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Aeglea BioTherapeutics, Inc.

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FY2021 Annual Report · Aeglea BioTherapeutics, Inc.
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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 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 December 31, 2021
☐☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from

to

Commission file number 001-37722

AEGLEA BIOTHERAPEUTICS, INC.

(Exact name of Registrant as specified in its charter)

Delaware
(State or Other Jurisdiction of
Incorporation or Organization)
805 Las Cimas Parkway
Suite 100
Austin, TX
(Address of Principal Executive Offices)

46-4312787
(I.R.S. Employer
Identification No.)

78746
(Zip Code)

Registrant’s Telephone Number, including area code: (512) 942-2935
Securities registered pursuant to Section 12(b) of the Exchange Act:

Title of each class

Trading Symbol(s)

Common Stock, $0.0001 Par Value Per Share

AGLE

Name of each exchange on which registered
The Nasdaq Stock Market LLC
)
(Nasdaq Global Market)
(

Securities registered pursuant to Section 12(g) of the Exchange 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 ☐ No ☒
Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Exchange Act.

Yes ☐ No ☒

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities

Exchange Act of 1934 during the preceding 12 months (or for such 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 ☐

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 ☐

Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting

company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and
“emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ☐
Non-accelerated filer ☒

Accelerated filer
☐
Smaller reporting company ☒
Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for

complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness

of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C 7262(b)) by the registered public
accounting firm that prepared or issued its audit report. ☐

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒
The aggregate market value of the voting stock held by non-affiliates of the Registrant on June 30, 2021 (the last business day of the

Registrant’s second fiscal quarter), based upon the closing price of $6.96 of the Registrant’s common stock as reported on The Nasdaq Global
Market, was approximately $337.4 million.

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

Class
Common stock, $0.0001 par value per share

Outstanding at February 24, 2022
49,362,080 shares

g

y

Portions of the Registrant’s Definitive Proxy Statement (“Proxy Statement”) relating to the 2022 Annual Meeting of Stockholders will be
filed with the Commission within 120 days after the end of the Registrant’s 2021 fiscal year and is incorporated by reference into Part III of this
Report.

Audit Firm ID: 238

Auditor Name: PricewaterhouseCoopers LLP

Auditor Location: New York, NY

DOCUMENTS INCORPORATED BY REFERENCE

TABLE OF CONTENTS

Page

PART I
Item 1. Business..............................................................................................................................................................
4
Item 1A.Risk Factors ........................................................................................................................................................ 26
Item 1B.Unresolved Staff Comments ............................................................................................................................... 72
Item 2. Properties ............................................................................................................................................................ 72
Item 3. Legal Proceedings............................................................................................................................................... 72
Item 4. Mine Safety Disclosures...................................................................................................................................... 72
PART II
Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity

Securities .......................................................................................................................................................... 73
Item 6.
[Reserved] ........................................................................................................................................................... 75
Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations............................... 76
Item 7A.Quantitative and Qualitative Disclosures About Market Risk .............................................................................. 84
Item 8. Financial Statements and Supplementary Data .................................................................................................. 85
Item 9. Changes in and Disagreements with Accountants on Accounting and Financial Disclosure.............................. 113
Item 9A.Controls and Procedures..................................................................................................................................... 113
Item 9B.Other Information ................................................................................................................................................ 114
Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections ................................................................ 114
PART III
Item 10. Directors, Executive Officers and Corporate Governance .................................................................................. 115
Item 11. Executive Compensation..................................................................................................................................... 115
Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters ............ 115
Item 13. Certain Relationships and Related Transactions, and Director Independence................................................... 115
Item 14. Principal Accountant Fees and Services............................................................................................................. 115
PART IV
Item 15. Exhibits and Financial Statement Schedules ...................................................................................................... 116
Item 16. Form 10-K Summary ........................................................................................................................................... 118
SIGNATURES .............................................................................................................................................................. 119

2

NOTE ABOUT FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K, or Annual Report, contains forward-looking statements within the meaning of
Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and section 27A of the Securities
Act of 1933, as amended, or the Securities Act. All statements contained in this Annual Report other than statements of
historical fact, including statements regarding our future results of operations and financial position, business strategy,
market size, potential growth opportunities, nonclinical and clinical development activities, efficacy and safety profile of our
product candidates, potential therapeutic benefits and economic value of our product candidates, use of net proceeds
from our public offerings, our ability to maintain and recognize the benefits of certain designations received by product
candidates, the timing and results of nonclinical studies and clinical trials, commercial collaboration with third parties, and
our ability to recognize milestone and royalty payments from commercialization agreements, the expected impact of the
COVID-19 pandemic on our operations, and the receipt and timing of potential regulatory designations, approvals and
commercialization of product candidates, are forward-looking statements. The words “believe,” “may,” “will,” “potentially,”
“estimate,” “continue,” “anticipate,” “predict,” “target,” “intend,” “could,” “would,” “should,” “project,” “plan,” “expect,” and
similar expressions that convey uncertainty of future events or outcomes are intended to identify forward-looking
statements, although not all forward-looking statements contain these identifying words.

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those

described in Item 1A, “Risk Factors” and elsewhere in this Annual Report. Moreover, we operate in a very competitive and
rapidly changing environment, and new risks emerge from time to time. It is not possible for our management to predict all
risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of
factors, may cause actual results to differ materially from those contained in any forward-looking statements we may
make. In light of these risks, uncertainties, and assumptions, the forward-looking events and circumstances discussed in
this Annual Report may not occur and actual results could differ materially and adversely from those anticipated or implied
in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the

expectations reflected in the forward-looking statements are reasonable, we cannot guarantee that the future results,
levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or
occur. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this
report to conform these statements to actual results or to changes in our expectations, except as required by law. You
should read this Annual Report with the understanding that our actual future results, levels of activity, performance and
events and circumstances may be materially different from what we expect.

Unless the context indicates otherwise, as used in this Annual Report, the terms “Aeglea,” “the Company,” “we,”
“us,” and “our” refer to Aeglea BioTherapeutics, Inc., a Delaware corporation, and its consolidated subsidiaries taken as a
whole, unless otherwise noted. “Aeglea” and all product candidate names are our common law trademarks. This Annual
Report contains additional trade names, trademarks and service marks of other companies, which are the property of their
respective owners. We do not intend our use or display of other companies’ trade names, trademarks or service marks to
imply a relationship with, or endorsement or sponsorship of us by, these other companies.

3

ITEM 1. BUSINESS

Overview

PART I

We are a clinical-stage biotechnology company redefining the potential of human enzyme therapeutics to benefit

people with rare metabolic diseases with limited treatment options. We believe our expertise in enzyme science,
bioengineering and rare disease drug development coupled with an approach focused on diseases with unmet medical
needs enables us to develop medicines with the potential to transform the lives of patients and families with rare
metabolic diseases.

We employ a distinctive platform to fuel our innovative pipeline of human enzymes, which we believe reduces key

risks throughout the development process and provides a greater likelihood of clinical success and commercial adoption.

Our mission is to provide transformative therapies to patient communities who have inadequate or no therapeutic

options available to address these debilitating diseases. Driven by this purpose and urgent patient need, we have taken a
focused approach to the selection and development of novel assets into clinical evaluation that is guided by defined
strategic considerations:

-

-

Clear, urgent unmet medical need

Rigorous preclinical data and strong scientific rationale

- Mechanistic opportunity to create or enhance enzymatic activity through novel engineering

- Meaningful and sustainable commercial opportunities

-

Potential to be first in class or best in class, with little competition

Our Strategy

We continually advance toward our vision to become the premier human enzyme company, dedicated to the

discovery, development, and commercialization of next generation human enzyme therapeutics that address defined
unmet medical needs and transform lives. With a strategic approach, we are:

•

•

•

Pursuing opportunities for novel human enzyme-based therapeutics in areas where regulation of
abnormal metabolism may deliver meaningful medical benefits.

