sections of this Agreement have been inserted for convenienceof reference only and shall not be deemed to be a part of this Agreement.19.Counterparts. This Agreement may be executed in one or more counterparts, each of which shall be deemed tobe an original, but all of which shall constitute the same instrument.20.Severability. The invalidity or unenforceability of any provisions of this Agreement in any jurisdiction shall notaffect the validity, legality, or enforceability of the remainder of this Agreement in such jurisdiction or the validity, legality, orenforceability of any provision of this Agreement in any other jurisdiction, it being intended that all rights and obligations of the partieshereunder shall be enforceable to the fullest extent permitted by law.21.Entire Agreement; Amendment. This Agreement, together with the Plan, contains the entire agreement betweenthe parties hereto with respect to the subject matter contained herein, and supersedes all prior agreements or prior understandings,whether written or oral, between the parties relating to such subject matter. The Committee shall have the right, in its sole discretion, tomodify or amend this Agreement from time to time in accordance with and as provided in the Plan. The Company shall give writtennotice to the Participant of any such modification or amendment of this Agreement as soon as practicable after the adoptionthereof. This Agreement may also be modified or amended by a writing signed by both the Company and the Participant.22.Mode of Communications. The Participant agrees, to the fullest extent permitted by applicable law, in lieu ofreceiving documents in paper format, to accept electronic delivery of any documents that the Company or any of its Affiliates maydeliver in connection with this Option grant and any other grants offered by the Company or its Affiliates, including, withoutlimitation, prospectuses, grant notifications, account statements, annual or quarterly6 reports, and other communications. Electronic delivery of a document may be made via the Company’s email system or by referenceto a location on the Company’s intranet, an internet website, or the online brokerage account system.23.Acquired Rights. The Participant acknowledges and agrees that: (a) the Company may terminate or amend thePlan at any time; (b) the award of the Option made under this Agreement is completely independent of any other award or grant and ismade at the sole discretion of the Company; (c) no past grants or awards (including, without limitation, the Option awarded hereunder)give the Participant any right to any grants or awards in the future whatsoever; and (d) any benefits granted under this Agreement arenot part of the Participant’s ordinary salary and shall not be considered as part of such salary in the event of severance, redundancy, orresignation. Remainder of Page Intentionally Left Blank7 IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above. Solid Biosciences Inc. By: Name: Title: Participant Name: Social Security Number: 8Exhibit 10.8Solid Biosciences Inc.2018 Omnibus Incentive PlanNonqualified Stock Option Agreement Participant: _________________________ Grant Date: _________________________ Per Share Exercise Price: $_____ Number of Shares of Common Stock subject to this Option: _____________________ * * * * * * * * * * * * *This Nonqualified Stock Option Award Agreement (this “Agreement”), dated as of the Grant Date specified above, isentered into by and between Solid Biosciences Inc., a Delaware corporation, (the “Company”) and the Participant specified above,pursuant to the Solid Biosciences Inc. 2018 Omnibus Incentive Plan, as in effect and as amended from time to time (the “Plan”),which is administered by the Committee; andWhereas, it has been determined that it would be in the best interests of the Company to grant the nonqualified stock optionprovided for herein to the Participant.Now, therefore, in consideration of the mutual covenants and promises hereinafter set forth and for other good and valuableconsideration, the parties hereto hereby mutually covenant and agree as follows:1.Incorporation by Reference; Plan Document Receipt. This Agreement is subject in all respects to the terms andprovisions of the Plan (including, without limitation, any amendments thereto adopted at any time and from time to time unless suchamendments are expressly intended not to apply to the award provided hereunder), all of which terms and provisions are made a part ofand incorporated in this Agreement as if they were each expressly set forth herein. Any capitalized term not defined in this Agreementshall have the same meaning as is ascribed thereto in the Plan. The Participant hereby acknowledges receipt of a true copy of the Planand that the Participant has read the Plan carefully and fully understands its content. In the event of any conflict between the terms ofthis Agreement and the terms of the Plan, the terms of the Plan shall control. No part of the Option granted hereby is intended toqualify as an “incentive stock option” under Section 422 of the Code.2.Grant of Option. The Company hereby grants to the Participant, as of the Grant Date specified above, anonqualified stock option (this “Option”) to acquire from the Company