Enanta Pharmaceuticals
Annual Report 2018

Plain-text annual report

2018 Annual Report Creating Small Molecule Drugs for Viral Infections and Liver Diseases January 15, 2019 To our Shareholders, Our goal for the past several years has been to become a leader in the fields of viral infections and liver diseases through investing in, and diversifying into, treatments for diseases in these fields that have significant unmet need and market opportunity. I’m proud to say that we have made significant progress toward this goal and I’m happy to provide you with this update. Enanta’s successful hepatitis C virus (HCV) collaboration with AbbVie continues to provide us the royalty funding to advance our wholly-owned research and development programs in respiratory syncytial virus (RSV), non-alcoholic steatohepatitis (NASH), primary biliary cholangitis (PBC), and hepatitis B virus (HBV). In our 2018 fiscal year, which began shortly after the launch of AbbVie’s MAVYRET™/MAVIRET™ HCV regimen, Enanta received approximately $192 million in AbbVie royalties. And by the end of 2018, MAVYRET™/MAVIRET™ had become the best-selling HCV treatment in the world. Our clinical development programs are advancing, and we have many milestones to look forward to during 2019. Our most advanced development program is for RSV, where a Phase 2a human challenge study in healthy adults inoculated with RSV is ongoing and we expect top-line data in mid-2019. This study is investigating EDP-938, our non-fusion inhibitor candidate targeting the N-Protein in the RSV virus, and the only N-inhibitor in clinical development today. RSV represents an opportunity to work in an area where we have a differentiated approach, with positive early clinical data and limited competition, and where there is no therapeutic treatment available. Our NASH and PBC programs continue to enroll for our two Phase 2 clinical studies with EDP-305, our FXR agonist candidate. Enrollment in the 12-week Phase 2a NASH trial is expected to conclude in the first quarter of 2019 allowing Enanta to report preliminary top line data in the third quarter of 2019. We also continue to advance discovery and preclinical development of follow-on FXR compounds and non-FXR compounds for NASH. Lastly, I am very excited about the selection of EDP-514 as our first development candidate from our HBV program. EDP-514 is a core inhibitor, also referred to as a capsid assembly modulator or a core protein allosteric modulator. This is a new class of HBV inhibitors that can disrupt the assembly and replication of the virus at multiple steps in the viral lifecycle. Based on our preclinical data, we believe EDP-514 has best-in-class potential for the core inhibitor mechanism and we expect to initiate a Phase 1 study this year. Enanta has made significant advances the past year with more to look forward to in 2019. I would like to thank our employees for all their efforts and you, our shareholders, for your support. I look forward to updating you on our progress throughout the coming year. Sincerely, Jay R. Luly Ph.D. President and Chief Executive Officer UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ⌧ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 2018 OR (cid:4) TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-35839 ENANTA PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) DELAWARE (State or other jurisdiction of incorporation or organization) 2834 (Primary Standard Industrial Classification Code Number) 04-3205099 (I.R.S. Employer Identification Number) 500 Arsenal Street Watertown, Massachusetts 02472 (617) 607-0800 (Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices) Securities registered pursuant to Section 12(b) of the Act: Title of each class: Common Stock, $0.01 Par Value Name of each exchange on which registered: The NASDAQ Stock Market LLC (NASDAQ Global Select Market) Securities registered pursuant to Section 12(g) of the Act: None Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes (cid:4) 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 (cid:4) 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 shorter period 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 (cid:4) 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 the preceding 12 months (or for such shorter period that the registrant was required to submit such files): Yes ⌧ No (cid:4) Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy 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, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act: Large accelerated filer ⌧ (cid:4) Non-accelerated filer Emerging growth company (cid:4) Accelerated filer Smaller reporting company (cid:4) (cid:4) 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 provided pursuant to Section 13(a) of the Exchange Act. (cid:4) Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act): Yes (cid:4) No ⌧ The aggregate market value of the registrant’s common stock held by non-affiliates of the registrant as of the last business day of the registrant’s most recently completed second fiscal quarter, March 31, 2018, based on the last reported sale price of the registrant’s common stock of $80.91 per share was $1,280,474,378. The number of shares of the registrant’s Common Stock, $0.01 par value, outstanding as of November 1, 2018 was 19,423,949 shares. DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s Definitive Proxy Statement for its 2018 Annual Meeting of Stockholders scheduled to be held on February 28, 2019, which Definitive Proxy will be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year end of September 30, 2018 are incorporated by reference into Part III of this Form 10-K. As used in this Form 10-K, “Enanta,” “the Company,” “we,” “our,” and “us” refer to Enanta Pharmaceuticals, Inc., and “MAVYRET/MAVIRET” refers to AbbVie’s HCV regimen consisting of tablets of glecaprevir/pibrentasvir, except where the context otherwise requires or as otherwise indicated. MAVYRET™, MAVIRET™, VIEKIRA PAK™, TECHNIVIE™, VIEKIRAX™, VIEKIRA XR™ and, EXVIERA™ are trademarks of AbbVie, Inc. NOTE REGARDING FORWARD LOOKING STATEMENTS This Annual Report on Form 10-K contains forward-looking statements concerning our business, operations and financial performance and condition, as well as our plans, objectives and expectations for our business operations and financial performance and condition. Any statements contained herein that are not statements of historical facts may be deemed to be forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “aim,” “anticipate,” “assume,” “believe,” “contemplate,” “continue,” “could,” “due,” “estimate,” “expect,” “goal,” “intend,” “may,” “objective,” “plan,” “predict,” “potential,” “positioned,” “seek,” “should,” “target,” “will,” “would,” and other similar expressions that are predictions of or indicate future events and future trends, or the negative of these terms or other comparable terminology. These forward-looking statements include, but are not limited to, statements about overall trends, royalty revenue trends, research and clinical development plans, liquidity and capital needs and other statements of expectations, beliefs, future plans and strategies, anticipated events or trends and similar expressions. These forward-looking statements are based on our management’s current expectations, estimates, forecasts and projections about our business and the industry in which we operate and our management’s beliefs and assumptions. These forward-looking statements are not guarantees of future performance or development and involve known and unknown risks, uncertainties and other factors that are in some cases beyond our control. As a result, any or all of our forward-looking statements in this Annual Report on Form 10-K may turn out to be inaccurate. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under “Risk Factors” and discussed elsewhere in this Annual Report on Form 10-K. These forward-looking statements speak only as of the date of this Annual Report on Form 10-K. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future. You should, however, review the factors and risks we describe in the reports we will file from time to time with the SEC after the date of this Annual Report on Form 10-K. ENANTA PHARMACEUTICALS, INC. ANNUAL REPORT ON FORM 10-K For the year ended September 30, 2018 INDEX Item No. Page PART I Business .................................................................................................................................................... Risk Factors............................................................................................................................................... Unresolved Staff Comments ..................................................................................................................... Properties .................................................................................................................................................. Legal Proceedings ..................................................................................................................................... Mine Safety Disclosures ........................................................................................................................... 1. 1A. 1B. 2. 3. 4. PART II 5. Market for the Company’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities ....................................................................................................................................... Selected Consolidated Financial Data....................................................................................................... 6. 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations ................... 7A. Quantitative and Qualitative Disclosures about Market Risk ................................................................... Consolidated Financial Statements and Supplementary Data................................................................... 8. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure................... 9. Controls and Procedures ........................................................................................................................... 9A. Other Information ..................................................................................................................................... 9B. 10. 11. 12. 13. 14. 15. 16. PART III Directors, Executive Officers and Corporate Governance........................................................................ Executive Compensation........................................................................................................................... Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters. Certain Relationships and Related Transactions, and Director Independence ......................................... Principal Accounting Fees and Services ................................................................................................... PART IV Exhibits, Financial Statement Schedules .................................................................................................. Form 10-K Summary ................................................................................................................................ Signatures.................................................................................................................................................. 1 26 54 54 54 54 55 57 58 71 71 71 72 72 73 73 73 74 74 74 76 77 ITEM 1. BUSINESS Overview PART I BUSINESS We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to create small molecule drugs primarily for the treatment of viral infections and liver diseases. We discovered glecaprevir, the second of two protease inhibitors discovered and developed through our collaboration with AbbVie for the treatment of chronic hepatitis C virus, or HCV. Glecaprevir is co-formulated as part of AbbVie’s newest direct-acting antiviral (DAA) combination and marketed under the tradenames MAVYRET™ (U.S.) or MAVIRET™ (ex-U.S.) (glecaprevir/pibrentasvir). Our royalties from our AbbVie collaboration and our existing financial resources provide us funding to support our wholly-owned research and development programs, which are currently focused on the following disease targets: (cid:129) (cid:129) (cid:129) (cid:129) respiratory syncytial virus, or RSV, the most common cause of bronchiolitis and pneumonia in children under one year of age in the U.S., resulting in an estimated 57,000 to 125,000 U.S. hospitalizations each year; non-alcoholic steatohepatitis, or NASH, a liver disease estimated to affect approximately 1.5% to 6.5% of the population in the developed world (which translates to approximately 5 to 20 million individuals in the U.S. alone); primary biliary cholangitis, or PBC, a chronic liver disease that slowly destroys bile ducts in the liver, which affects an estimated 17,000 individuals in the U.S.; and hepatitis B virus, or HBV, the most prevalent chronic hepatitis, which is estimated to affect approximately 250 million individuals worldwide. We had $325.1 million in cash, cash equivalents and marketable securities at September 30, 2018. In fiscal 2018, we earned $191.6 million in per-product royalties on AbbVie’s net sales of its HCV regimens and we earned the remaining $15.0 million milestone payment from AbbVie upon reimbursement approval for MAVIRET™ in Japan. We expect our existing financial resources and future royalties from our AbbVie collaboration will allow us to continue to fund our wholly-owned research and development programs for the foreseeable future. Our Wholly-Owned Programs Our wholly-owned research and development programs are in virology, namely RSV and HBV, and in liver disease (non-virology), namely NASH and PBC: (cid:129) RSV: We discovered EDP-938, a potent N-protein inhibitor of activity of both major subgroups of RSV, referred to as RSV-A and RSV-B, and have tested it as our first clinical candidate for RSV. We believe EDP-938 is differentiated from fusion inhibitors currently in development for RSV because N-protein inhibitors directly target the viral replication process of RSV and have demonstrated high barriers to resistance against RSV in vitro. o In our fiscal 2018, we completed a Phase 1 clinical study demonstrating that EDP-938 was generally safe and well tolerated over a broad range of single and multiple doses with good pharmacokinetic data. o We initiated a Phase 2a challenge study of EDP-938 in October 2018. The challenge study will test the effect of EDP-938 on healthy volunteers who will be infected with RSV and then treated with EDP-938 or placebo during the course of the study. Primary and secondary outcome measures include changes in viral load measurements and change of baseline symptoms. o Preclinical data demonstrated that EDP-938 is a potent inhibitor of both RSV-A and RSV-B activity, maintaining antiviral activity post-infection while presenting a high barrier to resistance in vitro. 1 (cid:129) (cid:129) NASH and PBC: We are working on multiple compounds that selectively bind to and activate the farnesoid X receptor, or FXR. We plan to develop these compounds, referred to as FXR agonists, for use in the treatment of NASH and PBC, both of which are liver diseases with very few therapeutic options. Our lead FXR agonist, EDP-305, represents a new class of FXR agonists designed to take advantage of increased binding interactions with the receptor. We believe this class is significantly different from other FXR agonists in clinical development. o In October 2017, we announced results of a Phase 1a/b clinical study of EDP-305, which was generally safe and well tolerated over a broad range of single and multiple doses with pharmacokinetic data supporting once daily oral dosing. Additional data from this study were also presented at the 2018 NASH-TAG conference and the International Liver CongressTM (ILC) 2018. The study included 98 healthy volunteer subjects, or HV subjects, and 48 subjects who were obese and with or without pre-diabetes or type 2 diabetes, whom we refer to as subjects with presumptive non-alcoholic fatty liver disease, or PN subjects. o We have presented data at the 2017 and 2018 annual meetings of the American Association for the Study of Liver Diseases (AASLD), the 2017 and 2018 NASH-TAG conferences and the 2017 and 2018 ILC conferences that demonstrated that EDP-305 is a highly selective FXR agonist and shows more potent activity in a variety of in vitro and in vivo NASH models compared to the most advanced NASH candidate in development today, obeticholic acid, or OCA. o We initiated a Phase 2 clinical study, known as ARGON-1, of EDP-305 in NASH patients and a Phase 2 clinical study, known as INTREPID, of EDP-305 in PBC patients. o o EDP-305 has been granted Fast Track designation by the U.S. Food and Drug Administration (FDA) for the treatment of NASH patients with liver fibrosis and separately for the treatment of PBC. In addition, we are pursuing research in other classes of FXR agonists as well as other mechanisms that may provide therapeutic benefit in NASH, any of which could be used in combination therapies for NASH. HBV: We also have a program to discover and develop new chemical entities for the treatment of HBV. Our initial focus is on core inhibitors, a mechanism with early clinical validation. In November 2018, we announced our first clinical candidate for HBV. EDP-514 is an HBV core inhibitor, also known as a core protein allosteric modulator or capsid assembly modulator. o o EDP-514 was selected from our lead class of HBV compounds that are characterized by potent antiviral activity. In vitro, they are capable of preventing the establishment of cccDNA, are pan- genotypic, are active against known nucleos(t)ide resistant mutants, and are additive to synergistic with nucleoside analogs and other core inhibitors. Members of this class have also demonstrated excellent reduction in HBV titers in a chimeric mouse model with human liver cells. In addition, we are also seeking patent protection and conducting preclinical experiments with compounds we have discovered that use other mechanisms to target HBV. We believe that it may be necessary to utilize more than one compound/mechanism for the treatment of HBV and therefore we are pursuing multiple approaches. We have utilized our internal chemistry and drug discovery capabilities to generate all of our development-stage programs. 2 Our Out-Licensed Products (cid:129) (cid:129) Through our Collaborative Development and License Agreement with AbbVie, we have developed and out-licensed to AbbVie two protease inhibitor compounds that have been clinically tested, manufactured, and commercialized by AbbVie. To date, we have earned all $330.0 million milestone payments under the agreement related to clinical development and commercialization regulatory approvals of these regimens in major markets. Glecaprevir: Glecaprevir is the protease inhibitor we discovered that was developed by AbbVie in a fixed-dose combination with its NS5A inhibitor, pibrentasvir, for the treatment of HCV. This combination, currently marketed under the brand name MAVYRET™ (U.S.) and MAVIRET™ (ex- U.S.) and referred to in this report as MAVYRET/MAVIRET, is a novel, once daily, all oral, fixed- dose, ribavirin-free treatment for HCV genotypes 1-6, or GT1-6, which is referred to as being pan- genotypic. In the U.S., EU and Japan it was approved as an 8-week treatment for patients without cirrhosis and new to treatment. Today, these patients are estimated to represent the majority of HCV patients in developed country markets. Since August 2017, substantially all of our royalty revenue has been derived from AbbVie’s net sales of MAVYRET/MAVIRET. Our ongoing royalty revenues from this regimen consist of annually tiered, double-digit, per-product royalties (see Note 7 in Notes to Consolidated Financial Statements) on 50% of the calendar year net sales of the 2-DAA glecaprevir/pibrentasvir combination in MAVYRET/MAVIRET. These royalties are calculated separately from the royalties on AbbVie’s paritaprevir-containing regimens. Paritaprevir: Paritaprevir is the protease inhibitor contained in AbbVie’s initial HCV treatment regimens sold under the tradenames VIEKIRAX® (ex-U.S.) and VIEKIRA PAK® (U.S.) (paritaprevir/ritonavir/ ombitasvir/dasabuvir). These regimens are no longer being actively marketed in markets where MAVYRET/MAVIRET is approved and reimbursed. AbbVie’s paritaprevir-containing regimens were first approved and sold in the U.S. in December 2014. Through our 2017 fiscal year end, our royalty revenues were generated substantially through worldwide net sales of these regimens. Our Strategy Our primary objective is to become a leader in the field of viral infections and liver diseases in order to provide new treatments for patients with unmet medical needs. Our focus is on antiviral targets for viruses such as RSV and HBV as well as liver diseases, such as NASH and PBC. All of these disease areas involve significant market opportunities and have attracted the research and development efforts of many competitors. Our strategy includes the following key elements: Develop novel treatment options for RSV, NASH, PBC and HBV. We have potential candidates in clinical development for RSV, NASH and PBC. We completed a Phase 1 clinical study of our lead RSV candidate, EDP-938, and have initiated a Phase 2a challenge study in RSV in October 2018. We also completed a Phase 1 a/b clinical study of EDP-305, our lead FXR agonist, and initiated two Phase 2 clinical studies of this compound during fiscal 2018 – one in NASH patients and one in PBC patients. In addition, we recently selected a development candidate for HBV, EDP-514, which we plan to test in a Phase 1 a/b clinical study initiating in 2019. Invest in research and development of additional product candidates in RSV, NASH/PBC and HBV. We are continuing to invest significant resources in our RSV, NASH, PBC and HBV research programs in an effort to identify and advance additional novel compounds that have the potential to address significant unmet medical needs in these disease areas. We may clinically explore other diseases where our assets could play a role. In addition, we may seek to augment our product candidate pipeline through the acquisition or in-licensing of external assets and/or technologies in one or more of our disease areas of focus. Use our existing resources and future cash flow from our AbbVie collaboration to fund our research and development activities. Our existing financial resources and future royalty payments from our AbbVie collaboration will provide us substantial resources to fund our research and development programs for the foreseeable future. These resources will allow us to continue to advance compounds in clinical development as well as to progress the most promising candidates at least through proof-of- (cid:129) (cid:129) (cid:129) 3 concept for further development as a monotherapy or in combinations with other therapeutic agents when we believe such combinations will provide the most promising opportunities. (cid:129) Collaborate, where and when appropriate, with pharmaceutical partners to create combination therapies and accelerate the development and commercialization of our proprietary compounds. We are prepared to join forces, where and when appropriate, with collaborators with compounds targeting other mechanisms of action in diseases such as NASH and HBV, where there is the potential for better treatments with combination therapies. Our decisions regarding our proprietary programs will be based on the results of our early phase clinical studies and the potential for combinations with one or more drugs targeting other mechanisms of action in these diseases. Our Research and Development Pipeline The following table summarizes our product development pipeline in our virology and liver disease programs: Our RSV Program Background and Overview of RSV Respiratory syncytial virus, or RSV, is a virus that infects the lungs and represents a serious unmet medical need in infants and children, as well as immune-compromised individuals and the elderly. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia in children under 1 year of age in the United States. Each year, 57,000 to 125,000 patients in the U.S. are hospitalized due to RSV infection. In one large U.S.-based study, RSV infection in children was associated with 20% of hospitalizations, 18% of emergency 4 department visits, and 15% of pediatric office visits for acute respiratory infections in the November-April timeframe. Though a prophylactic monoclonal antibody-based treatment is available for infants considered at high risk for RSV infection, this study found that most young children affected by RSV infection were previously healthy, and thus would not normally be considered for prophylaxis. There are currently no safe and effective therapies for already established RSV infection. Several companies are seeking new antiviral treatments for RSV infection in adult and pediatric settings and others are developing vaccines. Scientific Background RSV is a single-stranded, negative-sense RNA virus. The RSV genome consists of ten genes that encode for 11 proteins, namely NS1, NS2, N, P, M, SH, G, F, M2-1, M2-2, and L. The F and G proteins are the predominant target proteins for RSV vaccines. Similarly, small molecule therapeutics have focused primarily on the F (or fusion) protein, while some efforts have targeted the N and L proteins. There are two major subgroups of RSV, designated RSV-A and RSV-B, each of which contains numerous genotypes. Both groups are viewed as capable of causing RSV infections that can result in hospitalization. EDP-938 and Our Approach to the Treatment of RSV While a number of companies are developing potential approaches geared towards the F protein (or fusion protein, responsible for mediating viral entry of RSV into host cells), we are focused on other mechanisms, such as the N- protein pathway, that target the replication process of RSV. It is possible that N-protein inhibitors may also be effective treatments at later stages of infection. We are currently the only company with an N inhibitor in clinical development. Through our internal chemistry efforts, we identified a clinical candidate, EDP-938. During preclinical studies, EDP-938 demonstrated a greater than 4-log reduction in viral load in an animal model challenged with RSV. Further, EDP-938 maintained antiviral potency across all clinical isolates tested in vitro, as well as virus that was resistant to fusion inhibitors. The compound inhibited RSV at a post-entry replication step and maintained its activity in vitro when given 24 hours post infection. In addition, combination studies of EDP-938 with other types of RSV inhibitors, such as fusion inhibitors, showed synergistic antiviral effects. During fiscal 2018, we initiated and completed a Phase 1 clinical study of EDP-938. On November 1, 2018, we presented full Phase 1 data at the 11th International Respiratory Syncytial Virus Symposium. The Phase 1, randomized, double-blind, placebo (PBO)-controlled, first-in-human study was conducted to evaluate the safety, tolerability, and pharmacokinetics (PK) of single- and multiple- (7 days) ascending doses (SAD: 50 - 800 mg and MAD: 100 - 600 mg once daily and 300 mg twice daily) and food effect (FE) of EDP-938 in healthy subjects. In the SAD phase, 50 subjects [EDP-938 (n=38) and PBO (n=12)] were enrolled in 6 dose cohorts; in the MAD phase, 40 subjects [EDP-938 (n=30) and PBO (n=10)] were enrolled in 5 dose cohorts. Overall, no safety concerns were reported in 68 healthy subjects receiving a broad range of single and multiple doses of EDP-938. Headache was the most frequently reported AE during the SAD and MAD phases. There were no SAEs, and AEs were of mild intensity, with none leading to study drug discontinuation. EDP-938 was rapidly absorbed and exposure increased with increasing single and multiple dosing, resulting in a PK profile suitable for once or twice daily oral dosing regardless of food. In the MAD phase, half-life ranged from 12.9 to 17.6 hours, and at doses comparable to those under study in the Phase 2a trial, and mean trough levels were approximately 30x higher than the EC90 of EDP-938 against RSV-infected human cells. 5 Based on the results above, we initiated a Phase 2a challenge study of EDP-938 in October 2018. In this randomized, double-blind, placebo-controlled, human challenge study, up to 114 healthy adult subjects will be randomized into 1 of 3 arms (1:1:1) and will be dosed for 5 days. All subjects will be infected with RSV-A Memphis 37b virus, and approximately 76 subjects will receive EDP-938 and 38 subjects will receive placebo. Arm 1 will receive placebo, Arm 2 will receive a single 500 mg loading dose of EDP-938 followed by 300 mg doses twice daily, and Arm 3 will receive a 600 mg dose daily. Our FXR Program in NASH and PBC Background and Overview of NASH and PBC Non-alcoholic fatty liver disease, or NAFLD, is the accumulation of excessive fat in liver cells in the form of triglycerides, a process known as hepatic steatosis, that is not associated with alcohol abuse. It is normal for the liver to contain some fat. However, if more than 5%-10% of the liver’s weight is fat, then it is called a fatty liver. A subgroup of NAFLD patients have liver cell injury and inflammation (steatohepatitis) in addition to excessive fat. Progression of this condition leads to non-alcoholic steatohepatitis, or NASH. Patients with NASH can develop fibrosis, a fibrous scarring of the liver, and ultimately cirrhosis of the liver. Typically scored on a scale of 1-4, also referred to as F1-F4, fibrosis in its earlier stages has been shown to be reversible, but in its most advanced stage results in cirrhosis, which is understood to be a more advanced, irreversible scarring of the liver, potentially leading to hepatocellular carcinoma (HCC) or requiring a liver transplant. NASH is widely considered to be the liver expression of metabolic diseases related to type 2 diabetes, insulin resistance, obesity, hyperlipidemia and hypertension. Stages of Liver Injury According to the World Gastroenterology Organization Global Guidelines 2014, NASH is an increasingly common chronic liver disease with worldwide distribution that is closely associated with diabetes and obesity, which have both reached epidemic proportions. It is estimated that there are at least 1.46 billion obese adults worldwide. Approximately 3%-5% of individuals in the U.S. are estimated to have progressed to NASH, 20% of whom are likely to develop cirrhosis. NASH and NAFLD are now considered the number one cause of liver disease in Western countries. Currently, there are no approved treatments for NASH. While patients presenting with NASH are counseled on lifestyle modifications, new effective treatments are urgently needed, particularly in the setting of advanced fibrosis and cirrhosis. We expect significant competition from other companies in the development of treatments for NASH and related conditions. Currently, Intercept Pharmaceuticals, Genfit, Gilead and Allergan (Tobira) have compounds in one or more Phase 3 trials in NASH. In addition, many Phase 2 and earlier stage studies of other classes of compounds are underway by various companies. 6 Primary biliary cholangitis (formerly known as primary biliary cirrhosis), or PBC, is a chronic, or long-term, disease of the liver that slowly destroys the medium-sized bile ducts within the liver. Bile is a digestive liquid that is made in the liver. It travels through the bile ducts to the small intestine, where it helps digest fats and absorb fatty vitamins. In patients with PBC, the bile ducts are destroyed by inflammation. This causes bile to remain in the liver, where gradual injury damages liver cells and causes cirrhosis, or scarring of the liver. As cirrhosis progresses and the amount of scar tissue in the liver increases, the liver loses its ability to function, leading to potential liver failure, liver transplantation or hepatocellular carcinoma. While PBC is a relatively rare disease (the incidence in Europe, North America, Asia and Australia ranges from 0.33-5.8 cases per 100,000, and is 10 times more common in women than in men), it remains one of the major causes of liver failure and/or the need for liver transplant. Agonists of the farnesoid X receptor, referred to as FXR agonists, have shown promising activity in many preclinical models of liver disease. One FXR agonist, obeticholic acid, or OCA (brand name Ocaliva ®), which was approved by the FDA in May 2016 for the treatment of PBC, has already demonstrated favorable clinical results in NASH. We believe that new FXR agonists may provide substantial therapeutic benefit in NASH and PBC and may overcome some of the potential shortcomings of OCA, including limited effects on resolution of NASH, elevation of low-density lipoprotein, or LDL, and itching, also called pruritis. Scientific Background FXR is a nuclear hormone receptor that functions to modulate gene expression in response to various metabolic stimuli. FXRs are expressed at high levels in the liver and intestine. Bile acids have been identified as important physiological ligands for FXRs, able to bind and activate the receptor. The downstream gene modulation resulting from bile acid engagement of FXRs not only contribute to the regulation of bile acid synthesis and metabolism, but is also involved in a number of other metabolic processes, in particular lipid metabolism. More recently, it has been discovered that bile acids, via FXR, are able to promote insulin sensitivity and decrease lipid synthesis in the liver. In addition, studies have shown that bile acid-dependent FXR activation is able to provide beneficial effects on fibrosis in the liver as well. For these reasons, FXR is considered to be a viable target for NASH. Recent Phase 2b trials with OCA, a synthetic analog of natural bile acids known to activate FXR, demonstrated efficacy in NASH patients. In PBC, improved outcomes would be expected due to the reduction of bile acid synthesis by activation of FXR. OCA demonstrated efficacy in a Phase 3 trial in PBC, which was the basis for its conditional approval in the U.S. in May 2016 for the treatment of PBC in combination with first line therapy ursodeoxycholic acid (UDCA) in adults with an inadequate response to UDCA, or as monotherapy in adults unable to tolerate UDCA. EDP-305 and Our Approach to the Treatment of NASH and PBC Even though there has been clinical validation demonstrated by the FXR agonist, OCA, we believe that there is an opportunity for the development of a treatment that shows improvements in potency and efficacy and reductions in potential safety liabilities for the treatment of NASH and PBC. Using our strong chemistry capabilities, we have undertaken the discovery and development of new FXR agonists that we believe may provide substantial improvements over the FXR agonists currently in advanced clinical development. EDP-305, our lead FXR agonist candidate, represents a new class of FXR agonists that has been designed to take advantage of increased binding interactions with the receptor. Further, this non-bile acid class contains steroidal and non-steroidal components and does not contain the carboxylic acid group that can lead to the formation of taurine and glycine conjugates normally associated with bile acids, which may also be present in other classes of FXR agonists. We reported the results of our Phase 1 a/b clinical study of EDP-305 in October 2017. Our double-blind, placebo- controlled Phase 1 study was designed to evaluate the safety, tolerability and pharmacokinetics of single ascending doses, or SAD, and multiple ascending doses, or MAD, of EDP-305 in adult healthy volunteer subjects, or HV subjects, and subjects with presumptive NAFLD, or PN subjects. By presumptive NAFLD, we mean adults who are obese, with or without pre-diabetes or type 2 diabetes. 7 In this Phase 1 study, EDP-305 was shown to be generally safe and well tolerated over a broad range of single and multiple doses with pharmacokinetic, or PK, data supporting once daily oral dosing. EDP-305 exhibited strong engagement of the FXR receptor as evidenced by increased FGF19 levels and reduced C4 levels, which are proteins that can be monitored as downstream markers indicating FXR activity. The results of the study support the ability to administer EDP-305 in future trials at doses that neither elicit clinically significant changes in lipids nor result in pruritus. (cid:129) (cid:129) (cid:129) (cid:129) A total of 146 subjects received at least one dose of EDP-305 (n=110) or placebo (n=36) including 50 HV subjects in the SAD phases of the study and 96 (48 HV and 48 PN) subjects in the MAD phases of the study. Overall, mean body mass index, or BMI, in the PN cohort was 32 (29, 35). SAD had 6 cohorts at doses of 1, 5, 10, 20, 40 and 80 mg EDP-305/placebo, and MAD had 6 cohorts at doses of 0.5, 1, 2.5, 5, 10 and 20 mg EDP-305/placebo for 14 days. Strong FXR target engagement was demonstrated, with doses of EDP-305 > 1 mg increasing FGF19 and reducing C4 in all subjects, while PN subjects were even more sensitive with significant effects also observed in both parameters at the lowest multiple doses of 0.5 and 1 mg. No serious adverse events (SAEs) were reported, and EDP-305 was generally well tolerated at all doses tested. (cid:129) (cid:129) (cid:129) Treatment-emergent adverse events occurring in ≥ 2 EDP-305 treated subjects in MAD cohorts were: headache and pruritus in HV subjects, and constipation and pruritus in PN subjects. Of the cases of pruritus noted (9% for EDP-305, 3% in placebo), the majority were mild or moderate and occurred at multiple doses of 20 mg, with no cases below 10mg. Notably, EDP-305 demonstrated potent engagement of the FXR receptor across the lower dose range where there was no pruritus. Two subjects discontinued treatment in the MAD phase at the 20 mg dose level, one for a transient grade 2 elevation of ALT/AST liver enzymes, and one for moderate pruritus. No dose-related changes in lipids were observed in HV subjects at any doses; and no dose-related changes in lipids were observed in PN subjects except for reductions of total cholesterol and high- density lipoprotein, or HDL, cholesterol at the multiple 20mg dose, with no concomitant increase in low-density lipoprotein, or LDL, cholesterol. We initiated two Phase 2 dose-ranging studies in fiscal 2018 – one in PBC patients, known as INTREPID, and one in NASH patients, known as ARGON-1. Both studies are 12-week, dose ranging, randomized, double-blind, placebo-controlled trials. The main goals of the studies will be to evaluate safety, tolerability, PK, and efficacy based on reduction in the level of key enzymes in subjects’ plasma (alanine aminotransferase, or ALT, reduction in NASH and alkaline phosphatase, or ALP, reduction in PBC). A new tablet formulation will be utilized in these Phase 2 studies at strengths of 1mg and 2.5mgs (tablet formulation yields ~ 2X greater exposure than the suspension formulation used in the Phase 1 study. Our HBV Program Background and Overview of HBV Hepatitis B virus, or HBV, can cause potentially life-threatening liver infection. The virus is transmitted through contact with the blood or other bodily fluids of an infected person. It is estimated that approximately 250 million people worldwide are chronically infected, and 15-25% of patients with chronic HBV infection develop chronic liver disease, including cirrhosis, liver cancer, or liver decompensation. It is also estimated that more than 885,000 people worldwide died in 2015 due to complications of HBV. Estimates for the total number of persons chronically infected with HBV in the U.S. vary but generally range between 0.5 million and 2.0 million. Combining U.S., Japan, and major EU populations, estimates of HBV prevalence have been as high as 4.8 million. 8 Current approaches to treatment include interferon therapy and/or inhibitors of HBV reverse transcriptase, the enzyme responsible for viral DNA synthesis, which is necessary for HBV replication. Treatment with interferon offers modest cure rates, and is accompanied by serious side effects, including flu-like symptoms, fatigue, headache and nausea. Reverse transcriptase inhibitors can be very effective at suppressing the virus but often require lifelong therapy and rarely result in full eradication of the virus from the liver. New treatments that can provide functional cures to chronically-infected patients are urgently needed. Scientific Background HBV is a partially double-stranded DNA virus with a complex life cycle. There are multiple mechanisms associated with HBV replication that could potentially be targeted with new drugs, and combination approaches may ultimately provide the most effective therapy for HBV. Mechanisms under study for HBV include: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) Entry inhibitors that interfere with the initial binding of HBV to hepatocytes, thus preventing new infection from occurring. Inhibitors of covalently closed circular DNA, or cccDNA, the template for HBV replication, which are in early stages of development. Most of these inhibitors act in an indirect manner, such as preventing formation of cccDNA or silencing its transcription. RNA silencing of gene expression, another prominent approach in the search for HBV inhibitors, which utilizes small interfering RNA’s (siRNA’s). This mechanism has the potential to significantly reduce HBV RNA, HBV DNA, and HBV protein levels. Inhibition of the hepatitis B core protein, which plays a critical role in viral replication, intracellular trafficking, and maintenance of chronic infections. Using this core inhibitor mechanism (also known as capsid assembly inhibitor or core protein allosteric modifier), some initial data shows reduction in HBV DNA and HBV RNA in early clinical trials. The surface antigen of HBV, or HBsAg, which is the main envelope protein of the virus and, another target in the HBV life cycle. HBsAg is critical to ongoing infection, and loss of serum HBsAg is associated with a functional cure of HBV, characterized by no inflammation, normal liver enzymes, and normal liver biopsy. Therefore, HBsAg is the target of several therapeutic approaches, including indirect ones such as siRNA mentioned above, but also specific approaches including the inhibition of HBsAg release. The modulators of the human immune system, or immunomodulators, another major mechanism being researched. HBV has evolved to evade the natural host immune mechanisms that normally would clear a viral infection, thus approaches that can augment the immune response are being actively pursued. In fact, interferon has been used for the treatment of HBV for decades and while it can induce a functional cure, the cure is only seen in a small percentage of patients and the treatment is generally not well tolerated. More targeted immunological approaches are being studied, including agonists of toll-like receptors, modulators of apoptotic signaling, and checkpoint inhibition. Also, while past attempts at developing successful therapeutic vaccines have been unsuccessful, efforts continue to develop an effective HBV vaccine, using new vaccine technologies. 9 Our Approach to the Treatment of HBV We are initially focusing on new core inhibitors that we expect to have an impact on capsid assembly and possibly interfere with other viral processes. Core inhibitors, also known as capsid assembly modulators or core protein allosteric modulators, are a novel class of replication inhibitors that have been shown to act at multiple steps in the HBV lifecycle. These inhibitors would be expected to prevent proper uncoating, nuclear import, assembly, and recycling. This approach is supported by early clinical validation, with the core inhibitor NVR 3-778 from Novira, JNJ-56136379 from Janssen, and ABI-H0731 from Assembly, demonstrating clinical reduction of viral DNA in chronic HBV patients in short-term Phase 1b or Phase 2 clinical studies. We recently identified our first core inhibitor candidate, EDP-514, which we are planning to advance into a Phase 1 a/b study in 2019. In addition, we are conducting preclinical experiments with other mechanisms that target HBV. Due to the complex nature of HBV infection, it is widely believed that combination therapy may be necessary to provide the optimal therapeutic approach for this disease. Our Out-Licensed HCV Protease Inhibitor Products Background and Overview of HCV Market HCV is a virus that is a common cause of viral hepatitis, an inflammation of the liver. HCV is typically contracted by contact with the blood or other body fluids of another individual infected with HCV. HCV is a leading cause of chronic liver disease, including cirrhosis, liver failure and cancer, and the leading cause of death from liver disease in the United States. HCV disease progression occurs over a period of 20 to 30 years, with the majority of HCV- infected individuals generally exhibiting no major symptoms in the early stages of the disease. Therefore, until a major symptom is diagnosed, many individuals are unaware they are infected and live undiagnosed without seeking treatment. For that reason, combined with the new availability of effective treatments for HCV, the United States Centers for Disease Control and Prevention, or CDC, issued new guidelines in 2013 recommending screening for all Americans born between the years 1945 and 1965 so that HCV-infected individuals will be aware of their condition and can consider treatment options. An estimated 71 million people worldwide are chronically infected with HCV and have an increased risk of eventually developing liver cirrhosis or liver cancer. Approximately 399,000 people die every year from HCV- related liver diseases. The CDC estimated in 2016 that approximately 3.5 million people in the United States are chronically infected with HCV, with an estimated 41,200 new infections in 2016, the most recent year for which the CDC has published data. We believe that the chronically infected population remains significantly untreated, even with the introduction of several new regimens beginning in 2013. The approved treatments for HCV have provided significant benefit to HCV patients. To date, these treatments have cure rates approaching 100% in several subpopulations. Medical practice defines a “cure” as the point at which there is no quantifiable virus in a patient’s blood for a sustained period of time after cessation of therapy, which is often referred to as a sustained virologic response, or SVR. For AbbVie’s MAVYRET/MAVIRET regimen, the majority of chronic HCV patients only require 8 weeks of treatment compared to 12 weeks with VIEKIRA PAK® and other HCV regimens, including Gilead’s EPCLUSA® and HARVONI® in almost all HCV genotypes. 