Our focus is on rare metabolic diseases where there is a plausible link between disease development,
progression, and metabolite levels including amino acids, opening an opportunity for novel engineered enzyme
therapeutics. Grounded by our enzyme expertise, we purposefully select programs to advance into clinical
development based on strong biological rationale and robust preclinical evidence where potential therapy can
transform patient outcomes.

Leveraging patient identification capabilities to maximize the value of our product candidates.

An integral part of our overall strategy is to identify patient populations with the greatest potential to benefit
from our metabolism focused approach. This approach is designed to increase the probability of clinical
success, accelerate development timelines, and improve our ability to identify the appropriate patients and
healthcare professionals, and represents a key element of our launch planning efforts.

Progressing our most advanced product candidates, pegzilarginase and AGLE-177, through clinical
development and into commercialization.

We believe pegzilarginase is the only therapeutic in clinical development that addresses the underlying drivers
of disease progression for the treatment of Arginase 1 Deficiency. We reported topline data for pegzilarginase
for our global pivotal PEACE (Pegzilarginase Effect on Arginase 1 Deficiency Clinical Endpoints) Phase 3 trial
in December 2021 and are continuing to evaluate pegzilarginase in two long term extension studies in the
PEACE Phase 3 trial and Phase 1/2 open-label extension study for the treatment of Arginase 1 Deficiency.
PEACE achieved the primary endpoint of a statistically significant 80% reduction in plasma arginine from
baseline after 24 weeks of treatment with pegzilarginase (p value <0.0001) and normal plasma arginine levels
(40-115μM) were achieved in 90.5% of pegzilarginase treated patients. In addition, plasma arginine reduction
was accompanied by a positive trend in Gross Motor Function Measure Part E (GMFM-E) (p value =0.1087),

4

one of two key clinical assessments of patient mobility that were evaluated equally in the statistical analysis.
Based on these results and the entirety of data from the pegzilarginase program, we plan to submit a Biologics
License Application, or BLA, to the U.S. Food and Drug Administration, or FDA, in the second quarter of 2022
and our commercial partner in Europe and certain countries in the Middle East, Immedica Pharma AB,
Immedica, plans to submit an EMA application during 2022.

We believe AGLE-177 has the potential to be the first approved therapy that addresses the underlying drivers
of disease progression for the treatment of Homocystinuria due to cystathionine β-synthase (CBS) deficiency,
also known as Classical Homocystinuria. We are evaluating AGLE-177 in a Phase 1/2 clinical trial to assess
safety and efficacy in patients with Homocystinuria. We expect to report initial clinical data from the Phase 1/2
clinical trial in the second half of 2022.

•

Concurrently developing multiple product candidates with the goal of approval and commercialization
in the US and internationally.

We are building a diversified portfolio with multiple human enzyme therapeutic candidates, with complementary
opportunities to evaluate enzyme solutions for patient communities with few options today. With this multi-
asset strategy, we are leveraging organizational efficiencies and economies of scale, and are investing in our
internal research, development, and commercialization capabilities to continually enrich our portfolio.

In developing programs for diseases with substantial unmet medical need, we seek opportunities with
meaningful commercial potential and with limited or no current competition. We intend to maximize the
commercial opportunity and value for each of our product candidates by pursuing regulatory approval in the
United States and other select regions on our own or with commercial partners. In the United States, we are
building the commercial capabilities and infrastructure to successfully launch pegzilarginase, if approved.
Additionally, we licensed the pegzilarginase product rights to Immedica for commercialization in the European
Economic Area, United Kingdom, Switzerland, Andorra, Monaco, San Marino, Vatican City, Turkey, Saudi
Arabia, United Arab Emirates, Qatar, Kuwait, Bahrain, and Oman. We retain all other intellectual property
rights for pegzilarginase in the United States and other regions. We retain worldwide intellectual property rights
for all other product candidates in our portfolio.

Our Focus—Enzyme-based Therapeutic Opportunities

We leverage our enzyme engineering capabilities to focus on developing therapeutics to treat diseases with

abnormally high levels of metabolites. Many of these diseases arise due to genetic mutations causing abnormal
metabolism. Metabolism refers to a network of life sustaining chemical reactions in the body. Metabolism follows specific
pathways that are comprised of various biochemical reactions generally catalyzed by proteins known as enzymes.
Enzymes accelerate complex reactions and serve as key regulators of metabolic pathways by responding to changes in
the cell’s environment or signals from other cells.

An in-depth understanding of abnormal metabolic pathways is crucial to developing therapies that may address
various disease states, including rare metabolic diseases. Our differentiated protein engineering expertise has allowed us
to develop a new generation of human enzyme therapies enhancing specific properties of existing enzymes or generating
enzymes with novel activity. By leveraging engineered human enzymes to reduce harmful levels of metabolites, including
amino acids, we believe we can deliver transformative therapeutics for multiple diseases where enzyme approaches have
not previously been considered.

Rare Metabolic Disease and Arginase 1 Deficiency Overview

The incidence of a single metabolic abnormality typically occurs in fewer than one per 100,000 live births. While
rare, most of these diseases have severe or life-threatening characteristics and many metabolic abnormalities are likely to
be under-diagnosed. Current treatment options for these disorders are limited. While diet modification or nutrient
supplementation can provide some benefit to patients, several metabolic abnormalities have been treated successfully
with enzyme therapy.

We are targeting Arginase 1 Deficiency with our lead product candidate, pegzilarginase. Arginase 1 Deficiency is a

serious progressive disease with significant morbidity and early mortality. This disease is caused by deficiency of a key
arginine metabolizing enzyme, Arginase 1. This leads to two important harmful metabolic effects: (1) the accumulation of
high levels of arginine and other arginine derived metabolites, and (2) an impairment of the urea cycle which leads to
elevation of ammonia levels, especially at times of stress. The high plasma arginine level is believed to be the key driver

5

of the spasticity, developmental delays, and seizures that develop in early childhood and progress over time. The
impairment of the urea cycle also means that these patients are at risk of episodic and sometimes persistent
hyperammonemia, which causes irritability, nausea, and vomiting with potential to progress to brain swelling,
encephalopathy, reduced life expectancy, and death.

There are currently no effective treatment options or approved therapeutic agents specifically indicated for Arginase
1 Deficiency that treat the underlying driver of this disease. Current disease management practice includes a medical diet
with protein restriction, ammonia scavengers, and adjustments to essential amino acids. Medical literature suggests that
disease progression can be slowed with strict adherence to dietary protein restriction, which often includes the use of
specially formulated supplements. Such dietary modification has been shown to partially reduce plasma arginine levels,
but generally does not consistently reach the range stipulated by medical guidelines. Therefore, this disease management
approach is generally inadequate to treat the majority of patients, unpalatable, and difficult to manage. Ammonia-
scavenging drugs such as RAVICTI (glycerol phenylbutyrate) and BUPHENYL (sodium phenylbutyrate) are used to
manage elevated ammonia levels. In some cases, liver transplantation has been utilized to treat Arginase 1 Deficiency;
however, this intervention is available only to a small fraction of patients and carries significant procedural risk.

The lack of effective treatment options that directly address the cause of Arginase 1 Deficiency supports the need for

a therapy that manages the harmful metabolic effects caused by accumulation of high levels of arginine and other
arginine-derived metabolites (also referred to as guanidino compounds). The development of an arginine-reducing
therapeutic introduced early in a patient’s life could potentially minimize the exposure to the neurotoxic effects of elevated
arginine and its metabolites, as well as potentially enabling improved protein intake. Reduction and maintenance of
plasma arginine levels to within levels recommended by medical guidance for an extended period during the
pegzilarginase dosing schedule has the potential to slow or halt the progression of the disease, thereby offering the
potential for more normal growth and development in these patients.