at the Per Share Exercise Price specified above, the aggregatenumber of shares of Common Stock specified above (the “Option Shares”). Except as otherwise provided by the Plan, the Participantagrees and understands that nothing contained in this Agreement provides, or is intended to 2750/32824-015 CURRENT/92843455v4 provide, the Participant with any protection against potential future dilution of the Participant’s interest in the Company for any reason.The Participant shall have no rights as a stockholder with respect to any shares of Common Stock covered by this Option unless anduntil the Participant has become the holder of record of the shares of Common Stock, and no adjustments shall be made for dividendsin cash or other property, distributions, or other rights in respect of any such shares, except as otherwise specifically provided for in thePlan or this Agreement.3.Vesting; Detrimental Activity; Expiration.(a)Vesting. The Option subject to this grant shall become vested in accordance with thevesting schedule above. All vesting of the Option granted hereunder shall occur only on the appropriate vesting date specified above,subject to the Participant’s continued service with the Company or any of its Subsidiaries through each applicable vesting date. Thereshall be no proportionate or partial vesting in the periods before each vesting date.(b)Effect of Detrimental Activity. The provisions of Section 6.3(c)(ii) of the Plan regardingDetrimental Activity shall apply to the Option. The Participant acknowledges and agrees that the restrictions herein and in the Planregarding Detrimental Activity are necessary for the protection of the business and goodwill of the Company and its Affiliates, and areconsidered by the Participant to be reasonable for such purposes. Without intending to limit the legal or equitable remedies available inthe Plan and in this Agreement, the Participant acknowledges that engaging in Detrimental Activity will cause the Company and itsAffiliates material irreparable injury for which there is no adequate remedy at law, that it will not be possible to measure damages forsuch injuries precisely and that, in the event of such activity or threat thereof, the Company shall be entitled, in addition to the remediesprovided under the Plan, to obtain from any court of competent jurisdiction a temporary restraining order or a preliminary or permanentinjunction restraining the Participant from engaging in Detrimental Activity or such other relief as may be required to specificallyenforce any of the covenants in the Plan and this Agreement without the necessity of posting a bond, and in the case of a temporaryrestraining order or a preliminary injunction, without having to prove special damages.(c)Expiration. The term of the Option shall be until the tenth anniversary of the Grant Date,after which time it shall expire (such tenth anniversary date, the “Expiration Date”), subject to earlier termination in the event of theParticipant’s Termination as specified in the Plan and this Agreement. Upon the Expiration Date, the Option (whether vested or not)shall automatically be cancelled for no consideration, shall no longer be exercisable, and shall cease to be outstanding. 4.Termination. Subject to the terms of the Plan and this Agreement, the Option, to the extent vested at the time ofthe Participant’s Termination, shall remain exercisable as follows:(a)Termination due to Death or Disability. In the event of the Participant’s Termination byreason of death or Disability, the vested portion of this Option shall remain exercisable until the earlier of (i) one year from the date ofsuch Termination, and (ii) the Expiration Date.2  (b)Termination Without Cause. In the event of the Participant’s involuntary Termination bythe Company without Cause, the vested portion of this Option shall remain exercisable until the earlier of (i) ninety days from the dateof such Termination, and (ii) the Expiration Date.(c)Voluntary Termination. In the event of the Participant’s voluntary Termination, thevested portion of this Option shall remain exercisable until the earlier of (i) thirty days from the date of such Termination, and (ii) theExpiration Date.(d)Termination for Cause. In the event of the Participant’s Termination by the Companyfor Cause (or in the event of a voluntary Termination by the Participant after the occurrence of an event that would be grounds for aTermination for Cause), the Option granted hereunder (whether or not vested) shall terminate and expire upon such Termination.