10 Since the introduction of Gilead’s Harvoni® and AbbVie’s VIEKIRA PAK® in late 2014, the reported worldwide sales of the leading HCV therapies have declined from $23 billion in 2015 to $12 billion in 2017. Through the first nine months of calendar 2018, reported worldwide net sales were $2.1 billion in the first calendar quarter, $2.1 billion for the second calendar quarter and $1.9 billion for the third calendar quarter. HCV sales have declined since their peak in 2015 due to payers obtaining additional discounts, competitive market dynamics and a decline in the number of patients treated annually after the initial wave of diagnosed chronic HCV patients who had urgency for treatment. After the regulatory approvals of MAVYRET and Gilead’s VOSEVI in 2017, Johnson & Johnson and Merck announced they had terminated their development of additional HCV treatments. Despite the high numbers of HCV patients that have been successfully treated, there remains a large population of chronic HCV-infected patients who have yet to be treated with one of the newer “high cure” regimens. In addition, and as noted above, new HCV infections (principally in association with IV drug use) also represent an ongoing target population for treatment. Scientific Background Most of the currently approved HCV therapies targeting HCV focus directly on the viral life cycle and proteins that are critical to HCV replication. Replication of the HCV genome occurs on intracellular membranes and requires the participation of multiple viral proteins, some of which have enzymatic activities. Agents, often referred to as inhibitors, that target viral proteins directly are generally referred to as direct acting antivirals, or DAAs. All currently approved DAA therapies include one or a combination of two or more inhibitors of the NS3 protease, the NS5A protein, and the NS5B polymerase. NS3 Protease. As HCV replicates, it generates long strands of protein that must be processed into many individual active functional proteins that are referred to as non-structural proteins with the designated abbreviation NS, including NS3 and NS5A. The NS3 protease is responsible for most of this protein processing of the newly translated HCV protein, and plays an essential role in the viral life cycle. Inhibition of the protease prevents these new critical proteins from forming and therefore prevents replication and survival of the virus. NS5A. The NS5A protein has key roles in both the RNA replication of HCV and modulation of the physiology of its host cell in the body. Research has shown that targeting NS5A gives rise to profound antiviral activity, and as a result, this protein has emerged as an additional important DAA target for anti-HCV drugs. NS5B Polymerase. HCV is a single-stranded RNA virus, and NS5B is an HCV RNA polymerase responsible for synthesis of new HCV RNA, allowing the HCV genome to be copied and the virus to survive and replicate. Two separate classes of DAA inhibitors of NS5B polymerase are used as treatments for HCV. Nucleoside/nucleotide inhibitors of NS5B directly inhibit the active site of that enzyme and prevent further elongation of the RNA, and thus are equally active against all HCV genotypes. A second class, known as non-nucleoside inhibitors, affects replication of the RNA by altering the shape of the enzyme at remote sites on the enzyme surface, with the result being that any given non-nucleoside inhibitor is usually only active against certain HCV genotypes. Our Out-Licensed Products in AbbVie’s Marketed Therapies Glecaprevir - Our protease inhibitor, glecaprevir, which is part of the latest HCV regimen from AbbVie, was developed by AbbVie in combination with pibrentasvir, AbbVie’s second NS5A inhibitor. This co-formulated combination, marketed as MAVYRET™ (U.S.) and MAVIRET™ (ex-U.S.), contains two novel DAAs that target and inhibit proteins essential for the replication of the hepatitis C virus. MAVYRET/MAVIRET is approved in the U.S., EU and Japan as an 8-week, pan-genotypic, fixed-dose combination treatment, dosed once-daily as three oral tablets, taken with food, for chronic HCV patients without cirrhosis and new to treatment. MAVYRET/MAVIRET is also approved as a treatment for patients with specific treatment challenges, including those GT-1 patients not cured by prior treatment experience with either a protease inhibitor or an NS5A inhibitor (but not both), and in patients with limited treatment options, such as those with severe chronic kidney disease (CKD) or those with genotype 3 chronic HCV. MAVYRET/MAVIRET is approved for use in patients across all stages of CKD with any of the major HCV genotypes (GT1-6). The approvals of MAVYRET/MAVIRET are supported by data from nine registrational studies in AbbVie’s clinical development program, which evaluated more than 2,300 patients in 27 countries across all major HCV genotypes (GT1-6) and special populations: (cid:129) 8 weeks for treatment-naïve, non-cirrhotics: In November 2016, results from several Phase 3 studies of this combination demonstrated 97.5% of chronic HCV infected patients without cirrhosis and new to treatment across all major genotypes (GT1-6) achieved sustained virologic response at 12 weeks post- treatment, referred to as SVR12, with just 8 weeks of MAVYRET/MAVIRET treatment. 11 (cid:129) (cid:129) (cid:129) 8 weeks with chronic kidney disease: Results were also presented from AbbVie’s EXPEDITION-4 study in chronic HCV patients with chronic kidney disease (CKD), in which 98% of patients (n=102/104) across all major genotypes (GT1-6) achieved SVR12 with 12 weeks of treatment with MAVYRET/MAVIRET. 8 weeks for GT-3: Data from AbbVie’s ENDURANCE-3 study were presented at the 2017 ILC, demonstrating that 95% of patients with challenging-to-treat, genotype 3 (GT3) chronic HCV infection, without cirrhosis and new to treatment, achieved SVR12 after 8 weeks of treatment with MAVYRET/MAVIRET. Compensated cirrhosis: Based on data from AbbVie’s EXPEDITION-1 study, which demonstrated that 99% of HCV-infected patients with genotype 1, 2, 4, 5 or 6 and compensated cirrhosis (Child-Pugh A) achieved SVR12 following 12 weeks of MAVYRET/MAVIRET treatment without ribavirin, 12 weeks of treatment with MAVYRET/MAVIRET is the approved duration for this regimen. Note: Results from one recently announced cohort of AbbVie’s Phase 3b EXPEDITION-8 study showed that with 8 weeks of MAVYRET treatment, 100 percent (n=273/273) of genotype 1, 2, 4, 5 and 6 patients achieved a sustained virologic response 12 weeks after treatment (SVR12) per protocol analysis. A second cohort of the study is ongoing in genotype 3 (GT3) chronic HCV-infected patients. Paritaprevir - The first protease inhibitor developed through our collaboration with AbbVie, paritaprevir, is part of AbbVie’s 3-DAA regimen approved for the treatment of genotype 1 and 4 HCV patients. This 3-DAA combination was sold as VIEKIRA PAK® (paritaprevir/ritonavir/ombitasvir/dasabuvir) in the U.S. from December 2014 to December 2018, and as VIEKIRAX®+EXVIERA® in most other jurisdictions, for non-cirrhotic patients and those with early stage, or compensated, cirrhosis. These regimens are in the process of being replaced by MAVYRET/MAVIRET in jurisdictions around the world since the latter was introduced in the U.S. in August 2017. Collaboration and License Agreement with AbbVie We entered into a Collaborative Development and License Agreement with Abbott Laboratories in November 2006 to develop and commercialize HCV NS3 and NS3/4A protease inhibitors. The agreement, which was amended in January and December 2009, was then assigned to AbbVie Inc. on January 1, 2013 in connection with Abbott’s transfer of its research-based pharmaceuticals business to AbbVie. Under the agreement, we have granted AbbVie an exclusive, worldwide, royalty-bearing license, including a right to grant sublicenses, to specified intellectual property, including several issued U.S. patents, relating to protease inhibitors. We also granted AbbVie access to our drug discovery capabilities in the HCV NS3 and NS3/4A protease inhibitor field. AbbVie granted us a co-exclusive (together with AbbVie), royalty-free, fully paid license, without the right to grant sublicenses, to certain of AbbVie’s intellectual property, AbbVie’s interest in joint intellectual property and improvements discovered by AbbVie, for the purpose of allowing us to conduct certain development and commercialization activities in the United States relating to protease inhibitors. AbbVie is responsible for and has funded all costs associated with the development, manufacturing and commercialization of paritaprevir, glecaprevir and any other compounds under this agreement. Under the agreement, we are eligible to receive milestone payments and royalties with respect to these compounds. So long as a product candidate is being developed or commercialized under the agreement, we undertake not to conduct any activity, or grant licenses to a third party, relating to protease inhibitors. A joint steering committee was established under the agreement with review and oversight responsibilities for all research, development and commercialization activities. The joint steering committee is comprised of three of our senior personnel and three senior personnel from AbbVie; however, AbbVie has final authority to make all decisions regarding development and commercialization activities. The research program and the evaluation period, which was performed by both parties, ended in June 2011. The first commercialized compound was paritaprevir with the second commercialized compound, glecaprevir, approved in 2017 and marketed under the tradenames MAVYRET™ (U.S.) or MAVIRET™ (ex-U.S.). Under this collaboration, we have received payments from AbbVie for license fees, proceeds from a sale of preferred stock, research funding payments and milestone payments totaling $396.0 million through September 30, 2018. 12 We also receive annually tiered, double-digit royalties per protease inhibitor product developed under the agreement, which range from ten percent up to twenty percent, or on a blended basis from the low double digits up to the high teens. However, if a product is determined to be a combination product, as is the case for both glecaprevir and paritaprevir, the net sales of the combination product are adjusted on a country-by-country and product-by-product basis to reflect a good faith determination of the relative value of each pharmaceutically active ingredient, based on the estimated fair market value. This means that a portion of AbbVie’s worldwide annual net sales of a combination product or regimen is first allocated to one of our protease inhibitors and then that royalty- bearing portion is multiplied by the annually tiered royalty rates to determine our actual royalty for the protease product in that regimen in a given period. Under the terms of our agreement, as amended in October 2014, 50% of AbbVie’s net sales of MAVYRET/MAVIRET are allocated to glecaprevir. In the case of regimens containing paritaprevir, 30% of net sales of 3-DAA regimens containing paritaprevir and 45% of net sales of 2-DAA regimens containing paritaprevir are allocated to paritaprevir for purposes of calculating our annually tiered royalties. Beginning with each January 1, the cumulative net sales of a given royalty-bearing protease inhibitor product start at zero for purposes of calculating the tiered royalties on a product-by-product basis. Under this collaboration, we have received royalty payments from AbbVie totaling $254.0 million through September 30, 2018. Further details of these tiered royalties are set forth in Note 7 in Notes to Consolidated Financial Statements included in this report, which are incorporated herein by this reference. Royalties owed to us under the agreement can be reduced by AbbVie in certain circumstances, including (i) if AbbVie exercises its right to license or otherwise acquire rights to intellectual property controlled by a third party where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, (ii) where a product developed under the collaboration agreement is sold in a country and not covered by a valid patent claim in such country, or (iii) where sales of a generic product are equal to at least a specified percentage of AbbVie’s market share of a product in a country. AbbVie’s obligation to pay royalties on products developed under the agreement expires on a country-by-country and product-by-product basis upon the later of (i) the date of expiration of the last of the licensed patents with a valid claim covering the product in the applicable country, and (ii) ten years after the first commercial sale of the product in the applicable country. Our intellectual property existing as of the effective date of the agreement remains our property. Any intellectual property jointly developed is jointly owned. We will have the unilateral right to enforce our patent rights on any covered product following the first commercial sale of such product, as will AbbVie. In the event of infringement related to any of our patents, we will have the first right and option to initiate legal proceedings or take other actions. In the event of infringement related to any AbbVie patents, AbbVie will have the first right and option to initiate legal proceedings or take other actions. In the event of infringement of a joint patent right, we will discuss with AbbVie whether to initiate legal proceedings or take other actions. AbbVie will have the obligation to defend at its sole expense any actions brought against either party alleging infringement of third-party rights by reason of the activities conducted under the agreement and we will have the right to obtain separate counsel at our own expense. Additionally, AbbVie, at its sole expense, will be responsible for all trademark prosecution. Subject to the exceptions described above, a party’s rights and obligations under the agreement continue until: (i) such time as AbbVie is no longer developing a product candidate or (ii) if, as of the time AbbVie is no longer developing any product candidates, AbbVie is commercializing any other protease inhibitor product, such time as all royalty terms for all covered products and all co-development terms for all co-developed products have ended. Accordingly, the final expiration date of the agreement is currently indeterminable. Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice. If we terminate the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted us (i) a non-exclusive, perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate and (ii) an exclusive (even as to AbbVie), perpetual, fully paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds. Upon our request, AbbVie will also transfer to us all right, title and interest in any related product trademarks, regulatory filings and clinical trials. 13 If AbbVie terminates the agreement for our uncured breach, the milestone and royalty payments payable by AbbVie may be reduced, the licenses granted to AbbVie will remain in place, we will be deemed to have granted AbbVie an exclusive license under our interest in joint intellectual property, AbbVie will continue to have the right to commercialize any covered products, and all rights and licenses granted to us by AbbVie will terminate. Drug Discovery We have internally discovered all of the compounds in our research and development programs. Our scientists have expertise in the areas of medicinal chemistry, molecular virology, pharmacology, and toxicology, with highly developed sets of skills in compound generation, target selection, screening and pharmacology, preclinical development and lead optimization. We are utilizing these skills and capabilities in our discovery and development of virology and liver disease product candidates. We focus on virology and liver disease indications representing large and growing market opportunities with significant unmet medical needs. Our selection of a particular therapeutic target within those disease indications takes into consideration the experience and expertise of our scientific team and includes our ability to generate robust medicinal chemistry structure-activity relationships to assist lead optimization and secure relevant intellectual property rights. Once we have identified lead compounds, they are tested using in vitro and in vivo pharmacology studies and in vivo research models of antiviral or antibacterial efficacy. Competition We are engaged in segments of the pharmaceutical industry that are highly competitive and rapidly changing. Many large pharmaceutical and biotechnology companies, academic institutions, governmental agencies and other public and private research organizations are commercializing or pursuing the development of products that target HCV, NASH, PBC, RSV and HBV and other viral infections or liver diseases that we may target in the future. Many of our competitors have substantially greater commercial infrastructures and financial, technical and personnel resources than we have, as well as drug candidates in late-stage clinical development. We will not be able to compete successfully unless we are able to: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) design and develop products that are superior to other products in the market; attract qualified scientific, medical, regulatory, sales and marketing and commercial personnel; obtain patent and/or other proprietary protection for our processes and product candidates; obtain required regulatory approvals; and collaborate with others in the development and commercialization of new products. Established competitors may invest heavily to quickly discover and develop novel compounds that could make our product candidates obsolete. In addition, any new product that competes with an approved product must demonstrate compelling advantages in efficacy, convenience, tolerability and safety, or some combination of these factors, to overcome competition and to be commercially successful. We expect AbbVie’s MAVYRET/MAVIRET to continue to face price competition from existing approved products in the HCV market. This regimen currently faces competition in various world markets and subpopulations of HCV from Gilead’s Epclusa® (a fixed dose combination of sofosbuvir and velpatasvir), Vosevi™ (a triple combination therapy of sofosbuvir, velpatasvir and voxilaprevir approved by the FDA in July 2017 for specified sofosbuvir - treatment failures and NS5A-inhibitor treatment failures) and Harvoni® (a fixed-dose combination of sofosbuvir and ledipasvir); and to a lesser extent - Merck’s Zepatier® (a fixed-dose combination of grazoprevir and elbasvir). Lastly, Gilead has announced plans to launch its own authorized generic versions of Epclusa and Harvoni in January 2019 to be more competitive with MAVYRET/MAVIRET in managed Medicaid and Medicare Part D accounts. Gilead has announced that it will price these authorized generics to reflect more closely the discounts that health insurers and government payers receive for the branded versions of Epclusa and Harvoni. There are no other generic versions of Epclusa or Harvoni on the market and none are anticipated given the patents covering these drugs. 14 Competitive products in the form of other treatment methods or a vaccine for HCV may render AbbVie’s MAVYRET/MAVIRET obsolete or noncompetitive. This regimen will face competition based on its price, reimbursement coverage, AbbVie’s marketing and sales capabilities, patent position, safety and effectiveness, and other factors. If any of AbbVie’s HCV regimens face competition from generic versions of these products, the collaboration agreement provides that the royalty rate applicable to our protease product contained in the regimen is reduced significantly by a specified percentage on a product-by-product, country-by-country basis. If AbbVie is not able to compete effectively against its competitors in HCV, our business will not grow and our financial condition, operations and stock price will suffer. We also expect our other product candidates will face intense and increasing competition in the antiviral and NASH markets as advanced technologies and products become available. For RSV, there are currently no safe and effective therapies for already established RSV infection. Several companies are seeking new antiviral treatments for RSV infection in adult and pediatric settings. Ark Bioscienes, Johnson & Johnson, Gilead, Pulmocide and ReViral each have compounds in clinical development, as does Ablynx with a potential therapeutic antibody. A prophylactic, monoclonal-antibody-based treatment from MedImmune, which is commercialized by AbbVie outside of the U.S., is approved for infants considered at high risk for RSV infection; however studies have found that most young children with RSV infection were previously healthy, and thus would not normally be prescribed prophylactic treatment. In addition, a number of companies have RSV vaccines in development, primarily directed at prevention of RSV infection, and some companies are also evaluating vaccines in a therapeutic mode for treatment of established RSV infection. Though there is currently no approved treatment for NASH, we expect significant competition from other companies in the development of new treatments for NASH and related conditions. We are aware of several companies with NASH programs that are significantly more advanced than ours, including companies with compounds in Phase 3 clinical trials in NASH, namely Intercept, Genfit, Gilead, and Tobira (Allergan). In May 2016, the FDA granted conditional approval for Intercept’s FXR agonist (brand name Ocaliva®) for the treatment of primary biliary cholangitis (PBC) in combination with first line therapy ursodeoxycholic acid (UDCA) in adults with an inadequate response to UDCA, or as monotherapy in adults unable to tolerate UDCA. In addition, a number of companies have NASH or related programs with compounds in Phase 2 clinical trials. These companies include Astra-Zeneca, BMS, Boehringer Ingelheim, Can-Fite BioPharma, Conatus, Cirius, Cymabay, Galectin, Galmed, Gilead, GlaxoSmithKline, Immuron, Inventiva, Madrigal, Medicinova, Novartis, NGM, Novo Nordisk, Pfizer, Viking, and Zydus. A significant number of other companies are conducting earlier stage clinical trials that may be applicable in NASH and other cholestatic diseases. There are also additional companies conducting preclinical studies in these disease areas. Similarly, HBV represents a competitive therapeutic area. While there are antiviral medications prescribed for treatment for HBV, they generally have low true cure rates. Many companies are seeking to develop new HBV drugs that alone or in combination with other mechanisms could lead to a functional cure of HBV. Arbutus, Assembly, Gilead, HEC, Ionis/GSK, Johnson & Johnson, Maxwell, Replicor, and Spring Bank have Phase 2 programs in progress, with many of these companies conducting earlier stage programs as well. In addition, a number of companies have Phase 1 or earlier stage HBV programs, including Aicuris, Alnylam, Altimmune, Arrowhead, Contravir, Dicerna, Enyo, Roche and Transgene. If we are not able to develop new products that can compete effectively against our current and future competitors, our business will not grow and our financial condition, operations and stock price will suffer. Intellectual Property As part of our business strategy, we actively seek patent protection for our product candidates in the United States and certain major foreign jurisdictions and file additional patent applications, when appropriate, to cover improvements to our compounds. We also rely on trade secrets, internal know-how, technological innovations and agreements with third parties to develop, maintain and protect our competitive position. Our ability to be competitive will depend on the success of this strategy. 15 Each of our major programs, including RSV, NASH, PBC, HBV and HCV, typically has several issued patents and pending patent claims in the program area containing claims to compounds, methods of use and processes for synthesis. However, only a few of the issued patents and/or pending patent applications cover the lead product candidate in a given program. RSV, NASH, PBC and HBV Programs. Our patent portfolio directed to N-protein inhibitors for RSV, FXR agonists for NASH, PBC and fibrosis, and core inhibitors for HBV includes pending U.S. patent applications as well as numerous foreign patent applications. HCV NS3 Protease Inhibitor Program. The patent portfolio directed to the HCV protease inhibitor program with AbbVie includes U.S. patents and foreign patents, as well as non-provisional applications. The issued U.S. composition-of-matter patent covering paritaprevir is expected to expire in 2031. The issued U.S. composition-of- matter patent covering glecaprevir is expected to expire in 2032. AbbVie is a joint owner of a number of the non- provisional patent applications. AbbVie also has rights to some or all of these patents and patent applications pursuant to its collaboration agreement with us. We may obtain patents for certain compounds many years before we obtain marketing approval for products containing such compounds. Because patents have a limited life, which usually begins to run well before the first commercial sale of the related product, the commercial value of the patent may be limited. However, we may be able to apply for patent term extensions in the United States and in a number of European countries, compensating in part for delays in obtaining marketing approval, but we cannot be certain we will obtain such extensions. It is also very important that we do not infringe patents or other proprietary rights of others. If we do infringe such patents or other proprietary rights, we could be prevented from developing or selling products or from using the processes covered by those patents, could be required to pay substantial damages, or could be required to obtain a license from the third party to allow us to use their technology, which may not be available on commercially reasonable terms or at all. If we were not able to obtain a required license or develop alternative technologies, we may be unable to develop or commercialize some or all of our products, and our business could be adversely affected. In addition, we jointly own patent applications, together with AbbVie, that claim paritaprevir and glecaprevir as a chemical entity. However, there is no guarantee that such applications will issue. Further, the existence of issued patents does not guarantee our right to practice the patented technology or commercialize the patented product. Third parties may have already or could obtain rights to patents that could be used to prevent or attempt to prevent us from commercializing our product candidates. If these other parties are successful in obtaining valid and enforceable patents, and establishing our infringement of those patents, we could be prevented from commercializing our product candidates unless we were able to obtain a license under such patents, which may not be available on commercially reasonable terms or at all. Much of our scientific capabilities depend upon the knowledge, experience and skills of key scientific and technical personnel. To protect our rights to our proprietary know-how and technology, we endeavor to require all employees, as well as our consultants and advisors, when feasible, to enter into confidentiality agreements that require disclosure and assignment to us of ideas, developments, discoveries and inventions made by these employees, consultants and advisors in the course of their service to us. We may be unable to obtain, maintain and protect the intellectual property rights necessary to conduct our business, and we may be subject to claims that we infringe or otherwise violate the intellectual property rights of others, which could materially harm our business. For more information, see “Risk Factors—Risks Related to Our Intellectual Property Rights.” Government Regulation Government authorities in the United States, at the federal, state and local level, and in other countries extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, labeling, packaging, storage, record-keeping, promotion, advertising, distribution, post-approval monitoring and reporting, 16 marketing and export and import of products such as those we develop. Any pharmaceutical candidate that we develop must be approved by the FDA before it may be legally marketed in the United States and by the appropriate foreign regulatory agency before it may be legally marketed in foreign countries. United States Drug Development Process In the United States, the FDA regulates drugs under the Federal Food, Drug and Cosmetic Act, or FDCA, and implementing regulations. Drugs are also subject to other federal, state and local statutes and regulations. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources. Failure to comply with the applicable United States requirements at any time during the product development process, approval process or after approval, may subject an applicant to administrative or judicial sanctions. FDA sanctions could include refusal to approve pending applications, withdrawal of an approval, a clinical hold, warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement or civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us. The process required by the FDA before a drug may be marketed in the United States generally involves the following: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) Completion of preclinical laboratory tests, animal studies and formulation studies according to Good Laboratory Practice, or GLPs, or other applicable regulations; Submission to the FDA of an Investigational New Drug Application, or an IND, which must become effective before human clinical trials may begin; Performance of adequate and well-controlled human clinical trials according to the FDA’s current Good Clinical Practice, or GCPs, to establish the safety and efficacy of the proposed drug for its intended use; Submission to the FDA of a New Drug Application, or an NDA, for a new drug product; Satisfactory completion of an FDA inspection of the manufacturing facility or facilities where the drug is to be produced to assess compliance with the FDA’s current Good Manufacturing Practice standards, or cGMP, to assure that the facilities, methods and controls are adequate to preserve the drug’s identity, strength, quality and purity; Potential FDA audit of the nonclinical and clinical trial sites that generated the data in support of the NDA; and FDA review and approval of the NDA. The lengthy process of seeking required approvals, which can often take anywhere from six months from the time the NDA is filed if there is a priority review for a breakthrough therapy to twelve months for a standard review, and the continuing need for compliance with applicable statutes and regulations require the expenditure of substantial resources. There can be no certainty that approvals will be granted. Before testing any compounds with potential therapeutic value in humans, the product candidate enters the preclinical testing stage. Preclinical tests include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies to assess the potential safety and activity of the product candidate. The conduct of the preclinical tests must comply with GLP and other federal regulations and requirements. The sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA places the clinical trial on a clinical hold within that 30-day time period. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical trial can begin. The FDA may also impose clinical holds on a drug at any time before or during clinical trials due to safety concerns or non-compliance. Accordingly, we cannot assure that submission of an IND will result in the FDA allowing clinical trials to begin, or that, once begun, issues will not arise that result in suspension or termination of such trial. 17 Clinical trials involve the administration of the product candidate to healthy volunteers or patients having the disease being studied under the supervision of qualified investigators, generally physicians not employed by or under the trial sponsor’s control. Clinical trials are conducted under protocols detailing, among other things, the objectives of the clinical trial, dosing procedures, subject selection and exclusion criteria, and the parameters to be used to monitor subject safety. Each protocol must be submitted to the FDA as part of the IND. Clinical trials must be conducted in accordance with the FDA’s GCP requirements. Further, each clinical trial must be reviewed and approved by an independent institutional review board, or IRB, at or servicing each institution at which the clinical trial will be conducted. An IRB is charged with protecting the welfare and rights of trial participants and considers such items as whether the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the informed consent form that must be provided to each clinical trial subject or his or her legal representative and must monitor the clinical trial until it is completed. Human clinical trials prior to approval are typically conducted in three sequential phases that may overlap or be combined: (cid:129) (cid:129) (cid:129) Phase 1. The drug is initially introduced into healthy humans and tested for safety, dosage tolerance, absorption, metabolism, distribution and excretion. In the case of some products for severe or life- threatening diseases, especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted only in patients having the specific disease. Phase 2. The drug is evaluated in a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance, optimal dosage and dosing schedule for patients having the specific disease. Phase 3. Clinical trials are undertaken to further evaluate dosage, clinical efficacy and safety in an expanded patient population at geographically dispersed clinical trial sites. These clinical trials, which usually involve more patients than earlier trials, are intended to establish the overall risk/benefit ratio of the product and provide an adequate basis for product labeling. Generally, at least two adequate and well-controlled Phase 3 clinical trials are required by the FDA for approval of an NDA. Post-approval studies, or Phase 4 clinical trials, may be conducted after initial marketing approval. These studies are used to gain additional experience from the treatment of patients in the intended therapeutic indication and may be required by the FDA as part of the approval process. Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and written IND safety reports must be submitted to the FDA by the investigators for serious and unexpected adverse events or any finding from tests in laboratory animals that suggests a significant risk for human patients. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, if at all. The FDA, or the sponsor or its data safety monitoring board, may suspend a clinical trial at any time on various grounds, including a finding that the research patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. Concurrent with clinical trials, companies usually complete additional animal studies and develop additional information about the chemistry and physical characteristics of the drug as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, must include methods for testing the identity, strength, quality and purity of the final drug. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life. U.S. Review and Approval Processes The results of product development, preclinical studies and clinical trials, along with descriptions of the manufacturing process, analytical tests conducted on the chemistry of the drug, proposed labeling and other relevant information are submitted to the FDA as part of an NDA requesting approval to market the product. The submission of an NDA is subject to the payment of substantial user fees by the applicant; a waiver of such fees may be obtained under certain limited circumstances. 18 In addition, under the Pediatric Research Equity Act, or PREA, an NDA or supplement to an NDA must contain data to assess the safety and effectiveness of the drug for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may grant deferrals for submission of pediatric data or full or partial waivers. The FDA reviews all NDAs submitted before it accepts them for filing and may request additional information rather than accepting an NDA for filing. Once the submission is accepted for filing, the FDA begins an in-depth review of the NDA. Under the goals and policies agreed to by the FDA under the Prescription Drug User Fee Act, or PDUFA, the FDA has twelve months in which to complete its initial review of a standard NDA and respond to the applicant, and six months for a priority NDA. The FDA does not always meet its PDUFA goal dates for standard and priority NDAs. After the NDA submission is accepted for filing, the FDA reviews the NDA to determine, among other things, whether the proposed product is safe and effective for its intended use and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity, strength, quality and purity. In addition to its own review, the FDA may refer applications for novel drug products or drug products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy, or REMS, is necessary to assure the safe use of the drug. If the FDA concludes that a REMS is needed, the sponsor of the NDA must submit a proposed REMS; the FDA will not approve the NDA without a REMS, if required. Before approving an NDA, the FDA will inspect the facilities at which the product is to be manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and are adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. If the FDA determines that the application, manufacturing process or manufacturing facilities are not acceptable it will outline the deficiencies in the submission and often will request additional testing or information. The NDA review and approval process is lengthy and difficult, and the FDA may refuse to approve an NDA if the applicable regulatory criteria are not satisfied or may require additional clinical data or other data and information. Even if such data and information is submitted, the FDA may ultimately decide that the NDA does not satisfy the criteria for approval. Data obtained from clinical trials are not always conclusive and may be susceptible to varying interpretations, which could delay, limit or prevent regulatory approval. The FDA will issue a “complete response” letter if the agency decides not to approve the NDA. The complete response letter usually describes all of the specific deficiencies in the NDA identified by the FDA. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the NDA, addressing all of the deficiencies identified in the letter, or withdraw the application. If a product receives regulatory approval, the approval may be limited to specific diseases and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling. In addition, the FDA may require Phase 4 testing, which involves clinical trials designed to further assess a product’s safety and effectiveness and may require testing and surveillance programs to monitor the safety of approved products that have been commercialized. Expedited Development and Review Programs The FDA has four programs intended to expedite the development and review of new drugs addressing unmet medical needs or treating serious or life-threatening conditions: fast track, breakthrough therapy, priority review, and accelerated approval. 19 The FDA “fast track” program is intended to expedite or facilitate the process for reviewing new products to treat serious or life-threatening conditions and address unmet medical needs. Fast track designation applies to the combination of the product and the specific indication for which it is being studied. Under the fast track program, the sponsor will have more frequent interactions with the FDA during drug development, and may also submit sections of the NDA on a rolling basis to the FDA for review before submitting the complete application. Fast track does not guarantee that a product will be reviewed more quickly or receive FDA approval. The FDA “breakthrough therapy” program is intended to expedite the development and review of drugs for serious or life-threatening conditions. Preliminary clinical evidence must show that the drug may have substantial improvement over existing therapies on one or more clinically significant endpoints. Although the drug does not have to address an unmet medical need, designation of breakthrough therapy status carries all the “fast track” program features. Additionally, the breakthrough therapy program entitles the sponsor to earlier and more frequent interaction with the FDA review team regarding development of nonclinical and clinical data, and allows the FDA to offer product development and regulatory advice necessary to shorten the time for product approval. The breakthrough therapy status does not guarantee a quicker development or review of the product, and does not ensure FDA approval. The FDA also has a “priority review” program for products offering significant improvement in the treatment, diagnosis or prevention of a disease. The goal of the priority review program is to shorten the review period to six months from the ten months required for standard review. Any drug with breakthrough therapy, accelerated approval designation, or fast track can be granted priority review if it meets the necessary criteria. The FDA “accelerated approval” program is intended to expedite the development and review of products with the potential to treat serious or life-threatening illnesses and provide meaningful therapeutic benefit over existing treatments. The program allows approval of a product on the basis of adequate and well-controlled clinical studies establishing that the product has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit, or on the basis of an effect on a clinical endpoint that can be measured earlier than survival or irreversible morbidity. As a condition of approval, the FDA generally requires that a sponsor of the product perform adequate and well-controlled post-marketing clinical studies to establish safety and efficacy for the approved indication. Failure to conduct such studies or failure of the studies to establish required safety and efficacy may result in revocation of approval. The FDA also requires, as a condition for accelerated approval, pre-approval of promotional materials, which could adversely impact the timing of the commercial launch or subsequent marketing of the product. Post-Approval Requirements Any drug products for which we receive FDA approvals are subject to continuing regulation by the FDA. Certain requirements include, among other things, record-keeping requirements, reporting of adverse experiences with the product, providing the FDA with updated safety and efficacy information on an annual basis or more frequently for specific events, product sampling and distribution requirements, complying with certain electronic records and signature requirements and complying with FDA promotion and advertising requirements. These promotion and advertising requirements include, among others, standards for direct-to-consumer advertising, prohibitions against promoting drugs for uses or in patient populations that are not described in the drug’s approved labeling (known as “off-label use”), rules for conducting industry-sponsored scientific and educational activities and promotional activities involving the internet. Failure to comply with FDA requirements can have negative consequences, including the immediate discontinuation of noncomplying materials, adverse publicity, enforcement letters from the FDA, mandated corrective advertising or communications with doctors, and civil or criminal penalties. Although physicians may prescribe legally available drugs for off-label uses, manufacturers may not market or promote such off-label uses. 20 We rely, and expect to continue to rely, on third parties for the production of clinical and commercial quantities of our product candidates. Manufacturers of our product candidates are required to comply with applicable FDA manufacturing requirements contained in the FDA’s cGMP regulations. These regulations require, among other things, quality control and quality assurance as well as the corresponding maintenance of comprehensive records and documentation. Drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are also required to register their establishments and list any products they make with the FDA and to comply with related requirements in certain states. These entities are further subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMP and other laws. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance. Discovery of problems with a product after approval may result in serious and extensive restrictions on a product, manufacturer or holder of an approved NDA. These restrictions may include suspension of a product until the FDA is assured that quality standards can be met, continuing oversight of manufacturing by the FDA under a “consent decree,” which frequently includes the imposition of costs and continuing inspections over a period of many years, as well as possible withdrawal of the product from the market. In addition, changes to the manufacturing process generally require prior FDA approval before being implemented. Other types of changes to the approved product, such as adding new indications and additional labeling claims, are also subject to further FDA review and approval. The FDA also may require post-marketing testing, known as Phase 4 testing, as well as risk minimization action plans and surveillance to monitor the effects of an approved product or place conditions on an approval that could otherwise restrict the distribution or use of the product. U.S. Patent Term Restoration and Marketing Exclusivity Drug Price Competition and Patent Term Restoration Act of 1984 Depending upon the timing, duration and specifics of the FDA approval of the use of our product candidates, some of our United States patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch-Waxman Amendments. The Hatch- Waxman Amendments permit a patent restoration term of up to five years as compensation for patent term lost during federal regulatory review preceding the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. The patent term restoration period is generally one-half the time between the effective date of an IND and the submission date of an NDA plus the time between the submission date of an NDA and the approval of that application. Only one patent applicable to an approved drug is eligible for the extension and the application for the extension must be submitted within 60 days of approval, prior to the expiration of the patent. The United States Patent and Trademark Office, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we may apply for restoration of patent term for one of our currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical trials and other factors involved in the filing of the relevant NDA. However, there is no guarantee that any such application will be approved. Federal Food, Drug and Cosmetic Act (“FDCA”) Market exclusivity provisions under the FDCA, which are independent of patent status and any patent related extensions, can also delay the submission or the approval of certain applications of other companies seeking to reference another company’s NDA. If the new drug is a new chemical entity subject to an NDA, the FDCA provides a five-year period of non-patent marketing exclusivity within the United States to the first applicant to obtain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or functional group of a molecule responsible for the action of the drug substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application, or ANDA, or a so-called Section 505(b)(2) NDA, submitted by another company for another version of such drug where the applicant does not own or have a legal right of reference to all the data required for approval. However, such an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement to one of the patents listed with the FDA by the innovator NDA holder. The FDCA also provides three years of marketing exclusivity for an NDA, or supplement to an existing 21 NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example new indications, dosages or strengths of an existing drug. This three-year exclusivity covers only the conditions associated with the new clinical investigations and does not prohibit the FDA from approving ANDAs for drugs containing the original active agent. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA. However, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness. Other U.S. Healthcare Laws and Compliance Requirements In the United States, our activities are potentially subject to regulation by various federal, state and local authorities in addition to the FDA, including the Centers for Medicare and Medicaid Services (formerly the Health Care Financing Administration), other divisions of the United States Department of Health and Human Services (e.g., the Office of Inspector General), the United States Department of Justice and individual United States Attorney offices within the Department of Justice, state attorney generals and state and local governments. For example, sales, marketing and scientific/educational grant programs must comply with the anti-fraud and abuse provisions of the Social Security Act, the False Claims Act, the privacy and security provisions of the Health Insurance Portability and Accountability Act, or HIPAA, and similar state laws, each as amended. Pricing and rebate programs must comply with the Medicaid rebate requirements of the Omnibus Budget Reconciliation Act of 1990 and the Veterans Health Care Act of 1992, each as amended. If products are made available to authorized users of the Federal Supply Schedule of the General Services Administration, additional laws and requirements apply. Under the Veterans Health Care Act, or VHCA, drug companies are required to offer certain pharmaceutical products at a reduced price to a number of federal agencies including the United States Department of Veterans Affairs and United States Department of Defense, the Public Health Service and certain private Public Health Service—designated entities in order to participate in other federal funding programs including Medicare and Medicaid. Recent legislative changes purport to require that discounted prices be offered for certain United States Department of Defense purchases for its TRICARE program via a rebate system. Participation under the VHCA requires submission of pricing data and calculation of discounts and rebates pursuant to complex statutory formulas, as well as the entry into government procurement contracts governed by the Federal Acquisition Regulations. In order to distribute products commercially, we must comply with state laws that require the registration of manufacturers and wholesale distributors of pharmaceutical products in a state, including, in certain states, manufacturers and distributors who ship products into the state even if such manufacturers or distributors have no place of business within the state. Some states also impose requirements on manufacturers and distributors to establish the pedigree of product in the chain of distribution, including some states that require manufacturers and others to adopt new technology capable of tracking and tracing product as it moves through the distribution chain. Several states have enacted legislation requiring pharmaceutical companies to establish marketing compliance programs, file periodic reports with the state, make periodic public disclosures on sales, marketing, pricing, clinical trials and other activities, and/or register their sales representatives, as well as to prohibit pharmacies and other healthcare entities from providing certain physician prescribing data to pharmaceutical companies for use in sales and marketing, and to prohibit certain other sales and marketing practices. All of our activities are potentially subject to federal and state consumer protection and unfair competition laws. Europe / Rest of World Government Regulation In addition to regulations in the United States, we will be subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of clinical trials or marketing of the product in those countries. Certain countries outside of the United States have a similar process that requires the submission of a clinical trial application much like the IND prior to the commencement of human clinical trials. In the European Union, for example, a clinical trial application, or CTA, must be submitted to each country’s national health authority and an independent ethics committee, much like the FDA and IRB, respectively. Once the CTA is approved in accordance with a country’s requirements, clinical trials may proceed. 22 The requirements and process 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 International Conference on Harmonisation (ICH) / WHO Good Clinical Practice standards and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. To obtain regulatory approval of an investigational drug under European Union regulatory systems, we must submit a marketing authorization application to the European Medicines Agency, or the EMA. The application used to file an NDA in the United States is similar to that required in the European Union, with the exception of, among other things, country-specific document requirements. For other countries outside of the European Union, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical trials are conducted in accordance with GCPs and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution. Pharmaceutical Coverage, Pricing and Reimbursement Significant uncertainty exists as to the coverage and reimbursement status of any product candidates for which we obtain regulatory approval. In the United States and markets in other countries, sales of any products for which we receive regulatory approval for commercial sale will depend in part on the availability of reimbursement from third- party payors. Third-party payors include government health administrative authorities, managed care providers, private health insurers and other organizations. The process for determining whether a payor will provide coverage for a drug product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the drug product. Third-party payors may limit coverage to specific drug products on an approved list, or formulary, which might not include all of the FDA-approved drug products for a particular indication. Third-party payors are increasingly challenging the price and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. We may need to conduct expensive pharmaco- economic studies in order to demonstrate the medical necessity and cost-effectiveness of our products, in addition to the costs required to obtain the FDA approvals. Our product candidates may not be considered medically necessary or cost-effective. A payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved. Adequate third-party reimbursement may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development. In 2003, the United States government enacted legislation providing a partial prescription drug benefit for Medicare recipients, which became effective at the beginning of 2006. Government payment for some of the costs of prescription drugs may increase demand for any products for which we receive marketing approval. However, to obtain payments under this program, we would be required to sell products to Medicare recipients through prescription drug plans operating pursuant to this legislation. These plans will likely negotiate discounted prices for our products. Federal, state and local governments in the United States continue to consider legislation to limit the growth of healthcare costs, including the cost of prescription drugs. Future legislation could limit payments for pharmaceuticals such as the product candidates that we are developing. The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, collectively known as the Affordable Care Act, substantially changed the way healthcare is financed by both governmental and private insurers, and significantly impacted the pharmaceutical industry. 23 The comprehensive overhaul has extended coverage to approximately 20 million previously uninsured Americans. Since its adoption, the Affordable Care Act contains a number of provisions, including those governing enrollment in federal healthcare programs, reimbursement changes and fraud and abuse, which have affected existing government healthcare programs and have resulted in the development of new programs, including Medicare payment for performance initiatives and improvements to the physician quality reporting system and feedback program. Additionally, the Affordable Care Act, as limited by the United States Supreme Court’s decision in June 2012: (cid:129) (cid:129) (cid:129) (cid:129) increases the minimum level of Medicaid rebates payable by manufacturers of brand-name drugs from 15.1% to 23.1%; requires collection of rebates for drugs paid by Medicaid managed care organizations; requires manufacturers to participate in a coverage gap discount program, under which they must agree to offer 50% point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D, beginning January 2011; and imposes a non-deductible annual fee on pharmaceutical manufacturers or importers who sell “branded prescription drugs” to specified federal government programs. There have been proposals by President Trump and the Republican majorities in both houses of the U.S. Congress to repeal or replace all or portions of the Affordable Care Act but to date no such legislation has been agreed upon. At this time, it remains unclear what legislation, if any, to repeal or replace the Affordable Care Act will become law, or what impact any such legislation may have on our existing product candidates, any of our future product candidates or AbbVie’s commercialization of its HCV regimens. Different pricing and reimbursement schemes exist in other countries. In the European Union, governments influence the price of pharmaceutical products through their pricing and reimbursement rules and control of national healthcare systems that fund a large part of the cost of those products to consumers. Some jurisdictions operate positive and negative list systems under which products may only be marketed once a reimbursement price has been agreed. To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost-effectiveness of a particular product candidate to currently available therapies. Other member states allow companies to fix their own prices for medicines but monitor and control company profits. The downward pressure on healthcare costs in general, particularly prescription drugs, has become very intense. As a result, increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross-border imports from low-priced markets exert a commercial pressure on pricing within a country. The marketability of any drug candidates for which we receive regulatory approval for commercial sale may suffer if the government and third-party payers fail to provide adequate coverage and reimbursement. In addition, emphasis on managed care in the United States has increased and we expect will continue to increase the pressure on pharmaceutical drug pricing. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future. Research and Development Our research and development expenses were $94.9 million, $57.5 million and $40.5 million for the fiscal years ended September 30, 2018, 2017 and 2016, respectively. Manufacturing We do not have our own manufacturing capabilities, except with respect to limited amounts of active pharmaceutical ingredients needed for preclinical development. In the past, we have relied on third-party manufacturers, including manufacturers in China, for supply of active pharmaceutical ingredients, and we expect that in the future we will rely on such manufacturers for the supply of ingredients that will be used in clinical trials of our product candidates that we are developing ourselves and to produce commercial quantities of any product candidates that we commercialize ourselves. Manufacturing for paritaprevir and glecaprevir are conducted by AbbVie. Wherever possible, we seek to identify multiple suppliers for raw materials and key intermediaries to be used in our manufacturing process. 24 Sales and Marketing We currently do not have any commercialization or sales and marketing capabilities, and currently have no fixed plans to invest in or build such capabilities internally. We have partnered our protease inhibitor compounds for HCV with AbbVie. We may also partner or collaborate with, or license commercial rights to, other larger pharmaceutical or biopharmaceutical companies to support the development of one or more of our wholly-owned product candidates through late-stage clinical development and, if successful, commercialization. However, we still retain all commercial rights to our independent programs and we will continue to evaluate our alternatives for commercializing them once they are more advanced in their clinical development. Our Corporate Information We are a Delaware corporation, incorporated in 1995. Our principal executive offices are located at 500 Arsenal Street, Watertown, Massachusetts 02472, and our telephone number is (617) 607-0800. Our web site address is www.enanta.com. Segment Information We provide segment information in Note 2 to our Consolidated Financial Statements included in Item 8 of this report. We are incorporating that information into this section by this reference. Employees As of September 30, 2018, we had 113 full-time employees, 59 of whom hold Ph.D. or M.D. degrees. None of our employees are subject to a collective bargaining agreement or represented by a trade or labor union. We consider our relations with our employees to be good. Available Information Our Internet website address is http://www.enanta.com. Through our website, we make available, free of charge, our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and any amendments to those reports, as well as proxy statements, and, from time to time, other documents as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Securities and Exchange Commission, or SEC. These SEC reports can be accessed through the “Investors” section of our website. The information found on our website is not part of this or any other report we file with or furnish to the SEC. Investors may read and copy any materials we file with the SEC at the SEC’s Public Reference Room at 100 F Street, NE, Washington, DC 20549. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC also maintains an Internet website that contains reports, proxy and information statements, and other information regarding Enanta Pharmaceuticals, Inc. and other issuers that file electronically with the SEC. The SEC’s Internet website address is http://www.sec.gov. 25 ITEM 1A. RISK FACTORS RISK FACTORS Our business faces significant risks and uncertainties. Certain factors may have a material adverse effect on our business prospects, financial condition and results of operations, and you should carefully consider them. Accordingly, in evaluating our business, we encourage you to consider the following discussion of risk factors, in its entirety, in addition to other information contained in or incorporated by reference into this Annual Report on Form 10-K and our other public filings with the SEC. Other events that we do not currently anticipate or that we currently deem immaterial may also affect our business, prospects, financial condition and results of operations. Risks Related to Our Business Our financial prospects for the next several years are dependent upon the commercialization efforts of AbbVie for combination therapies incorporating our protease inhibitor, glecaprevir, for the treatment of HCV. AbbVie may act in its best interest rather than in our best interest, which could adversely affect our business. We rely on AbbVie to fund and conduct the commercialization of its regimen containing glecaprevir (our second protease inhibitor, which is one of the two DAAs in AbbVie’s MAVYRET/MAVIRET treatment), over which we have granted AbbVie complete control. Our ability to generate revenue will depend primarily on the success of AbbVie’s continued efforts to commercialize MAVYRET/MAVIRET. Such success is subject to significant uncertainty, and we have no control over the resources, time and effort that AbbVie may devote to this regimen. Any of several events or factors could have a material adverse effect on our ability to generate revenue from AbbVie’s commercialization of glecaprevir in combination therapies. For example, AbbVie: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) may not achieve satisfactory levels of market acceptance and reimbursement by physicians, patients and third-party payers for the MAVYRET/MAVIRET regimen in the various markets of the world where it is being introduced and sold by AbbVie; may not compete successfully with its MAVYRET/MAVIRET regimen against other products and therapies for HCV; may have to comply with additional requests and recommendations from the FDA, including label restrictions for its regimen containing glecaprevir; may not make all regulatory filings and obtain all necessary approvals from foreign regulatory agencies and all commercially necessary reimbursement approvals; may not commit sufficient resources to the marketing and distribution of MAVYRET/MAVIRET, whether for competitive or strategic reasons or otherwise due to a change in business priorities; may cease to perform its obligations under the terms of our collaboration agreement; may unilaterally terminate our collaboration agreement on specified prior notice without any reason and without any further commitment; and may not be able to manufacture paritaprevir or glecaprevir in compliance with requirements of the FDA and similar foreign regulatory agencies and in commercial quantities sufficient to meet market demand. We do not have access to all information regarding the HCV regimens being commercialized by AbbVie, including certain information about spontaneous safety reports for any marketed product, regulatory affairs, process development, manufacturing, marketing, sales and other areas known by AbbVie. Thus, our ability to keep our stockholders informed about the status of products licensed under our collaboration is limited by the degree to which AbbVie keeps us informed. If AbbVie does not perform in the manner we expect or fulfill its responsibilities in a timely manner, or at all, the global commercialization of MAVYRET/MAVIRET could be delayed or terminated in selected jurisdictions or be commercially unsuccessful. In addition, AbbVie has the right to make decisions regarding the commercialization of licensed products without consulting us. For example, in November 2018, AbbVie entered into a royalty-free licensing agreement with the Medicines Patent Pool to accelerate access to AbbVie’s pan-genotypic HCV treatment glecaprevir/pibrentasvir (G/P) in 99 low- and middle-income countries and 26 territories by granting World Health Organization prequalified generic manufacturers licenses to manufacture and supply generic versions of G/P for distribution in those countries. AbbVie may also make decisions with which we do not agree. If AbbVie acts in a manner that is not in our best interest, then it could adversely affect our business and prospects. Our royalty revenues are primarily derived from AbbVie’s net sales of its MAVYRET/MAVIRET regimen for HCV. If AbbVie is unable to maintain sales of this regimen at or above current levels of sales, our royalty revenues would be adversely affected. Our quarterly royalty revenue from AbbVie’s net sales of its MAVYRET/MAVIRET regimen have grown substantially even as it is priced well below the pricing of AbbVie’s first HCV regimens, and below that of its principal competitor, Gilead. While commercialization of this regimen is exclusively in AbbVie’s control without any input from us, we believe it is possible that prices will decline further due to payers obtaining additional discounts or competitive market dynamics and that there may be fluctuation in AbbVie’s market share over time due to competitive actions by Gilead. We also note Gilead has reported a decline year over year across most major geographic markets in the number of new patients starting on DAA treatments for HCV. In addition, in light of continued fiscal crises experienced by several countries in the European Union and Japan, governments have announced or implemented measures to manage and reduce healthcare expenditures. AbbVie may experience global pricing pressure for its HCV regimens from such measures, which may be reflected in larger discounts or rebates on its regimens or delayed reimbursement. Also, private and public payers may choose to exclude AbbVie’s MAVYRET/MAVIRET regimen from their formulary coverage lists or limit the types of patients for whom coverage will be provided. Any such change in formulary coverage, discounts or rebates or reimbursement for MAVYRET/MAVIRET would negatively affect the demand for such regimen and our royalty revenue derived from its sale. We and AbbVie face substantial competition in the markets for HCV drugs, and there are many companies developing potential therapies for NASH, PBC, RSV and HBV, as well as other liver diseases and viral infections, which may result in others discovering, developing or commercializing products before we do or doing so more successfully than we do. The pharmaceutical and biotechnology industries are intensely competitive and rapidly changing. Many large pharmaceutical and biotechnology companies, academic institutions, governmental agencies and other public and private research organizations are commercializing or pursuing the development of products that target HCV, NASH, PBC, RSV, HBV and other viral infections or liver diseases that we may target in the future. Many of our competitors have substantially greater commercial infrastructure and greater financial, technical and personnel resources than we have, as well as drug candidates in late-stage clinical development. In all the disease areas currently under the focus of our research and development efforts, there are other companies with product candidates that are more advanced than ours. Our competitors may succeed in developing these product candidates or others and obtaining regulatory approval before we can do so with any of our product candidates. If we are not “first to market” with one of our product candidates in one or more of these disease indications, our competitive position could be compromised because it may be more difficult for us to obtain marketing approval for that product candidate and market acceptance of that product candidate as a follow-on competitor. In addition, any new product that competes with an approved product typically must demonstrate compelling advantages in efficacy, convenience, tolerability or safety, or some combination of these factors, in order to gain regulatory approvals, overcome price competition and be commercially successful. We expect AbbVie’s MAVYRET/MAVIRET to continue to face intense competition due to existing approved products in the HCV market. AbbVie’s HCV treatment regimens currently face competition in various world markets and subpopulations of HCV from Gilead’s Epclusa® (a fixed dose combination of sofosbuvir and velpatasvir), Vosevi™ (a triple combination therapy of sofosbuvir, velpatasvir and voxilaprevir approved by the FDA in July 2017 for specified sofosbuvir -treatment failures and NS5A-inhibitor treatment failures) and Harvoni® (a fixed-dose combination of sofosbuvir and ledipasvir); and to a lesser extent - Merck’s Zepatier® (a fixed-dose combination of grazoprevir and elbasvir). Recently, Gilead announced plans to launch authorized generic versions of Epclusa and Harvoni in January 2019 through a newly created subsidiary, Asegua Therapeutics, LLC. Competitive products in the form of other treatment methods or a vaccine for HCV may render AbbVie’s HCV 27 regimens obsolete or noncompetitive. AbbVie’s regimens that contain one of our collaboration’s protease inhibitors will face competition based on their safety and effectiveness, reimbursement coverage, price, patent position, AbbVie’s marketing and sales capabilities, and other factors. If any of AbbVie’s HCV regimens face competition from generic products, the collaboration agreement provides that the royalty rate applicable to our protease product contained in the regimen is reduced significantly by a specified percentage on a product-by-product, country-by- country basis. If AbbVie is not able to compete effectively against its competitors in HCV, our business will not grow and our financial condition, operations and stock price will suffer. We also expect our other product candidates to face intense and increasing competition in the NASH and antiviral markets as advanced technologies and products become available. Though there is currently no approved treatment for NASH, we expect significant competition from other companies in the development of new treatments for NASH and related conditions. We are aware of several companies with NASH programs that are significantly more advanced than ours, including companies with compounds in Phase 3 clinical trials in NASH, namely Intercept, Genfit, Gilead, and Tobira (Allergan). In May 2016, the FDA granted conditional approval for Intercept’s FXR agonist (brand name Ocaliva®) for the treatment of primary biliary cholangitis (PBC) in combination with first line therapy ursodeoxycholic acid (UDCA) in adults with an inadequate response to UDCA, or as monotherapy in adults unable to tolerate UDCA. In addition, a number of companies have NASH or related programs with compounds in Phase 2 clinical trials. These companies include Alberio, Astra-Zeneca, BMS, Boehringer Ingelheim, Can-Fite BioPharma, Conatus, Cirius, Cymabay, Galectin, Galmed, Gemphire Therapeutics, Gilead, GlaxoSmithKline, Immuron, Inventiva, Madrigal, Medicinova, Northsea Therapeutics, Novartis, NGM, Novo Nordisk, Pfizer and Viking. A significant number of other companies are conducting earlier stage clinical trials that may be applicable in NASH and other cholestatic diseases. There are also additional companies conducting preclinical studies in these disease areas. Similarly, HBV and RSV represent competitive therapeutic areas. While there are effective antiviral medications prescribed for HBV, they generally have low true cure rates. Many companies are seeking to develop new HBV drugs that alone or in combination with other mechanisms could lead to a functional cure of HBV. Arbutus, Gilead, HEC, Ionis, Johnson & Johnson, Maxwell, Replicor, Roche and Spring Bank have Phase 2 programs in progress, with many of these companies conducting earlier stage programs as well. In addition, a number of companies have Phase 1 or earlier stage HBV programs, including Aicuris, Alnylam, Altimmune, Assembly, Arrowhead, Enyo and Transgene. For RSV, there are currently no safe and effective therapies for already established RSV infection. Several companies are seeking new antiviral treatments for RSV infection in adult and pediatric settings. Ark Bioscienes, Johnson & Johnson, Gilead, Pulmocide and ReViral each have compounds in clinical development, as does Ablynx with a potential therapeutic antibody. A prophylactic, monoclonal-antibody-based treatment from MedImmune, which is commercialized by AbbVie outside of the U.S., is approved for infants considered at high risk for RSV infection; however studies have found that most young children with RSV infection were previously healthy, and thus would not normally be prescribed prophylactic treatment. In addition, a number of companies have RSV vaccines in development, primarily directed at prevention of RSV infection, and some companies are also evaluating vaccines in a therapeutic mode for treatment of established RSV infection. If we are not able to develop new products that can compete effectively against our current and future competitors, our business will not grow and our financial condition, operations and stock price will suffer. 28 We have not developed independently any approved products and we have limited clinical development experience, which makes it difficult to assess our ability to develop and commercialize our product candidates. AbbVie has been responsible for all of the clinical development of our paritaprevir and glecaprevir protease inhibitor products. We have not yet demonstrated an ability to address successfully many of the risks and uncertainties associated with late stage clinical development, regulatory approval and commercialization of therapeutic products such as the ones we plan to develop independently. For example, to execute our business plan for development of our independent RSV, NASH, PBC and HBV programs, we will need to successfully: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) execute clinical development of our product candidates and demonstrate acceptable safety and efficacy for them alone or in combination with other drugs or drug candidates; obtain required regulatory approvals for the development and commercialization of our product candidates; develop and maintain any future collaborations we may enter into for any of these programs; obtain and maintain patent protection for our product candidates and freedom from infringement of intellectual property of others; establish acceptable commercial manufacturing arrangements with third-party manufacturers; build and maintain robust sales, distribution and marketing capabilities, either independently or in collaboration with future collaborators; gain market acceptance for our product candidates among physicians, payers and patients; and manage our spending as costs and expenses increase due to clinical trials, regulatory approvals and commercialization. If we are unsuccessful in accomplishing these objectives, we may not be able to successfully develop and commercialize our product candidates and expand our business or continue our operations. If we are not successful in developing EDP-305, EDP-938 and/or EDP-514 or in discovering further product candidates in addition to those product candidates, our ability to expand our business and achieve our strategic objectives will be impaired. Much of our internal research is at preclinical stages. Research programs designed to identify product candidates require substantial technical, financial and human resources, whether or not any product candidates are ultimately identified. Our research programs may initially show promise in identifying additional potential product candidates, yet fail to yield product candidates for clinical development or commercialization for many reasons, including the following: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) the research methodology used may not be successful in identifying additional potential product candidates; competitors may develop alternatives that render our product candidates less commercially viable or obsolete; competitors may obtain intellectual property protection that effectively prevents us from developing a product candidate; a product candidate may, on further study, be shown not to be an effective treatment in humans or to have harmful side effects or other characteristics that indicate it is unlikely to be effective or otherwise does not meet applicable regulatory criteria; and a product candidate may not be capable of being produced in commercial quantities at an acceptable cost, or at all. 29 Additional drug candidates that we may develop will require significant research, preclinical and clinical studies, regulatory approvals and commitments of resources before they can be commercialized. We cannot give assurance that our research will lead to the discovery of any additional drug candidates that will generate additional revenue for us. If we are unable to identify additional compounds suitable for preclinical and clinical development, we may not be able to obtain sufficient product revenue in future periods, which likely would result in significant harm to our financial position and adversely impact our stock price. Expenses associated with development of our product candidates may cause our results of operations to fluctuate from period to period, which may result in operating losses. Many of the preclinical and clinical development activities required for our product candidates must be contracted out to contract research organizations (CROs) at significant expense. We expect these expenses to increase substantially in the coming years as we advance compounds and conduct more clinical studies. It is difficult to accurately predict the timing and amounts of these expenses, and we expect that they will vary from quarter to quarter. In addition, the FDA or other regulatory agencies may require more preclinical or clinical testing than we originally anticipated for any of our product candidates. We may also be required to purchase expensive competitor drugs for use in our trials, either to demonstrate potential treatment combinations or as comparators to our product candidates. We also conduct clinical development activities outside the U.S. and are therefore exposed to foreign currency fluctuations for payments made to CROs in currencies other than the U.S. dollar. As a result, the expenses of our development programs and our operating results may fluctuate significantly from quarter to quarter, and our stock price may be adversely affected. If we fail to attract and keep senior management and key scientific personnel, we may be unable to successfully develop our product candidates, conduct our clinical trials and commercialize our product candidates. Our success depends in part on our continued ability to attract, retain and motivate highly qualified management, clinical and scientific personnel. We are highly dependent upon our senior management, particularly Jay R. Luly, Ph.D., our Chief Executive Officer and President, Yat Sun Or, Ph.D., our Senior Vice President, Research and Development and Chief Scientific Officer, and Nathalie Adda, M.D., our Senior Vice President, Chief Medical Officer, as well as other employees and consultants. Although none of these individuals has informed us to date that he or she intends to retire or resign in the near future, the loss of the services of any of these individuals or one or more of our other members of senior management could delay or prevent the successful development of our product candidates. Although we have not historically experienced unique difficulties attracting and retaining qualified employees, we could experience such problems in the future. For example, competition for qualified personnel in the biotechnology and pharmaceutical fields is intense. In addition, we will need to hire additional personnel as we expand our clinical development and ultimately seek regulatory approvals and prepare for commercial activities. We may not be able to attract and retain quality personnel on acceptable terms. We may encounter difficulties in managing our growth and expanding our operations successfully. As we expand our research efforts and seek to advance our product candidates through clinical trials, we will need to expand our development, regulatory, manufacturing, marketing and sales capabilities or contract with third parties to provide these capabilities for us. As our operations expand, we expect that we will need to manage additional relationships with various strategic partners, suppliers and other third parties. Future growth will impose significant added responsibilities on members of management. Our future financial performance and our ability to commercialize our product candidates and to compete effectively will depend, in part, on our ability to manage any future growth effectively. To that end, we must be able to manage our development efforts and clinical trials effectively and hire, train and integrate additional management, administrative and sales and marketing personnel. We may not be able to accomplish these tasks, and our failure to accomplish any of them could prevent us from successfully growing our company. 30 To date, our principal sources of revenue have been our collaboration agreements, including our current agreement with AbbVie. Future levels of royalties under the AbbVie agreement are uncertain. We have had no other products approved for commercial sale by us. Therefore, it is possible that we may incur operating losses in one or more years in the future, and our ability to achieve sustained profitability is unproven. In each of our past four fiscal years, our net income resulted primarily from license payments, including milestone payments we earned from AbbVie and royalties we earned since December 2014 on net sales of AbbVie’s HCV regimens allocated to our protease inhibitors included in those regimens. There is no assurance, however, that we will report net income in subsequent years. To date, we have not commercialized any products ourselves. Our principal source of revenue historically has been our collaboration agreements, including our current agreement with AbbVie. The level of future royalties on products containing paritaprevir or glecaprevir is uncertain given the competitive nature of the market for HCV therapies. This is attributed to price competition, the changing nature of payer contracts of AbbVie and others, and the varying rates of reimbursement in different countries. At any time, AbbVie may choose not to continue its commercialization activities for the MAVYRET/MAVIRET regimen. If we are unable to develop and commercialize any more of our product candidates, either alone or with a collaborator, or if any such product candidate does not achieve market acceptance, we may not generate sufficient product sales or product royalties. In addition, for any of our product candidates included in a treatment regimen with more than one active compound, it would be uncertain what portion of net sales of the regimen would be allocated to our product candidate. Even if we do generate significant product royalties or product sales, we may not be able to sustain profitability on a quarterly or annual basis. Our failure to sustain profitability could depress the market price of our common stock and ultimately could impair our ability to raise capital, expand our business, diversify our product offerings or continue our operations. A decline in the market price of our common stock also could cause you to lose all or a part of your investment. We may require substantial additional financing in the longer term to achieve our goals if the further commercialization of MAVYRET/MAVIRET is not successful. A failure to obtain this necessary capital when needed could force us to delay, limit, reduce or terminate some or all of our product development efforts. Since our inception, most of our resources have been dedicated to the discovery and preclinical development of our product candidates. In particular, we have expended, and believe that we will continue to expend for the foreseeable future, substantial resources discovering and developing our proprietary product candidates. These expenditures will include costs associated with research and development, preclinical manufacturing of product candidates, conducting preclinical experiments and clinical trials and obtaining regulatory approvals, as well as commercializing any products later approved for sale. For the foreseeable future, we expect to incur substantial additional costs associated with research and development for our internally developed programs, exclusive of costs incurred by AbbVie in developing MAVYRET/MAVIRET. In addition, we may seek opportunities to in-license or otherwise acquire new therapeutic candidates and therapies. Our future capital requirements depend on many factors, including: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) whether our existing collaboration continues to generate substantial royalties to us; the number and characteristics of the product candidates we pursue; the scope, progress, results and costs of researching and developing any of our product candidates on our own, including conducting preclinical research and clinical trials; opportunities to in-license or otherwise acquire new therapeutic candidates and therapies; the timing, receipt and amount of royalties on paritaprevir and glecaprevir and any sales of our product candidates, if any, or royalties thereon; the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; 31 (cid:129) (cid:129) (cid:129) the cost of manufacturing our product candidates and any products we successfully commercialize independently, including manufacturing for clinical development; our ability to maintain our existing collaboration and to establish new collaborations, licensing or other arrangements and the financial terms of such agreements; and the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation. Additional funds may not be available if and when we need them, on terms that are acceptable to us, or at all. Our ability to raise funds will depend on financial, economic and market conditions and other factors, many of which are beyond our control. If adequate funds are not available to us on a timely basis, we may be required to delay, limit, reduce or terminate preclinical studies, clinical trials or other research and development activities for one or more of our product candidates. The U.S. Tax Cuts and Jobs Act enacted in December 2017 includes significant changes from prior tax law which could result in significant changes to our future tax positions. The U.S. Tax Cuts and Jobs Act (the “Tax Act”) enacted in December 2017 contains many provisions which differ from prior tax law. These changes include, but are not limited to, the reduction in the federal corporate income tax rate from 35% to 21%, the elimination of a corporation’s ability to carryback net operating losses to prior taxable income periods and the elimination of the deductibility of certain performance-based equity awards under Section 162(m). We accounted for the Tax Act during the year ended September 30, 2018 , which resulted in an adjustment that decreased our deferred tax assets by $3.8 million due to the reduction of the federal corporate income tax rate from 35% to 21%. Estimates used to prepare our income tax expense are based on our analysis of the Tax Act. Given the complexity of the act, anticipated guidance from the U.S. Treasury regarding implementation of the Tax Act, and potential for guidance from the Securities and Exchange Commission or the Financial Accounting Standards Board related to the act, these estimates may be adjusted in future periods to reflect any such guidance provided. Risks Related to Development, Clinical Testing and Regulatory Approval of Our Product Candidates Clinical drug development involves a lengthy and expensive process with uncertain timelines and uncertain outcomes. If clinical trials of any of our proprietary product candidates are prolonged or delayed, we may be unable to commercialize our product candidates on a timely basis. Clinical testing is expensive and, depending on the stage of development, can take a substantial time period to complete. Its outcome is inherently uncertain, and failure can occur at any time during clinical development. None of our product candidates in our pipeline other than paritaprevir and glecaprevir, which have been clinically developed by AbbVie, has yet to advance beyond completion of Phase 2 clinical trials. Any future clinical trials of our product candidates may fail to demonstrate sufficient safety and efficacy. Moreover, regulatory and administrative delays for any product candidate in our pipeline may adversely affect our or any future collaborator’s clinical development plans and jeopardize our or any future collaborator’s ability to attain product approval, commence product sales and compete successfully against other therapies. Clinical trials can be delayed for a variety of reasons, including delays related to: (cid:129) (cid:129) (cid:129) (cid:129) reaching an agreement on acceptable terms with prospective contract research organizations, or CROs, and clinical trial sites, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites; failure of third-party contractors, such as CROs, or investigators to comply with regulatory requirements; delay or failure in obtaining the necessary approvals from regulators or institutional review boards, or IRBs, in order to commence a clinical trial at a prospective trial site, or their suspension or termination of a clinical trial once commenced; difficulty in recruiting suitable patients to participate in a trial; 32 (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) difficulty in having patients complete a trial or return for post-treatment follow-up; clinical sites deviating from trial protocol or dropping out of a trial; problems with drug product or drug substance storage and distribution; adding new clinical trial sites; our inability to manufacture, or obtain from third parties, adequate supply of drug product sufficient to complete our preclinical studies and clinical trials; governmental or regulatory delays and changes in regulatory requirements, policy and guidelines, including guidelines specifically addressing requirements for the development of treatments for RSV, NASH, PBC or HBV; program discontinuations or clinical holds for a program of a competitor, which could increase the level of regulatory scrutiny or delay data review or other response times by regulators with respect to one of our programs in the same class as the competitor’s program; or varying interpretations of data by the FDA, the EMA and similar foreign regulatory agencies. We could also encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions in which such trial is being conducted, by any Data Safety Monitoring Board, or DSMB, for such trial, or by the FDA, the EMA or other regulatory authorities. Such authorities may impose such a suspension or termination due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. In addition, delays can occur due to safety concerns arising from trials or other clinical data regarding another company’s product candidate in the same compound class as one of ours. If we or any future collaborators experience delays in the completion of, or termination of, any clinical trial of one of our product candidates, the commercial prospects of the product candidate will be harmed, and our ability to commence product sales and generate product revenues from the product candidate will be delayed. In addition, any delays in completing our clinical trials will increase our costs and slow down our product candidate development and approval process. Any of these occurrences may harm our business, financial condition and prospects significantly. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates. We may choose to test any of our clinical candidates preclinically and/or clinically in combination with other compounds with different mechanisms of action, and any adverse results from such testing may have adverse consequences for the further development potential of not only the combination but also the clinical candidate itself as a monotherapy or in combination with other mechanisms of action. We expect that the further development of successful therapies in our principal disease areas of RSV, NASH and HBV may require combining one or more of our compounds with other compounds with different mechanisms of action. To advance our programs and achieve favorable opportunities for any such combinations we may conduct preclinical testing, as well as clinical testing, with one of our other compounds or with a compound of a third party, with or without a longer-term collaboration with any such party. We may choose to disclose such testing in advance, but we can anticipate that some of the testing would be done without any public disclosure. If any such testing produces adverse results, we may have to disclose it to regulatory authorities as part of the data available with respect to our product candidate and the data may have adverse consequences for the further development and the ultimate conditions attached to any approved use of the product candidate, whether in the combination tested or even as a monotherapy or in combination with other mechanisms. 33 EDP-305, EDP-938, EDP-514 or any other product candidate emerging from our current NASH, PBC, RSV and HBV programs may have undesirable side effects which may delay or prevent marketing approval, or, if approval is received, require our product candidate to be taken off the market, require us to include safety warnings or otherwise limit sales. In our NASH/PBC program, we are developing agonists of the farnesoid X receptor, or FXR, that are designed to bind to that receptor and then trigger a response from it. The adverse effects from long-term exposure to the FXR drug class are not well known since within this class only two drugs have been approved by the FDA—Ocaliva®, approved in May 2016 for PBC, and an older drug not commonly used but approved to treat cholesterol gallstones (by dissolving them) and a rare lipid storage disease. Unforeseen side effects from any of our product candidates could arise either during clinical development or, if approved, after the approved product has been marketed. The range and potential severity of possible side effects from systemic therapies like FXR agonists could be significant. In addition, our drug candidates for NASH may be developed as a potential treatment for a severe disease that commonly occurs in patients with other serious conditions, including metabolic syndrome and diabetes. Any clinical trials in NASH will necessarily be conducted in patient populations that may be more prone than the general population to exhibit certain disease states or adverse events. It may be difficult to discern whether certain events or symptoms observed during our trials were due to our drug candidates or placebo, resulting in our company and our development programs being negatively affected even if such events or symptoms are ultimately determined to be unlikely related to our drug candidates. In our RSV program, we are developing inhibitors of the N protein. No inhibitor of the RSV N protein has progressed beyond a Phase 2 clinical trial, so we are not yet able to assess the potential liabilities of an N inhibitor in large scale studies or in the general population. In addition, in RSV the principal target populations, namely infants, the elderly, and the immunocompromised, represent sensitive patient populations that could be more prone to adverse effects of therapy. In our HBV program, we are developing modulators of capsid assembly. This is a new mechanistic approach to HBV, and no capsid assembly modulators have advanced beyond Phase 2 clinical studies. Thus, we are not able to predict what adverse effects may arise in longer term studies conducted in larger populations. In addition, in HBV, long term consequences of an HBV infection can include hepatocellular carcinoma, liver failure, or liver transplant. It may be difficult to determine whether our drug candidates are playing a direct role in contributing to (or protecting from) these downstream effects of HBV infection. If any of our product candidates receives marketing approval and we or others later identify undesirable or unacceptable side effects caused by such products: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) regulatory authorities may require the addition of labeling statements, specific warnings, a contraindication or field alerts to physicians and pharmacies; we may be required to change instructions regarding the way the product is administered, conduct additional clinical trials or change the labeling of the product; we may be subject to limitations on how we may promote the product; sales of the product may decrease significantly; regulatory authorities may require us to take our approved product off the market; we may be subject to litigation or product liability claims; and our reputation and our stock price may suffer. Any of these events could prevent us from achieving or maintaining market acceptance of the affected product or could substantially increase commercialization costs and expenses, which in turn could delay or prevent us from generating significant revenue from the sale of any product we develop. 34 If we are required to suspend or discontinue clinical trials due to side effects or other safety risks associated with our product candidates, or if we are required to conduct studies on the long-term effects associated with the use of any of those product candidates, commercialization any of those product candidates could be delayed or halted. Clinical trials involving our product candidates may be suspended or terminated at any time for a number of safety- related reasons. For example, we may voluntarily suspend or terminate clinical trials if at any time one of our product candidates, or a combination therapy including any of them, presents an unacceptable safety risk to the clinical trial patients. In addition, IRBs or regulatory agencies may order the temporary discontinuation or termination of clinical trials at any time if they believe that the clinical trials are not being conducted in accordance with applicable regulatory requirements, including if they present an unacceptable safety risk to patients. Administering any product candidate to humans may produce undesirable side effects. The existence of undesirable side effects resulting from any of our product candidates, or a combination therapy including any of them, could cause us or regulatory authorities, such as the FDA or EMA, to interrupt, delay or halt clinical trials of our product candidates and could result in the FDA or EMA or other regulatory agencies denying further development or approval of our product candidates for any or all targeted indications. This, in turn, could prevent us from commercializing our product candidates. Results of earlier clinical trials may not be predictive of the results of later-stage clinical trials. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials, if any. In addition, results of Phase 3 clinical trials in one or more ethnic groups are not necessarily indicative of results in other ethnic groups. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy results despite having progressed through preclinical studies and initial clinical trials. Many companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to adverse safety profiles or lack of efficacy, notwithstanding promising results in earlier studies. Similarly, future clinical trial results may not be successful for these or other reasons. Product candidate development risk is heightened by any changes in the planned clinical trials compared to the completed clinical trials. As product candidates are developed through preclinical early and late stage clinical trials towards approval and commercialization, it is customary that various aspects of the development program, such as manufacturing and formulation, are altered along the way in an effort to optimize processes and results. Such changes carry the risk that they will not achieve these intended objectives. Any of these changes could make the results of planned clinical trials or other future clinical trials we may initiate less predictable and could cause our product candidates to perform differently, which could delay completion of clinical trials, delay approval of our product candidates and/or jeopardize our ability to commence product sales and generate revenues. The regulatory approval processes of the FDA, the EMA and other comparable foreign authorities are lengthy, time-consuming and inherently unpredictable, and if we are ultimately unable to obtain timely regulatory approval for our product candidates, our business will be substantially harmed. The regulatory approval process is expensive and, while the time required to gain FDA and foreign regulatory approval is uncertain, it may take years. Regulatory approvals are unpredictable and depend upon numerous factors, including the substantial discretion of the regulatory authorities. In addition, approval policies, regulations, or the type and amount of preclinical and clinical data necessary to gain approval may change during the course of a product candidate’s clinical development and may vary among jurisdictions. We may be required to undertake and complete certain additional preclinical studies to generate toxicity and other data required to support the submission of a New Drug Application, or NDA, to the FDA or comparable application to other regulatory authorities. AbbVie obtained all regulatory approvals for its paritaprevir-containing regimens and for MAVYRET/MAVIRET, which contains glecaprevir. We have not obtained regulatory approval by ourself for any of our wholly-owned product candidates and it is possible that none of our existing product candidates or any of our future product candidates will ever obtain regulatory approval. Furthermore, approval in the United States by the FDA does not ensure approval by regulatory authorities in other countries or jurisdictions, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. 35 Our product candidates could fail to receive regulatory approval for many reasons, including the following: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) the FDA, the EMA or other comparable foreign regulatory authorities may disagree with the design or implementation of our clinical trials; we may be unable to demonstrate to the satisfaction of the FDA, the EMA or other comparable foreign regulatory authorities that a product candidate is safe and effective for its proposed indication; the results of clinical trials may not meet the level of statistical significance required by the FDA, the EMA or other comparable foreign regulatory authorities for approval; we may be unable to demonstrate that a product candidate’s clinical and other benefits outweigh its safety risks; the FDA, the EMA or other comparable foreign regulatory authorities may disagree with our interpretation of data from preclinical studies or clinical trials; the data collected from clinical trials of our product candidates may not be sufficient to support the submission of an NDA or other submissions or to obtain regulatory approval in the United States or elsewhere; the FDA or comparable foreign regulatory authorities may fail to approve the manufacturing processes or facilities of third-party manufacturers with which we contract for clinical and commercial supplies of any of our product candidates; and the approval policies or regulations of the FDA, the EMA or other comparable foreign regulatory authorities may significantly change in a manner rendering our clinical data insufficient for approval. We cannot be assured that after spending substantial time and resources, we will obtain regulatory approvals in any desired jurisdiction. Even if we were to obtain approval, regulatory authorities may grant approval contingent on the performance of costly post-marketing clinical trials, or may approve a product candidate with a label that does not include the labeling claims necessary or desirable for the successful commercialization of that product candidate. Significant clinical trial delays could allow our competitors to obtain marketing approval before we do or could in effect shorten the patent protection period during which we may have the exclusive right to commercialize our product candidates. In addition, it may ultimately not be possible to achieve the prices intended for our products. In many foreign countries, including those in the European Union, a product candidate must be approved for reimbursement before it can be approved for sale in that country. Any of the foregoing scenarios could materially harm the commercial prospects for our product candidates and our business. Even if we receive regulatory approval for any of our product candidates we develop independently, we will be subject to ongoing FDA obligations and continued regulatory review in other jurisdictions, which may result in significant additional expense. Additionally, our product candidates, if approved, could be subject to labeling and other restrictions and market withdrawal and we may be subject to penalties if we or our collaborators fail to comply with regulatory requirements or experience unanticipated problems with our products. Any regulatory approvals that we receive for our product candidates we develop independently may be subject to limitations on the approved indicated uses for which the product may be marketed or subject to certain conditions of approval, or may contain requirements for potentially costly post-marketing testing, including Phase 4 clinical trials, and surveillance to monitor the safety and efficacy of the product candidate. 36 In addition, if the FDA approves any of our product candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion and recordkeeping for the product will be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-marketing information and reports, as well as continued compliance with current good manufacturing practices, or cGMP, and good clinical practices, or GCP, for any clinical trials that we or our collaborators conduct post-approval. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) restrictions on the marketing or manufacturing of the product, withdrawal of the product from the market or voluntary or mandatory product recalls; fines, warning letters or holds on any post-approval clinical trials; refusal by the FDA to approve pending applications or supplements to approved applications filed by us, or suspension or revocation of product license approvals; product seizure or detention, or refusal to permit the import or export of products; and injunctions or the imposition of civil or criminal penalties. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad. If we, or AbbVie in the case of any licensed HCV product, are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or AbbVie are not able to maintain regulatory compliance, our product candidates or AbbVie’s licensed HCV products may lose any marketing approval that may have been obtained and we may not achieve or sustain profitability, which would adversely affect our business. We may delay or terminate the development of a product candidate at any time if we believe the perceived market or commercial opportunity does not justify further investment, which could materially harm our business and adversely affect our stock price. Even though the results of preclinical studies and clinical trials that we have conducted or may conduct in the future may support further development of one or more of our product candidates, we may delay, suspend or terminate the future development of a product candidate at any time for strategic, business, financial or other reasons, including the determination or belief that the emerging profile of the product candidate is such that it may not receive regulatory approvals in key markets, gain meaningful market acceptance, otherwise provide any competitive advantages in its intended indication or market or generate a significant return to stockholders. Such a delay, suspension or termination could materially harm our business, results of operations or financial condition. In addition, AbbVie has the right to make decisions regarding the commercialization of paritaprevir and glecaprevir without consulting us, and may make decisions with which we do not agree. Risks Related to Commercialization of Our Product Candidates Even if AbbVie continues to successfully commercialize MAVYRET/MAVIRET, or even if we are able to commercialize any other treatment regimen containing one of our product candidates from any of our proprietary discovery programs, MAVYRET/MAVIRET or the resulting products, as the case may be, may become subject to unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives in the United States, which would harm our business. The regulations that govern marketing approvals, pricing and reimbursement for new drug products vary widely from country to country. In the United States, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Affordability Reconciliation Act of 2010, collectively referred to as the ACA, is significantly changing the way healthcare is financed by both governmental and private insurers. While we cannot predict what impact on federal reimbursement policies this law or any amendment to it will continue to have in general or specifically on any product or regimen that we may commercialize, the ACA or any such amendment may result in downward pressure on pharmaceutical reimbursement, which could negatively affect market acceptance of new products. In addition, although the United States Supreme Court has upheld the constitutionality 37 of most of the ACA, several states have not implemented certain sections of the ACA, including 14 that have rejected the expansion of Medicaid eligibility for low income citizens, and some members of the U.S. Congress are still working to repeal the ACA. More recently, President Trump and the Republicans in both houses of the U.S. Congress have been seeking to repeal or replace all or portions of the ACA but to date they have been unable to agree on any such legislation. We cannot predict what legislation, if any, to repeal or replace the ACA will become law, or what impact any such legislation may have on us or on AbbVie’s commercialization of its HCV regimens. Our ability to commercialize any product candidate successfully, as well as AbbVie’s commercialization of MAVYRET/MAVIRET, will also depend in part on the extent to which reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. A primary trend in the U.S. healthcare industry is cost containment. Government authorities and third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. In the case of HCV, limitations of coverage have recently been used to limit access to HCV treatments for only those patients with more advanced fibrosis. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and, in many cases involving HCV drugs, seeking discounts in exchange for greater patient access to a particular HCV drug. In addition, there are private and public payors challenging the prices charged for medical products. We cannot be sure that reimbursement will be available for any product that we may commercialize and, if reimbursement is available, the level of reimbursement. In addition, reimbursement may impact the demand for, or the price of, MAVYRET/MAVIRET or any product candidate for which we may obtain marketing approval. If reimbursement is not available or is available only to limited levels, AbbVie may not be successful in commercializing MAVYRET/MAVIRET and we may not be able to successfully commercialize any product candidate for which we may seek marketing approval. There may be significant delays in obtaining reimbursement for newly approved drugs, and coverage may be more limited than the purposes for which the drug is approved by the FDA or comparable authorities in other jurisdictions. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim reimbursement levels for new drugs, if applicable, may also be insufficient to cover our and any collaborator’s costs and may not be made permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies. AbbVie’s inability to promptly obtain coverage and profitable payment rates from both government-funded and private payors for MAVYRET/MAVIRET, or our inability to do the same for any product candidate that we develop, could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize products and our overall financial condition. In general, the United States and several other jurisdictions are considering a number of legislative and regulatory proposals to change the healthcare system in ways that could affect our ability to sell our products profitably. Among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access to healthcare. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives. We expect to experience pricing pressures in connection with the sale of any products that we develop or that are being commercialized under our collaboration with AbbVie. The implementation of cost containment measures or other healthcare reforms may limit our ability to generate revenue, maintain profitability or commercialize our product candidates. Foreign governments tend to impose strict price controls, which may adversely affect our future profitability. In most foreign countries, particularly in the European Union and Japan, prescription drug pricing and/or reimbursement is subject to governmental control. In those countries that impose price controls, pricing negotiations with governmental authorities 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 candidate to other available therapies. 38 Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some foreign markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we (or AbbVie in the case of MAVYRET/MAVIRET) might obtain marketing approval for a product in a particular country, but then be subject to price regulations that delay commercial launch of the product, possibly for lengthy time periods, and negatively impact the revenues that are generated from the sale of the product in that country. If reimbursement of MAVYRET/MAVIRET or of any of our product candidates is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, or if there is competition from lower priced cross- border sales, our results of operations will be negatively affected. If, in the future, we are unable to establish our own sales, marketing and distribution capabilities or enter into licensing or collaboration agreements for these purposes, we may not be successful in commercializing any product candidates. We do not have a sales or marketing infrastructure and have no sales, marketing or distribution experience. We will seek to either build our own commercial infrastructure to commercialize any products if and when they are approved, or enter into licensing or collaboration agreements where our collaborator is responsible for commercialization, as in the case of our collaboration with AbbVie, or where we have the right to assist in the future development and commercialization of such products. To develop internal sales, distribution and marketing capabilities, we will have to invest significant amounts of financial and management resources, some of which will be committed prior to any confirmation that any of our proprietary product candidates will be approved. For product candidates for which we decide to perform sales, marketing and distribution functions ourselves, we could face a number of additional risks, including: (cid:129) (cid:129) (cid:129) (cid:129) our inability to recruit and retain adequate numbers of effective sales and marketing personnel; the inability of sales personnel to obtain access to physicians or persuade adequate numbers of physicians to prescribe any products; the lack of complementary products to be offered by sales personnel, which may put us at a competitive disadvantage relative to companies with more extensive product lines; and unforeseen costs and expenses associated with creating an independent sales and marketing organization. Where and when appropriate, we may elect to utilize contract sales forces or distribution partners to assist in the commercialization of our product candidates. If we enter into arrangements with third parties to perform sales, marketing and distribution services for our products, the resulting revenues or the profitability from these revenues to us are likely to be lower than if we had sold, marketed and distributed our products ourselves. In addition, we may not be successful in entering into arrangements with third parties to sell, market and distribute our product candidates or may be unable to do so on terms that are favorable to us. We likely will have little control over such third parties, and any of these third parties may fail to devote the necessary resources and attention to sell, market and distribute our products effectively. If we do not establish sales, marketing and distribution capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our product candidates. 39 Commercial success of our product candidates depends upon significant market acceptance among physicians, patients and healthcare payors of any resulting approved drug. MAVYRET/MAVIRET, as well as EDP-305, EDP-938, EDP-514 or any other product candidate that we may develop in the future, whether as part of a combination therapy or as a monotherapy, may not gain market acceptance among physicians, healthcare payors, patients and the medical community. The degree of market acceptance of MAVYRET/MAVIRET or of any product candidate for which we obtain approval for commercial sale, will depend on a number of factors, including: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) the efficacy and safety of treatment regimens containing one of our product candidates, as demonstrated in clinical trials, and the degree to which these regimens represent a clinically meaningful improvement in care as compared with other available therapies; the clinical indications for which any treatment regimen containing one of our product candidates become approved; acceptance among physicians, major operators of clinics, payors and patients of any treatment regimen containing one of our product candidates; the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies; the potential and perceived advantages of treatment regimens containing one of our product candidates over alternative treatments; the cost of treatment of regimens containing one of our product candidates in relation to the cost of alternative treatments; the availability of adequate reimbursement and pricing by third parties and government authorities and successful negotiation of favorable agreements with payors by us or any collaborator of ours, as well as the impact of any agreements among any of the foregoing and one or more of our competitors limiting access to our product in favor of one or more competitive products; the continued longevity of the HCV drug market or growth and longevity of any other market for which we develop a drug; the levels of funding provided by government-funded healthcare for HCV treatment or treatment of any other disease for which we develop a drug; the relative convenience and ease of administration of any treatment regimen containing one of our product candidates compared to competitive regimens; the prevalence and severity of adverse side effects, whether involving the use of treatment regimens containing one of our products candidates or similar, competitive treatment regimens; and the effectiveness of our sales and marketing efforts and those of AbbVie in the case of MAVYRET/MAVIRET. If treatment regimens containing one of our product candidates are approved and then fail to achieve market acceptance, we may not be able to generate significant additional revenue. Further, if new, more favorably received therapies are introduced after any such regimen achieves market acceptance, then we may not be able to maintain that market acceptance over time. 40 Risks Related to Our Dependence on Third Parties We may not be successful in establishing new product collaborations, which could adversely affect our ability to develop and commercialize one or more of our product candidates. If we are unsuccessful in maintaining or forming alliances on favorable terms, our business may not succeed. We may seek to enter into additional product collaborations in the future, including alliances with other biotechnology or pharmaceutical companies, to enhance and accelerate the development and commercialization of one or more of our product candidates. We face significant competition in seeking appropriate collaborators and the negotiation process is time-consuming and complex. Moreover, we may not be successful in our efforts to establish other product collaborations or other alternative arrangements for any product candidates and programs because our research and development pipeline may be insufficient, our product candidates and programs may be deemed to be at too early of a stage of development for collaborative effort and/or third parties may not view our product candidates and programs as having the requisite potential to demonstrate safety and efficacy. Even if we are successful in our efforts to establish product collaborations, the terms that we agree upon may not be favorable to us and we may not be able to maintain such product collaborations if, for example, development or approval of a product candidate is delayed or sales of an approved product are disappointing. If our existing collaboration agreement with AbbVie is terminated, or if we determine that entering into other product collaborations is in our best interest but we either fail to enter into, delay in entering into or fail to maintain such collaborations: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) the development of certain of our product candidates may be terminated or delayed; our cash expenditures related to development of certain of our product candidates would increase significantly and we may need to seek additional financing; we may be required to hire additional employees or otherwise develop expertise, such as clinical, regulatory, sales and marketing expertise, which we do not currently have; we will bear all of the risk related to the development of any such product candidates; and the competitiveness of any product candidate that is commercialized could be reduced. We intend to rely on third-party manufacturers to produce our development-stage product candidate supplies and any commercial supplies of any approved product candidates. Any failure by a third-party manufacturer to produce acceptable supplies for us may delay or impair our ability to initiate or complete our clinical trials or sell any resulting product. We do not currently own or operate any manufacturing facilities. We plan to continue to work with third-party contract manufacturers to produce sufficient quantities of any product candidates for preclinical testing, clinical trials and commercialization. If we are unable to arrange for such a third-party manufacturing source for any of our product candidates, or fail to do so on commercially reasonable terms, we may not be able to successfully produce, develop and market one or more of our product candidates, or we may be delayed in doing so. Reliance on third-party manufacturers entails risks to which we would not be subject if we manufactured product candidates ourselves, including reliance on the third party for regulatory compliance and quality control and assurance, volume production, the possibility of breach of the manufacturing agreement by the third party because of factors beyond our control (including a failure to synthesize and manufacture our product candidates in accordance with our product specifications) and the possibility of termination or nonrenewal of the agreement by the third party at a time that is costly or damaging to us. In addition, the FDA and other regulatory authorities require that our product candidates be manufactured according to cGMP and similar foreign standards. Pharmaceutical manufacturers and their subcontractors are required to register their facilities and/or products manufactured at the time of submission of the marketing application and then annually thereafter with the FDA and certain state and foreign agencies. They are also subject to periodic unannounced inspections by the FDA, state and other foreign authorities. Any subsequent discovery of problems with a product, or a manufacturing or laboratory facility used by us or our collaborators, may result in restrictions on the product or on the manufacturing or laboratory facility, including marketed product recall, suspension of manufacturing, product seizure, or a voluntary withdrawal of the drug from the market. Any failure by our third-party manufacturers to comply with cGMP or failure to scale up manufacturing processes, including any failure to deliver sufficient quantities of product candidates in a timely manner, could lead to a delay in, or failure to obtain, regulatory approval of any of our product candidates. 41 We plan to rely on third-party manufacturers to purchase from third-party suppliers the materials necessary to produce our product candidates for our clinical studies. There are a small number of suppliers for certain capital equipment and materials that we plan to use to manufacture our drugs. Such suppliers may not sell these materials to our manufacturers at the times we need them or on commercially reasonable terms. Moreover, we currently do not have any agreements for the production of these materials. Although we do not intend to begin a clinical trial unless we believe we have a sufficient supply of a product candidate to complete the clinical trial, any significant delay in the supply of a product candidate or the material components thereof for an ongoing clinical trial due to the need to replace a third-party manufacturer could considerably delay completion of our clinical studies, product testing and potential regulatory approval of our product candidates. If our manufacturers or we are unable to purchase these materials after regulatory approval has been obtained for our product candidates, the commercial launch of our product candidates would be delayed or there would be a shortage in supply, which would impair our ability to generate revenue from the sale of our product candidates. Contract manufacturers may not be able to manufacture our product candidates at a cost or in quantities or in a timely manner necessary to develop and commercialize them. If we successfully commercialize any of our product candidates, to meet our projected needs we may need to find third parties that will increase their scale of production, or we may have to establish or access large-scale commercial manufacturing capabilities. We may require additional funds, personnel and other resources to build, lease or operate any manufacturing facility. A portion of our research and a portion of our manufacturing of certain key intermediates used in the manufacture of the active pharmaceutical ingredients for our product candidates takes place in China through third-party researchers and manufacturers. A significant disruption in the operation of those researchers or manufacturers, a trade war, or political unrest in China could materially adversely affect our business, financial condition and results of operations. Although manufacturing for MAVYRET/MAVIRET is being conducted by AbbVie, we have relied on third parties located in China to manufacture and supply certain key intermediates used in the manufacture of our active pharmaceutical ingredients, or API, for our current product candidates, and we expect to continue to use such third party manufacturers for such intermediates for any product candidates we develop independently. Any disruption in production or inability of our manufacturers in China to produce adequate quantities to meet our needs, whether as a result of a natural disaster or other causes, could impair our ability to operate our business on a day-to-day basis and to continue our research and development of our product candidates. We also use contract researchers in China to conduct a portion of our research for our early stage programs. Any disruption in the team conducting that research could cause delays in one or more of our research programs and could require us to curtail one or more programs, at least until we could contract for that research to be done elsewhere. Furthermore, since these researchers and manufacturers are located in China, we are exposed to the possibility of product supply disruption and increased costs in the event of changes in the policies of the United States or Chinese governments, political unrest or unstable economic conditions in China. For example, a trade war could lead to tarrifs on the chemical intermediates we use that are manufactured in China. Any of these matters could materially and adversely affect our business and results of operations. Any recall of the manufacturing lots or similar action regarding our API used in clinical trials could delay the trials or detract from the integrity of the trial data and its potential use in future regulatory filings. In addition, manufacturing interruptions or failure to comply with regulatory requirements by any of these manufacturers could significantly delay clinical development of potential products and reduce third-party or clinical researcher interest and support of proposed trials. These interruptions or failures could also impede commercialization of our product candidates and impair our competitive position. Further, we may be exposed to fluctuations in the value of the local currency in China. Future appreciation of the local currency could increase our costs. In addition, our labor costs could continue to rise as wage rates increase due to increased demand for skilled laborers and the availability of skilled labor declines in China. 42 We will rely on third parties to monitor, support, conduct and/or oversee clinical trials of our product candidates that we develop independently and, in some cases, to maintain regulatory files for those product candidates. If we are not able to maintain or secure agreements with such third parties on acceptable terms, if these third parties do not perform their services as required, or if these third parties fail to timely transfer any regulatory information held by them to us, we may not be able to obtain regulatory approval for, or commercialize, our product candidates. We will rely on CROs, hospitals, clinics, academic institutions and other third-party collaborators who are outside our control to monitor, support, conduct and/or oversee preclinical and clinical studies of our product candidates. We will also rely on third parties to perform clinical trials of our product candidates when they reach that stage. As a result, we have less control over the timing and cost of these studies and the ability to recruit trial subjects than if we conducted these trials wholly by ourselves. If we are unable to maintain or enter into agreements with these third parties on acceptable terms, or if any such engagement is terminated, we may be unable to enroll patients on a timely basis or otherwise conduct our trials in the manner we anticipate. In addition, there is no guarantee that these third parties will devote adequate time and resources to our studies or perform as required by a contract or in accordance with regulatory requirements, including maintenance of clinical trial information regarding our product candidates. If these third parties fail to meet expected deadlines, fail to timely transfer to us any regulatory information, fail to adhere to protocols or fail to act in accordance with regulatory requirements or our agreements with them, or if they otherwise perform in a substandard manner or in a way that compromises the quality or accuracy of their activities or the data they obtain, then clinical trials of our product candidates may be extended, delayed or terminated, or our data may be rejected by the FDA or regulatory agencies. To the extent we elect to enter into additional licensing or collaboration agreements to partner our product candidates, our dependence on such relationships may adversely affect our business. Our commercialization strategy for some of our product candidates may depend on our ability to enter into collaboration agreements with other companies to obtain access to other compounds for use in combination with any of our product candidates or for assistance and funding for the development and potential commercialization of any of these product candidates, similar to what we have done with AbbVie. Supporting diligence activities conducted by potential collaborators and negotiating the financial and other terms of a collaboration agreement are long and complex processes with uncertain results. Even if we are successful in entering into one or more additional collaboration agreements, collaborations can involve greater uncertainty for us, as we may have limited or no control over certain aspects of our collaborative programs. We may determine that continuing a collaboration under the terms provided is not in our best interest, and we may terminate the collaboration. Our collaborators could delay or terminate their agreements with us, and our product candidates subject to collaborative arrangements may never be successfully commercialized. Further, our collaborators may develop alternative products or pursue alternative technologies either on their own or in collaboration with others, including our competitors, and the priorities or focus of our collaborators may shift such that our programs receive less attention or resources than we would like, or they may be terminated altogether. Any such actions by our collaborators may adversely affect our business prospects and ability to earn revenue. In addition, we could have disputes with our collaborators, such as the interpretation of terms in our agreements. Any such disagreements could lead to delays in the development or commercialization of any potential products or could result in time-consuming and expensive litigation or arbitration, which may not be resolved in our favor. Even with respect to programs that we intend to commercialize ourselves, we may enter into agreements with collaborators to share in the burden of conducting clinical trials, manufacturing and marketing our product candidates or products. In addition, our ability to apply our proprietary technologies to develop proprietary compounds will depend on our ability to establish and maintain licensing arrangements or other collaborative arrangements with the holders of proprietary rights to such compounds. We may not be able to establish such arrangements on favorable terms or at all, and our collaborative arrangements may not be successful. 43 Risks Related to Our Intellectual Property Rights We could be unsuccessful in obtaining or maintaining adequate patent protection for one or more of our product candidates. Our commercial success will depend, in large part, on our ability to obtain and maintain patent and other intellectual property protection with respect to our product candidates. We cannot be certain that patents will be issued or granted with respect to our patent applications that are currently pending, or that issued or granted patents will not later be found to be invalid and/or unenforceable, be interpreted in a manner that does not adequately protect our products, or otherwise provide us with any competitive advantage. The patent position of biotechnology and pharmaceutical companies is generally uncertain because it involves complex legal and factual considerations. The standards applied by the United States Patent and Trademark Office and foreign patent offices in granting patents are not always applied uniformly or predictably. For example, there is no uniform worldwide policy regarding patentable subject matter or the scope of claims allowable in biotechnology and pharmaceutical patents. Consequently, patents may not issue from our pending patent applications. As such, we do not know the degree of future protection that we will have on our proprietary products and technology, if any, and a failure to obtain adequate intellectual property protection with respect to our product candidates and proprietary technology could have a material adverse impact on our business. In addition, certain of our activities have been funded, and may in the future be funded, by the United States federal government. For example, the preclinical and early clinical development of the lead antibiotic product candidate in our former antibiotic program, which we are no longer developing, was funded under a contract with NIAID, an entity of the United States federal government. When new technologies are developed with United States federal government funding, the government obtains certain rights in any resulting patents, including a nonexclusive license authorizing the government to use the invention for non-commercial purposes. These rights may permit the government to disclose our confidential information to third parties and to exercise “march-in” rights to use or allow third parties to use our patented technology. The government can exercise its march-in rights if it determines that action is necessary because we fail to achieve practical application of the United States government-funded technology, or because action is necessary to alleviate health or safety needs, to meet requirements of federal regulations or to give preference to United States industry. In addition, United States government-funded inventions must be reported to the government and United States government funding must be disclosed in any resulting patent applications. In addition, our rights in such inventions are subject to certain requirements to manufacture products in the United States. Issued patents covering one or more of our product candidates could be found invalid or unenforceable if challenged in court. Despite measures we take to obtain patent and other intellectual property protection with respect to our product candidates and proprietary technology, any of our intellectual property rights could be challenged or invalidated. For example, if we were to initiate legal proceedings against a third party to enforce a patent covering one of our product candidates, the defendant could counterclaim that our patent is invalid and/or unenforceable. In patent litigation in the United States and in some other jurisdictions, defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the United States Patent and Trademark Office, or the applicable foreign counterpart, or made a misleading statement, during prosecution. Although we believe that we have conducted our patent prosecution in accordance with the duty of candor and in good faith, the outcome following legal assertions of invalidity and unenforceability during patent litigation is unpredictable. With respect to the validity question, for example, we cannot be certain that there is no invalidating prior art, of which we and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity and/or unenforceability, we would lose at least part, and perhaps all, of the patent protection on a product candidate. Even if a defendant does not prevail on a legal assertion of invalidity and/or unenforceability, our patent claims may be construed in a manner that would limit our ability to enforce such claims against the defendant and others. Any loss of patent protection could have a material adverse impact on one or more of our product candidates and our business. 