Arginase 1 Deficiency is a rare disorder, and disease prevalence has not been well established in the medical
literature. Based on a genetic prevalence analysis commissioned by us, we estimate that the Arginase 1 Deficiency
population is greater than 2,500 patients in the global addressable markets and greater than 1,150 patients in the
territories with regulatory and launch plans underway. The genetic prevalence-based methodology has the ability to
account for misdiagnosis of the disease and to address limitations in newborn screening methodology, including naturally
low arginine levels in newborns and lack of geographic availability or standardization of testing. Presently, only 34 U.S.
states screen for Arginase 1 Deficiency, and screening in Europe is not universal. Because the manifestations of Arginase
1 Deficiency may overlap with other disorders such as hereditary spastic paraplegia, cerebral palsy or epilepsy, the
prevalence of Arginase 1 Deficiency may be underestimated in regions that do not mandate newborn screening for this
disease. We continue to make progress in patient identification, and insights from these efforts serve as a foundation for
our commercialization strategy and execution.

ff

Homocystinuria Overview

Homocystinuria is an inherited disorder of methionine metabolism that results in elevated homocysteine and its
dimer, homocystine, or tHcy, in plasma and urine. This leads to a broad range of serious consequences with irreversible
morbidity due to lens dislocation, skeletal abnormality, vascular complication and intellectual dysfunction, as well as
reduced life expectancy.

Classical Homocystinuria is the most common form of the disease with over 160 genetic mutations identified. These

mutations adversely impact CBS enzyme activity to a variable degree impacting the level of tHcy and the response to
some treatments.

The goal of treatment for Homocystinuria is to maintain consistent plasma tHcy levels below the currently defined

biochemical targets. Current disease management is lifelong and includes dietary protein (methionine) restriction with
amino acid replacement either alone or with pyridoxine (vitamin B6), and betaine supplementation, which is generally
insufficient to effectively control all but the mildest form of the disease. As is the case with other medical diets, adherence
is challenging and nutrient supplementation is often necessary to prevent deficiencies that arise from a lack of normal
natural dietary protein intake. Some Classical Homocystinuria patients respond to very high doses of pyridoxine (vitamin
B6) resulting in decreases of methionine and homocysteine and are considered B6-responsive. However, many patients
are unable to achieve target levels of tHcy through diet and/or pyridoxine alone and thus betaine is recommended as an
adjunctive treatment. Although considered to be generally well tolerated, some subjects dislike the taste and/or fishy odor,
and often large doses are required, both of which may lead to poor compliance. Additionally, a risk of hypermethioninemia
and cerebral edema has been reported.

6

The natural history of Classical Homocystinuria is understood and documented in the medical literature. Due to the

variability of effect of different mutations and response to treatment, some subjects have severe childhood-onset
multisystem disease, while others may be asymptomatic into adulthood; likewise the spectrum and severity of disease is
also variable. Patients can present with Homocystinuria in childhood with a significant event, such as thrombosis, ocular
lens dislocation, severe myopia, skeletal fracture, and/or other manifestations such as developmental delay or cognitive
impairment. In adulthood, the most common presentation is with a thrombotic event. Untreated, the disease results in
higher mortality, with B6-non-responsive patients having a 23% mortality by the age of 30. Medical literature has reported
that outcomes are better in patients with lower tHcy with fewer complications and improved intellectual function. While no
long-term prospective data exists, recent guidelines based on expert review recommend a target tHcy of less than 100
micromolar, or μM, for those that are unresponsive to pyridoxine, although some physicians aim for even lower targets
with a combination approach.

ff

There is a significant unmet need for patients in whom tHcy levels remain high, increasing the risk of complications.

In addition, many patients find compliance with diet to be restrictive and cannot maintain tHcy levels within the target
range. The lack of effective interventions to directly address the consequences of Classical Homocystinuria support the
need for a therapy to reduce the harmful effects of persistently raised tHcy. The introduction of a tHcy reducing
therapeutic could ultimately prevent major thrombotic, ocular and skeletal complications, offering the potential to reduce
morbidity and mortality in these patients.

While newborn screening is universally implemented in the U.S. (and widely available elsewhere), for technical
reasons it only detects a proportion of cases. We conducted an analysis of published literature and other data sources to
assess the estimated prevalence of Classical Homocystinuria and determined the population in global addressable
markets may exceed 30,000 patients, including B6-responsive and B6-non-responsive patients, with approximately
15,000 to 18,000 estimated B6-non-responsive patients (of which approximately 6,000 to 6,600 are estimated in the key
commercial markets of the United States, France, Germany, Italy, Spain, and the United Kingdom).

Impacts of the COVID-19 Pandemic

The extent of the impact of COVID-19 on our operational and financial performance will continue to depend on
certain developments, including the duration and spread of the outbreak, new variants, the vaccination and booster rate,
impact on our clinical studies, employee or industry events, and effect on our suppliers and manufacturers, all of which
are uncertain and cannot be predicted. The COVID-19 pandemic and its adverse effects have been prevalent in many of
the locations where we, our CROs, suppliers or third-party business partners conduct business and as a result, we have
experienced disruptions and may continue to experience more pronounced disruptions in our operations. With respect to
our clinical trials, we have had patients miss scheduled dosings and experienced delays in enrollment. We may continue
to experience such delays as well as delays in distribution of clinical trial materials, study monitoring and data analysis
that could materially adversely impact our business, results of operations and overall financial performance in future
periods. Specifically, we have experienced and expect to continue to experience impact from changes in how we and
companies worldwide conduct business due to the COVID-19 pandemic, including but not limited to restrictions on travel
and in-person meetings, disruptions in the supply chain including the raw materials needed for manufacturing, animals
used in research, delays in site activations and enrollment of clinical trials, and prioritization of hospital resources toward
pandemic effort. We may also experience delays in review by the FDA and comparable foreign regulatory agencies for
our product candidates. As of the filing date of this Annual Report on Form 10-K, the extent to which COVID-19 may
impact our financial condition, results of operations or guidance is uncertain. The effect of the COVID-19 pandemic will not
be fully reflected in our results of operations and overall financial performance until future periods. See Risk Factors for
further discussion of the possible impact of the COVID-19 pandemic on our business.

7

Our Development Programs

The following summarizes our most advanced product candidates, each of which is described in further detail below.

g

(cid:7)(cid:21)(cid:19)(cid:13)(cid:21)(cid:9)(cid:17)

(cid:8)(cid:12)(cid:22)(cid:12)(cid:9)(cid:21)(cid:10)(cid:14)

(cid:7)(cid:14)(cid:9)(cid:22)(cid:12)(cid:1)(cid:28)(cid:26)(cid:29)

(cid:7)(cid:14)(cid:9)(cid:22)(cid:12)(cid:1)(cid:30)

(cid:2)(cid:20)(cid:20)(cid:21)(cid:19)(cid:24)(cid:12)(cid:11)

(cid:6)(cid:23)(cid:21)(cid:1)(cid:7)(cid:15)(cid:20)(cid:12)(cid:16)(cid:15)(cid:18)(cid:12)

(cid:7)(cid:12)(cid:13)(cid:25)(cid:15)(cid:16)(cid:9)(cid:21)(cid:13)(cid:15)(cid:18)(cid:9)(cid:22)(cid:12)
(cid:2)(cid:27)(cid:19)(cid:21)(cid:24)(cid:13)(cid:28)(cid:17)(cid:1)(cid:38)(cid:1)(cid:5)(cid:17)(cid:18)(cid:21)(cid:15)(cid:21)(cid:17)(cid:24)(cid:15)(cid:32)