(e)Treatment of Unvested Option upon Termination. Any portion of this Option that is notvested as of the date of the Participant’s Termination for any reason shall terminate and expire as of the date of such Termination.5.Method of Exercise and Payment. Subject to Section 8 hereof, to the extent that the Option has become vestedand exercisable with respect to a number of shares of Common Stock as provided herein, the Option may thereafter be exercised by theParticipant, in whole or in part, at any time or from time to time before the expiration of the Option as provided herein and inaccordance with Section 6.3 of the Plan, including, without limitation, by the delivery of any form of exercise notice as may berequired by the Committee and payment in full of the Per Share Exercise Price multiplied by the number of shares of Common Stockunderlying the portion of the Option exercised.6.Non-transferability. The Option, and any rights and interests with respect thereto, issued under this Agreementand the Plan shall not, prior to vesting, be sold, exchanged, Transferred, assigned, or otherwise disposed of in any way by theParticipant (or any beneficiary(ies) of the Participant), other than by testamentary disposition by the Participant or the laws of descentand distribution. Notwithstanding the foregoing, the Committee may, in its sole discretion, permit the Option to be Transferred to aFamily Member for no value, provided that such Transfer shall only be valid upon execution of a written instrument in form andsubstance acceptable to the Committee in its sole discretion evidencing such Transfer and the transferee’s acceptance thereof signed bythe Participant and the transferee, and provided, further, that the Option may not be subsequently Transferred otherwise than by will orby the laws of descent and distribution or to another Family Member (as permitted by the Committee in its sole discretion) inaccordance with the terms of the Plan and this Agreement, and shall remain subject to the terms of the Plan and this Agreement. Anyattempt to sell, exchange, Transfer, assign, pledge, encumber, or otherwise dispose of or hypothecate in any way the Option, or thelevy of any execution, attachment, or similar legal process upon the Option, contrary to the terms and provisions of this Agreementand/or the Plan shall be null and void and without legal force or effect.7.Governing Law. All questions concerning the construction, validity, and interpretation of this Agreement shall begoverned by and construed in accordance with the internal laws of the State of Delaware without giving effect to its principles ofconflicts of laws.3  8.Withholding of Tax. The Company or any Affiliate shall have the power and the right to deduct or withhold,require the Participant to remit to the Company or such Affiliate, or make any other arrangements as it considers appropriate to ensurethat it has received an amount sufficient to satisfy any federal, state, local, and foreign taxes of any kind (including, but not limited to,the Participant’s FICA and SDI obligations) that the Company, in its sole discretion, deems necessary to be withheld or remitted tocomply with the Code and/or any other applicable law, rule, or regulation with respect to the Option and, if the Participant fails to doso, the Company may otherwise refuse to issue or Transfer any shares of Common Stock otherwise required to be issued pursuant tothis Agreement.9.Recoupment Policy. The Participant acknowledges and agrees that this Option (including any shares of CommonStock issued upon exercise thereof) shall be subject to the terms and provisions of any “clawback” or recoupment policy that may beadopted by the Company or its Affiliates from time to time or as may be required by any applicable law (including, without limitation,the Dodd-Frank Wall Street Reform and Consumer Protection Act and implementing rules and regulations thereunder).10.Notices. Any notice or communication given hereunder shall be in writing and shall be deemed to have been dulygiven: (i) when delivered in person; (ii) two days after being sent by United States mail; or (iii) on the first business day following thedate of deposit if delivered by a nationally recognized overnight delivery service, in each case, to the appropriate party at the addressset forth below (or such other address as the party may from time to time specify):If to the Company, to:Solid Biosciences Inc.141 Portland Street, 5th FloorCambridge, MA 02139Attention: Chief Financial Officer with a copy (which shall not constitute notice) to:WilmerHale60 State StreetBoston, MA 02109Attention: Lia Der MarderosianIf to the Participant, to the address on file with the Company.11.No Right to Employment. Nothing in this Agreement shall affect the right of the Company or any of itsAffiliates to terminate the Participant’s employment at any time, with or without Cause, or shall be deemed to create any rights toemployment or continued employment. The rights and obligations arising under this Agreement are not intended to and do not affectthe Participant’s employment relationship that otherwise exists between the Participant and the Company or any of its Affiliates,whether such employment relationship is at will or defined by an employment contract. Moreover, this Agreement is not intended toand does not amend any existing employment contract between the Participant and the Company or any of its Affiliates; to4  the extent there is a conflict between this Agreement and such an employment contract, the employment contract shall govern and takepriority.12.Data Protection. By executing this Agreement, the Participant hereby consents to the holding and processing ofpersonal information provided by the Participant to the Company, any Affiliate thereof, trustee, or third party service provider, for allpurposes relating to the operation of the Plan. These include, but are not limited to: (i) administering and maintaining Participantrecords; (ii) providing