44 Enforcing our intellectual property rights against third parties may also cause such third parties to file other counterclaims against us, which could be costly to defend and could require us to pay substantial damages, cease the sale of certain products or enter into a license agreement and pay royalties (which may not be possible on commercially reasonable terms or at all). Any efforts to enforce our intellectual property rights are also likely to be costly and may divert the efforts of our scientific and management personnel. Claims that our product candidates or the sale or use of our products infringe the patent or other intellectual property rights of third parties could result in costly litigation or could require substantial time and money to resolve, even if litigation is avoided. Our commercial success depends upon our ability to develop, manufacture, market and sell our product candidates and use our proprietary technology without infringing the intellectual property rights of others. We cannot guarantee that our product candidates or any uses of our product candidates do not and will not in the future infringe third- party patents or other intellectual property rights. Third parties might allege that we or our collaborators are infringing their patent rights or that we have misappropriated their trade secrets, or that we are otherwise violating their intellectual property rights, whether with respect to the manner in which we have conducted our research or to the composition, use or manufacture of the compounds we have developed or are developing with our collaborators. Such third parties might resort to litigation against us or other parties we have agreed to indemnify, which litigation could be based on either existing intellectual property or intellectual property that arises in the future. It is also possible that we failed to identify, or may in the future fail to identify, relevant patents or patent applications held by third parties that cover our product candidates. For example, applications filed before November 29, 2000 and certain applications filed after that date that will not be filed outside the United States remain confidential until patents issue. Other patent applications in the United States and several other jurisdictions are published approximately 18 months after the earliest filing for which priority is claimed, with such earliest filing date being commonly referred to as the priority date. Furthermore, publication of discoveries in the scientific or patent literature often lags behind actual discoveries. Therefore, we cannot be certain that we or our collaborators were the first to invent, or the first to file patent applications on, our product candidates or for their uses, or that our product candidates will not infringe patents that are currently issued or that are issued in the future. In the event that a third party has also filed a patent application covering one of our product candidates or a similar invention, we may have to participate in an adversarial proceeding, known as an interference, declared by the U.S. Patent and Trademark Office or its foreign counterpart to determine priority of invention. Additionally, pending patent applications which have been published can, subject to certain limitations, be later amended in a manner that could cover our products or their use. In order to avoid or settle potential claims with respect to any patent or other intellectual property rights of third parties, we may choose or be required to seek a license from a third party and be required to pay license fees or royalties or both, which could be substantial. These licenses may not be available on acceptable terms, or at all. Even if we were able to obtain a license, the rights may be nonexclusive, which could result in our competitors gaining access to the same intellectual property. Ultimately, we could be prevented from commercializing a product, or be forced, by court order or otherwise, to cease some or all aspects of our business operations, if, as a result of actual or threatened patent or other intellectual property claims, we are unable to enter into licenses on acceptable terms. Further, we could be found liable for significant monetary damages as a result of claims of intellectual property infringement. For example, we have received, and may in the future receive, offers to license and demands to license from third parties claiming that we are infringing their intellectual property or owe license fees and, even if such claims are without merit, there can be no assurance that we will successfully avoid or settle such claims. In addition, if AbbVie licenses or otherwise acquires rights to intellectual property controlled by a third party in various circumstances, for example, where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, it is entitled under our collaboration agreement to decrease payments payable to us on a product-by-product basis and, in certain cases, on a country-by-country basis. Any of the foregoing events could harm our business significantly. 45 Defending against claims of patent infringement, misappropriation of trade secrets or other violations of intellectual property rights could be costly and time consuming, regardless of the outcome. Thus, even if we were to ultimately prevail, or to settle at an early stage, such litigation could burden us with substantial unanticipated costs. In addition, litigation or threatened litigation could result in significant demands on the time and attention of our management team, distracting them from the pursuit of other company business. Claims that our product candidates or the sale or use of our future products infringe, misappropriate or otherwise violate third-party intellectual property rights could therefore have a material adverse impact on our business. Unfavorable outcomes in intellectual property litigation could limit our research and development activities and/or our ability to commercialize certain products. If third parties successfully assert their intellectual property rights against us, we might be barred from using certain aspects of our technology, or barred from developing and commercializing certain products. Prohibitions against using certain technologies, or prohibitions against commercializing certain products, could be imposed by a court or by a settlement agreement between us and a plaintiff. In addition, if we are unsuccessful in defending against allegations that we have infringed, misappropriated or otherwise violated patent or other intellectual property rights of others, we may be forced to pay substantial damage awards to the plaintiff. There is inevitable uncertainty in any litigation, including intellectual property litigation. There can be no assurance that we would prevail in any intellectual property litigation, even if the case against us is weak or flawed. If litigation leads to an outcome unfavorable to us, we may be required to obtain a license from the intellectual property owner in order to continue our research and development programs or to market any resulting product. It is possible that the necessary license will not be available to us on commercially acceptable terms, or at all. Alternatively, we may be required to modify or redesign our products in order to avoid infringing or otherwise violating third-party intellectual property rights. This may not be technically or commercially feasible, may render our products less competitive, or may delay or prevent the entry of our products to the market. Any of the foregoing could limit our research and development activities, our ability to commercialize one or more product candidates, or both. Most of our competitors are larger than we are and have substantially greater resources. They are, therefore, likely to be able to sustain the costs of complex intellectual property litigation longer than we could. In addition, the uncertainties associated with litigation could have a material adverse effect on our ability to raise the funds necessary to conduct our clinical trials, continue our internal research programs, in-license needed technology, or enter into strategic partnerships that would help us bring our product candidates to market. In addition, any future intellectual property litigation, interference or other administrative proceedings will result in additional expense and distraction of our personnel. An adverse outcome in such litigation or proceedings may expose us or any future strategic partners to loss of our proprietary position, expose us to significant liabilities, or require us to seek licenses that may not be available on commercially acceptable terms, if at all, each of which could have a material adverse effect on our business. Intellectual property litigation may lead to unfavorable publicity that harms our reputation and causes the market price of our common stock to decline. During the course of any intellectual property litigation, there could be public announcements of the results of hearings, rulings on motions, and other interim proceedings in the litigation. If securities analysts or investors regard these announcements as negative, the perceived value of our products, programs or intellectual property could be diminished. Accordingly, the market price of our common stock may decline. Such announcements could also harm our reputation or the market for our future products, which could have a material adverse effect on our business. Confidentiality agreements with employees and third parties may not prevent unauthorized disclosure of trade secrets and other proprietary information. In addition to patents, we rely on trade secrets, technical know-how and proprietary information concerning our business strategy and product candidates in order to protect our competitive position in the field of HCV, other antivirals and liver disease. In the course of our research and development activities and our business activities, we often rely on confidentiality agreements to protect our proprietary information. Such confidentiality agreements are used, for example, when we talk to vendors of laboratory or clinical development services or potential strategic 46 partners. In addition, each of our employees is required to sign a confidentiality agreement and invention assignment agreement upon joining our company. We take steps to protect our proprietary information, and our confidentiality agreements and invention assignment agreements are carefully drafted to protect our proprietary interests. Nevertheless, there can be no guarantee that an employee or an outside party will not make an unauthorized disclosure of our proprietary confidential information. This might happen intentionally or inadvertently. It is possible that a competitor will make use of such information, and that our competitive position will be compromised, in spite of any legal action we might take against persons making such unauthorized disclosures. In addition, to the extent that our employees, consultants or contractors use intellectual property owned by others in their work for us, disputes may arise as to the rights in related or resulting know-how and inventions. Trade secrets are difficult to protect. Although we use reasonable efforts to protect our trade secrets, our employees, consultants, contractors, business partners or outside scientific collaborators might intentionally or inadvertently disclose our trade secret information to competitors or our trade secrets may otherwise be misappropriated. Enforcing a claim that a third party illegally obtained and is using any of our trade secrets is expensive and time consuming, and the outcome is unpredictable. In addition, courts outside the United States sometimes are less willing than United States courts to protect trade secrets. Moreover, our competitors may independently develop equivalent knowledge, methods and know-how. Our collaborators may have rights to publish data and other information to which we have rights. In addition, we sometimes engage individuals or entities to conduct research relevant to our business. The ability of these individuals or entities to publish or otherwise publicly disclose data and other information generated during the course of their research is subject to certain contractual limitations. These contractual provisions may be insufficient or inadequate to protect our confidential information. If we do not apply for patent protection prior to such publication, or if we cannot otherwise maintain the confidentiality of our proprietary technology and other confidential information, then our ability to obtain patent protection or to protect our trade secret information may be jeopardized, which could adversely affect our business. Intellectual property rights do not necessarily protect us from all potential threats to our competitive advantage. The degree of future protection afforded by our intellectual property rights is uncertain because intellectual property rights have limitations, and may not adequately protect our business, or permit us to maintain our competitive advantage. The following examples are illustrative: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) others may be able to make compounds that are similar to our product candidates but that are not covered by the claims of the patents that we own or have exclusively licensed; we might not have been the first to make the inventions covered by the issued patents or pending patent applications that we own or may in the future exclusively license, which could result in the patent applications not issuing or being invalidated after issuing; we might not have been the first to file patent applications covering certain of our inventions, which could result in the patent applications not issuing or being invalidated after issuing; others may independently develop similar or alternative technologies or duplicate any of our technologies without infringing our intellectual property rights; it is possible that our pending patent applications will not lead to issued patents; issued patents that we own may not provide us with any competitive advantages, or may be held invalid or unenforceable, as a result of legal challenges by our competitors; we may obtain patents for certain compounds many years before we obtain marketing approval for products containing such compounds, and because patents have a limited life, which may begin to run prior to the commercial sale of the related product, the commercial value of our patents may be limited; our competitors might conduct research and development activities in countries where we do not have patent rights and then use the information learned from such activities to develop competitive products for sale in our major commercial markets; we may fail to develop additional proprietary technologies that are patentable; 47 (cid:129) (cid:129) the laws of certain foreign countries may not protect our intellectual property rights to the same extent as the laws of the United States, or we may fail to apply for or obtain adequate intellectual property protection in all the jurisdictions in which we operate; and the patents of others may have an adverse effect on our business, for example by preventing us from marketing one or more of our product candidates for one or more indications. Any of the aforementioned threats to our competitive advantage could have a material adverse effect on our business. Changes in patent law could diminish the value of patents in general, thereby impairing our ability to protect our products. As is the case with many other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. Obtaining, maintaining and enforcing patents in the biopharmaceutical industry involves both technological complexity and legal complexity. Therefore, the process of obtaining, maintaining and enforcing biopharmaceutical patents is costly, time-consuming and inherently uncertain. In addition, recent legislative and judicial developments in the United States and elsewhere have in some cases narrowed the protection afforded to patent owners, made patents more difficult to obtain, or increased the uncertainty regarding the ability to obtain, maintain and enforce patents. For example, Congress recently passed patent reform legislation, and may pass patent reform legislation in the future. The United States Supreme Court has ruled on several patent cases in recent years, and in certain circumstances has narrowed the scope of patent protection available or otherwise weakened the rights of patent owners. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions and actions by the United States Congress, the federal courts, the United States Patent and Trademark Office, and their respective foreign counterparts, the laws and regulations governing patents could change in unpredictable ways that could weaken our ability to obtain new patents or to maintain and enforce our existing patents and patents that we might obtain in the future. Risks Related to Our Industry If product liability lawsuits are brought against us, we may incur substantial liabilities and may be required to limit commercialization of our product candidates. We face an inherent risk of product liability as a result of the clinical testing of our product candidates, and we will face an even greater risk if we commercialize any product candidates. For example, we may be sued if any of our product candidates, including any that are developed in combination therapies, allegedly causes injury or is found to be otherwise unsuitable during product testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability and a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our product candidates. Even successful defense would require significant financial and management resources. There is also risk that third parties we have agreed to indemnify could incur liability. Regardless of the merits or eventual outcome, liability claims may result in: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) decreased demand for our product candidates or any resulting products; injury to our reputation; withdrawal of clinical trial participants; costs to defend the related litigation; a diversion of management’s time and our resources; substantial monetary awards to trial participants or patients; 48 (cid:129) (cid:129) (cid:129) (cid:129) product recalls, withdrawals or labeling, marketing or promotional restrictions; loss of revenue; the inability to commercialize our product candidates; and a decline in our stock price. Our inability to obtain and retain sufficient product liability insurance at an acceptable cost to protect against potential product liability claims could prevent or inhibit the commercialization of products we develop. We currently carry product liability insurance covering our clinical studies in the amount of $10.0 million in the aggregate. Although we maintain such insurance, any claim that may be brought against us could result in a court judgment or settlement in an amount that is not covered, in whole or in part, by our insurance or that is in excess of the limits of our insurance coverage. Our insurance policies also have various exclusions, and we may be subject to a product liability claim for which we have no coverage. We will have to pay any amounts awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts. Our internal computer systems, or those of our collaborator, CROs or other contractors or consultants, may fail or suffer security breaches, which could result in a material disruption of development programs for our product candidates. Despite the implementation of security measures, our internal computer systems and those of our collaborators, CROs, and other contractors and consultants are vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. Information security risks have significantly increased in recent years in part due to the proliferation of new technologies and the increased sophistication and activities of organized crime, hackers, terrorists and other external parties, including foreign state actors. As cyber threats continue to evolve, we may be required to expend significant additional resources to continue to modify or enhance our protective measures or to investigate and remediate any information security breaches. While we have not experienced any such system failure, accident or security breach to date, if such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our independent drug development programs. For example, the loss of clinical trial data from ongoing or future clinical trials for any of our product candidates could result in delays in regulatory approval efforts and significantly increase costs to recover or reproduce the data. Our information security systems are also subject to laws and regulations requiring that we take measures to protect the privacy and security of certain information we gather and use in our business. For example, HIPAA and its implementing regulations impose, among other requirements, certain regulatory and contractual requirements regarding the privacy and security of personal health information. In addition to HIPAA, numerous other federal and state laws, including, without limitation, state security breach notification laws, state health information privacy laws and federal and state consumer protection laws, govern the collection, use, disclosure and storage of personal information. To the extent that any disruption or security breach were to result in a loss of or damage to data or applications, or inappropriate disclosure of confidential or proprietary information or personal health information, we could incur substantial liability, our reputation would be damaged, and the further development of our product candidates could be delayed. 49 Our relationships with customers and third-party payors in the United States and elsewhere will be subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings. Healthcare providers, physicians and third-party payors in the United States and elsewhere play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute our products for which we obtain marketing approval. Restrictions under applicable federal, state and foreign healthcare laws and regulations include the following: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) the federal healthcare anti-kickback statute prohibits, among other things, persons from knowingly and willfully soliciting, offering, 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 under federal and state healthcare programs such as Medicare and Medicaid; the federal False Claims Act imposes criminal and civil penalties, including civil whistleblower or qui tam actions, against individuals or entities for knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent or making a false 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, as amended by the Health Information Technology for Economic and Clinical Health Act, imposes criminal and civil liability for executing a scheme to defraud any healthcare benefit program and also imposes obligations, including mandatory contractual terms, with respect to safeguarding the privacy, security and transmission of individually identifiable health information; the federal false statements statute prohibits knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false statement in connection with the delivery of or payment for healthcare benefits, items or services; the federal transparency requirements under the Patient Protection and Affordable Care Act of 2010 requires manufacturers of drugs, devices, biologics and medical supplies to report to the Department of Health and Human Services information related to physician payments and other transfers of value and physician ownership and investment interests; analogous state laws and regulations, such as state anti-kickback and false claims laws, may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non- governmental third-party payors, including private insurers, and some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug manufacturers to report information related to payments to physicians and other healthcare providers or marketing expenditures; and analogous anti-kickback, fraud and abuse and healthcare laws and regulations in foreign countries. Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, exclusion from government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations, which could have a material adverse effect on our business. If any of the physicians or other providers or entities with whom we expect to do business, including our collaborators, are found not to be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs, which could also materially affect our business. 50 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 could have 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 handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials 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 of hazardous materials or our or third parties’ disposal of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties. We may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or production efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions. We maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials. This insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of hazardous or radioactive materials. Our insurance policies are expensive and only protect us from specified business risks, which will leave us exposed to significant uninsured liabilities. We do not carry insurance for all categories of risk that our business may encounter. Some of the policies we currently maintain include general liability, employment practices liability, property, auto, workers’ compensation, products liability and directors’ and officers’ insurance. We do not know, however, if we have adequate levels of coverage for any liability we may incur, or whether we will always be able to continue to maintain such insurance. Any significant uninsured liability may require us to make substantial payments, which would adversely affect our financial position and results of operations. Furthermore, any increase in the volatility of our stock price may result in us being required to pay substantially higher premiums for our directors’ and officers’ liability insurance than those to which we are currently subject and may even cause one or more of our underwriters to be unwilling to insure us. Risks Related to Our Common Stock Our stock price has been, and is likely to continue to be, volatile, and thus our stockholders could incur substantial losses. Our stock price has been volatile and could be subject to wide fluctuations in response to various factors, many of which are beyond our control. Since our initial public offering in March 2013 and through November 1, 2018, the price of our common stock on the NASDAQ Global Select Market has ranged from $16.18 to $127.77. The stock market in general and the market for biopharmaceutical companies, and for those developing potential therapies for viral infections and liver diseases in particular, have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility, you may not be able to sell your common stock at or above your purchase price, if at all. The market price for our common stock may be influenced by many factors, including: (cid:129) (cid:129) actions by AbbVie regarding HCV treatment regimens containing paritaprevir or the MAVYRET/MAVIRET regimen containing glecaprevir as approved in the U.S., EU and Japan, including announcements regarding clinical, regulatory or commercial developments or our collaboration; market expectations about and response to the levels of sales or scripts achieved by, or the announced prices or discounts for, AbbVie’s MAVYRET/MAVIRET regimen or competitive HCV drugs; 51 (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) failure of AbbVie’s paritaprevir-containing HCV treatment regimens to maintain their sales levels or AbbVie’s MAVYRET/MAVIRET regimen to achieve commercial success; results from or delays of clinical trials of our other product candidates, as well as results of regulatory reviews relating to the approval of our product candidates; new products, product candidates or new uses for existing products or technologies introduced or announced by our competitors and the timing of these introductions or announcements; the results of our efforts to discover or develop additional product candidates; our dependence on third parties, including our collaborators, CROs, manufacturers, clinical trial sponsors and clinical investigators; regulatory, political or legal developments in the United States or other countries; developments or disputes concerning patent applications, issued patents or other proprietary rights; the recruitment or departure of key scientific or management personnel; our ability to commercialize our product candidates we develop independently, if approved; the level of expenses related to any of our product candidates or clinical development programs; actual or anticipated changes in estimates as to financial results, development timelines or recommendations by securities analysts; period-to-period variations in our financial results or those of companies that are perceived to be similar to us; sales of common stock by us or our stockholders in the future, as well as the overall trading volume of our common stock; changes in the structure of healthcare payment systems or other actions that affect the effective reimbursement rates for treatment regimens containing our products or for competitive regimens; market conditions in the pharmaceutical and biotechnology sectors; general economic, industry and market conditions and other factors that may be unrelated to our operating performance or the operating performance of our competitors, including changes in market valuations of similar companies; and the other factors described in this “Risk Factors” section. Provisions in our corporate charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management. Provisions in our corporate charter and our bylaws may discourage, delay or prevent a merger, acquisition or other change in control of us that stockholders may consider favorable, including transactions in which they might otherwise receive a premium for their shares. These provisions could also 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 our common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions: (cid:129) (cid:129) (cid:129) establish a classified or staggered board of directors such that not all members of the 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; 52 (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) establish advance notice requirements for stockholder proposals that can be acted on at stockholder meetings and nominations to our board of directors; require that stockholder actions must be effected at a duly called stockholder meeting and prohibit actions by our stockholders by written consent; limit who may call stockholder meetings; provide that the state courts or, in certain circumstances, the federal courts, in Delaware shall be the sole and exclusive forum for certain actions involving us, our directors, officers, employees and stockholders; provide our board of directors with the authority to designate the terms of and issue a new series of preferred stock without stockholder approval, which could be used to institute a “poison pill” that would work to dilute the stock ownership of a potential hostile acquirer, effectively preventing acquisitions that have not been approved by our board of directors; and require the approval of the holders of at least 66 2/3% of the votes that all our stockholders would be entitled to cast to amend or repeal certain provisions of our charter or bylaws. Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibit a person who owns 15% or more of our outstanding voting stock from merging or combining with us for a period of three years after 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 approved in a prescribed manner. Any provision in our corporate charter or our bylaws or Delaware law that has the effect of delaying or deterring a change in control could limit the opportunity for our stockholders to receive a premium for their shares of our common stock, and could also affect the price that some investors are willing to pay for our common stock. Our employment agreements with our executive officers may require us to pay severance benefits to any of those persons who are terminated in connection with a change of control of us, which could harm our financial condition or results. Our executive officers are parties to employment agreements that provide for aggregate cash payments of up to approximately $4.6 million for severance and other non-equity-based benefits in the event of a termination of employment in connection with a change of control of our company. In addition, based on the closing price of our common stock as of September 30, 2018 of $85.46 per common share, the aggregate intrinsic value of unvested stock options and other equity awards subject to accelerated vesting upon these events was $35.8 million. The accelerated vesting of awards options could result in dilution to our stockholders and harm the market price of our common stock. The payment of these severance benefits could harm our company’s financial condition and results. In addition, these potential severance payments may discourage or prevent third parties from seeking a business combination with us. If we fail to maintain an effective system of internal control over financial reporting, we may not be able to accurately report our financial results or prevent fraud. As a result, stockholders could lose confidence in our financial and other public reporting, which would harm our business and the trading price of our common stock. Effective internal controls over financial reporting are necessary for us to provide reliable financial reports and, together with adequate disclosure controls and procedures, are designed to prevent fraud. Any failure to implement newly required or improved controls, or difficulties encountered in their implementation, could cause us to fail to meet our reporting obligations. In addition, any testing by us conducted in connection with Section 404 of the Sarbanes-Oxley Act of 2002, or any subsequent testing by our independent registered public accounting firm, may reveal deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses or that may require prospective or retroactive changes to our financial statements or identify other areas for further attention or improvement. Inferior internal controls could also cause investors to lose confidence in our reported financial information, which could have a negative effect on the trading price of our common stock. 53 Because we do not anticipate paying cash dividends on our common stock for the foreseeable future, investors in our common stock may never receive a return on their investment. You should not rely on an investment in our common stock to provide dividend income. We do not anticipate that we will pay any cash dividends to holders of our common stock for the foreseeable future. Instead, we plan to retain any earnings to maintain and expand our existing operations. Accordingly, investors must rely on sales of their common stock after price appreciation, which may never occur, as the only way to realize any return on their investment. As a result, investors seeking cash dividends should not invest in our common stock. A sale of a substantial number of shares of our common stock in the public market could cause the market price of our common stock to drop significantly, even if our business is doing 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 that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock. As of September 30, 2018, we had 19.4 million shares of common stock outstanding. In addition, as of September 30, 2018, 2.6 million and 0.2 million shares of common stock that are subject to outstanding options or restricted stock unit awards, respectively, under our outstanding equity plans are eligible for sale in the public market to the extent permitted by the provisions of various vesting schedules, and Rules 144 and 701 under the Securities Act. If these additional shares of common stock are sold, or it is perceived that they will be sold, in the public market, the trading price of our common stock could decline. If securities or industry analysts do not publish research, or publish inaccurate or unfavorable research about our business, our stock price and trading volume could decline. The trading market for our common stock will depend in part on the research and reports that securities or industry analysts publish about us or our business. If those analysts are unable to predict accurately the demand and net sales of AbbVie’s HCV regimens, that could result in our reported revenues and earnings being lower than the so-called “market consensus” of our projected revenues, which could negatively affect our stock price. In addition, if too few securities or industry analysts cover our company, the trading price for our stock would likely be negatively impacted. In the event that one or more of the analysts who cover us downgrade our stock or publish inaccurate or unfavorable research about our business, our stock price would likely decline. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, demand for our stock could decrease, which might cause our stock price and trading volume to decline. ITEM 1B. UNRESOLVED STAFF COMMENTS None. ITEM 2. PROPERTIES Our corporate headquarters is located in Watertown, Massachusetts, where we lease approximately 49,000 square feet of office and laboratory space. The term of our current lease expires on September 1, 2022. We also lease additional office space located in Watertown, Massachusetts of approximately 18,000 square feet. The term of this lease expires August 1, 2024. ITEM 3. LEGAL PROCEEDINGS We are not a party to any material legal proceedings. ITEM 4. MINE SAFETY DISCLOSURES Not applicable. 54 PART II ITEM 5. MARKET FOR THE COMPANY’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES Market and Stockholder Information Our common stock has been listed on The NASDAQ Global Select Market under the symbol “ENTA” since March 21, 2013. The following table shows the high and low sales price for our common stock as reported by The NASDAQ Global Select Market for the quarterly periods in the fiscal years ended September 30, 2018 and 2017: First Quarter Second Quarter Third Quarter Fourth Quarter First Quarter Second Quarter Third Quarter Fourth Quarter Fiscal 2018 High Low 59.88 $ 95.91 $ 122.43 $ 127.77 $ 44.52 52.39 78.89 81.24 Fiscal 2017 High Low 34.53 $ 36.05 $ 37.54 $ 46.80 $ 22.32 27.72 29.45 33.42 $ $ $ $ $ $ $ $ As of November 1, 2018 there were 22 stockholders of record of our common stock, which excludes stockholders whose shares were held in nominee or street name by brokers. We have never declared or paid cash dividends on our common stock, and we do not expect to declare or pay any cash dividends for the foreseeable future. Performance Graph(1) The following graph shows a comparison from September 30, 2013 through September 30, 2018 of cumulative total return on assumed investments of $100.00 in cash in each of our common stock, the NASDAQ Composite Index and the NASDAQ Biotechnology Index. Such returns are based on historical results and are not intended to suggest future performance. Data for the NASDAQ Composite Index and the NASDAQ Biotechnology Index assume reinvestment of dividends. 55 COMPARISON OF FIVE YEARS CUMULATIVE TOTAL RETURN Among Enanta Pharmaceuticals, Inc., the NASDAQ Composite Index, and the NASDAQ Biotechnology Index (1) This performance graph shall not be deemed to be “soliciting material” or to be “filed” with the SEC for purposes of Section 18 of the Securities and Exchange Act of 1934, as amended, or otherwise subject to the liabilities under that Section, and shall not be deemed incorporated by reference into any filing of Enanta Pharmaceuticals, Inc. under the Securities Act of 1933, as amended. 56 ITEM 6. SELECTED CONSOLIDATED FINANCIAL DATA We have derived the consolidated statements of operations data for the years ended September 30, 2018, 2017, and 2016 and the consolidated balance sheet data as of September 30, 2018 and 2017 from our audited financial statements included elsewhere in this Annual Report on Form 10-K. The selected statements of operations data for the years ended September 30, 2015 and 2014 and the balance sheet data as of September 30, 2016, 2015 and 2014 are derived from our audited financial statements not included in this Annual Report on Form 10-K. Our historical results for any prior period are not necessarily indicative of any results to be expected for any future period. Consolidated Statements of Operations Data: Revenue Operating expenses: Research and development General and administrative Total operating expenses Income from operations Other income (expense), net Net income before income taxes Income tax (expense) benefit Net income Net income per share: Basic Diluted Weighted average common shares outstanding: Basic Diluted Consolidated Balance Sheet Data: Cash, cash equivalents and marketable securities Working capital Total assets Capital lease obligation Warrant liability Series 1 nonconvertible preferred stock Total stockholders’ equity 2018 Years Ended September 30, 2017 2015 2016 (in thousands, except per share data) 2014 $ 206,625 $ 102,814 $ 88,268 $ 160,880 $ 47,741 94,856 23,441 118,297 57,451 20,749 78,200 40,461 16,966 57,427 23,189 13,543 36,732 88,328 4,793 24,614 2,333 30,841 1,719 124,148 1,307 18,740 10,016 28,756 18,985 283 93,121 (21,165) 26,947 (9,237) $ 71,956 $ 17,710 32,560 (10,894) $ 21,666 125,455 (46,463) $ 78,992 19,268 15,170 $ 34,438 $ $ 3.74 $ 3.48 $ 0.93 0.91 $ $ 1.14 1.13 $ $ 4.23 4.09 $ $ 1.88 1.80 19,255 20,650 19,066 19,407 18,929 19,224 18,673 19,295 18,355 19,185 2018 2017 As of September 30, 2016 (in thousands) 2015 2014 $ 325,119 364,364 414,227 379 — 1,628 393,679 $ 293,707 $ 242,203 $ 209,443 $ 131,767 216,837 224,267 163,937 103,229 326,637 281,277 246,013 155,415 458 807 762 531 1,251 159 598 1,276 163 — 1,584 202 301,676 269,936 236,157 148,654 57 ITEM 7. RESULTS OF OPERATIONS MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND You should read the following discussion and analysis of financial condition and results of operations together with the section entitled “Selected Consolidated Financial Data” and our consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. This discussion and other parts of this Annual Report on Form 10-K contain forward-looking statements that involve risks and uncertainties, such as statements regarding our plans, objectives, expectations, intentions and projections. Our actual results could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the “Risk Factors” section of this Annual Report on Form 10-K. Overview We are a biotechnology company that uses our robust, chemistry-driven approach and drug discovery capabilities to create small molecule drugs primarily for the treatment of viral infections and liver diseases. We discovered glecaprevir, the second of two protease inhibitors discovered and developed through our collaboration with AbbVie for the treatment of chronic hepatitis C virus, or HCV. Glecaprevir is co-formulated as part of AbbVie’s newest direct-acting antiviral (DAA) combination and marketed under the tradenames MAVYRET™ (U.S.) or MAVIRET™ (ex-U.S.) (glecaprevir/pibrentasvir). Our royalties from our AbbVie collaboration and our existing financial resources provide us funding to support our wholly-owned research and development programs, which are currently focused on the following disease targets: (cid:129) (cid:129) (cid:129) (cid:129) respiratory syncytial virus, or RSV, the most common cause of bronchiolitis and pneumonia in children under one year of age in the U.S., resulting in an estimated 57,000 to 125,000 hospitalizations each year in the U.S.; non-alcoholic steatohepatitis, or NASH, a liver disease estimated to affect approximately 1.5% to 6.5% of the population in the developed world (which is the equivalent of approximately 5 to 20 million individuals in the U.S. alone); primary biliary cholangitis, or PBC, a chronic liver disease that slowly destroys bile ducts in the liver, which affects an estimated 17,000 individuals in the U.S.; and hepatitis B virus, or HBV, the most prevalent chronic hepatitis, which is estimated to affect approximately 250 million individuals worldwide. We had $325.1 million in cash, cash equivalents and marketable securities at September 30, 2018. In fiscal 2018, we earned $191.6 million in per-product royalties on AbbVie’s net sales of its HCV regimens and we earned the remaining $15.0 million milestone payment from AbbVie upon reimbursement approval for MAVIRET™ in Japan. We expect our existing financial resources and future royalties from our AbbVie collaboration will allow us to continue to fund our wholly-owned research and development programs for the foreseeable future. Our Wholly-Owned Programs Our wholly-owned research and development programs are in virology, namely RSV and HBV, and in liver disease (non-virology), namely NASH and PBC: (cid:129) RSV: We discovered EDP-938, a potent N-protein inhibitor of activity of both major subgroups of RSV, referred to as RSV-A and RSV-B, and have tested it as our first clinical candidate for RSV. We believe EDP-938 is differentiated from fusion inhibitors currently in development for RSV because N-protein inhibitors directly target the viral replication process of RSV and have demonstrated high barriers to resistance against RSV in vitro. o In our fiscal 2018, we completed a Phase 1 clinical study demonstrating that EDP-938 was generally safe and well tolerated over a broad range of single and multiple doses with good pharmacokinetic data. 58 (cid:129) (cid:129) o We initiated a Phase 2a challenge study of EDP-938 in October 2018. The challenge study will test the effect of EDP-938 on healthy volunteers who will be infected with RSV and then treated with EDP-938 or placebo during the course of the study. Primary and secondary outcome measures include changes in viral load measurements and change of baseline symptoms. o Preclinical data demonstrated that EDP-938 is a potent inhibitor of both RSV-A and RSV-B activity, maintaining antiviral activity post-infection while presenting a high barrier to resistance in vitro. NASH and PBC: We are working on multiple compounds that selectively bind to and activate the farnesoid X receptor, or FXR. We plan to develop these compounds, referred to as FXR agonists, for use in the treatment of NASH and PBC, both of which are liver diseases with very few therapeutic options. Our lead FXR agonist, EDP-305, represents a new class of FXR agonist designed to take advantage of increased binding interactions with the receptor. We believe this class is significantly different from other FXR agonists in clinical development. o In October 2017, we announced results of a Phase 1a/b clinical study of EDP-305, which was generally safe and well tolerated over a broad range of single and multiple doses with pharmacokinetic data supporting once daily oral dosing. Additional data from this study were also presented at the 2018 NASH-TAG conference and the International Liver CongressTM (ILC) 2018. The study included 98 healthy volunteer subjects, or HV subjects, and 48 subjects who were obese and with or without pre-diabetes or type 2 diabetes, whom we refer to as subjects with presumptive non-alcoholic fatty liver disease, or PN subjects. o We have presented data at the 2017 and 2018 annual meetings of the American Association for the Study of Liver Diseases (AASLD), the 2017 and 2018 NASH-TAG conferences and the 2017 and 2018 ILC conferences that demonstrated that EDP-305 is a highly selective FXR agonist and shows more potent activity in a variety of in vitro and in vivo NASH models compared to the most advanced NASH candidate in development today, obeticholic acid, or OCA. o We initiated a Phase 2 clinical study, known as ARGON-1, of EDP-305 in NASH patients and a Phase 2 clinical study, known as INTREPID, of EDP-305 in PBC patients. o o EDP-305 has been granted Fast Track designation by the U.S. Food and Drug Administration (FDA) for the treatment of NASH patients with liver fibrosis and separately for the treatment of PBC. In addition, we are pursuing research in other classes of FXR agonists as well as other mechanisms that may provide therapeutic benefit in NASH, any of which could be used in combination therapies for NASH. HBV: We also have a program to discover and develop new chemical entities for the treatment of HBV. Our initial focus is on core inhibitors, a mechanism with early clinical validation. In November 2018, we announced our first clinical candidate for HBV. EDP-514 is an HBV core inhibitor, also known as a core protein allosteric modulator, or CpAM, or capsid assembly modulator. o o EDP-514 was selected from our lead class of HBV compounds that are characterized by potent antiviral activity. In vitro, they are capable of preventing the establishment of cccDNA, are pan- genotypic, are active against known nucleos(t)ide resistant mutants, and are additive to synergistic with nucleoside analogs and other core inhibitors. Members of this class have also demonstrated excellent reduction in HBV titers in a chimeric mouse model with human liver cells. In addition, we are also seeking patent protection and conducting preclinical experiments with compounds we have discovered that use other mechanisms to target HBV. We believe that it may be necessary to utilize more than one compound/mechanism for the treatment of HBV and therefore we are pursuing multiple approaches. 