(cid:2)(cid:4)(cid:5)(cid:3)(cid:27)(cid:28)(cid:32)(cid:32)
(cid:7)(cid:25)(cid:23)(cid:25)(cid:15)(cid:32)(cid:28)(cid:29)(cid:21)(cid:24)(cid:30)(cid:27)(cid:21)(cid:13)

(cid:2)(cid:4)(cid:5)(cid:3)(cid:27)(cid:30)(cid:29)(cid:31)
(cid:4)(cid:32)(cid:28)(cid:29)(cid:21)(cid:24)(cid:30)(cid:27)(cid:21)(cid:13)

(cid:12)(cid:24)(cid:16)(cid:21)(cid:28)(cid:15)(cid:22)(cid:25)(cid:28)(cid:17)(cid:16)(cid:1)
(cid:10)(cid:13)(cid:27)(cid:17)(cid:1)(cid:5)(cid:21)(cid:28)(cid:17)(cid:13)(cid:28)(cid:17)(cid:28)

Pegzilarginase in Arginase 1 Deficie

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yncy

Overview: Our lead product candidate, pegzilarginase, is a recombinant human Arginase 1 that enzymatically
degrades the amino acid arginine. We engineered pegzilarginase with modifications that enhance the stability and
arginine-degrading activity of the enzyme in human plasma. For Arginase 1 Deficiency, which is a rare progressive
disease, we believe pegzilarginase may reduce the harmful effects caused by the accumulation of high levels of arginine
and other arginine-derived metabolites.

PEACE - Global Pivotal Phase 3 Study of Pegzilarginase in Patients with Arginase 1 Deficiency: We completed the

double-blind placebo-controlled portion of our PEACE Phase 3 trial in December 2021 and are currently conducting a
long-term extension study to evaluate the safety and efficacy of pegzilarginase. The trial is believed to be the first-ever
investigative therapy that directly addresses the high arginine levels that are believed to be the key drivers of this
devastating disease for patients with Arginase 1 Deficiency.

PEACE is a single, global, randomized, double-blind, placebo-controlled trial designed to assess the effects of

treatment with pegzilarginase versus placebo over 24 weeks with a primary endpoint of statistically significant plasma
arginine reduction from baseline. The primary endpoint assessed the effectiveness of pegzilarginase in lowering plasma
arginine levels, given the evidence that plasma arginine control has the potential to improve the clinical status and slow
disease progression in patients with Arginase 1 Deficiency. Secondary endpoints included clinical outcome assessments
focused primarily on mobility, including the key secondary endpoints consisting of GMFM-E and 2 Minute Walk Test, or
2MWT, in addition to safety and pharmacokinetics.

The pivotal trial enrolled 32 patients aged two years and older, who had plasma arginine levels greater than 250 μM

and a baseline deficit in at least one clinical response assessment. Patients enrolled in the trial were randomized on a
two-to-one basis to receive weekly infusions of pegzilarginase (0.1 mg/kg starting dose), or placebo for the double-blind
treatment period. Dose adjustments during this period were allowed in order to optimize plasma arginine control for levels
outside the range of 50 to 150 μM. Patients remained on current disease management for the duration of the PEACE
Phase 3 trial. Upon completion of the 24-week treatment period, patients were eligible to participate in a long-term
extension study of pegzilarginase, with all 31 patients who completed the double-blind period continuing into the long-term
extension study and switching to subcutaneous (sc) administration. We will review the (sc) administration data with the
health authorities from our PEACE Phase 3 long-term extension trial and Phase 2 open-label extension trial to determine
the best path for preferred route(s) of administration.

In December 2021, we announced the topline results for the PEACE Phase 3 trial. The primary endpoint was met

with a statistically significant reduction in plasma arginine from baseline after 24 weeks of treatment with pegzilarginase (p

8

value <0.0001). In addition, plasma arginine reduction was accompanied by a positive trend in GMFM-E (p value
=0.1087), one of two key clinical assessments of patient mobility that were evaluated equally in the statistical analysis.
Topline results are summarized as follows:

•

•

•

PEACE achieved the primary endpoint of the clinical trial and demonstrated a highly statistically significant
80% reduction in mean plasma arginine in pegzilarginase-treated patients (p value <0.0001). Importantly,
normal plasma arginine levels (40-115μM) were achieved in 90.5% of pegzilarginase treated patients
compared to none of the patients in the placebo arm.
For the key secondary endpoints, improvements in walking, running and jumping were captured using GMFM-
E, and the distance a patient walks in two minutes was captured using the 2MWT. The least squares mean
GMFM-E score improved by 4.2 units for pegzilarginase-treated patients and worsened by 0.4 units in the
placebo arm (p value =0.1087; 95% CI [-1.1, 10.2]), establishing a positive trend in this mobility assessment.
The least squares mean 2MWT distance increased 7.4 meters in pegzilarginase-treated patients and 1.9
meters in the placebo arm (p value =0.5961; 95% CI [-15.6, 26.7]).
Pegzilarginase was well-tolerated and safety data were consistent with results from the Phase 1/2 and open-
label extension clinical trials. Most Treatment-Emergent Adverse Events (TEAEs) were mild or moderate in
severity. Common TEAEs occurring in >=15% of subjects in treatment and placebo arms included vomiting,
increased ammonia, cough, hyperammonemia, nausea, abdominal pain, pyrexia, and decreased appetite. With
the exception of vomiting, cough, and pyrexia, each event occurred at a lower rate compared to placebo. There
were four subjects in each treatment arm who experienced serious adverse events with hyperammonemia
being the most frequent occurring in three subjects (19%) in the pegzilarginase group compared to four
subjects (36%) in the placebo group.

Prior to the results of the PEACE study being available, the FDA and EMA indicated that data from the PEACE
Phase 3 trial showing plasma arginine reduction in conjunction with improvements in clinically meaningful aspects of the
disease may be sufficient to support a marketing application for pegzilarginase in Arginase 1 Deficiency. Based on the
results of the PEACE Phase 3 trial and the entirety of data from the pegzilarginase program, we plan to submit a BLA to
the FDA in the second quarter of 2022 seeking full approval of pegzilarginase and Immedica plans to submit an EMA
application during 2022.

Phase 1/2 Open-Label Study of Pegzilarginase in Patients with Arginase 1 Deficiency: We completed a Phase 1/2

clinical trial for the treatment of patients with Arginase 1 Deficiency to assess the safety and clinical activity of
pegzilarginase. The Phase 1/2, multi-center, single-arm, open-label trial of pegzilarginase enrolled 16 adult and pediatric
patients with Arginase 1 Deficiency on background therapy in the U.S., Canada, and Europe, exceeding the initial target
of 10 patients. The Phase 1/2 dosing was completed in February 2019, with 14 patients completing 8 weeks of repeat
dosing. The trial investigated both single ascending doses and repeated dosing. The primary endpoint of the trial was
safety and tolerability of intravenous administration of pegzilarginase in patients with Arginase 1 Deficiency. The trial also
evaluated the pharmacokinetic and pharmacodynamic effects of repeated doses of pegzilarginase on plasma arginine
levels. Additionally, patients who completed the repeat dose part of the Phase 1/2 trial were eligible to enroll in a long-
term open-label extension study, with 14 out of 14 patients who completed the Phase 1/2 trial enrolling into the extension
study. One patient later discontinued for non-medical reasons.

Phase 2 Open-Label Extension Study to Evaluate the Long-Term Safety, Tolerability and Effects of Pegzilarginase

O

in Patients with Arginase 1 Deficiency Who Received Treatment in a Previous Study: After completing the repeat dose
portion of the Phase 1/2 study and at least four weeks of post-treatment observation, patients were allowed to continue
treatment with pegzilarginase, including subcutaneous (sc) administration, by enrolling in a long-term open-label
extension study. All 13 eligible patients enrolled in the Phase 2 open-label extension trial switched to subcutaneously
dosed pegzilarginase. This study is expected to provide important insights into the longer-term clinical effects of reducing
plasma arginine.