information to the Company, its Affiliates, trustees of any employee benefit trust, registrars, brokers, or third-party administrators of the Plan; (iii) providing information to future purchasers or merger partners of the Company or any Affiliatethereof, or the business in which the Participant works; and (iv) transferring information about the Participant to any country or territorythat may not provide the same protection for the information as the Participant’s home country.13.Market Stand-Off. If requested by the Company, any Affiliate, or a lead underwriter of any public offering ofthe shares of Common Stock (a “Lead Underwriter”), the Participant shall irrevocably agree, and by execution of this Agreementshall irrevocably be deemed to have agreed, not to sell, contract to sell, grant any option to purchase, transfer the economic risk ofownership in, make any short sale of, pledge, or otherwise Transfer or dispose of, any interest in any shares of Common Stock or anysecurities convertible into, derivative of, or exchangeable or exercisable for shares of Common Stock, or any other rights to purchase oracquire shares of Common Stock (except shares of Common Stock included in such public offering or acquired on the public marketafter such offering) during such period of time following the effective date of a registration statement of the Company filed under theSecurities Act that a Lead Underwriter shall specify (the “Lock-up Period”). The Participant hereby further agrees to sign suchdocuments as may be requested by a Lead Underwriter, the Company, or any Affiliate to effect the foregoing and agree that theCompany or an Affiliate may impose stop transfer instructions with respect to shares of Common Stock acquired pursuant to anAward until the end of such Lock-up Period.14.Compliance with Laws. The issuance of this Option (and the shares of Common Stock upon exercise of thisOption) pursuant to this Agreement shall be subject to, and shall comply with, any applicable requirements of any foreign and U.S.federal and state securities laws, rules, and regulations (including, without limitation, the provisions of the Securities Act, the ExchangeAct, and in each case any respective rules and regulations promulgated thereunder) and any other law or regulation applicable thereto.The Company shall not be obligated to issue this Option or any of the shares of Common Stock pursuant to this Agreement if any suchissuance would violate any such requirements.15.Section 409A. Notwithstanding anything herein or in the Plan to the contrary, the Option is intended to beexempt from the applicable requirements of Section 409A and shall be limited, construed, and interpreted in accordance with suchintent.16.Binding Agreement; Assignment. This Agreement shall inure to the benefit of, be binding upon, and beenforceable by the Company and its successors and assigns. The Participant shall not assign any part of this Agreement without theprior express written consent of the Company.5  17.Headings. The titles and headings of the various sections of this Agreement have been inserted for convenienceof reference only and shall not be deemed to be a part of this Agreement.18.Counterparts. This Agreement may be executed in one or more counterparts, each of which shall be deemed tobe an original, but all of which shall constitute the same instrument.19.Severability. The invalidity or unenforceability of any provisions of this Agreement in any jurisdiction shall notaffect the validity, legality, or enforceability of the remainder of this Agreement in such jurisdiction or the validity, legality, orenforceability of any provision of this Agreement in any other jurisdiction, it being intended that all rights and obligations of the partieshereunder shall be enforceable to the fullest extent permitted by law.20.Entire Agreement; Amendment. This Agreement, together with the Plan, contains the entire agreement betweenthe parties hereto with respect to the subject matter contained herein, and supersedes all prior agreements or prior understandings,whether written or oral, between the parties relating to such subject matter. The Committee shall have the right, in its sole discretion, tomodify or amend this Agreement from time to time in accordance with and as provided in the Plan. The Company shall give writtennotice to the Participant of any such modification or amendment of this Agreement as soon as practicable after the adoptionthereof. This Agreement may also be modified or amended by a writing signed by both the Company and the Participant.21.Mode of Communications. The Participant agrees, to the fullest extent permitted by applicable law, in lieu ofreceiving documents in paper format, to accept electronic delivery of any documents that the Company or any of its Affiliates maydeliver in connection with this Option grant and any other grants offered by the Company or its Affiliates, including, withoutlimitation, prospectuses, grant notifications, account statements, annual or quarterly reports, and other communications. Electronicdelivery of a document may be made via the Company’s email system or by reference to a location on the Company’s intranet, aninternet website, or the online brokerage account system.22.Acquired Rights. The