59 We have utilized our internal chemistry and drug discovery capabilities to generate all of our development-stage programs. Our Out-Licensed Products Through our Collaborative Development and License Agreement with AbbVie, we have developed and out-licensed to AbbVie two protease inhibitor compounds that have been clinically tested, manufactured, and commercialized by AbbVie. To date, we have earned all $330.0 million milestone payments under the agreement related to clinical development and commercialization regulatory approvals of these regimens in major markets. (cid:129) (cid:129) Glecaprevir: Glecaprevir is the protease inhibitor we discovered that was developed by AbbVie in a fixed-dose combination with its NS5A inhibitor, pibrentasvir, for the treatment of HCV. This combination, currently marketed under the brand name MAVYRET™ (U.S.) and MAVIRET™ (ex- U.S.) and referred to in this report as MAVYRET/MAVIRET, is a novel, once daily, all oral, fixed- dose, ribavirin-free treatment for HCV genotypes 1-6, or GT1-6, which is referred to as being pan- genotypic. In the U.S., EU and Japan it was approved as an 8-week treatment for patients without cirrhosis and new to treatment. Today, these patients are estimated to represent the majority of HCV patients in developed country markets. Since August 2017, substantially all of our royalty revenue has been derived from AbbVie’s net sales of MAVYRET/MAVIRET. Our ongoing royalty revenues from this regimen consist of annually tiered, double-digit, per-product royalties (see Note 7 in Notes to Consolidated Financial Statements) on 50% of the calendar year net sales of the 2-DAA glecaprevir/pibrentasvir combination in MAVYRET/MAVIRET. These royalties are calculated separately from the royalties on other paritaprevir-containing regimens. Paritaprevir: Paritaprevir is the protease inhibitor contained in AbbVie’s initial HCV treatment regimens sold under the tradenames VIEKIRAX® (ex-U.S.) and VIEKIRA PAK® (U.S.) (paritaprevir/ritonavir/ombitasvir/dasabuvir). These regimens are no longer being actively marketed in markets where MAVYRET/MAVIRET is approved and reimbursed. AbbVie’s paritaprevir-containing regimens were first approved and sold in the U.S. in December 2014. Through our 2017 fiscal year end, our royalty revenues were generated substantially through worldwide net sales of these regimens. Financial Operations Overview We are currently funding all research and development for our wholly-owned programs, which are targeted towards the discovery and development of novel compounds for the treatment of viral infections and liver diseases. In fiscal 2018, we initiated two Phase 2 studies of EDP-305, one in PBC patients, known as the INTREPID study, and one in NASH patients, known as the ARGON-1 study. We also initiated a Phase 2a clinical study of our lead RSV candidate, EDP-938, in October 2018. In November 2018 we announced our selection of EDP-514 as our first candidate for HBV. As a result of these efforts as well as efforts to advance other compounds into substantial preclinical development, we increased our research and development expenses in fiscal year 2018, as compared to our fiscal year 2017. We expect to incur substantially greater expenses in fiscal 2019 as we continue to advance our FXR agonist program as well as our RSV and HBV programs. We are funding our operations primarily through payments received under our collaboration agreement with AbbVie. Our revenue from our collaboration agreement has resulted in our reporting net income in each of our past seven fiscal years. Our revenue is dependent on royalty payments we receive from AbbVie on its sales of MAVYRET/MAVIRET. For its MAVYRET/MAVIRET regimen, which in the majority of chronic HCV patients only requires 8 weeks of treatment compared to 12 weeks with VIEKIRA PAK® and other HCV regimens, AbbVie initially set a lower list price compared to its original HCV regimens and other HCV products on the market. In 2018, AbbVie has reported increasing MAVYRET/MAVIRET market share and has become the leading HCV treatment in the U.S. and several market geographies in developed countries where it is approved. However, the market for HCV therapies remains very dynamic in several jurisdictions where MAVYRET/MAVIRET is already approved or AbbVie is seeking approval, and we cannot predict how that market will continue to evolve. 60 Given the uncertainty regarding the level of AbbVie’s future MAVYRET/MAVIRET sales that will generate our royalty revenue and the development risks affecting the extent and timing of our future expenditures for the advancement of our internally developed compounds, it is uncertain whether we will continue to report net income in fiscal 2019 and thereafter. Revenue Our revenue is derived from our collaboration agreement with AbbVie. In our fiscal year ended September 30, 2016, we generated royalty revenue from AbbVie’s net sales allocable to paritaprevir, which was part of AbbVie’s initial treatment regimens for HCV approved in the U.S. in December 2014 and in the EU and dozens of other countries subsequently. Since then, AbbVie received approvals of its newest HCV regimen, MAVYRET/MAVIRET, in the U.S. and EU in the summer of 2017. Substantially all our royalty revenues are now derived from the MAVYRET/MAVIRET as this regimen generally has a shorter treatment duration (8-week treatment as approved in the EU, U.S. and Japan versus 12 weeks for paritaprevir and competitive regimens) and is pan-genotypic. The following table is a summary of revenue recognized for the years ended September 30, 2018, 2017, and 2016: AbbVie agreement: Milestones Royalties NIAID contract: Total revenue AbbVie Agreement Years Ended September 30, 2018 2017 (in thousands) 2016 $ $ 15,000 191,625 — 206,625 $ $ 65,000 37,814 — 102,814 $ $ 30,000 57,692 576 88,268 Since all of our research obligations under the AbbVie agreement were concluded by June 30, 2011, all milestone payments received since then have been recognized as revenue upon achievement of each milestone by AbbVie. During the fiscal year ended September 30, 2018, we earned and recognized as revenue the last milestone payment for glecaprevir, which was a $15.0 million milestone payment upon AbbVie’s achievement of commercialization regulatory approval of MAVIRET™ in Japan. During the fiscal year ended September 30, 2017, we earned and recognized as revenue a total of $65.0 million in milestone payments upon approval of the MAVYRET/MAVIRET regimen in the U.S. and EU. During the fiscal year ended September 30, 2016, we earned and recognized the last milestone payment for paritaprevir, a $30.0 million milestone payment, upon AbbVie’s achievement of commercialization regulatory approval of its paritaprevir-containing regimen in Japan. We currently receive annually tiered, double-digit royalties per protease inhibitor product on AbbVie’s net sales allocable to either of our collaboration’s protease inhibitor products. Under the terms of our AbbVie agreement, as amended in October 2014, 50% of AbbVie’s net sales of MAVYRET/MAVIRET are allocated to glecaprevir. In the case of regimens containing paritaprevir, 30% of net sales of 3-DAA regimens containing paritaprevir and 45% of net sales of 2-DAA regimens containing paritaprevir are allocated to paritaprevir for purposes of calculating our annually tiered royalties. Beginning with each January 1, the cumulative net sales of each royalty-bearing product start at zero for purposes of calculating the tiered royalties on a product-by-product basis. For detail regarding the royalty tier, see Note 7 in Notes to Consolidated Financial Statements of this report which is incorporated herein by this reference. We expect all of our revenue in 2019 to be generated from our collaboration agreement with AbbVie. Internal Programs As our internal product candidates are currently in preclinical or early clinical development, we have not generated any revenue from our own product sales and do not expect to generate any revenue from product sales derived from these product candidates for at least the next several years. 61 Operating Expenses The following table summarizes our operating expenses for the years ended September 30, 2018, 2017, and 2016: 2018 Years Ended September 30, 2017 (in thousands) 2016 Research and development General and administrative Total operating expenses $ 94,856 $ 23,441 $ 118,297 $ 57,451 $ 20,749 78,200 $ 40,461 16,966 57,427 Research and Development Expenses Research and development expenses consist of costs incurred to conduct basic research, such as the discovery and development of novel small molecules as therapeutics, as well as any external expenses of preclinical and clinical development activities. We expense all costs of research and development as incurred. These expenses consist primarily of: (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) personnel costs, including salaries, related benefits and stock-based compensation for employees engaged in scientific research and development functions; third-party contract costs relating to research, formulation, manufacturing, preclinical study and clinical trial activities; laboratory consumables; allocated facility-related costs; and third-party license fees. Project-specific expenses reflect costs directly attributable to our clinical development candidates and preclinical candidates nominated and selected for further development. Remaining research and development expenses are reflected in research and drug discovery, which represents early-stage drug discovery programs. At any given time, we typically have several active early stage research and drug discovery projects. Our internal resources, employees and infrastructure are not directly tied to any individual research or drug discovery project and are typically deployed across multiple projects. As such, we do not report information regarding costs incurred for our early-stage research and drug discovery programs on a project-specific basis. We expect that our research and development expenses will continue to increase in the future as we advance our RSV, NASH, PBC, and HBV programs. Our research and drug discovery programs are at early stages; therefore, the successful development of our product candidates is highly uncertain and may not result in approved products. Completion dates and completion costs can vary significantly for each product candidate and are difficult to predict. Given the uncertainty associated with clinical trial enrollments and the risks inherent in the development process, we are unable to determine the duration and completion costs of the current or future clinical trials of our product candidates or if, or to what extent, we will generate revenue from the commercialization and sale of any of our product candidates. We anticipate that we will make determinations as to which development programs to pursue and how much funding to direct to each program on an ongoing basis in response to the preclinical and clinical success and prospects of each product candidate, as well as ongoing assessments of the commercial potential of each product candidate. General and Administrative Expenses General and administrative expenses consist primarily of personnel costs, which include salaries, related benefits and stock-based compensation, of our executive, finance, business and corporate development and other administrative functions. General and administrative expenses also include travel expenses, allocated facility-related costs not otherwise included in research and development expenses, directors and officers liability insurance premiums, and professional fees for auditing, tax, and legal services and patent expenses. We expect that general and administrative expenses will increase in the future primarily due to ongoing expansion of our operating activities in support of our own research and development programs, as well as potential additional costs associated with operating a growing publicly traded company. 62 Other Income (Expense) Other income (expense) consists of interest income, interest expense and the change in fair value of our outstanding Series 1 nonconvertible preferred stock and, during the periods the Series 1 nonconvertible preferred stock warrants were outstanding, the change in fair value of our warrant liability. Interest income consists of interest earned on our cash equivalents and short-term and long-term marketable securities balances as well as interest earned for any refunds received from tax authorities. Interest expense consists of interest expense related to our capital lease obligation. The change in fair value of our Series 1 nonconvertible preferred stock (and warrant liability when the warrants were outstanding) relates to the remeasurement of these financial instruments from period to period as these instruments may require a transfer of assets because of the liquidation preference features of the underlying stock. The change in fair value also includes the forfeiture of unexercised warrants which expired on October 4, 2017. Income Tax Expense Income tax expense for the years ended September 30, 2018, 2017, and 2016 resulted from federal and state taxes attributable to our operating income. Critical Accounting Policies Our consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and assumptions that affect the reported amount of assets, liabilities, revenue, costs and expenses, and related disclosures. We believe that the estimates and assumptions involved in the accounting policies described below may have the greatest potential impact on our consolidated financial statements and, therefore, consider these to be our critical accounting policies. We evaluate our estimates and assumptions on an ongoing basis. Actual results may differ from these estimates under different assumptions and conditions. See also Note 2 to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K for information about these critical accounting policies as well as a description of our other significant accounting policies. Revenue Recognition Our revenue has been generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration. The majority of revenue is derived under our agreement with AbbVie. Under this agreement, we have no ongoing deliverables and therefore, royalties and milestones received under this arrangement are recognized when earned. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectibility of the resulting receivable is reasonably assured, and we have fulfilled our performance obligations under the contract. We apply Accounting Standards Codification No. 605-25, Revenue Recognition Multiple-Deliverable Revenue Arrangements, or ASC 605-25, for multiple element arrangements entered into or materially modified on or after October 1, 2011. The selling prices of deliverables under the arrangement may be derived using third-party evidence, (“TPE”) or a best estimate of selling price (“BESP”), if vendor-specific objective evidence (“VSOE”), is not available. The objective of BESP is to determine the price at which we would transact a sale if the element within the license agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors such as those factors contemplated in negotiating the agreements as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success, and the time needed to commercialize a product candidate pursuant to the license. In validating our BESP, we consider whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. Deliverables under a multiple element arrangement are separated into multiple units if (i) the delivered item has value to the customer on a standalone basis and (ii) if 63 the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within our control. In determining the separate units of accounting, we evaluate whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, we consider whether or not (i) the collaborator can use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license is dependent on the undelivered items, and (iii) the collaborator or other vendors can provide the undelivered items. We may exercise significant judgment in determining whether a deliverable is a separate unit of accounting. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. The appropriate revenue recognition model is applied to each element and revenue is accordingly recognized as each element is delivered. Royalty revenue is recognized based on contractual terms when reported sales are reliably measurable and collectibility is reasonably assured, provided that there are no performance obligations remaining. During the year ended September 30, 2016, we also generated revenue from a government contract under which we were reimbursed for certain allowable costs incurred for the funded project. Revenue from the government contract was recognized when the related service was performed. The related costs incurred by us under the government contract were included in research and development expense in the consolidated statements of operations. This contract was completed in August 2015. Amounts received prior to satisfying all revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the next twelve months of the consolidated balance sheet date are classified as long-term deferred revenue. In the event that a collaborative research and license agreement is terminated and we then have no further performance obligations, we recognize as revenue any amounts that had not previously been recorded as revenue but were classified as deferred revenue at the date of such termination. Stock-Based Compensation - Stock Options and Restricted Stock Unit Awards We measure stock awards with service-based conditions granted to employees and directors at fair value on the date of grant and recognize the corresponding stock-based compensation expense of those awards over the requisite service period, which is generally the vesting period of the respective award. Stock awards granted with service- based vesting conditions, which include restricted stock units and stock options, are recorded as an expense using the straight-line method. In the case of performance-based options, we recognize stock-based compensation expense related to these awards when achievement of the underlying research and development performance-based targets become probable, which have typically been in the same period as when the targets are achieved. The fair value of each restricted stock unit granted is based on the fair value of our common stock on the date of grant. The fair value of each stock option award is estimated on the date of grant using the Black-Scholes option- pricing model. We only grant stock options with exercise prices equivalent to the fair value of our common stock on the date of grant. Generally, our expected volatility has been measured based on a combination of our historical stock volatility since our March 2013 IPO and the historical volatility of our publicly traded peer companies. We expect in fiscal 2019 to solely utilize our historical stock volatility as we will have adequate historical data regarding the volatility of our traded stock price following our March 2013 IPO. The expected term of our options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Our expected dividend yield is 0 and is based on the fact that we have never paid cash dividends and do not expect to pay any cash dividends in the foreseeable future. We recognize stock-based compensation expense for only the portion of awards that vest. We recognize actual pre- vesting forfeitures for service-based options as they occur. These assumptions represent our best estimates, but the estimates involve inherent uncertainties and the application of our judgment. As a result, if factors change and we use significantly different assumptions or estimates, our stock- based compensation expense could be materially different. 64 Stock-Based Compensation - Market and Performance-based Stock Unit Awards In addition to awards with service-based vesting conditions, we also have granted performance share units, or PSUs, and relative total stockholder return units, or rTSRUs, to certain of our executives. The number of units represents the target number of shares of common stock that may be earned; however, the actual number of shares that may be earned ranges from 0% to 200% or 0% to 150% of the target number, depending on the terms of the award. The fair value of PSUs is based on the fair value of our common stock on the date of grant. The fair value of rTSRUs is based on a Monte Carlo simulation model. Assumptions and estimates utilized in the calculation of the fair value of the rTSRUs include the risk-free interest rate, dividend yield, average closing price, expected volatility based on the historical volatility of publicly traded peer companies and the remaining performance period of the award. The PSUs vest and result in issuance, at settlement, of common shares for each recipient based upon the recipient’s continued employment with us through the settlement date of the award and our achievement of specified research and development milestones. The requisite service period of the PSUs is generally 2 years. In the case of PSUs, we recognize stock-based compensation expense based on the grant date fair value of the award when achievement of the underlying research and development performance-based targets become probable, which have typically been in the same period as when the targets are achieved. The rTSRUs vest and result in the issuance of common stock based upon the recipient’s continuing employment with us through the settlement date of the award and the relative ranking of the total stockholder return, or TSR, of our common stock in relation to the TSR of the component companies in the NASDAQ Biotech Index, generally over a two-year period based on a comparison of average closing stock prices in specified periods noted in the award agreement. The fair value related to the rTSRUs is recorded as stock-based compensation expense over the period from date of grant to the settlement date regardless of whether the related target relative total stockholder return is achieved. Research and Manufacturing Contract Accruals We have entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. We record accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, we analyze progress of the research and development and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from our estimates. Our historical accrual estimates have not been materially different from the actual costs. Income Taxes Income taxes are provided for tax effects of transactions reported in the consolidated financial statements and consist of income taxes currently due plus deferred income taxes related to timing differences between the basis of certain assets and liabilities for financial statement reporting purposes and the basis for income tax reporting purposes. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. A valuation allowance is provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. At each balance sheet date, we assess the likelihood that deferred tax assets will be realized and recognize a valuation allowance if it is more likely than not that some portion of the deferred tax assets will not be realized. Assessment of the potential recovery of deferred tax assets requires judgment and is evaluated by estimating the future taxable income expected and considering prudent and feasible tax planning strategies. As of September 30, 2018, we continue to believe it is more likely than not that we will be able to realize our deferred tax assets and therefore no valuation allowance has been recorded. Uncertain tax positions represent tax positions for which reserves have been established. We account for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more likely than not to 65 be sustained, the tax position is then assessed to determine the amount to be recognized in the financial statements. The amount that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. Income tax expense includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Results of Operations Comparison of Years Ended September 30, 2018, 2017, and 2016 Revenue Research and development General and administrative Other income (expense): Interest income (expense), net Change in fair value of warrant liability and Series 1 nonconvertible preferred stock, net Income tax expense Years Ended September 30, 2018 2017 2016 $ 206,625 94,856 23,441 (in thousands) $ 102,814 57,451 20,749 $ 88,268 40,461 16,966 4,852 2,492 1,690 (59) (21,165) (159) (9,237) 29 (10,894) Revenue. We recognized revenue of $206.6 million during the year ended September 30, 2018, as compared to $102.8 million during the year ended September 30, 2017. The increase in revenue of $103.8 million year-over-year was due to increased royalties of $153.8 million earned under our AbbVie agreement as a result of the launch of MAVYRET/MAVIRET in late 2017, which was partially offset by lower milestone revenue earned in fiscal 2018 under our AbbVie agreement based on timing of milestone payments earned for MAVYRET/MAVIRET commercialization regulatory approvals. During the years ended September 30, 2018 and 2017, we recognized royalty revenue of $191.6 million and $37.8 million, respectively. Substantially all of our royalties earned in fiscal 2018 were related to royalties earned on the portion of AbbVie’s net sales of MAVRYET/MAVIRET. Our fiscal 2017 royalties were primarily based on royalties earned on the portion of AbbVie’s net sales of paritaprevir- containing regimen, which carry a lower royalty allocation rate compared to MAVYRET/MAVIRET. MAVYRET/MAVIRET has become a leading HCV treatment in the U.S. and the countries where it is approved and has resulted in our cumulative annual royalties earned in calendar 2018 reaching the 17% royalty tier per our calendar year royalty rate schedule under our agreement with AbbVie. We recognized revenue of $102.8 million during the year ended September 30, 2017 compared to $88.3 million during the year ended September 30, 2016. In fiscal 2017, we earned and received milestone payments totaling $65.0 million as a result of commercialization regulatory approvals for MAVYRET/MAVIRET in the EU and U.S. In early fiscal 2016, we earned and received a $30.0 million milestone payment as a result of commercialization regulatory approval for AbbVie’s paritaprevir-containing regimen in Japan. We earned royalties of $37.8 million and $57.7 million during the years ended September 30, 2017 and 2016, respectively, primarily based on the portion of AbbVie’s net sales of its HCV regimens allocable to paritaprevir. We recognized lower royalty revenue in 2017 compared to 2016 due to lower sales of paritaprevir-containing regimens as a result of increased competition from other HCV products on the market. We began earning royalties on the portion of AbbVie’s net sales of glecaprevir- containing regimens in the fourth quarter of fiscal 2017. Our royalty revenues eligible to be earned in the future will be dependent on AbbVie’s HCV market share, the pricing of the MAVYRET/MAVIRET regimen and the number of patients treated. In addition, at the beginning of each calendar year (the second quarter of our fiscal year), our royalty rates reset to the lowest tier for each of our royalty-bearing products licensed to AbbVie. (See Note 7 to our consolidated financial statements for further details on our royalty rate tier.) 66 Research and development expenses. 2018 Years Ended September 30, 2017 (in thousands) 2016 R&D programs: Liver disease Virology Other Total research and development expenses $ $ 54,691 $ 40,047 118 94,856 $ 34,750 $ 22,399 302 57,451 $ 17,840 21,692 929 40,461 Research and development expense increased by $37.4 million for the year ended September 30, 2018 as compared to the same period in 2017. The increase was primarily due to progression of preclinical and clinical activities in our liver disease and virology programs. In fiscal 2018 we initiated two Phase 2 studies of EDP-305 and advanced other compounds in preclinical development in our liver program. In fiscal 2018 we completed a Phase 1 clinical study of EDP-938 and prepared for a Phase 2a challenge study of EDP-938, which we initiated in October 2018, in our virology program. In November 2018, we announced our first clinical candidate for HBV, also in our virology program. Increases in our research and development expenses were driven by an increase in headcount to support our programs and an increase in external costs for clinical and preclinical activities. Research and development expenses increased by $17.0 million for the year ended September 30, 2017 as compared to the same period in 2016. The increase was primarily due to progression of preclinical and clinical activities in our liver disease and virology programs. Increases were driven by an increase in headcount to support our preclinical activities, expansion of our research facility and an increase in external costs for clinical and preclinical activities. We expect that our research and development expenses will continue to increase in the future as we advance our RSV, NASH, PBC and HBV programs. General and administrative expenses. General and administrative expenses increased by $2.7 million for the year ended September 30, 2018 as compared to the same period in 2017. The increase was primarily due to an increase in compensation expense due to increased headcount and to a lesser extent an increase in external accounting and consulting fees. General and administrative expenses increased by $3.8 million for the year ended September 30, 2017 as compared to the same period in 2016. The increase was primarily due to an increase in compensation expense due to increased headcount as well as the achievement of milestones in 2017 under existing performance-based stock unit awards in 2017. We expect our general and administrative expenses will continue to increase in the future as our operations grow to support further research and development Other income (expense). Changes in components of other income (expense) were as follows: Interest income (expense), net. Interest income (expense), net, increased by $2.4 million for the year ended September 30, 2018 as compared to the same period in 2017, primarily due to higher average investment balances in 2018 as a result of receipt of significant milestones and royalties in 2018 under our AbbVie agreement and an increase in interest rates for fiscal 2018 as compared to the same period in 2017. Interest income (expense), net, increased by $0.8 million for the year ended September 30, 2017 as compared to the same period in 2016 primarily due to higher average investment balances in fiscal 2017 as compared to the same period in 2016. Change in fair value of warrant liability and Series 1 nonconvertible preferred stock. We recognized other expense of $0.1 million and expense of $0.2 million for the years ended September 30, 2018 and 2017, respectively. We recognized expense in fiscal 2018 due to the increase in fair value of outstanding Series 1 nonconvertible preferred 67 stock year over year, offset by the expiration of unexercised warrants outstanding as of October 4, 2017. We recognized expense in our fiscal 2017 due to an increase in fair value of the outstanding liabilities year over year and income in our fiscal 2016 due to a decrease in fair value of the outstanding liabilities year over year. Income tax expense. Income tax expense was $21.2 million and $9.2 million for the years ended September 30, 2018 and 2017, respectively. The effective tax rates for the years ended September 30, 2018 and 2017 were 22.7% and 34.3%, respectively. The increase in income tax expense was primarily due to an increase in income before income taxes as a result of an increase in royalties earned under our AbbVie agreement year over year as well as a revaluation adjustment against deferred tax assets due to a decrease in the federal corporate income tax rate as enacted under the U.S. Tax Cuts and Jobs Act (the “Tax Act”) in December 2017. The decrease in the effective tax rate was primarily due to the enactment of the Tax Act in December 2017, which decreased the U.S. federal statutory rate from 35.0% to 21.0%, as well as an increase in federal research and development tax credits as part of our advancement of our wholly-owned research and development programs and tax benefits from stock option exercises and restricted stock units vesting during 2018. Estimates used to prepare our 2018 income tax expense are based on our analysis of the Tax Act. Given the complexity of the Tax Act, anticipated guidance from the U.S. Treasury regarding implementation of the act, and potential for guidance from the Securities and Exchange Commission or the Financial Accounting Standards Board related to the act, these estimates may be adjusted during our fiscal 2019 to reflect any such guidance provided. Income tax expense was $9.2 million and $10.9 million for the years ended September 30, 2017, and 2016, respectively. The effective tax rates for the years ended September 30, 2017 and 2016 were 34.3%, and 33.5%, respectively. The decrease in income tax expense was primarily due to lower income before income taxes as well as an increase in federal research and development tax credits which were deductible for tax purposes. The increase in the effective tax rate was primarily due to an increase in non-deductible stock-based compensation expense but was partially offset by an increase in federal research and development credits as part of our advancement of our wholly- owned research and development programs in 2017. Income tax expense for all periods presented was attributable to the tax provision on the earnings of our operations, all of which are domestic. Liquidity and Capital Resources During fiscal 2018, 2017 and 2016, we funded our operations with cash flows generated from operations. At September 30, 2018, our principal sources of liquidity were cash and cash equivalents and marketable securities of $325.1 million. The following table shows a summary of our cash flows for each of the years ended September 30, 2018, 2017, and 2016: 2018 Years Ended September 30, 2017 (in thousands) 2016 Cash provided by (used in): Operating activities Investing activities Financing activities Net increase (decrease) in cash and cash equivalents $ $ 29,220 $ (35,402) 4,409 52,653 $ (4,572) 1,017 35,809 (43,663) 2,705 (1,773) $ 49,098 $ (5,149) 68 Net cash provided by operating activities Cash provided by operating activities was $29.2 million for the year ended September 30, 2018 as compared to $52.7 million for the same period in 2017. The decrease in cash provided by operating activities was primarily driven by an increase in accounts receivable due to the timing of payments received under our collaboration with AbbVie and by increased tax payments, partially offset by increased net income year-over-year. The increase in cash provided by operating activities of $16.8 million for the year ended September 30, 2017 as compared to the same period in 2016 was primarily driven by a $15.9 million increase in cash receipts under our collaboration with AbbVie. We received $105.1 million in cash from AbbVie during 2017, including royalties and $65.0 million in milestone payments, compared to $89.2 million in cash during 2016, including royalties and a $30.0 million milestone payment. In addition, our taxes paid, net of refunds received, decreased by $17.5 million, due to lower profit before tax and timing of tax payments and refunds. These increases were partially offset by increased cash spending on research and development during 2017 in order to progress clinical development and preclinical research in our proprietary programs. Net cash used in investing activities The increase in cash used in investing activities of $30.8 million for the year ended September 30, 2018 as compared to the same period in 2017 was driven by timing of purchases, sales and maturities of marketable securities. The decrease in cash used in investing activities of $39.1 million for the year ended September 30, 2017 as compared to the same period in 2016 was driven by timing of purchases, sales and maturities of marketable securities. In addition, our capital asset outlay decreased by $2.2 million year over year due to the expansion of our research facility which was completed in fiscal 2016. Net cash provided by financing activities The increase in cash provided by financing activities of $3.4 million for the year ended September 30, 2018 as compared to the same period in 2017 was driven primarily by an increase in proceeds from stock option exercises as a result of the increase in the price of our common stock year over year and was partially offset by an increase in tax withholding payments for the vesting of performance-based stock unit awards in 2018. The decrease in cash provided by financing activities of $1.7 million for the year ended September 30, 2017 as compared to the same period in 2016 was driven primarily by tax withholding payments for the vesting of performance-based stock unit awards in 2017 and a lower income tax benefit from stock options exercised in fiscal 2017 as compared to fiscal 2016. Funding Requirements As of September 30, 2018, we had $325.1 million in cash, cash equivalents and short-term and long-term marketable securities. We believe that our existing cash, cash equivalents and marketable securities as of September 30, 2018 will be sufficient to meet our anticipated cash requirements for the foreseeable future. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially. Our future capital requirements are difficult to forecast and will depend on many factors, including: (cid:129) (cid:129) (cid:129) (cid:129) the amount of royalties generated from our existing collaboration with AbbVie; the number and characteristics of the future product candidates we pursue; the scope, progress, results and costs of researching and developing any of our product candidates on our own, including conducting advanced clinical trials; the cost of manufacturing our product candidates and any products we successfully commercialize independently, including manufacturing for clinical development; 69 (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) (cid:129) opportunities to in-license or otherwise acquire new technologies, therapeutic candidates and therapies; the timing and amount of royalties and any sales of our product candidates, if any, or royalties thereon; the timing of, and the costs involved in, obtaining regulatory approvals for any product candidates we develop independently; the cost of commercialization activities, if any, of any product candidates we develop independently that are approved for sale, including marketing, sales and distribution costs; our ability to establish new collaborations, licensing or other arrangements, if any, and the financial terms of such agreements; and the costs involved in preparing, filing, prosecuting, maintaining, defending and enforcing patents, including any litigation costs and the outcomes of any such litigation. potential fluctuations in foreign currency exchange rates; We do not believe that inflation had a material effect on our business, financial condition or results of operations in the last three fiscal years. If our costs were to become subject to significant inflationary pressures, we could not offset such higher costs through revenue increases because our revenues are substantially outside of our control. Our inability to do so could harm our business, financial condition and results of operations. Off-Balance Sheet Arrangements We do not engage in any off-balance sheet financing activities. We do not have any interest in entities referred to as variable interest entities, which include special purpose entities and other structured finance entities. Recently Issued Accounting Pronouncements A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is set forth in Note 2 to the consolidated financial statements included in this Annual Report on Form 10-K. Contractual Obligations and Commitments We lease space in Watertown, Massachusetts under two separate lease agreements. The first lease, located at 500 Arsenal Street, commenced on October 1, 2011 and was amended in 2015 to expand the rented space and extend the lease term through September 2022. This lease is for office and laboratory space. In conjunction with the amendment of the lease, the Company entered into a capital lease agreement to fund certain leasehold improvements and the purchase of lab equipment. The second lease, located at 400 Talcott Ave, commenced on September 24, 2018 for office space and extends through August 1, 2024. The Company estimates it will spend approximately $2.0 million in tenant and capital improvements to the space during fiscal 2019. 70 The following table summarizes our contractual obligations at September 30, 2018 and the effect such obligations are expected to have on our liquidity and cash flow in future periods: Operating leases Capital leases Payments Due by Period Less than 1 year 1-3 years 3-5 years More than 5 years Total $ $ 2,209 86 5,531 194 (in thousands) 3,292 $ 99 $ 519 — $ 11,551 379 Total contractual commitments and obligations $ 2,295 $ 5,725 $ 3,391 $ 519 $ 11,930 As of September 30, 2018, we had 1.9 million outstanding shares of Series 1 nonconvertible preferred stock, all of which we classified as long-term liabilities on our consolidated balance sheet and recorded at fair value of $1.6 million. The fair value of the preferred stock was measured based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The fair value of these instruments represents less than 10% of liabilities measured at fair value as of September 30, 2018. The Series 1 nonconvertible preferred stock issued would require the payment of $2.0 million in the event of a qualifying merger or sale of the company. The table above does not include this liability because we are unable to estimate the timing of this required payment, or if it will be required at all. ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK Interest Rate Risk We had cash, cash equivalents and marketable securities of $325.1 million at September 30, 2018, which consisted of cash, money market funds, agency securities, commercial paper, treasury notes and corporate bonds. Interest income is sensitive to changes in the general level of interest rates; however, due to the nature of these investments, a change in market interest rates of 100 basis points would not be expected to have a material impact on our financial condition or results of operations. Other than our capital lease obligation, we had no debt outstanding as of September 30, 2018. Foreign Exchange Risk As we continue to progress our wholly-owned programs into clinical development we will conduct clinical trials outside of the U.S. and thus will face exposure to movements in foreign currency exchange rates, primarily the British Pound and Euro, against the U.S. Dollar, arising from our accounts payable and accrued expenses. During fiscal 2018, the impact of foreign currency exposure was immaterial and thus did not have a significant impact on our consolidated financial statements. In fiscal 2019, we expect to face increasing exposure to the British Pound as we conduct our Phase 2a challenge study of EDP-938 in the U.K. However, based on our current contractual commitments outside of the U.S., we estimate that a change of 10% in foreign currency exchange rates would not materially affect our operations. Our operations may become subject to more significant fluctuations in foreign currency exchange rates in the future if we continue to contract with vendors outside of the U.S. ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA Our consolidated financial statements, together with the report of our independent registered public accounting firm, appear on pages F-1 through F-32 of this Annual Report on Form 10-K. ITEM 9. None. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE 71 ITEM 9A. CONTROLS AND PROCEDURES Conclusion Regarding the Effectiveness of Disclosure Controls and Procedures We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in the Company’s reports under the Securities Exchange Act of 1934, as amended (the Exchange Act), is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms, and that such information is accumulated and communicated to management, including our Chief Executive Officer (CEO) and Chief Financial Officer (CFO), as appropriate, to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, management recognized that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, as the Companies are designed to do, and management necessarily was required to apply its judgment in evaluating the risk related to controls and procedures. In connection with the preparation of this Form 10-K, as of September 30, 2018, an evaluation was performed under the supervision and with the participation of our management, including the CEO and CFO, of the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act). Based on that evaluation, our management concluded that our disclosure controls and procedures were effective at a reasonable assurance level as of September 30, 2018. These conclusions were communicated to the Audit Committee. Management’s Report on Internal Control Over Financial Reporting Our management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rule 13a-15(f) and Rule 15d-15(f) under the Exchange Act. Our internal control system is designed to provide reasonable assurance to the Company’s management and Board of Directors regarding the preparation and fair presentation of published financial statements. All internal control systems, no matter how well designed, have inherent limitations. Therefore, even those systems determined to be effective can provide only reasonable assurance with respect to financial statement preparation and presentation. Our management has assessed the effectiveness of our internal control over financial reporting as of September 30, 2018. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in its 2013 Internal Control—Integrated Framework. Based on this assessment, our management has concluded that as of September 30, 2018 our internal control over financial reporting is effective. The effectiveness of the Company’s internal control over financial reporting as of September 30, 2018, has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report which appears in Item 8 above. Change in Internal Control over Financial Reporting—There were no changes in our internal control over financial reporting that occurred during our last quarter that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. ITEM 9B. OTHER INFORMATION None. 72 PART III ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE Portions of the response to this item are incorporated herein by reference from the discussion responsive thereto under the captions “Proposal 1 - Election of Directors—Nominees for Director and Current Directors”, “Section 16(a) Beneficial Ownership Reporting Compliance”, “Executive Officers” and “Corporate Governance—Board and Committee Matters” in the Company’s Definitive Proxy Statement relating to the 2019 Annual Meeting of Stockholders, also referred to as the 2019 Proxy Statement, which will be filed within 120 days after September 30, 2018. We have adopted a Code of Business Conduct and Ethics (the code of ethics) that applies to all of our directors, officers and employees. The code of ethics is available on our website at http://www.enanta.com. In addition, if we make any substantive amendments to the code of ethics or grant any waiver, including any implicit waiver, from a provision of the code to any of our executive officers or directors, we will disclose the nature of such amendment or waiver as required by applicable law. ITEM 11. EXECUTIVE COMPENSATION The response to this item is incorporated herein by reference from the discussion responsive thereto under the following captions in the 2019 Proxy Statement: “Executive Compensation” and “Corporate Governance—Certain Relationships and Related Transactions.” ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED STOCKHOLDER MATTERS The response to this item is incorporated herein by reference in part from the discussion responsive thereto under the caption “Beneficial Ownership of Common Stock” in the 2019 Proxy Statement. The following table provides information about the securities authorized for issuance under the Company’s equity compensation plans as of September 30, 2018: Equity Compensation Plan Information (in thousands, except per share information) Plan Category Equity compensation plans approved by security holders (1) Equity compensation plans not approved by security holders Totals Number of securitie s to be issued upon exercise of outstanding options, warrants and rights (a) Weighted average exercise price of outstanding options, warrants and rights (b) Number of securities remaining available for future issuance under equity compensation plan s (excluding securities reflected in column (a)) (c) 2,873 (2) $ 33.47 — 2,873 — 437 (3) — 437 (1) Consists of, the Company’s 2012 Equity Incentive Plan, as amended, the Company’s Amended and Restated 1995 Equity Incentive Plan, as amended, and the Company’s Employee Stock Purchase Plan. (2) Consists of shares of the Company’s common stock issuable upon exercise of outstanding options issued under the Company’s 2012 Equity Incentive Plan, and the Company’s Amended and Restated 1995 Equity Incentive Plan. 73 (3) Consists of shares of the Company’s common stock reserved for future issuance under the Company’s 2012 Equity Incentive Plan and the Company’s Employee Stock Purchase Plan. This does not include 583 shares that were automatically added to the Company’s 2012 Equity Incentive Plan by its terms as of October 1, 2018. ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE The response to this item is incorporated herein by reference from the discussion responsive thereto under the caption “Corporate Governance—Certain Relationships and Related Transactions” and “Corporate Governance— Board and Committee Matters” in the 2019 Proxy Statement. ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES The response to this item is incorporated herein by reference from the discussion responsive thereto under the captions “Corporate Governance—Board and Committee Matters” and “Audit Committee Report—Audit Fees” in the 2019 Proxy Statement. PART IV ITEM 15. EXHIBITS, FINANCIAL STATEMENT SCHEDULES (a) 1. FINANCIAL STATEMENTS The financial statements are included under Part II, Item 8 of this Report. 2. FINANCIAL STATEMENTS SCHEDULE Schedules are omitted because they are not applicable, or are not required, or because the information is included in the consolidated financial statements and notes thereto. 3. EXHIBITS – The exhibits are listed below under Part IV, Item 15(b) of this Report. (b) EXHIBITS Exhibit Number 3.1 3.2 4.1 4.2 Exhibit Description Restated Certificate of Incorporation of Enanta Pharmaceuticals, Inc. Amended and Restated Bylaws of Enanta Pharmaceuticals, Inc. (as amended and restated in August 2015). Specimen certificate evidencing shares of common stock. Specimen certificate evidencing shares of Series 1 Non-Convertible Preferred Stock Incorporated by Reference Form 8-K Date 03/28/2013 Exhibit Number 3.1 Filed Herewith File Number 001-35839 8-K 08/18/2015 3.2 001-35839 S-1/A 02/05/2013 10-K 12/11/2017 4.1 4.3 333-184779 001-35839 10.1# Form of Indemnification Agreement for S-1/A 02/05/2013 10.7 333-184779 directors and officers. 10.2# Amended and Restated Employment Agreement S-1/A 03/05/2013 10.5 333-184779 between the Company and Jay R. Luly, Ph.D., dated as of March 4, 2013. 10.3# Form of Amended and Restated Employment Agreement for Executive Officers other than the Chief Executive Officer. S-1/A 03/05/2013 10.17 333-184779 74 Exhibit Number 10.4† Collaborative Development and License Exhibit Description Form 10-Q Date 02/09/2016 Exhibit Number 10.1 File Number 001-35839 Filed Herewith Incorporated by Reference Agreement between the Company and Abbott Laboratories, dated November 27, 2006; as amended by a First Amendment to Collaborative Development and License Agreement dated January 27, 2009 and a Second Amendment to Collaborative Development and License Agreement dated December 9, 2009 (assigned to AbbVie Inc. as of January 1, 2013). 10.5† Third Amendment to Collaborative Development 10-K 12/11/2014 10.5 001-35839 and License Agreement between the Company and AbbVie dated October 20, 2014. Fourth Amendment to Collaborative Development and License Agreement between the Company and AbbVie dated as of March 3, 2015. Lease Agreement between Company and ARE- 500 Arsenal Street LLC, dated as of April 15, 2011. First Amendment to Lease Agreement made as of March 5, 2015 between the Company and ARE-500 Arsenal Street LLC. Third Amended and Restated Registration Rights Agreement, dated as of August 23, 2012. 10.6 10.7 10.8 10.9 10.10 Lease Agreement between Company and Athena Arsenal, LLC, dated as of September 27, 2018. 10-Q 05/08/2015 10.1 001-35839 S-1 11/06/2012 10.6 333-184779 10-Q 05/08/2015 10.2 001-35839 S-1/A 11/06/2012 10.4 333-184779 10.10# Amended and Restated 1995 Equity Incentive S-1/A 03/05/2013 10.8 333-184779 Plan. 10.11# Form of Incentive Stock Option Certificate under Amended and Restated 1995 Equity Incentive Plan. 10.12# Form of Non-Statutory Stock Option Certificate under Amended and Restated 1995 Equity Incentive Plan. 10.13# Form of Non-Statutory Stock Option Certificate for directors under Amended and Restated 1995 Equity Incentive Plan. S-1/A 03/05/2013 10.9 333-184779 S-1/A 03/05/2013 10.10 333-184779 S-1/A 03/05/2013 10.11 333-184779 10.14# 2012 Equity Incentive Plan (As adjusted to 10-K/A 01/06/2017 10.14 001-35839 reflect the application of the 1-for-4.31 reverse stock split of the Company’s common stock effected on March 1, 2013). 10.15# Form of Incentive Stock Option Agreement under 2012 Equity Incentive Plan. S-1/A 03/05/2013 10.13 333-184779 10.16# Form of Non-Statutory Stock Option Agreement S-1/A 03/05/2013 10.14 333-184779 under 2012 Equity Incentive Plan. 10.17# Form of Non-Statutory Stock Option Certificate S-1/A 03/05/2013 10.15 333-184779 for directors under 2012 Equity Incentive Plan. 10.18# Form of Performance Share Unit Certificate 10-K 12/11/2017 10.18 001-35839 under 2012 Equity Incentive Plan. 10.19# Form of Relative Total Stockholder Return Unit 10-K 12/11/2017 10.19 001-35839 Certificate under 2012 Equity Incentive Plan. 10.20# Employee Stock Purchase Plan. 21.1 Subsidiaries of the Company. S-1/A 02/05/2013 10.16 333-184779 X X 75 Incorporated by Reference Exhibit Number File Number Filed Herewith X X X X X Exhibit Number 23.1 31.1 31.2 32.1 101 Exhibit Description Form Date Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm. Certification of the Chief Executive Officer pursuant to Rule 13a-14(a) or 15d-14(a) of the Securities Exchange Act of 1934. Certification of Chief Financial Officer pursuant to Rule 13a-14(a) or 15d-14(a) of the Securities Exchange Act of 1934. Certification of the Chief Executive Officer and Chief Financial Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002. The following materials from the Annual Report of Enanta Pharmaceuticals, Inc. on Form 10-K for the year ended September 30, 2018 formatted in XBRL (eXtensible Business Reporting Language): (i) Consolidated Balance Sheets as of September 30, 2018 and September 30, 2017 of Enanta Pharmaceuticals, Inc., (ii) Consolidated Statements of Operations for the years ended September 30, 2018, 2017, and 2016 of Enanta Pharmaceuticals, Inc., (iii) Consolidated Statements of Comprehensive Income for the years ended September 30, 2018, 2017, and 2016 of Enanta Pharmaceuticals, Inc., (iv) Consolidated Statements of Stockholders’ Equity for the years ended September 30, 2018, 2017, and 2016 of Enanta Pharmaceuticals, Inc., (v) Consolidated Statements of Cash Flows for the years ended September 30, 2018, 2017, and 2016 of Enanta Pharmaceuticals, Inc., and (vi) Notes to Consolidated Financial Statements of Enanta Pharmaceuticals, Inc. # † †† Management contract or compensatory plan, contract or agreement. Confidential treatment granted as to portions of this Exhibit. The confidential portions of this Exhibit have been omitted and are marked by asterisks. This Exhibit has been filed separately with the commission pursuant to an application for confidentiality treatment. The confidential portions of this Exhibit have been omitted and are marked by asterisks. ITEM 16. FORM 10-K SUMMARY None. 76 SIGNATURES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Company has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized, this 29th day of November, 2018. ENANTA PHARMACEUTICALS, INC. By: /s/ Jay R. Luly, Ph.D. Jay R. Luly, Ph.D. Chief Executive Officer Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Company in the capacities and on the dates indicated. Signature Title Date /s/ Jay R. Luly, Ph.D. Jay R. Luly, Ph.D. /s/ Paul J. Mellett Paul J. Mellett President and Chief Executive Officer and Director (Principal Executive Officer) Chief Financial Officer (Principal Financial and Accounting Officer) /s/ Stephen Buckley, Jr. Stephen Buckley, Jr. /s/ Bruce L.A. Carter, Ph.D. Bruce L.A. Carter, Ph.D. /s/ George S. Golumbeski, Ph.D. George S. Golumbeski, Ph.D. /s/ Kristine Peterson Kristine Peterson /s/ Lesley Russell, MB. Ch.B., MRCP Lesley Russell, MB. Ch.B., MRCP /s/ Terry Vance Terry Vance Director Director Director Director Director Director November 29, 2018 November 29, 2018 November 29, 2018 November 29, 2018 November 29, 2018 November 29, 2018 November 29, 2018 November 29, 2018 77 ENANTA PHARMACEUTICALS, INC. INDEX TO CONSOLIDATED FINANCIAL STATEMENTS Report of Independent Registered Public Accounting Firm Consolidated Balance Sheets Consolidated Statements of Operations Consolidated Statements of Comprehensive Income Consolidated Statements of Stockholders’ Equity Consolidated Statements of Cash Flows Notes to Consolidated Financial Statements Page F-2 F-4 F-5 F-6 F-7 F-8 F-9 F-1 ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA Report of Independent Registered Public Accounting Firm To the Board of Directors and Stockholders of Enanta Pharmaceuticals, Inc. Opinions on the Financial Statements and Internal Control over Financial Reporting We have audited the accompanying consolidated balance sheets of Enanta Pharmaceuticals, Inc. and its subsidiary (“the Company”) as of September 30, 2018 and 2017, and the related consolidated statements of operations, comprehensive income, stockholders’ equity and cash flows for each of the three years in the period ended September 30, 2018, including the related notes (collectively referred to as the “consolidated financial statements”). We also have audited the Company's internal control over financial reporting as of September 30, 2018, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of September 30, 2018 and 2017, and the results of its operations and its cash flows for each of the three years in the period ended September 30, 2018 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of September 30, 2018, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO. Basis for Opinions The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in Management’s Report on Internal Control Over Financial Reporting under Item 9A. Our responsibility is to express opinions on the Company’s consolidated financial statements and on the Company's internal control over financial reporting 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 the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB. We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects. Our audits of the consolidated financial statements 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 disclosures in 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. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions. F-2 Definition and Limitations of Internal Control over Financial Reporting A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements. Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate. /s/ PricewaterhouseCoopers LLP Boston, Massachusetts November 29, 2018 We have served as the Company’s auditor since 1999. F-3 ENANTA PHARMACEUTICALS, INC. CONSOLIDATED BALANCE SHEETS (in thousands, except per share data) Assets Current assets: Cash and cash equivalents Short-term marketable securities Accounts receivable Prepaid expenses and other current assets Total current assets Long-term marketable securities Property and equipment, net Deferred tax assets Restricted cash Other long-term assets Total assets Liabilities and Stockholders' Equity Current liabilities: Accounts payable Accrued expenses and other current liabilities Income taxes payable Total current liabilities Warrant liability Series 1 nonconvertible preferred stock Other long-term liabilities Total liabilities Commitments and contingencies (Note 12) Stockholders' equity: Common stock; $0.01 par value per share, 100,000 shares authorized; 19,395 and 19,120 shares issued and outstanding at September 30, 2018 and September 30, 2017, respectively Additional paid-in capital Accumulated other comprehensive loss Retained earnings Total stockholders' equity Total liabilities and stockholders' equity September 30, 2018 September 30, 2017 $ $ $ $ 63,902 $ 244,828 67,205 4,454 380,389 16,389 8,374 8,375 608 92 414,227 $ 4,745 $ 9,892 1,388 16,025 — 1,628 2,895 20,548 65,675 157,994 10,614 3,536 237,819 70,038 8,049 10,123 608 — 326,637 3,714 7,970 9,298 20,982 807 762 2,410 24,961 194 276,526 (398) 117,357 393,679 414,227 $ 191 256,241 (112) 45,356 301,676 326,637 The accompanying notes are an integral part of these consolidated financial statements. F-4 ENANTA PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF OPERATIONS (in thousands, except per share data) Revenue Royalties Milestones Other Total revenue Operating expenses: Research and development General and administrative Total operating expenses Income from operations Other income (expense): Interest income (expense), net Change in fair value of warrant liability and Series 1 nonconvertible preferred stock Total other income (expense), net Income before income taxes Income tax expense Net income Net income per share: Basic Diluted Weighted average shares outstanding: Basic Diluted $ $ $ $ Years Ended September 30, 2017 2016 2018 191,625 15,000 — 206,625 94,856 23,441 118,297 88,328 $ $ 37,814 65,000 — 102,814 57,451 20,749 78,200 24,614 57,692 30,000 576 88,268 40,461 16,966 57,427 30,841 4,852 2,492 1,690 (59) 4,793 93,121 (21,165) $ 71,956 (159) 2,333 26,947 (9,237) $ 17,710 3.74 3.48 $ $ 0.93 0.91 $ $ 19,255 20,650 19,066 19,407 29 1,719 32,560 (10,894) 21,666 1.14 1.13 18,929 19,224 The accompanying notes are an integral part of these consolidated financial statements. F-5 ENANTA PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (in thousands) Net income Other comprehensive loss: Years Ended September 30, 2017 2016 2018 $ 71,956 $ 17,710 $ 21,666 Net unrealized losses on marketable securities, net of tax benefit of ($109), ($78), and ($9) Total other comprehensive loss Comprehensive income (286) (286) 71,670 $ (131) (131) 17,579 $ (14) (14) 21,652 $ The accompanying notes are an integral part of these consolidated financial statements. F-6 ) 4 1 ( 6 2 0 , 1 4 5 3 , 9 7 4 7 , 1 6 6 6 , 1 2 6 3 9 , 9 6 2 ) 2 0 2 ( 9 7 0 , 1 1 7 0 , 3 1 3 1 2 ) 1 3 1 ( 4 4 2 , 6 ) 6 5 7 , 1 ( 5 4 8 , 5 1 0 1 7 , 7 1 6 7 6 , 1 0 3 — ) 6 8 2 ( 6 5 9 , 1 7 9 7 6 , 3 9 3 — — — — 6 6 6 , 1 2 6 4 6 , 7 2 — — — — — 0 1 7 , 7 1 6 5 3 , 5 4 — — — 5 4 — $ 6 5 9 , 1 7 7 5 3 , 7 1 1 3 3 — — — ) 4 1 ( — 9 1 — — — — ) 1 3 1 ( — ) 2 1 1 ( — — — — — ) 6 8 2 ( $ 7 5 9 , 9 2 2 $ 7 8 1 $ 7 1 7 , 8 1 — — 3 2 0 , 1 4 5 3 , 9 7 4 7 , 1 ) 2 0 2 ( 8 7 0 , 1 1 7 0 , 3 1 1 8 0 , 2 4 2 — — 3 1 2 2 4 2 , 6 ) 7 5 7 , 1 ( 5 4 8 , 5 1 1 4 2 , 6 5 2 ) 5 4 ( — — 3 — — — — 0 9 1 1 — — — — — 1 9 1 2 1 — — — — — — — — 9 1 3 6 3 0 , 9 1 2 7 2 1 — — — — 5 4 — 0 3 2 — — — 0 2 1 , 9 1 $ ) 8 9 3 ( $ 6 2 5 , 6 7 2 $ 4 9 1 $ 5 9 3 , 9 1 7 5 1 , 6 3 2 $ 0 8 9 , 5 $ l a t o T ' s r e d l o h k c o t S y t i u q E d e n i a t e R s g n i n r a E e v i s n e h e r p m o C ) s s o L ( e m o c n I d e t a l u m u c c A r e h t O l a n o i t i d d A n I - d i a P l a t i p a C k c o t S n o m m o C t n u o m A s e r a h S . C N I , S L A C I T U E C A M R A H P A T N A N E Y T I U Q E ’ S R E D L O H K C O T S F O S T N E M E T A T S D E T A D I L O S N O C ) s d n a s u o h t n i ( s e s i c r e x e n o i t p o k c o t s m o r f t i f e n e b x a t e m o c n I 5 1 0 2 , 0 3 r e b m e t p e S t a s e c n a l a B s n o i t p o k c o t s f o e s i c r e x E e s n e p x e n o i t a s n e p m o c d e s a b - k c o t S 6 1 0 2 , 0 3 r e b m e t p e S t a s e c n a l a B s n o i t p o k c o t s f o e s i c r e x E s s o l e v i s n e h e r p m o c r e h t O e m o c n i t e N g n i d l o h h t i w f o t e n , s t i n u k c o t s d e t c i r t s e r f o g n i t s e V s e s i c r e x e n o i t p o k c o t s m o r f t i f e n e b x a t e m o c n I e s n e p x e n o i t a s n e p m o c d e s a b - k c o t S s t n a r r a w d n a s n o i t p o k c o t s f o e s i c r e x E 7 1 0 2 , 0 3 r e b m e t p e S t a s e c n a l a B s s o l e v i s n e h e r p m o c r e h t O e m o c n i t e N g n i d l o h h t i w f o t e n , s t i n u k c o t s d e t c i r t s e r f o g n i t s e V w e n f o n o i t p o d a r o f t n e m t s u j d a t c e f f e e v i t a l u m u C e s n e p x e n o i t a s n e p m o c d e s a b - k c o t S 8 1 0 2 , 0 3 r e b m e t p e S t a s e c n a l a B ) 2 e t o N ( e c n a d i u g g n i t n u o c c a s s o l e v i s n e h e r p m o c r e h t O e m o c n i t e N . s t n e m e t a t s l a i c n a n i f d e t a d i l o s n o c e s e h t f o t r a p l a r g e t n i n a e r a s e t o n g n i y n a p m o c c a e h T 7 - F ENANTA PHARMACEUTICALS, INC. CONSOLIDATED STATEMENTS OF CASH FLOWS (in thousands) Cash flows from operating activities Net income Adjustments to reconcile net income to net cash provided by operating activities: Stock-based compensation expense Depreciation and amortization expense Deferred income taxes Income tax benefit from stock awards Premium paid on marketable securities Amortization of (accretion of) premium (discount) on marketable securities Change in fair value of warrant liability and Series 1 nonconvertible preferred stock Other non-cash items Change in operating assets and liabilities: Accounts receivable Unbilled receivables Prepaid expenses and other current assets Accounts payable Accrued expenses Income taxes payable Other long-term liabilities Other long-term assets Net cash provided by operating activities Cash flows from investing activities Purchase of marketable securities Proceeds from maturities and sale of marketable securities Purchase of property and equipment Net cash used in investing activities Cash flows from financing activities Proceeds from exercise of stock options and warrants Income tax benefit from exercise of stock options Payments for settlement of share-based awards Payments of capital lease obligations Net cash provided by financing activities Net increase (decrease) in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental disclosure of cash flow information: Cash paid for income taxes Non-cash items: Purchases of fixed assets included in accounts payable and accrued expenses Years Ended September 30, 2017 2016 2018 $ 71,956 $ 17,710 $ 21,666 15,845 2,518 1,858 — (319) 13,071 2,137 (1,654) (213) (1,229) 9,354 1,661 (2,294) (1,747) (518) (835) 702 1,511 59 (75) (56,591) — (918) 1,317 1,843 (7,910) 564 (92) 29,220 159 — 2,227 — 5,678 633 3,443 9,511 478 — 52,653 (29) 34 2,448 433 (964) 1,451 1,858 548 397 — 35,809 (293,103) 260,682 (2,981) (35,402) (251,371) 249,305 (2,506) (4,572) (192,429) 153,504 (4,738) (43,663) 6,244 — (1,756) (79) 4,409 (1,773) 65,675 63,902 $ 1,079 213 (202) (73) 1,017 49,098 16,577 65,675 $ 1,026 1,747 — (68) 2,705 (5,149) 21,726 16,577 26,088 $ 1,588 $ 12,616 111 $ 318 $ 637 $ $ $ The accompanying notes are an integral part of these consolidated financial statements. F-8 ENANTA PHARMACEUTICALS, INC. NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Amounts in thousands, except per share data) 1. Nature of the Business Enanta Pharmaceuticals, Inc. (the “Company”), incorporated in Delaware in 1995, is a biotechnology company that uses its robust, chemistry-driven approach and drug discovery capabilities to create small molecule drugs primarily for the treatment of viral infections and liver diseases. The Company discovered glecaprevir, the second protease inhibitor discovered and developed through its collaboration with AbbVie, which is marketed as part of AbbVie’s direct-acting antiviral (DAA) regimen under the tradenames MAVYRET™ (U.S.) or MAVIRET™ (ex-U.S.) (glecaprevir/pibrentasvir) for the treatment of chronic hepatitis C virus, or HCV. The other protease inhibitor under its HCV collaboration, which is part of AbbVie’s initial DAA regimens for the treatment of chronic HCV, is currently marketed outside the U.S. under the tradename VIEKIRAX® (paritaprevir/ritonavir/ombitasvir). Royalties from the Company’s AbbVie collaboration and its existing financial resources provide funding to support its wholly- owned research and development programs, which are currently focused on the following disease targets: respiratory syncytial virus (“RSV”), non-alcoholic steatohepatitis (“NASH”); primary biliary cholangitis (“PBC”); and hepatitis B virus (“HBV”). The Company is subject to many of the risks common to companies in the biotechnology industry including, but not limited to, the uncertainties of research and development, competition from technological innovations of others, dependence on collaborative arrangements, protection of proprietary technology, dependence on key personnel and compliance with government regulation. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approvals, prior to commercialization. These efforts require significant amounts of capital, adequate personnel infrastructure, and extensive compliance reporting capabilities. 2. Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements include those of the Company and its subsidiary, Enanta Pharmaceuticals Security Corporation, after elimination of all intercompany accounts and transactions. The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, management’s judgments with respect to its revenue arrangements; valuation of warrants, Series 1 nonconvertible preferred stock and stock-based awards; the accrual of research and development expenses, and the accounting for income taxes, including uncertain tax positions and the valuation of net deferred tax assets. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates. Cash Equivalents and Marketable Securities The Company considers all short-term, highly liquid investments with original maturities of ninety days or less at acquisition date to be cash equivalents. Marketable securities with original maturities of greater than ninety days and remaining maturities of less than one year from the balance sheet date are classified as short-term marketable securities. Marketable securities with remaining maturities of greater than one year from the balance sheet date are classified as long-term marketable securities. F-9 The Company classifies all of its marketable securities as available-for-sale. The Company continually evaluates the credit ratings of its investment portfolio and underlying securities. The Company invests in accordance with its investment policy and invests at the date of purchase in securities with a rating of A3 or higher and A- or higher according to Moody’s and S&P, respectively. The Company reports available-for-sale investments at fair value as of each balance sheet date and records any unrealized gains or losses as a component of stockholders’ equity. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense), net within the consolidated statements of operations. If any adjustment to fair value reflects a decline in the value of the investment, the Company considers available evidence to evaluate the extent to which the decline is “other than temporary” and reduces the investment to fair value through a charge to the consolidated statements of operations. There were no such adjustments necessary during the years ended September 30, 2018, 2017, and 2016. Restricted Cash As of September 30, 2018 and 2017 the Company had an outstanding letter of credit collateralized by a money market account of $608 to the benefit of the landlord of the Company’s current building lease. This amount was classified as long-term restricted cash as of September 30, 2018 and 2017. Concentration of Credit Risk and of Significant Customers and Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents, marketable securities and accounts receivable. The Company has all cash and investment balances at one accredited financial institution, including cash in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. The Company has historically generated all of its revenue from its collaborative research and license agreements as well as a U.S. government contract (see Note 7). As of September 30, 2018 and 2017, accounts receivable consisted of amounts due from the Company’s principal collaborator (see Note 7). The Company is completely dependent on third-party manufacturers for product supply for preclinical and clinical research activities in its non-partnered programs. The Company relies and expects to continue to rely exclusively on several manufacturers to supply the Company with its requirements for the active pharmaceutical ingredients related to these programs. These research programs would be adversely affected by a significant interruption in the supply of its active pharmaceutical ingredients. Fair Value Measurements Certain 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 to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. A fair value hierarchy is based on three levels of inputs which are used to measure fair value, of which the first two levels are considered observable and the last is considered unobservable: (cid:129) (cid:129) (cid:129) 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, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable 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 the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. F-10 The Company’s instruments that are carried at fair value are cash equivalents, marketable securities and the warrant and Series 1 nonconvertible preferred stock liabilities. The carrying values of accounts receivable, accounts payable and accrued expenses approximate their fair value due to the short-term nature of these assets and liabilities. Property and Equipment Property and equipment are stated at cost less accumulated depreciation or amortization. Depreciation and amortization expense is recognized using the straight-line method over the following estimated useful lives: Laboratory and office equipment Leasehold improvements Purchased software Computer equipment Furniture 5 years Shorter of life of lease or estimated useful life 3 years 3 years 7 years Expenditures for repairs and maintenance of assets are charged to expense as incurred. Costs of major additions and betterments are capitalized and depreciated on a straight-line basis over their useful lives. Upon retirement or sale, the cost and related accumulated depreciation or amortization of assets disposed are removed from the accounts and any resulting gain or loss is included in income from operations in the consolidated statements of operations. Impairment of Long-Lived Assets The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, the Company 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 carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long-lived assets. Revenue Recognition The Company’s revenue has been generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables, which may include (i) licenses, (ii) research and development activities, and (iii) participation in joint research and development steering committees. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, and royalty payments based on product sales derived from the collaboration. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectibility of the resulting receivable is reasonably assured, and the Company has fulfilled its performance obligations under the contract. The consideration received under multiple-element arrangements that is fixed or determinable is allocated among the separate units of accounting based on the relative selling prices of the separate units of accounting. The Company determines the selling price of a unit of accounting within each arrangement following the hierarchy of evidence prescribed by ASC 605-25. The selling prices of deliverables under the arrangement may be derived using third-party evidence (“TPE”) or a best estimate of selling price (“BESP”), if vendor-specific objective evidence (“VSOE”) is not available. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the license agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors including those factors contemplated in negotiating the agreements as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability F-11 of success, and the time needed to commercialize a product candidate pursuant to the license. Deliverables under a multiple-element arrangement are separated into multiple units if (i) the delivered item has value to the customer on a standalone basis, and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within the control of the Company. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices derived using TPE or BESP. The appropriate revenue recognition model is applied to each element, and revenue is accordingly recognized as each element is delivered. The Company may exercise significant judgment in determining whether a deliverable is a separate unit of accounting. In determining the separate units of accounting, the Company evaluates whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers whether or not (i) the collaborator can use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license is dependent on the undelivered items, and (iii) the collaborator or other vendors can provide the undelivered items. For all periods presented, whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model or a straight-line model over the period of performance, which is typically the research and development term. Full-time equivalents (“FTEs”) are typically used as the measure of performance. At each reporting period, the Company reassesses its cumulative measure of performance and makes appropriate adjustments, if necessary. The Company recognizes revenue using the proportional performance model whenever the Company can make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement. Revenue recognized under the proportional performance model at each reporting period is determined by multiplying the total expected payments under the contract (excluding royalties and payments contingent upon achievement of milestones) by the ratio of the level of effort incurred to date to the estimated total level of effort required to complete the performance obligations under the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model as of each reporting period. Alternatively, if the Company cannot make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement, then revenue under the arrangement is recognized on a straight-line basis over the period expected to complete the Company’s performance obligations. If and when a contingent milestone payment is earned, the additional consideration to be received is allocated to the separate units of accounting in the arrangement based on their relative selling prices at the inception of the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined on a straight-line basis as of the period end date. If the Company cannot reasonably estimate when its performance obligation period ends, then revenue is deferred until the Company can reasonably estimate when the performance obligation period ends. Royalty revenue is recognized based on contractual terms when reported sales are reliably measurable and collectibility is reasonably assured, provided that there are no performance obligations remaining. During the year ended September 30, 2016, the Company also generated revenue from a government contract, under which the Company was reimbursed for certain allowable costs for the funded project. Revenue from the government contract was recognized when the related service was performed. The related costs incurred by the Company under the government contract were included in research and development expenses in the consolidated statements of operations. Amounts received prior to satisfying all revenue recognition criteria are recorded as deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the next twelve months of the consolidated balance sheet date are classified as long-term deferred revenue. In the event that a collaborative research and license agreement is terminated and the Company then has no further performance obligations, the Company recognizes as revenue any amounts that had not previously been recorded as revenue but were classified as deferred revenue at the date of such termination. F-12 Research and Development Costs Research and development costs are expensed as incurred. Included in research and development costs are wages, stock-based compensation and benefits of employees, third-party license fees and other operational costs related to the Company’s research and development activities, including facility-related expenses and external costs of outside contractors engaged to conduct both preclinical and clinical studies and manufacture quantities of product for preclinical and clinical studies. The Company also includes in research and development expense the costs to complete the Company’s obligations under research collaborations. Upfront payments and milestone payments made for the licensing of technology are expensed as research and development in the period in which they are incurred. Advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related goods are delivered or the services are performed. Research and Manufacturing Contract Accruals The Company has entered into various research and development and manufacturing contracts. These agreements are generally cancelable, and related payments are recorded as the corresponding expenses are incurred. The Company records accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research and development and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company's estimates. The Company's historical accrual estimates have not been materially different from the actual costs. Patent Costs All patent-related costs incurred in connection with filing and prosecuting patent applications are recorded as general and administrative expenses as incurred. Stock-Based Compensation The Company measures all stock options and other stock-based awards granted to employees at fair value on the date of grant. The Company uses the Black-Scholes option-pricing model in the valuation of its stock options. The fair value of performance-based awards and restricted stock units is based on intrinsic value of the stock on the date of grant. The Company uses the Monte-Carlo model in order to calculate the fair value of the market-based awards. The fair value of options is recognized as stock-based compensation expense over the requisite service period, which is generally the vesting period of the respective award. Commencing with the adoption of ASU No. 2016-09 on October 1, 2017, the Company accounts for stock-based compensation expense related to forfeitures as the forfeitures occur. The straight-line method of expense recognition is applied to all awards with service-based and market-based conditions. The Company records stock-based compensation expense related to performance-based awards when the performance-based targets are probable of being achieved. The Company classifies stock-based compensation expense in the consolidated statements of operations in the same manner in which the award recipient’s payroll costs are classified. Income Taxes The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the financial statements or in the Company’s tax returns. Deferred taxes are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. F-13 Uncertain tax positions represent tax positions for which reserves have been established. The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing 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 to be recognized in the financial statements. The amount that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. Income tax expense includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Net Income per Share Basic net income per common share is computed by dividing the net income by the weighted average number of shares of common stock outstanding for the period. Diluted net income per common share is computed by dividing net income by the weighted average number of common shares outstanding for the period, including potential dilutive common shares assuming the dilutive effect of outstanding stock options and unvested restricted stock units. Market-based awards are included in diluted net income per common share to the extent they would have vested if the period end date was the market criteria measurement date. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is a biotechnology company focused on discovering and developing small molecule drugs for the treatment of viral infections and liver diseases. Revenue is generated exclusively from transactions occurring with partners located in the United States and all assets are held in the United States. Comprehensive Income Comprehensive income includes net income as well as other changes in stockholders’ equity that result from transactions and economic events other than those with stockholders. The Company’s only element of other comprehensive income is unrealized gains and losses on available-for-sale marketable securities. Going Concern In August 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU 2014-15, Presentation of Financial Statements - Going Concern (Subtopic 205-40) (“ASU 2014-15”). The Company adopted this standard as of September 30, 2017. The standard requires the Company to assess its ability to continue as a going concern one year beyond the date of filing and, in certain circumstances, provide additional footnote disclosures. Based on a detailed cash forecast incorporating current research and development activities and related spending plans, the Company believes that current cash, cash equivalents and marketable securities on hand at September 30, 2018 should be sufficient to fund operations for the foreseeable future, including at least the next twelve months beyond the date of issuance of these financial statements. The amount of capital available will depend on the Company’s management of its existing cash, cash equivalents and marketable securities, as well as the level of future royalties the Company earns under its agreement with AbbVie. If the Company should require financing beyond these resources to fund its research and development efforts, it may not be able to obtain financing on acceptable terms, or at all. F-14 Recently Issued Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), which intends to simplify several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, a choice to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. This amendment was effective for the Company in the fiscal year beginning October 1, 2017. As a result of the adoption, the Company changed its forfeiture rate policy to recognize forfeitures as they occur. Upon adoption, the cumulative impact of this accounting policy change on retained earnings, additional paid-in capital and deferred tax assets in the consolidated balance sheet was not material. In addition, the consolidated statements of cash flows now presents excess tax benefits as part of cash flows from operating activities. The Company elected to adopt this change on a prospective basis and, therefore, excess tax benefits from prior periods in the consolidated statements of cash flow were not restated. The adoption of the standard is also expected to create variability in the consolidated statements of operations in years in which the Company is expected to have taxable income, as the tax consequences of settled share-based payments will be recognized in income tax expense when share-based payment awards are settled. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”) which supersedes all existing revenue recognition requirements, including most industry-specific guidance. The new standard requires a company to recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration that the company expects to receive for those goods or services. The FASB has continued to issue accounting standards updates to clarify and provide implementation guidance related to Revenue from Contracts with Customers, including ASU 2016-08, Revenue from Contract with Customers: Principal versus Agent Considerations, ASU 2016-10, Revenue from Contracts with Customers: Identifying Performance Obligations and Licensing, and ASU 2016-12, Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients. These amendments address a number of areas, including an entity’s identification of its performance obligations in a contract, collectibility, non-cash consideration, presentation of sales tax and an entity’s evaluation of the nature of its promise to grant a license of intellectual property and whether or not that revenue is recognized over time or at a point in time. The new guidance must be adopted using either a modified retrospective approach or a full retrospective approach for all periods presented. Under the modified retrospective method, the cumulative effect of applying the new standard would be recognized at the adoption date in retained earnings on the consolidated balance sheet. Under the full retrospective approach, the new standard would be applied to each prior reporting period presented. These new standards will be effective for the Company beginning October 1, 2018. The Company will adopt the standard under the modified retrospective method, the impact of which is not expected to have a material impact on the Company’s consolidated financial statements as the AbbVie Agreement is the only revenue-generating arrangement outstanding and all performance obligations under the agreement have been completed by the end of fiscal 2011. The adoption of ASU 2014-09 did not have an impact on the Company’s accounting for contingent milestone or royalty payments. All contingent milestone payments earned since fiscal 2011 have been recognized as revenue when the associated milestone was achieved by AbbVie. The Company is currently earning annually tiered per-product royalties on the portion of AbbVie’s net sales of its HCV regimens allocable to the protease inhibitor product in the regimen. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (“ASU 2016-18”) that changes the presentation of restricted cash and cash equivalents on the statement of cash flows. Restricted cash and restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. Upon adoption, the Company will adjust the presentation of the statement of cash flows to include restricted cash related to an outstanding letter of credit collateralized by a money market fund of $608 so that it is included in the balances of cash and cash equivalents. In May 2017, the FASB issued ASU No. 2017-09, Compensation—Stock Compensation (Topic 718) (“ASU 2017- 09”) which provides updated guidance about changes to the terms or conditions of a share-based payment award that requires companies to apply modification accounting under Topic 718. This amendment is effective for the Company in the fiscal year beginning October 1, 2018, but early adoption is permissible. The Company does not expect the adoption of ASU 2017-09 to have a material impact on its consolidated financial statements. F-15 In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which will replace the existing guidance in ASC 840, “Leases.” The updated standard aims to increase transparency and comparability among organizations by requiring lessees to recognize leased assets and leased liabilities on the consolidated balance sheets and requiring disclosure of key information about leasing arrangements. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2016-02 may have on its financial position and results of operations. In March 2017, the FASB issued ASU No. 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities (“ASU 2017-08”) which requires companies to amend the amortization period for premiums on debt securities with explicit call features to be the earliest call date rather than through the contractual life of the debt instrument. This amendment aims to more closely align the recognition of interest income with the manner in which market participants price such instruments. This amendment is effective for the Company in the fiscal year beginning October 1, 2019, but early adoption is permissible. The Company is currently evaluating the potential impact that ASU 2017-08 may have on its financial position and results of operations. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (“ASU 2016-13”), which introduces a new methodology for accounting for credit losses on financial instruments, including available-for-sale debt securities. The guidance establishes a new “expected loss model” that requires entities to estimate current expected credit losses on financial instruments by using all practical and relevant information. Any expected credit losses are to be reflected as allowances rather than reductions in the amortized cost of available-for-sale debt securities. This amendment is effective for the Company in the fiscal year beginning October 1, 2020. The Company is currently evaluating the potential impact that ASU 2016-13 may have on its financial position and results of operations. Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s consolidated financial statements upon adoption. 3. Fair Value of Financial Assets and Liabilities The following tables present information about the Company’s financial assets and liabilities that were subject to fair value measurement on a recurring basis as of September 30, 2018 and 2017 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value: Fair Value Measurements at September 30, 2018 Using: Level 1 Level 2 Level 3 Total (in thousands) Assets: Cash equivalents: Money market funds Commercial paper Corporate bonds Marketable securities: U.S. Treasury notes Commercial paper Corporate bonds Liabilities: Series 1 nonconvertible preferred stock $ 51,025 $ — — — $ 6,987 3,998 42,703 — — 113,885 — 104,629 93,728 $ 229,499 $ — $ — — 51,025 6,987 3,998 — 42,703 — 113,885 — 104,629 — $ 323,227 — — $ — — $ 1,628 1,628 $ 1,628 1,628 $ $ F-16 Assets: Cash equivalents: Money market funds Commercial paper Corporate bonds Marketable securities: U.S. Treasury notes Corporate bonds Commercial paper U.S. Agency bonds Liabilities: Warrant liability Series 1 nonconvertible preferred stock $ $ $ Fair Value Measurements at September 30, 2017 Using: Level 1 Level 2 Level 3 Total (in thousands) $ 19,863 $ — — — $ 29,756 3,000 60,843 — — 150,731 — 12,458 — 4,000 80,706 $ 199,945 $ — $ — — 19,863 29,756 3,000 — 60,843 — 150,731 — 12,458 — 4,000 — $ 280,651 — $ — — $ — $ — — $ 807 $ 762 1,569 $ 807 762 1,569 Cash equivalents at September 30, 2018 and 2017 consist of money market funds, corporate bonds and commercial paper which are readily convertible to cash and with less than 90 days until maturity. During the years ended September 30, 2018, 2017, and 2016, there were no transfers between Level 1, Level 2 and Level 3. As of September 30, 2017, the Company’s warrant liability was comprised of the value of warrants for the purchase of its Series 1 nonconvertible preferred stock. These warrants were financial instruments that might have required a transfer of assets because of the liquidation features in the contract and were therefore recorded as liabilities and measured at fair value. These warrants expired on October 4, 2017, and are therefore no longer outstanding. The outstanding shares of Series 1 nonconvertible preferred stock as of September 30, 2018 and 2017 were also measured at fair value. The fair values of both of these instruments were based on significant inputs not observable in the market, which represented a Level 3 measurement within the fair value hierarchy. The Company utilized a probability-weighted valuation model which takes into consideration various outcomes that may require the Company to transfer assets upon exercise. Changes in the fair values of the warrant liability and Series 1 nonconvertible preferred stock are recognized in other income (expense) in the consolidated statements of operations. The recurring Level 3 fair value measurements of the Company’s warrant liability and Series 1 nonconvertible preferred stock using probability-weighted discounted cash flow include the following significant unobservable inputs: Unobservable Input Probabilities of payout Discount rate Range (Weighted Average) September 30, 2018 2017 0%-70% 0%-65% 5.25% 6.25% F-17 The following table provides a rollforward of the aggregate fair values of the Company’s warrants for the purchase of Series 1 nonconvertible preferred stock and the outstanding Series 1 nonconvertible preferred stock for which fair value is determined by Level 3 inputs: Series 1 Nonconvertible Preferred Stock Warrant Liability Balance, September 30, 2015 Decrease in fair value Balance, September 30, 2016 Warrants exercised Increase in fair value Balance, September 30, 2017 Warrants exercised Warrants expired Increase in fair value Balance, September 30, 2018 (in thousands) $ $ 1,276 (25) 1,251 (549) 105 807 (766) (41) — — $ $ 163 (4) 159 549 54 762 766 — 100 1,628 4. Marketable Securities As of September 30, 2018 and 2017, the fair value of available-for-sale marketable securities, by type of security, was as follows: Commercial paper Corporate bonds U.S. Treasury notes Corporate bonds U.S. Treasury notes Commercial paper U.S. Agency bonds September 30, 2018 Gross Gross Unrealized Unrealized Losses Gains Amortized Cost Fair Value $ 113,885 $ 105,105 42,801 $ 261,791 $ (in thousands) — $ 1 — 1 $ — $ 113,885 (477) 104,629 (98) 42,703 (575) $ 261,217 September 30, 2017 Gross Gross Unrealized Unrealized Losses Gains Amortized Cost Fair Value $ 150,841 $ 60,908 12,458 4,004 $ 228,211 $ (in thousands) 9 $ — — — 9 $ (119) $ 150,731 (65) 60,843 — 12,458 4,000 (4) (188) $ 228,032 As of September 30, 2018 and 2017, marketable securities consisted of investments that mature within one year, with the exception of certain corporate bonds and U.S. Treasury notes, which have maturities between one and three years and an aggregate fair value of $16,389 and $70,038, respectively. F-18 5. Property and Equipment, Net Property and equipment, net consisted of the following as of September 30, 2018 and 2017: Laboratory and office equipment Leasehold improvements Purchased software Furniture Computer equipment Construction in progress Less: Accumulated depreciation and amortization September 30, 2018 2017 (in thousands) $ $ $ 11,110 3,739 1,039 630 331 617 17,466 (9,092) $ 8,374 9,521 3,717 775 595 245 250 15,103 (7,054) 8,049 Depreciation and amortization expense for property and equipment, including assets acquired under capital leases, was $2,518, $2,137 and $1,661 for the years ended September 30, 2018, 2017, and 2016, respectively. 6. Accrued Expenses and Other Current Liabilities and Other Long-Term Liabilities Accrued expenses and other current liabilities and other long-term liabilities consisted of the following as of September 30, 2018 and 2017: Accrued expenses and other current liabilities: Accrued preclinical and clinical expenses Accrued payroll and related expenses Accrued vendor manufacturing Accrued professional fees Accrued other Other long-term liabilities: Uncertain tax positions Accrued rent expense Capital lease obligation Asset retirement obligation 7. Collaboration Agreements AbbVie Collaboration September 30, 2018 2017 (in thousands) 3,617 $ 3,274 1,901 507 593 9,892 $ 1,792 $ 593 293 217 2,895 $ 3,156 2,829 1,130 456 399 7,970 1,175 676 379 180 2,410 $ $ $ $ On November 27, 2006, the Company entered into a Collaborative Development and License Agreement (the “AbbVie Agreement”) with Abbott Laboratories to identify, develop and commercialize HCV NS3 and NS3/4A protease inhibitor compounds, including paritaprevir and glecaprevir. The agreement was assigned by Abbott to AbbVie Inc. on January 1, 2013 in connection with Abbott’s transfer of its research-based pharmaceuticals business to AbbVie. F-19 Under the terms of the AbbVie Agreement, as amended, AbbVie paid the Company upfront license payments and FTE reimbursements to fund research activities. The Company is also eligible to receive milestone payments for the successful development by AbbVie of one or more HCV compounds, as well as annually tiered, per-product royalties on the portion of AbbVie’s net sales of its HCV treatment regimens allocated to the protease inhibitor product. The Company determined that the deliverables under the AbbVie Agreement included (i) the non-exclusive, royalty- free, worldwide research license and the exclusive, royalty-bearing development and commercialization license, (ii) the research services, and (iii) a commitment to participate on a steering committee, all of which were to be delivered over a three-year period. The Company concluded that the license did not have standalone value as it was dependent, in part, upon the Company’s continuing involvement in the HCV protease inhibitor research and its involvement in the joint steering committee. Additionally, the undelivered items, including the Company’s participation in the joint steering committee, which was considered participatory due to its decision making responsibilities, and the research services, did not have VSOE or VOE of fair value. Therefore, the license, the research services, and the joint steering committee participation were treated as a single unit of accounting. Accordingly, all amounts received were deferred, and revenue was recognized using the proportional performance model over the period during which the Company performed research services in connection with the AbbVie Agreement, as amended. Subsequent to the research and evaluation period, which ended in June 2011, all decisions related to the development, commercialization and marketing have been made by AbbVie. The Company has the right to continue to attend the joint steering committee meetings to monitor the development and marketing plans; however, the Company has no decision-making rights. As such, the joint steering committee commitment became protective in nature as of June 16, 2011. During the years ended September 30, 2018, 2017, and 2016, the Company received $15,000, $65,000, and $30,000, respectively, in milestone payments under the AbbVie Agreement as a result of AbbVie’s commercialization regulatory approvals. From commencement of the collaboration through September 30, 2018 the Company has received an upfront license payment, research funding, milestone payments, and preferred stock financing totaling $396,000 under the AbbVie agreement. Since the Company completed all its performance obligations under the AbbVie Agreement by the end of fiscal 2011, any milestone payments earned since then have been recognized as revenue when the associated milestone was achieved by AbbVie. The Company is also receiving annually tiered royalties per Company protease product ranging from ten percent up to twenty percent, or on a blended basis from the low double digits up to the high teens, on the portion of AbbVie’s calendar year net sales of each HCV regimen that is allocated to the protease inhibitor product in the regimen. Beginning with each January 1, the cumulative net sales of a given royalty-bearing protease inhibitor product start at zero for purposes of calculating the tiered royalties on a product-by-product basis. The following table details the royalty tiers associated with cumulative calendar year net sales allocated to each royalty-bearing product as provided in the AbbVie Agreement: Calendar Year Net Sales Royalty Tier (in thousands) up to $500,000 from $500,000 up to $750,000 from $750,000 up to $1,000,000 from $1,000,000 up to $2,500,000 greater than or equal to $2,500,000 (%) 10% 12% 14% 17% 20% Royalties owed to the Company under the agreement can be reduced by AbbVie in certain circumstances, including (i) if AbbVie exercises its right to license or otherwise acquire rights to intellectual property controlled by a third party where a product could not be legally developed or commercialized in a country without the third-party intellectual property right, (ii) where a product developed under the collaboration agreement is sold in a country and not covered by a valid patent claim in such country, and (iii) where sales of a generic product are equal to at least a specified percentage of AbbVie’s market share of its product in a country. F-20 AbbVie’s obligation to pay royalties on a product developed under the agreement expires on a country-by-country basis upon the later of (i) the date of expiration of the last of the licensed patents with a valid claim covering the product in the applicable country, or (ii) ten years after the first commercial sale of the product in the applicable country. Subject to certain exceptions, a party’s rights and obligations under the agreement continue until (i) such time as AbbVie is no longer developing a product candidate or (ii) if, as of the time AbbVie is no longer developing any product candidates, AbbVie is commercializing any other protease inhibitor product, such time as all royalty terms for all covered products have ended. Accordingly, the final expiration date of the agreement is currently indeterminable. Either party may terminate the agreement for cause in the event of a material breach, subject to prior notice and the opportunity to cure, or in the event of the other party’s bankruptcy. Additionally, AbbVie may terminate the agreement for any reason upon specified prior notice. If the Company terminates the agreement for cause or AbbVie terminates without cause, any licenses and other rights granted to AbbVie will terminate and AbbVie will be deemed to have granted the Company (i) a non- exclusive, perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s intellectual property used in any product candidate, and (ii) an exclusive (even as to AbbVie), perpetual, fully-paid, worldwide, royalty-free license, with the right to sublicense, under AbbVie’s interest in any joint intellectual property rights to develop product candidates resulting from covered compounds and to commercialize any products derived from such compounds. Upon the Company’s request, AbbVie will also transfer to the Company all right, title and interest in any related product trademarks, regulatory filings and clinical trials. If AbbVie terminates the agreement for the Company’s uncured breach, the milestone and royalty payments payable by AbbVie may be reduced, the licenses granted to AbbVie will remain in place, the Company will be deemed to have granted AbbVie an exclusive license under the Company’s interest in joint intellectual property, AbbVie will continue to have the right to commercialize any covered products, and all rights and licenses granted to the Company by AbbVie will terminate. NIAID Contract On September 30, 2011, the Company entered into a contract with the National Institute of Allergy and Infectious Diseases (“NIAID”), a division of the National Institutes of Health (“NIH”), providing development funding to the Company for the preclinical and clinical development of a bridged bicyclic antibiotic. The contract was completed in August 2015 upon the Company’s delivery of the study report for the Phase 1 clinical study. The Company recognized revenue under this contract as development services were performed in accordance with the funding agreement. During the year ended September 30, 2016, the Company recognized revenue of $576 under this contract. The Company received aggregate payments of $20,637 under the NIAID contract from its commencement through January 31, 2016. 8. Stockholders’ Equity The Company is authorized to issue 100,000 shares of common stock at a par value of $0.01. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to receive such dividends as may be declared by the board of directors, if any. 9. Series 1 Nonconvertible Preferred Stock and Warrants The Company’s Certificate of Incorporation authorizes the issuance of up to 2,000 shares of Series 1 nonconvertible preferred stock at a par value of $0.01 per share. Holders of Series 1 nonconvertible preferred stock are not entitled to receive dividends. In the event of any liquidation, deemed liquidation, dissolution or winding up of the Company, the Series 1 nonconvertible preferred stockholders are entitled to receive in preference to all other stockholders, an amount equal to $1.00 per share, adjusted for any stock dividends, stock splits or reclassifications. Series 1 F-21 nonconvertible preferred stockholders will not be entitled to vote unless required by the Company pursuant to the laws of the State of Delaware. The Company may redeem the Series 1 nonconvertible preferred stock with the approval of the holders of a majority of the outstanding shares of Series 1 nonconvertible preferred stock at a redemption price of $1.00 per share. The Company must redeem the stock within 60 days of such election. Shares that are redeemed will be retired or canceled and not reissued by the Company. As these shares qualify as a derivative, they are classified as a liability on the Company’s consolidated balance sheet. In October and November 2010, a total of 2,000 warrants to purchase Series 1 nonconvertible preferred stock were issued. The warrants had an expiration date of October 4, 2017. As these warrants were free-standing financial instruments that might have required the Company to transfer assets upon exercise, up to a maximum of $2,000, these warrants were classified as liabilities on the Company’s consolidated balance sheet as of September 30, 2017. The following table summarizes the activity of the warrants to purchase Series 1 nonconvertible preferred stock: Outstanding, as of September 30, 2015 Granted Expired Exercised Outstanding, as of September 30, 2016 Granted Expired Exercised Outstanding, as of September 30, 2017 Granted Expired Exercised Outstanding, as of September 30, 2018 Weighted Average Exercise Price Series 1 Nonconvertible Preferred Stock Warrant s Exercisable (in thousands, except per share data) 1,775 $ — — — 1,775 $ — — (745) 1,030 $ — (52) (978) — 0.01 — — — 0.01 — — 0.01 0.01 — 0.01 0.01 For the years ended September 30, 2018, 2017, and 2016, the remeasurement of the warrants and Series 1 nonconvertible preferred stock resulted in other income (expense) recorded in the consolidated statements of operations of ($59), $(159), and $29, respectively. As of September 30, 2018 and 2017, the total fair value of the Series 1 nonconvertible preferred stock was $1,628 and $762, respectively. During the year ended September 30, 2018, warrants to purchase a total of 978 shares of Series 1 nonconvertible preferred stock were exercised prior to warrant expiration, resulting in the issuance of 970 shares of Series 1 nonconvertible preferred stock. On October 4, 2017, a total of 52 outstanding warrants expired unexercised. The liability associated with these expired warrants was reversed, resulting in other income of $41 during the year ended September 30, 2018. 10. Stock-Based Awards The Company’s 2012 Equity Incentive Plan (the “2012 Plan”) permits the Company to sell or issue awards of common stock or restricted common stock or to grant awards of incentive stock options or nonqualified stock options for the purchase of common stock, restricted stock units, performance units, stock appreciation rights or other cash incentive awards, to employees, members of the board of directors and consultants of the Company. The number of shares of common stock that may be issued under the 2012 Plan is subject to increase by the number of shares forfeited under any options forfeited and not exercised under the 2012 Plan or a predecessor plan, known as F-22 the 1995 Equity Incentive Plan, as well as by the number of shares added on the first day of each fiscal year, which is the lowest amount among the following: (i) 3% of the Company’s outstanding shares of common stock as of that date, (ii) 2,088 shares of common stock, or (iii) an amount determined by the Compensation Committee of the Board of Directors. On October 1, 2018, the number of shares of common stock that might be issued under the 2012 Plan was increased by 583 shares. As of September 30, 2018, 251 shares remained available for future award. The 2012 Plan replaces and is the successor to the 1995 Equity Incentive Plan (the “1995 Plan”). The 1995 Plan provided for the Company to sell or issue awards of common stock or restricted common stock, or to grant awards of incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the board of directors and consultants of the Company. Sales, issuances or grants of shares entitle the holder to purchase common stock from the Company, for a specified exercise price, during a period specified by the applicable equity award agreement. Upon the closing of the Company’s initial public offering, all remaining shares reserved for issuance under the 1995 Plan were transferred to the 2012 Plan and no further awards were or will be made under the 1995 Plan. Under the Company’s Employee Stock Purchase Plan (“ESPP”) a total of 186 shares of common stock are reserved for issuance. As of September 30, 2018, the Company had not commenced any offering under the ESPP and no plan shares have been issued. The Company applies the fair value recognition provisions for all stock-based awards granted or modified. In the case of service-based awards, the compensation cost is recorded over the requisite service period of the award on the straight-line method based on the grant-date fair value. The requisite service period for service-based option awards is generally four years. Options granted under the 2012 Plan to employees generally vest over four years and to non- employee directors over one year, and expire after ten years. Stock Option Valuation The fair value of each stock option award is determined on the date of grant using the Black-Scholes option-pricing model. The Company estimates expected volatility based on a combination of the Company’s historical stock volatility since its March 2013 IPO and the historical volatility of publicly traded peer companies. The Company expects to continue to do so until 2019, at which time the Company will have adequate historical data regarding the volatility of the Company’s traded stock price following our March 2013 IPO. The expected term of the Company’s options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. The expected dividend yield is zero on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. As required by the 1995 Plan and the 2012 Plan, the exercise price for awards granted is not to be less than the fair value of common shares as estimated by the Company as of the date of grant. The relevant data used to determine the value of the stock option awards are as follows, presented on a weighted average basis: Years Ended September 30, 2017 2016 2018 Risk-free interest rate Expected term (in years) Expected volatility Expected dividends 2.29% 6.05 57% 0% 1.97% 6.05 60% 0% 1.77% 6.1 70% 0% As discussed in Note 2, the Company adopted ASU 2016-09 during the year ended September 30, 2018. ASU 2016- 09 intends to simplify several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity awards or liability awards, a choice to recognize gross stock compensation expense with actual forfeitures recognized as they occur, as well as certain classifications on the statement of cash flows. As a result of the adoption, the Company changed its forfeiture rate policy to recognize forfeitures as they occur. Upon adoption, the cumulative impact of this change in policy on retained earnings and deferred tax assets in the consolidated balance sheet was not material. In addition, the consolidated statements of cash flows presents excess tax benefits, if any, as part of cash flows from operating activities. The Company elected F-23 to adopt this change on a prospective basis and, therefore, excess tax benefits from prior periods in the statement of cash flow were not retroactively restated. The adoption of the standard is also expected to create variability in the consolidated statements of operations in years in which the Company is expected to have taxable income, as the tax consequences of settled share-based payments will be recognized in income tax expense when share-based payment awards are settled. The following table summarizes stock option activity, including aggregate intrinsic value for the year ended September 30, 2018: Weighted Average Remaining Contractual Term in years Weighted Average Exercise Price Shares Issuable Under Options (in thousands) 2,298 $ 606 (229) (51) 2,624 $ 30.36 57.96 27.23 48.74 36.65 Aggregate Intrinsic Value (in thousands) 37,821 7.4 $ 7.1 $ 129,115 2,624 $ 1,646 $ 36.65 31.84 7.1 $ 129,115 6.2 $ 88,289 Outstanding as of September 30, 2017 Granted Exercised Forfeited Outstanding as of September 30, 2018 Options vested and expected to vest as of September 30, 2018 Options exercisable as of September 30, 2018 The aggregate intrinsic value of options is calculated as the difference between the exercise price of the options and the fair value of the Company’s common stock. The following tables summarize additional exercise and grant date information: 2018 Years Ended September 30, 2017 (in thousands) 2016 Aggregate intrinsic value of stock options exercised Proceeds to Company from stock options exercised $ $ 14,180 $ 6,243 $ 1,503 $ 1,079 $ 7,705 1,026 Weighted average grant date fair value of options granted (per share) $ 31.84 $ 17.52 $ 19.12 Years Ended September 30, 2018 2017 2016 Performance-Based Options In March 2013, the Company granted to certain executives 167 options that would vest upon the achievement of certain performance-based targets. The aggregate grant date fair value of these options was $2,479. During the years ended September 30, 2017 and 2016, certain performance-based targets were achieved and the Company recorded stock-based compensation expense of $413 and $620, respectively, related to achievement of those targets. No stock-based compensation expense related to these options was recognized during the year ended September 30, 2018 as the performance period for these options ended during the year ended September 30, 2017. Market and Performance-Based Stock Unit Awards The Company awards both performance share units, or PSUs, and relative total stockholder return units, or rTSRUs, to its executive officers. F-24 The PSUs will vest and result in issuance, or settlement, of common shares for each recipient, based upon the recipient’s continued employment with the Company through the settlement date of the award and the Company’s achievement of specified research and development milestones. The requisite service period of the PSUs is generally 2 years. The rTSRUs will vest and result in the issuance of common stock based upon the recipient’s continuing employment with the Company through the settlement date of the award and the relative ranking of the total stockholder return, or TSR, of the Company’s common stock in relation to the TSR of the component companies in the NASDAQ Biotech Index over a two-year period based on a comparison of average closing stock prices in specified periods noted in the award agreement. The number of market-based rTSRUs awarded represents the target number of shares of common stock that may be earned; however, the actual number of shares that may be earned ranges from 0% to 150% or 200% of the target number, depending on the award agreement and the year of the award. The Company used a Monte Carlo model to estimate the grant-date fair value of the rTSRUs. Assumptions and estimates utilized in the calculation of the fair value of the rTSRUs include the risk-free interest rate, dividend yield, expected volatility based on the historical volatility of publicly traded peer companies and the remaining performance period of the award. The table below sets forth the weighted average grant date fair value assumptions used to value the rTSRUs: Years Ended September 30, 2017 2016 2018 Risk-free interest rate Dividend yield Expected volatility Remaining performance period (years) 2.18% 0% 62% 1.83 1.24% 0% 66% 1.99 0.94% 0% 65% 1.93 The following table summarizes PSU and rTSRU activity (at target) for the year ended September 30, 2018: PSUs rTSRUs Weighted Average Grant Date Fair Value per Share Shares Weighted Average Grant Date Fair Value per Share Shares Unvested at September 30, 2017 Granted Vested Cancelled Unvested at September 30, 2018 (in thousands, except per share data) $ $ 70 25 (20) (5) $ 70 34.51 77.93 32.04 32.04 50.97 70 25 (25) — 70 $ 43.07 84.70 37.67 — 59.96 A total of 80% of target PSUs and 192.91% of target rTSRUs granted in December 2015 vested during the year ended September 30, 2018, resulting in the issuance of an aggregate of 68 common shares, net of share withholding. F-25 Restricted Stock Units In November 2016, the Company awarded restricted stock units to its employees, which vest as to 50% of the units in three years and 50% in four years, provided the employee remains employed with the Company at the time of vesting. The fair value of these awards was determined based on the intrinsic value of the stock on the date of grant and is recognized as stock-based compensation expense over the requisite service period. The following table summarizes the restricted stock unit activity for the year to date period ending September 30, 2018: Unvested at September 30, 2017 Granted Vested Cancelled Unvested at September 30, 2018 Weighted Average Grant Date Fair Value per Share Restricted Stock Units (in thousands, except per share data) 110 $ — — (1) 109 $ 30.00 — — 30.00 30.00 Stock-Based Compensation Expense The Company recorded the following stock-based compensation expense for the years ended September 30, 2018, 2017, and 2016: Research and development General and administrative (in thousands) $ $ 6,160 $ 9,685 15,845 $ 4,078 $ 8,993 13,071 $ 2,882 6,472 9,354 Years Ended September 30, 2017 2016 2018 2018 Years Ended September 30, 2017 (in thousands) 2016 Stock options rTSRUs Restricted stock units PSUs $ $ 12,694 $ 1,721 789 641 15,845 $ 10,442 $ 1,267 694 668 13,071 $ 8,661 693 — — 9,354 As of September 30, 2018, the Company had an aggregate of $30,064 of unrecognized stock-based compensation cost, which is expected to be recognized over a weighted average period of 2.2 years. F-26 11. Net Income Per Share Basic and diluted net income per common share was calculated as follows for the years ended September 30, 2018, 2017, and 2016: Basic net income per share: Numerator: Net income Denominator: Years Ended September 30, 2018 2016 2017 (in thousands, except per share data) $ 71,956 $ 17,710 $ 21,666 Weighted average common shares outstanding — basic 19,255 19,066 18,929 Net income per share common share — basic $ 3.74 $ 0.93 $ 1.14 Diluted net income per share: Numerator: Net income Denominator: $ 71,956 $ 17,710 $ 21,666 Weighted average common shares outstanding — basic Dilutive effect of common stock equivalents Weighted average common shares outstanding — diluted Net income per share common share — diluted Anti-dilutive common stock equivalents excluded from above 19,255 19,066 18,929 1,395 341 295 20,650 19,407 19,224 $ 3.48 $ 0.91 $ 1.13 295 2,161 1,475 The impact of certain common stock equivalents were excluded from the computation of diluted net income per common share attributable to common stockholders for the years ended September 30, 2018, 2017, and 2016, because those options had an anti-dilutive impact due to the assumed proceeds per share using the treasury stock method being greater than the average fair value of the Company’s common shares for those periods. As of September 30, 2018, 2017, and 2016, the Company excluded unvested performance stock unit awards from the calculation of diluted net income per common share as these awards contain performance conditions that would not have been achieved as of the end of each reporting period had the measurement period ended as of that date. 12. Commitments and Contingencies Leases The Company has two leases located in Watertown, Massachusetts. The first lease, for office and laboratory space at 500 Arsenal Street, was effective from fiscal 2011 to 2018. During the year ended September 30, 2015, the Company amended the lease to expand the rented space and extend the lease term through September 2022. Payment escalations specified in the lease agreement, as amended, are accrued such that rent expense is recognized on a straight-line basis over the term of occupancy. The amended lease also included a $598 tenant improvement allowance from the landlord, which was accounted for as a capital lease obligation. In connection with the 500 Arsenal Street lease, the Company has a total outstanding letter of credit in the amount of $608 as of September 30, 2018 and 2017, collateralized by a money market account. As of September 30, 2018 and 2017, the Company classified the money market account as long-term restricted cash. F-27 The second lease, for office space, located at 400 Talcott Avenue, was entered into on September 27, 2018 with a lease term that extends through August 1, 2024. The lease includes a free rent period as well as escalating rent payments over the course of the lease. The net amount of these escalations and the free rent period will be accrued and recognized as rent expense on a straight-line basis over the term of the lease. For the years ended September 30, 2018, 2017, and 2016, the Company recognized rent expense of $2,033, $2,025, and $2,025, respectively, in the consolidated statements of operations. Future minimum lease payments under both leases as of September 30, 2018 are as follows: Years Ended September 30, Operating Leases Capital Leases 2019 2020 2021 2022 2023 Thereafter Total $ $ $ (in thousands) 2,209 2,728 2,803 2,684 608 519 11,551 $ 86 93 101 99 — — 379 Intellectual Property Licenses In 2012 the Company entered into a non-exclusive intellectual property license agreement with a licensor of research technology under which the Company was required to pay the third party licensor an upfront license fee and additional fees up to the third anniversary of the agreement. In addition, the Company was required to pay annual maintenance fees for each year that the agreement remained in effect. During the years ended September 30, 2017 and 2016, the Company paid $115 and $120, respectively, under the agreement. The license agreement was terminated during the year ended September 30, 2017. During the year ended September 30, 2013, the Company amended an existing license agreement to extend rights to patents previously licensed for one of its programs for use in its HCV research. Under the license, the Company is obligated to pay milestones totaling up to $5,000 plus low single-digit royalties, for the development and regulatory approval of each HCV product outside of the Company’s collaboration with AbbVie and any other collaboration it may enter into in the future with a partner that has already licensed these patents. During the year ended September 30, 2016, the Company paid a $500 milestone payment under this amended agreement as a result of the Company’s filing to commence clinical development of its own HCV product candidate which was recorded as a research and development expense. The Company stopped further development of its own HCV product candidate in 2016 and there were no further payments made under this license. Litigation and Contingencies Related to Use of Intellectual Property From time to time, the Company may become subject to legal proceedings, claims and litigation arising in the ordinary course of business. The Company currently is not a party to any threatened or pending litigation. However, third parties might allege that the Company or its collaborators are infringing their patent rights or that the Company is otherwise violating their intellectual property rights. Such third parties may resort to litigation against the Company or its collaborators, which the Company has agreed to indemnify. With respect to some of these patents, the Company expects that it will be required to obtain licenses and could be required to pay license fees or royalties, or both. These licenses may not be available on acceptable terms, or at all. A costly license, or inability to obtain a necessary license, would have a material adverse effect on the Company’s financial condition, results of operations or cash flows. The Company accrues contingent liabilities when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. F-28 Indemnification Agreements In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to customers, vendors, lessors, business partners, and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from services to be provided to the Company, or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and its executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. In addition, the Company maintains officers and directors insurance coverage. 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 has not accrued any liabilities related to such obligations in its financial statements as of September 30, 2018 and 2017. 13. Income Taxes Income before income taxes for all periods presented is from domestic operations, which are the Company’s only operations. During the years ended September 30, 2018, 2017, and 2016, the Company recorded income tax expense as follows: 2018 Years Ended September 30, 2017 (in thousands) 2016 Current income tax (expense) benefit: Federal State Deferred income tax (expense) benefit: Federal State $ (16,449) $ (10,078) $ (12,233) (956) (2,858) (813) (2,245) 387 $ (21,165) $ 1,503 151 2,136 159 (9,237) $ (10,894) A reconciliation of the U.S. federal statutory income tax rate to the Company’s effective tax rate is as follows: Years Ended September 30, 2017 2016 2018 Federal statutory income tax rate State taxes, net of federal benefit Federal research and development tax credit Remeasurement of net deferred tax assets Share-based compensation Other Effective income tax rate 24.5% 2.6 (5.2) 4.2 (2.8) (0.6) 22.7% 35.0% 2.7 (7.4) — 4.5 (0.5) 34.3% 35.0% 2.7 (3.8) — 2.6 (3.0) 33.5% F-29 Net deferred tax assets as of September 30, 2018 and 2017 consisted of the following: Deferred tax assets: Share-based compensation Accrued expenses Capitalized research and development expenses Unrealized loss Other temporary differences Total deferred tax assets $ Valuation allowance Net deferred tax assets Deferred tax liabilities: Depreciation Prepaid expenses Total deferred tax liabilities Net deferred income tax assets (liabilities) $ September 30, 2018 2017 (in thousands) $ 7,372 756 223 139 828 9,318 — 9,318 (798) (145) (943) $ 8,375 7,899 1,001 1,199 67 1,171 11,337 — 11,337 (1,026) (188) (1,214) 10,123 The net deferred tax asset is presented as a long-term asset on the consolidated balance sheets. Estimates used to prepare income tax expense are based on the Company’s initial analysis of the Tax Act enacted in December 2017. Given the complexity of the act, anticipated guidance from the U. S. Treasury regarding implementation of the act, and potential for additional guidance from the SEC and the Financial Accounting Standards Board related to the act, these estimates may be adjusted during fiscal 2019 to reflect any such guidance provided. While the Company believes it has adequately provided for all tax positions during the year ended September 30, 2018, amounts asserted by taxing authorities could materially differ from the Company’s accrued positions as a result of uncertain and complex application of tax law and regulations. Additionally, the recognition and measurement of certain tax benefits include estimates and judgment by management. Accordingly, the Company could record additional provisions or benefits for U.S. federal and state tax matters in future periods as new information becomes available. After consideration of all the evidence, both positive and negative, the Company determined that no valuation allowance was needed for all or a portion of its deferred tax assets as of September 30, 2018 because it is more likely than not that the deferred tax assets will be realized. In subsequent periods, the Company may determine that it is more likely than not that the deferred tax assets will not be realized and thus, a valuation allowance may be recorded against all or any portion of its deferred tax assets on the Company’s consolidated balance sheet with a corresponding non-cash charge to income tax expense in the consolidated statements of operations. 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 subject to examination by federal and state jurisdictions, where applicable. The Company’s tax years are still open under statute from 2014 to the present. Earlier years may be examined to the extent that tax credit or net operating loss carryforwards are used in future periods. During 2018, the Company received notice of examination by the Internal Revenue Service (“IRS”) for the year ending September 30, 2016. The Company received and agreed to a notice of proposed adjustment from the IRS which was paid in September 2018, the amount of which was immaterial to the financial statements. The Company is in the process of finalizing the completion of the IRS audit. During October 2018, the Company received notice of examination by the Massachusetts Department of Revenue (“DOR”) for the years ending September 30, 2015 and September 30, 2016. No adjustments have been proposed to date. The Company has not received notice of examination by any other jurisdictions for any other tax year open under statute. F-30 Uncertain tax positions represent tax positions for which reserves have been established. The Company’s policy is to record interest and penalties related to uncertain tax positions as part of income tax expense. A reconciliation of the beginning and ending amount of uncertain tax positions is summarized as follows: September 30, 2018 2017 Beginning Balance Additions based on tax positions for the current period Additions based on tax positions for prior periods Reductions for tax positions of prior periods Ending Balance $ $ $ (in thousands) 1,175 563 — (59) $ 1,679 745 134 355 (59) 1,175 The Company does not expect that its uncertain tax position will materially change within the next twelve months. 14. 401(k) Plan The Company has a 401(k) plan. This plan covers substantially all employees who meet minimum age and service requirements. During the years ended September 30, 2018, 2017, and 2016 the Company recognized $852, $712 and $513, respectively, of expense related to its contributions to this plan. 15. Selected Quarterly Financial Data (unaudited) Quarterly financial information for fiscal 2018 and 2017 is presented in the following table: 2018 Quarter Ended December 31, 201 7 September 30, 201 8 $ Revenue (1) Operating expenses Other income (expense) Income tax (expense) Net income Net income per common share — basic(3) $ Net income per common share — diluted(3) $ Revenue (2) Operating expenses Other income (expense) Income tax (expense) benefit Net income (loss) Net income (loss) per common share — basic(3) Net income (loss) per common share — diluted(3) $ $ $ 2017 Quarter Ended December 31, 201 6 September 30, 201 7 March 31, 2018 June 30, 2018 (in thousands, except per share data) 57,262 $ 34,622 1,338 (3,690) 20,288 1.05 $ 0.97 $ 44,049 $ 27,190 1,066 (5,370) 12,555 0.65 $ 0.61 $ 38,109 $ 23,732 960 (3,644) 11,693 0.61 $ 0.59 $ March 31, 2017 June 30, 2017 (in thousands, except per share data) 7,511 $ 20,640 600 4,103 (8,426) 8,959 $ 18,465 549 3,565 (5,392) 10,417 $ 17,463 524 1,542 (4,980) (0.26) $ (0.28) $ (0.44) $ (0.26) $ (0.28) $ (0.44) $ 67,205 32,753 1,429 (8,461) 27,420 1.41 1.30 75,927 21,632 660 (18,447) 36,508 1.91 1.86 (1) During the first quarter of 2018, the Company recognized $15,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in Japan. F-31 (2) During the fourth quarter of 2017, the Company recognized $65,000 in milestone revenue from AbbVie upon achievement of commercialization regulatory approval of AbbVie’s glecaprevir-containing regimen in the U.S. and the EU. The earnings per share amounts for each quarter may not sum to the fiscal year amounts due to rounding and the effect of weighting. (3) F-32 Corporate Headquarters Enanta Pharmaceuticals, Inc. 500 Arsenal Street Watertown, MA 02472 Investor Inquiries Investor Inquiries (including requests for a copy of Enanta’s Form 10-K, available free of charge) should be directed to: Enanta Pharmaceuticals, Inc. 500 Arsenal Street Watertown, MA 02472 Attention: Investor Relations Phone: 617-607-0800 The 2018 Annual Report on Form 10-K and other investor information are available in the Investors section of Enanta’s website at www.enanta.com. Independent Registered Public Accounting Firm PricewaterhouseCoopers LLP 101 Seaport Boulevard, Suite 500 Boston, MA 02210 Legal Counsel Foley Hoag LLP Seaport West 155 Seaport Boulevard Boston, Massachusetts 02210 Transfer Agent Computershare Trust Company, N.A. 250 Royall Street Canton, MA 02021 Stock Listing NASDAQ Global Select Market: ENTA Web Site www.enanta.com Management Team Jay R. Luly, Ph.D. President, Director and Chief Executive Officer Nathalie Adda, M.D. Senior Vice President and Chief Medical Officer Nathaniel S. Gardiner, J.D. Senior Vice President and General Counsel Paul J. Mellett Senior Vice President, Finance & Administration and Chief Financial Officer Timothy D. Ocain, Ph.D. Senior Vice President, New Product Strategy & Development Yat Sun Or, Ph.D. Senior Vice President, Research & Development and Chief Scientific Officer Board of Directors Bruce L.A. Carter, Ph.D. Non-Executive Chairman of the Board, Enanta Pharmaceuticals, Inc. Former President and Chief Executive Officer, ZymoGenetics, Inc. Stephen Buckley, Jr. Retired partner of Ernst & Young LLP George S. Golumbeski, Ph.D. President and Member of the Board of Directors, GRAIL, Inc. Jay R. Luly, Ph.D. President and Chief Executive Officer, Enanta Pharmaceuticals, Inc. Kristine Peterson Former Chief Executive Officer, Valeritas, Inc. Lesley Russell, MBChB, MRCP Former Chief Medical Officer, Cephalon, Inc. and other companies Terry C. Vance Private consultant and former biotechnology venture capital investor HCV NASH /PBC HBV RSV Enanta Pharmaceuticals, Inc 500 Arsenal Street Watertown, MA 02472 www.enanta.com Cover graphics: Molecular model represents glecaprevir, Enanta’s protease inhibitor contained in AbbVie’s HCV regimens marketed as MAVYRET™ (U.S.) MAVIRET™ (ex-U.S.) 

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