We announced 20-week and 56-week data on 14 and 13 patients, respectively, from our completed Phase 1/2 trial

and ongoing Phase 2 open-label extension trial for pegzilarginase in patients with Arginase 1 Deficiency. In each of the
interim data announcements, we reported all patients continued to demonstrate marked and sustained reductions in
plasma arginine following 20-weeks and 56-weeks of pegzilarginase administration and 79% (11 of 14) and 85% (11 of
13) of patients were clinical responders, respectively, based on a clinical meaningful improvement in one or more of three
complementary mobility assessments. For GMFM-E, the mean change from baseline at the 56-week analyses was 6
units. When analyzing the subset of patients who had a baseline deficit (equal to seven patients), the mean change for
GMFM-E was 9 units. For the 6 Minute Walk Test, or 6MWT, the mean change from baseline at the 56-week analyses
was 45 meters. Pegzilarginase was well tolerated and the rates of treatment-related adverse events decreased over time.
Serious adverse events included hypersensitivity and hyperammonemia, which were infrequent, expected, and managed
with standard treatment and did not lead to any patient discontinuations.

y p

9

Additionally, we announced 104-week mobility data from our completed Phase 1/2 trial and ongoing Phase 2 open-

label extension trial on the nine patients that had completed assessments through the period. The mean change from
baseline for GMFM-E and the 6MWT was 7 units and 38 meters, respectively, at the 104-week analyses. The clinical
outcome assessment represented continued improvements over baseline after two years on treatment with pegzilarginase
in the context of pa p grogressive disease.

Regulatory Designations: We have obtained Orphan Drug Designation from the FDA and EMA, as well as Fast

Track and Breakthrough Therapy Designations from the FDA, for pegzilarginase for the treatment of patients with
Arginase 1 Deficiency. In addition, the FDA granted a Rare Pediatric Disease designation for pegzilarginase for the
treatment of Arginase 1 Deficiency. This designation by the FDA confirms our eligibility to receive a Rare Pediatric
Disease priority review voucher upon approval of a qualifying BLA for pegzilarginase if approved before October 1, 2026.

ff

Licensing: We licensed to Immedica the rights to the commercialization of pegzilarginase in the European Economic

Area, United Kingdom, Switzerland, Andorra, Monaco, San Marino, Vatican City, Turkey, Saudi Arabia, United Arab
Emirates, Qatar, Kuwait, Bahrain, and Oman. The license and supply agreement, or Immedica Agreement, we entered
into with Immedica includes a non-refundable upfront payment of $21.5 million from Immedica and development services
provided to Immedica, up to $3.0 million. Under the terms of the Immedica Agreement, we are eligible to receive
additional payments of up to approximately $125.0 million in regulatory and commercial milestone payments, assuming an
exchange rate of $1.13 to €1.00. Additionally, we are entitled to receive royalties in the mid-20 percent range on net sales
of the product in countries included in the Immedica Agreement. We will continue to be responsible for certain clinica
development activities and the manufacturing of pegzilarginase and will retain commercialization rights in the United
States and the rest of the world.

ff

l

AGLE-177 in Homocystinuria

Overview: Our product candidate, AGLE-177, is a novel PEGylated, or polyethylene glycol modified, human enzyme
engineered to degrade free homocysteine and its dimer homocystine. We engineered AGLE-177 by directed mutagenesis
of amino acid residues into human cystathionine γ-lyase, resulting in an enzyme that has high substrate specificity for
homocysteine as a monomer and dimer. For Classical Homocystinuria patients, we believe AGLE-177 may ameliorate the
adverse impact of CBS enzyme deficiency in the transsulfuration pathway by providing an alternate pathway for
enzymatic degradation of high plasma total homocysteine levels.

Phase 1/2 Open-Label Study of AGLE-177 in Patients with Homocystinuria: We are currently conducting a Phase
1/2 clinical trial for the treatment of patients with Homocystinuria to assess the safety and clinical activity of AGLE-177.
The primary objective of the trial is to evaluate the safety and tolerability of AGLE-177 in subjects with Homocystinuria. As
a secondary objective, the trial will also characterize the pharmacokinetics and pharmacodynamics relationship of AGLE-
177 after single and multiple doses following intravenous and
subcutaneous administration, as well as the magnitude of
change in plasma tHcy. We plan to enroll 16 to 20 patients diagnosed with Homocystinuria, aged 12 years or older and
have plasma homocysteine levels greater than 80 μM. Patients will be dosed once weekly for four weeks, with four
patients in each of the four dosing cohorts and an option to include a fifth cohort as needed.

ff

We announced the dosing of the first patient in June 2021 and subsequently completed dosing in the 0.15 mg/kg

intravenous cohort in the Phase 1/2 clinical trial in 2021. AGLE-177 was well tolerated with no safety concerns and data
from the first cohort showed reductions in total homocysteine in all patients. Following the results from the first cohort, we
are advancing to the next cohort at a once weekly subcutaneous dose of 0.45mg/kg and have begun dosing patients in
this cohort. We expect to report initial clinical data from the Phase 1/2 trial in the second half of 2022.

Regulatory Designations: We have obtained Orphan Drug Designation from the FDA and EMA for AGLE-177 for the

treatment of patients with Homocystinuria. In addition, the FDA granted a Rare Pediatric Disease designation for AGLE-
177 for the treatment of Homocystinuria. This designation by the FDA enables the potential to receive a Rare Pediatric
Disease priority review voucher upon approval of a qualifying BLA for AGLE-177 if approved before October 1, 2026.
Given recent developments relating to the COVID-19 global pandemic, we have been taking steps to minimize potential
impacts of COVID-19 related disruptions on our Phase 1/2 clinical trial. We currently have sufficient supply available for
completion of our ongoing clinical trials. Patient screening and dosing have been impacted by COVID-19, and there is
uncertainty as to the cadence of screenings as sites are impacted by COVID-19 related restrictions, including staff
members contracting COVID-19 and limiting operations.

ff

10

Preclinical Pipeline

AGLE-325 in Cystinuria

y

Cystinuria is a rare genetic disease characterized by frequent and recurrent kidney stone formation requiring
multiple procedural interventions, and by an increased risk of chronic kidney disease. Cystinuria occurs due to genetic
mutations in amino acid transporters that lead to increased amounts of cystine in the urine. This results in high cystine
concentrations in the urine and formation of kidney stones. As such, we engineered and optimized AGLE-325 to reduce
plasma cystine and cysteine levels with accompanying reductions in urine cystine concentrations as an approach to inhibit
both cystine crystal and kidney stone formation.

We presented preclinical data on a precursor molecule to AGLE-325 demonstrating reduced kidney stone formation

in a preclinical model of Cystinuria. Given the compelling preclinical data and the limitations of current disease
management approaches, we plan to advance AGLE-325 through IND-enabling studies in 2022.

P
Research Programs

A significant number of metabolic diseases remain without an effective treatment. Our in-house team of scientists

and clinicians assess whether human enzymes are available to decrease the potential disease promoting metabolites in
diseases with unmet medical need. If a human enzyme is not available, our team of protein engineers will introduce
changes into alternative human enzyme to alter their specificity for the proposed disease-causin
generation of lead molecules using this approach enables us to investigate the preclinical impact of these molecules in
animal models of the disease, and with supporting positive data, additional engineering may be performed to ensure the
clinical candidate meets manufacturing requirements and has characteristics that are compatible with the patient needs.

g metabolite. The

ff

Intellectual Property

Our success depends in part on our ability to obtain and maintain patents and other forms of intellectual property

rights, including in-licenses of intellectual property rights of others, for our product candidates, methods used to
manufacture our product candidates and methods for treating patients using our product candidates, as well as our ability
to preserve our trade secrets, to prevent third parties from infringing upon our proprietary rights and to operate without
infringing upon the proprietary rights of others.