Participant acknowledges and agrees that: (a) the Company may terminate or amend thePlan at any time; (b) the award of the Option made under this Agreement is completely independent of any other award or grant and ismade at the sole discretion of the Company; (c) no past grants or awards (including, without limitation, the Option awarded hereunder)give the Participant any right to any grants or awards in the future whatsoever; and (d) any benefits granted under this Agreement arenot part of the Participant’s ordinary salary and shall not be considered as part of such salary in the event of severance, redundancy, orresignation. Remainder of Page Intentionally Left Blank6  IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above. SOLID BIOSCIENCES INC. By: Ilan Ganot, CEO PARTICIPANT Name: Social Security Number: 7 Exhibit 10.20SOLID BIOSCIENCES INC.NON-EMPLOYEE DIRECTOR COMPENSATION POLICYEffective as of December 13, 2018, the non-employee directors of Solid Biosciences Inc. (the “Company”) shall receive thefollowing compensation for their service as members of the Board of Directors of the Company (the “Board”).Director CompensationOur goal is to provide compensation for our non-employee directors in a manner that enables us to attract and retainoutstanding director candidates and reflects the substantial time commitment necessary to oversee the Company’s affairs. We also seekto align the interests of our directors and our stockholders, and we have chosen to do so by compensating our non-employee directorswith a mix of cash and equity-based compensation.Cash CompensationThe fees that will be paid to our non-employee directors for service on the Board, and for service on each committee of theBoard on which the director is then a member, and the fees that will be paid to the chairperson of each committee of the Board will beas follows: Member Annual FeeChairperson Incremental Annual FeeBoard of Directors$35,000$35,000Audit Committee$7,500$7,500Clinical Committee$7,500$7,500Compensation Committee$5,000$5,000Nominating and Corporate Governance Committee$4,000$4,000 The foregoing fees will be payable in arrears in equal semi-annual installments not later than the 15th business day followingthe end of the second and fourth calendar quarters, provided that the amount of such payment will be prorated for any portion of suchsemi-annual period that the director is not serving on the Board, on such committee or in such position, and no fee shall be payable inrespect of any period prior to the completion of our initial public offering.Equity CompensationInitial Stock Option Grants. Upon initial election to our Board, each non-employee director will be granted, automaticallyand without the need for any further action by the Board, an initial equity award of an option to purchase 20,000 shares of our commonstock. The option shall have a term of ten years from the grant date and shall vest and become exercisable as to 1/3 of the sharesunderlying such option on each anniversary of the grant date until the third anniversary of the grant date, subject to the director’scontinued service as a director through each applicable vesting date. The vesting shall accelerate as to 100% of the shares upon achange in control of the Company. The exercise price shall be the closing price of our common stock on the date of grant.Annual Stock Option Grants. Each non-employee director who has served as a member of our Board for at least six monthsprior to the date of our annual meeting of stockholders for a particular year will be granted, automatically and without the need for anyfurther action by the Board, an equity award on the date of such annual meeting of an option to purchase 10,000 shares of our common stock. The option shall have a term of tenyears from the grant date and shall vest and become exercisable in full on the earlier to occur of the one-year anniversary of the grantdate and immediately prior to our first annual meeting of stockholders occurring after the grant date, subject, in each case, to thedirector’s continued service as a director through the applicable vesting date. The vesting shall accelerate as to 100% of the sharesupon a change in control of the Company. The exercise price shall be the closing price of our common stock on the date of grant.The foregoing share amounts shall be adjusted in the event of certain changes in the capital structure or business of theCompany, including any stock split, reverse stock split, stock dividend, combination or reclassification of shares, recapitalization, spinoff or other similar change in the Company’s capitalization and any non-cash dividend or distribution to holders of common stock, ineach case in accordance with the terms of our 2018 Omnibus Incentive Plan, or any successor plan.The initial stock option awards and the annual stock option awards shall be subject to the terms and conditions of our 2018Omnibus Incentive Plan, or any successor plan, and the terms of the option agreements entered into with each director in connectionwith such awards.ExpensesUpon presentation of documentation of such expenses reasonably satisfactory to the Company, each non-employee directorshall be reimbursed for his or her reasonable out-of-pocket business expenses incurred