Patents

We own three granted US Patents directed towards compositions of pegzilarginase as well as to various mutations

in the arginase 1 amino acid sequence. These patents will expire in 2029 in the absence of any patent term extension.
There are also granted patents directed towards the composition of pegzilarginase in Europe and Japan, as well as
pending patent applications in the US, Europe and Canada. We also own a pending US application and pending foreign
counterpart applications directed towards the use of pegzilarginase in the treatment of arginase 1 deficiency. Any patents
that issue from these applications will expire in 2038, absent any patent term adjustment or patent term extension. We
further own a granted US patent and pending US and foreign counterpart applications directed towards the use of
pegzilarginase in the treatment of cancer. This patent and any further patents that issue from these applications will expire
in 2037, absent any patent term adjustment or patent term extension. We also own a pending US application and pending
foreign counterpart applications directed towards the manufacturing of pegzilarginase, and any patents that issue from
these applications will expire in 2040, absent any patent term adjustment or patent term extension.

We are the exclusive licensee of a granted US patent, a pending US application and pending foreign counterpart

applications directed towards the AGLE-177 program which covers recombinant human enzymes that degrade the amino
acid homocysteine and homocystine. Any patents that issue from these applications will expire in 2038 absent any patent
term adjustment or patent term extension. We also own a pending PCT patent application directed to a method of
treatment for homocystinuria. Any patents that issue from this application will expire in 2040, absent any patent term
adjustment or patent term extension.

We also are the exclusive licensee of US patents and applications, as well as foreign counterpart patents and
applications, directed towards modified cystathionine-γ-lyase (CGL) enzymes with activity to degrade plasma cystine and
cysteine and the use thereof. These patents and any further patents issued from these applications will expire variously
between 2034 and 2039, absent any patent term adjustment or patent term extension.

We are also the exclusive licensee of US patents and foreign counterpart patents and applications directed towards
modified cystathionine-y-lyase (CGL) enzymes with activity to degrade the amino acid methionine. These patents and any

11

further patents that issue from these applications will expire in 2034, absent any patent term adjustment or patent term
extension. We own four granted US patents and granted foreign counterpart patents, as well as pending US and foreign
patent applications directed towards the compositions of the methioninase. These patents and any further patents that
issue from these applications will expire in 2031, absent any patent term adjustment or patent term extension.

ff

We aim to take advantage of all of the intellectual property rights that are available to us and believe that this

comprehensive approach will provide us with proprietary positions for our product candidates, where available.

Patents may extend for varying periods according to the date of patent filing or grant and the legal term of patents in

various countries where patent protection is obtained. The actual protection afforded by a patent, which can vary from
country to country, depends on the type of patent, the scope of its coverage and the availability of legal remedies in the
country.
y

We also protect our proprietary information by requiring our employees, consultants, contractors and other advisors
to execute nondisclosure and assignment of invention agreements upon commencement of their respective employment
or engagement. In addition, we also require confidentiality or service agreements from third parties that receive our
confidential information or materials.

Licensing

In December 2013, our wholly owned subsidiaries AECase, Inc. and AEMase, Inc. each entered into an exclusive,

worldwide license agreement, including the right to grant sublicenses, with the University of Texas at Austin, or the
University, for certain intellectual property owned by the University related to cystinase and methioninase. In January
2017, we and the University entered into an Amended and Restated Patent License Agreement, or the Restated License,
which consolidated the two license agreements, revised certain obligations, and licensed additional patent applications
and invention disclosures to us. The Restated License was amended in August 2017, December 2017, and December
2018 to revise diligence milestones and license additional patent applications, including our program candidates under the
AGLE177 and Cystinuria programs.

With respect to each program candidate covered by the Restated License, we could be required to pay the

University up to $6.4 million in milestone payments based on the achievement of certain development milestones,
including clinical trials and regulatory approvals, the majority of which are due upon the achievement of later development
milestones, including a $5.0 million payment due on regulatory approval of a product and a $0.5 million payment payable
on final regulatory approval of a product for a second indication. In addition, we are required to pay the University a low
single digit royalty on worldwide-net sales of products covered under the Restated License, together with a revenue share
on non-royalty consideration received from sublicensees. The rate of the revenue share ranges from 6.5% to 25%,
depending on the date the sublicense agreement is signed. The term of the Restated License continues until the
expiration of the last to expire of the patents licensed thereunder. The University may terminate the agreement under
certain circumstances, including for a breach by us that is not cured within 30 or 60 days of notice (depending on the type
of breach), or if we or any of our affiliates or sublicensees participate in any proceeding to challenge the licensed patent
rights (unless, with respect to sublicensees, we terminate the applicable sublicense). As of December 31, 2021, we have
paid $0.3 million under these license agreements.

Grant Agreement

In June 2015, we entered into a Cancer Research Grant Contract, or the Grant Contract, with the Cancer Prevention

and Research Institute of Texas, or CPRIT, under which CPRIT awarded us a grant not to exceed $19.8 million to be
used to develop novel cancer treatments by exploiting the unique metabolism of cancer cells. The contract ended in May
2018 with the full $19.8 million in grant proceeds collected and recognized as revenue under the Grant Contract.

Pursuant to the Grant Contract, we granted to CPRIT a non-exclusive, irrevocable, royalty-free, perpetual, worldwide

license to any technology and intellectual property resulting from the grant-funded activities and any other intellectual
property that is owned by us and necessary for the exploitation of the technology and intellectual property resulting from
the grant-funded activities, or the Project Results, for and on behalf of CPRIT and other governmental entities and
agencies of the State of Texas and private or independent institutions of higher education located in Texas for education,
research and other non-commercial purposes only. The terms of the Grant Contract require that we pay tiered royalties in
the low- to mid-single digit percentages on revenues from sales and licenses of products or services that are based upon,
utilize, are developed from or materially incorporate Project Results. Such royalties reduced to less than one percent after
a mid-single-digit multiple of the grant funds have been repaid to CPRIT in royalties. Such royalties are payable for so
long as we have marketing exclusivity or patents covering the applicable product or service (or twelve years from first
commercial sale of such product or service in certain countries if there is no such exclusivity or patent protection).

12

If we abandon patent applications or patents covering Project Results in certain major market countries, CPRIT can,

at its own cost, take over the prosecution and maintenance of such patents and is granted a non-exclusive, irrevocable,
royalty-free, perpetual license with right to sublicense in such country to the applicable Project Results. We are required to
use diligent and commercially reasonable efforts to commercialize at least one commercial product or service or otherwise
bring to practical application the Project Results. If CPRIT notifies us of our failure with respect to the foregoing, and such
failure is not owing to material safety concerns, then, at CPRIT’s option, the applicable Project Results would be
transferred to CPRIT and CPRIT would be granted a non-exclusive license to any other intellectual property that is owned
by us and necessary for the exploitation of the Project Results, and CPRIT, at its own cost, can commercialize products or
services that are based upon, utilize, are developed from or materially incorporate Project Results. CPRIT’s option is
subject to our ability to cure any failures identified by CPRIT within 60 days and a requirement to negotiate in good faith
with us with respect to an alternative commercialization strategy for a period of 180 days.

Competition

While we believe that our expertise in enzyme science, bioengineering, and rare disease drug development provide

us with competitive advantages, we face potential competition from many different sources, including major
pharmaceutical companies, specialty pharmaceutical companies, biotechnology companies, and ultimately biosimilar and
generic drug companies. Recent advances in gene-based medicine, such as gene therapy have resulted in market
approvals of DNA and RNA-based therapeutics in certain rare genetic diseases. However, no gene therapy drugs have
demonstrated clinical success in the type of complex diseases targeted by our research approach with novel enzyme
therapeutics. Any product candidates that we successfully develop and commercialize will compete with existing therapies
and new therapies that may become available in the future.

The acquisition or licensing of pharmaceutical products is also very competitive, and a number of more established

companies, which have acknowledged strategies to license or acquire products, may have competitive advantages as
may other emerging companies taking similar or different approaches to product acquisitions. These established
companies may have a competitive advantage over us due to their size, cash flows, and institutional experience.

We compete in the segments of the pharmaceutical, biotechnology and other related markets that address rare

genetic disease.

With respect to pegzilarginase for Arginase 1 Deficiency, there are currently no effective treatment options or
approved therapeutics agents that address the underlying cause of the disease and we are not aware of any other
therapeutics that do so in clinical development. It is possible that competitors may produce, develop, and commercialize
therapeutics, or utilize other approaches to treat Arginase 1 Deficiency. The current disease management practice for
patients with Arginase 1 Deficiency includes one or more of the following: dietary protein restriction, essential amino acid
supplementation, and ammonia scavengers. The dietary restrictions with amino acid supplementation are intended to
reduce plasma arginine levels, while ammonia scavengers (such as Horizon Therapeutics’ RAVICTI (glycerol
phenylbutyrate) and BUPHENYL (sodium phenylbutyrate)) are used to manage elevated ammonia levels in patients with
urea cycle disorders. From a clinical development perspective, Acer Therapeutics Inc. is developing a taste-masked,
immediate-release formulation of sodium phenylbutyrate for the treatment of hyperammonemia, and in 2021 they signed a
worldwide development and commercialization agreement with Relief Therapeutics Holding AG, and have disclosed a
PDUFA target action date of June 5, 2022. A small number of companies have an interest in the role of arginine depletion
in other therapeutic areas, but we are not aware of any active preclinical or clinical development activities in Arginase 1
Deficiency. In the oncology field, Polaris Group has conducted numerous clinical trials of ADI-PEG 20, an enzyme derived
from mycoplasma, and Athenex has conducted preclinical research with PT01, a PEGylated genetically modified human
arginase enzyme, in numerous tumor models.

With respect to AGLE-177 for Homocystinuria, there is currently one FDA-approved prescription therapy for the

treatment of Homocystinuria and several medical foods for the
ff
The primary treatment goal in patients with Homocystinuria is to maintain consistent plasma tHcy levels below the
currently defined biochemical targets. Current disease management practice for the majority of Homocystinuria patients
consists of dietary restriction, vitamin B6, vitamin B12, folate supplementation, medical foods, and betaine.
CYSTADANE® (betaine anhydrous for oral solution) was approved by the FDA in 1986 for the treatment of
Homocystinuria, and Recordati Rare Diseases Inc. currently own the North American marketing rights to this product.
Medical foods are manufactured by Breckenridge Pharmaceutical, Inc. and Upsher-Smith Laboratories, LLC.

dietary management of individuals with Homocystinuria.

We are also aware of a limited number of investigational therapies for the treatment of Homocystinuria. Travere

Therapeutics Inc. is focused on the development of pegtibatinase, an enzyme replacement therapy in patients with
Homocystinuria due to cystathionine β-synthase deficiency. Travere released topline data in December 2021 from its
Phase 1/2 study of pegtibatinase which showed a 55% reduction in homocysteine at the highest dose cohort (1.5mg/kg,
2x/week). We are aware of three other investigational therapies in preclinical stages. The first is Synlogic, studying
SYNB1353, an oral synthetic biotic platform that consumes toxic metabololites in the GI tract. Synlogic presented pre-

13

clinical data on this molecule at the International Congress of Inborn Errors of Metabolism, or ICIEM, in November 2021.
The second is Codexis, studying CDX-6512, an oral methionine-gamma-lyase enzyme therapy. Codexis also presented
pre-clinical data on this molecule at ICIEM in November 2021. Additionally, Erytech Pharma SA has a product candidate
for Homocystinuria in preclinical development. It is possible that competitors may produce, develop, and commercialize
therapeutics, or utilize other approaches to treat Homocystinuria.

Many of our competitors may have significantly greater financial resources and expertise in research and

development, manufacturing, nonclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing
approved medicines than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result
in even more resources being concentrated among a smaller number of our competitors. These competitors also compete
with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and
patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our
programs. Smaller or early stage companies may also prove to be significant competitors, particularly through
collaborative arrangements with large and established companies.

The key competitive factors affecting the success of all of our product candidates, if approved, are likely to be their

efficacy, safety, convenience, price, the effectiveness of assays or tests that are essential to identifying an appropriate
patient population, which we refer to as diagnostics, in guiding the use of related therapeutics, the level of biosimilar
competition and the availability of reimbursement from government and other third-party payors.

Manufacturing

We currently contract with third parties for the process development, manufacturing, and testing of our product

candidates for nonclinical and clinical studies and intend to do so for future studies as well. We may qualify additional
manufacturers to provide potential alternative sources for the drug substance and fill-and-finish services for
pegzilarginase, AGLE-177, and other pipeline candidates as the compounds progress through clinical development. We
believe we have sufficient supplies of pegzilarginase for our ongoing Phase 3 pivotal trial in conjunction with the open-
label extension study for the treatment of patients with Arginase 1 Deficiency and sufficient supplies of AGLE-177 for our
planned Phase 1/2 clinical trial for the treatment of patients with Homocystinuria.

The Diosynth Agreement

In November 2018, we entered into a master services agreement, or the Diosynth Agreement, with Fujifilm Diosynth
Biotechnologies UK Limited, Fujifilm Diosynth Biotechnologies Texas, LLC, and Fujifilm Diosynth Biotechnologies U.S.A.,
Inc., collectively, Fujifilm. Under the Diosynth Agreement, Fujifilm provides research, development, testing and
manufacturing services of certain of our products, which are or will be designated as programs pursuant to scope of work
agreements. The fees for such services are or will be set out in each scope of work agreement. We may pay additional
fees in consideration of certain research and development and technical consultancy services in relation to the
procurement, testing and management of consumables, subcontracted work (including delivery of material to and from
such subcontractors), process-specific equipment (including installation and qualification thereof), modifications and
special waste. Either party may terminate the Diosynth Agreement by giving six months written notice to the other party,
provided there are no uncompleted programs existing at the date such notice is given, or upon material breach. We may
also be required to pay Fujifilm cancellation fees in the event that we decide to terminate any scope of work prior to its
completion, calculated as a percentage of the fees payable under the applicable scope of work agreement. Additionally,
upon providing written notice, we may cancel certain stages or programs for convenience, and Fujifilm may terminate for
certain unforeseen technical errors.

Government Regulation and Product Approval

Government authorities in the United States, at the federal, state and local level, and in other countries and

jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing,
manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution,
marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for
obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent
compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial
time and financial resources.

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FDA approval process

In the United States, pharmaceutical products are subject to extensive regulation by the United States Food and
Drug Administration, or the FDA. The Federal Food, Drug, and Cosmetic Act, or the FDC Act, and other federal and state
statutes and regulations, govern, among other things, the research, development, testing, manufacture, storage,
recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting,
sampling, and import and export of pharmaceutical products. Biological products used for the prevention, treatment, or
cure of a disease or condition of a human being are subject to regulation under the FDC Act, except the section of the
FDC Act which governs the approval of new drug applications, or NDAs. Biological products are approved for marketing
under provisions of the Public Health Service Act, or PHSA, via a Biologics License Application, or BLA. However, the
application process and requirements for approval of BLAs are very similar to those for NDAs, and biologics are
associated with similar approval risks and costs as drugs. Failure to comply with applicable U.S. requirements may
subject a company to a variety of administrative or judicial sanctions, such as clinical hold, FDA refusal to approve
pending NDAs or BLAs, warning or untitled letters, product recalls, product seizures, total or partial suspension of
production or distribution, injunctions, fines, civil penalties, and criminal prosecution.