in connection with the performance of theirduties as directors, including travel expenses in connection with their attendance in-person at Board and committee meetings.2ActiveUS172060134v.1Exhibit 21.1Subsidiaries of Solid Biosciences Inc. Name of Subsidiary Jurisdiction of OrganizationSolid Biosciences UK Limited United Kingdom Solid Suit, LLC Massachusetts Solid Biosciences Securities Corporation Massachusetts Exhibit 23.1CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRMWe hereby consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-222763) of Solid Biosciences Inc. of our reportdated March 13, 2019 relating to the financial statements, which appears in this Form 10-K. /s/ PricewaterhouseCoopers LLPBoston, Massachusetts March 13, 2019 Exhibit 31.1CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OFTHE SARBANES-OXLEY ACT OF 2002I, Ilan Ganot, certify that:1. I have reviewed this Annual Report on Form 10-K of Solid Biosciences Inc.;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in ExchangeAct Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrantand have:a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure thatmaterial information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly duringthe period in which this report is being prepared;b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, toprovide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordancewith generally accepted accounting principles;c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; andd) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscalquarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to theregistrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely toadversely affect the registrant’s ability to record, process, summarize and report financial information; andb) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control overfinancial reporting. Date: March 13, 2019 By:/s/ Ilan Ganot Ilan Ganot President and Chief Executive Officer(Principal Executive Officer) Exhibit 31.2CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OFTHE SARBANES-OXLEY ACT OF 2002I, Jennifer Ziolkowski, certify that:1. I have reviewed this Annual Report on Form 10-K of Solid Biosciences Inc.;2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make thestatements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financialcondition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in ExchangeAct Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrantand have:a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure thatmaterial information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly duringthe period in which this report is being prepared;b) Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, toprovide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordancewith generally accepted accounting principles;c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of thedisclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; andd) Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscalquarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, theregistrant’s internal control over financial reporting; and5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to theregistrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely toadversely affect the registrant’s ability to record, process, summarize and report financial information; andb) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control overfinancial reporting. Date: March 13, 2019 By:/s/ Jennifer Ziolkowski Jennifer Ziolkowski Chief Financial Officer(Principal Financial and Accounting Officer) Exhibit 32.1CERTIFICATION PURSUANT TO18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TOSECTION 906 OF THE SARBANES-OXLEY ACT OF 2002In connection with the Annual Report of Solid Biosciences Inc. (the “Company”) on Form 10-K for the year ended December 31, 2018 as filed withthe Securities and Exchange Commission on the date hereof (the “Report”), I, Ilan Ganot, Chief Executive Officer of the Company, certify, pursuant to 18U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge: (1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and (2)The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of theCompany. Date: March 13, 2019 By:/s/ Ilan Ganot Ilan Ganot President and Chief Executive Officer(Principal Executive Officer) Exhibit 32.2CERTIFICATION PURSUANT TO18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TOSECTION 906 OF THE SARBANES-OXLEY ACT OF 2002In connection with the Annual Report of Solid Biosciences Inc. (the “Company”) on Form 10-K for the year ended December 31, 2018 as filed withthe Securities and Exchange Commission on the date hereof (the “Report”), I, Jennifer Ziolkowski, Chief Financial Officer of the Company, certify, pursuantto 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that, to my knowledge: (1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and (2)The information contained in the Report fairly presents, in all material respects, the financial condition and result of operations of theCompany. Date: March 13, 2019 By:/s/ Jennifer Ziolkowski Jennifer Ziolkowski Chief Financial Officer(Principal Financial and Accounting Officer) 

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