Biological product development for a new product or certain changes to an approved product in the United States

typically involves preclinical laboratory and animal tests, the submission to the FDA of an investigational new drug
application, or IND, which must become effective before clinical testing may commence, and adequate and well-controlled
clinical trials to establish the safety and effectiveness of the drug for each indication for which FDA approval is sought.
Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary
substantially based upon the type, complexity, and novelty of the product or disease.

Preclinical tests include laboratory evaluation of product chemistry, formulation, and toxicity, as well as animal trials
to assess the characteristics and potential safety and efficacy of the product. The conduct of some preclinical tests must
comply with federal regulations and requirements, including good laboratory practices. The results of preclinical testing
are submitted to the FDA as part of an IND along with other information, including information about product chemistry,
manufacturing and controls, and a proposed clinical trial protocol. Long term preclinical tests, such as animal tests of
reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the
submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has neither
commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin. Clinical
trials involve the administration of the investigational biologic to healthy volunteers or patients under the supervision of a
qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with
good clinical practice, or GCP, an international standard meant to protect the rights and health of patients and to define
the roles of clinical trial sponsors, administrators, and monitors; as well as (iii) under protocols detailing the objectives of
the trial, the parameters to be used in monitoring safety, and the effectiveness criteria to be evaluated. Each protocol
involving testing on U.S. patients and subsequent protocol amendments must be submitted to the FDA as part of the IND.

The FDA may order the temporary, or permanent, discontinuation of a clinical trial at any time, or impose other

sanctions, if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or
presents an unacceptable risk to the clinical trial patients. The trial protocol and informed consent information for patients
in clinical trials must also be submitted to an institutional review board, or IRB, for approval. An IRB may also require the
clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or
may impose other conditions.

Clinical trials to support BLAs for marketing approval are typically conducted in three sequential phases, but the
phases may overlap. In Phase 1, the initial introduction of the biologic into healthy human subjects or patients, the product
is tested to assess safety, metabolism, pharmacokinetics, pharmacological actions, side effects associated with
increasing doses, and, if possible, early evidence on effectiveness. Phase 2 usually involves trials in a limited patient
population to determine the effectiveness of the drug or biologic for a particular indication, dosage tolerance, and optimal
dosage, and to identify common adverse effects and safety risks. If a compound demonstrates evidence of effectiveness
and an acceptable safety profile in Phase 2 evaluations, Phase 3 trials are undertaken to obtain the additional information
about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to
permit the FDA to evaluate the overall benefit-risk relationship of the drug or biologic and to provide adequate information
for the labeling of the product. In most cases, the FDA requires two adequate and well-controlled Phase 3 clinical trials to
demonstrate the efficacy of the biologic. A single Phase 3 trial may be sufficient in rare instances where: (1) the trial is a
large multicenter trial demonstrating internal consistency and a statistically very persuasive finding of a clinically
meaningful effect on mortality, irreversible morbidity or prevention of a disease with a potentially serious outcome and
confirmation of the result in a second trial would be practically or ethically impossible or (2) the trial has a statistically
significant finding in combination with other confirmatory evidence.

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In addition, the manufacturer of an investigational drug in a Phase 2 or Phase 3 clinical trial for a serious or life-

threatening disease is required to make available, such as by posting on its website, its policy on evaluating and
responding to requests for expanded access to such investigational drug.

After completion of the required clinical testing, a BLA is prepared and submitted to the FDA. FDA approval of the
BLA is required before marketing of the product may begin in the United States. The BLA must include the results of all
preclinical, clinical, and other testing and a compilation of data relating to the product’s pharmacology, chemistry,
manufacture, and controls. The cost of preparing and submitting a BLA is substantial. The submission of most BLAs is
additionally subject to a substantial application user fee, and the applicant under an approved BLA is also subject to an
annual program fee for each prescription product. These fees are typically increased annually. The FDA has 60 days from
its receipt of a BLA to determine whether the application will be filed based on the agency’s threshold determination that it
is sufficiently complete to permit substantive review. Once the submission is filed, the FDA begins an in-depth review. The
FDA has agreed to certain performance goals in the review of BLAs. Most such applications for standard review biologic
products are reviewed within ten months of the date the FDA files the BLA; most applications for priority review biologics
are reviewed within six months of the date the FDA files the BLA. Priority review can be applied to a biologic that the FDA
determines has the potential to treat a serious or life-threatening condition and, if approved, would be a significant
improvement in safety or effectiveness compared to available therapies. The review process for both standard and priority
review may be extended by the FDA for three additional months to consider certain late-submitted information, or
information intended to clarify information already provided in the submission.

ff

The FDA may also refer applications for novel biologic products, or biologic 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. The FDA is not bound by the
recommendation of an advisory committee, but it generally follows such recommendations. Before approving a BLA, the
FDA will typically inspect one or more clinical sites to assure compliance with GCP. Additionally, the FDA will inspect the
facility or the facilities at which the biologic product is manufactured. The FDA will not approve the product unless
compliance with current good manufacturing practice, or cGMP, is satisfactory and the BLA contains data that provide
substantial evidence that the biologic is safe, pure, potent and effective in the intended indication.

After the FDA evaluates the BLA and the manufacturing facilities, it issues either an approval letter or a complete

response letter. A complete response letter generally outlines the deficiencies in the submission and may require
substantial additional testing, or information, in order for the FDA to reconsider the application. If, or when, those
deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the BLA, the FDA will issue an approval
letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information
included. An approval letter authorizes commercial marketing of the biologic with specific prescribing information for
specific indications. As a condition of BLA approval, the FDA may require a risk evaluation and mitigation strategy, or
REMS, to help ensure that the benefits of the biologic outweigh the potential risks. REMS can include medication guides,
communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU can include, but
are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain
circumstances, special monitoring, and the use of patient registries. The requirement forff
a REMS can materially affect the
potential market and profitability of the product. Moreover, product approval may require substantial post-approval testing
and surveillance to monitor the product’s safety or efficacy.

Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or

problems are identified following initial marketing. Changes to some of the conditions established in an approved
application, including changes in indications, labeling, or manufacturing processes or facilities, require submission and
FDA approval of a new BLA or BLA supplement before the change can be implemented. A BLA supplement forff
a new
indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures
and actions in reviewing BLA supplements as it does in reviewing BLAs.

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Fast track designation and accelerated approval

The FDA is required to facilitate the development, and expedite the review, of drugs or biologics that are intended for

the treatment of a serious or life-threatening disease or condition for which there is no effective treatment and which
demonstrate the potential to address unmet medical needs for the condition. Under the fast track program, the sponsor of
a new product candidate may request that the FDA designate the candidate for a specific indication as a fast track
biologic concurrent with, or after, the filing of the IND for the candidate. The FDA must determine if the product candidate
qualifies for fast track designation within 60 days of receipt of the sponsor’s request. In addition to other benefits such as
the ability to engage in more frequent interactions with the FDA, the FDA may initiate review of sections of a fast track
product’s BLA before the application is complete. This rolling review is available if the applicant provides, and the FDA
approves, a schedule for the submission of the remaining information and the applicant pays applicable user fees.
However, the FDA’s time period goal for reviewing an application does not begin until the last section of the BLA is
submitted. Additionally, the fast track designation may be withdrawn by the FDA if the FDA believes that the designation is
no longer supported by data emerging in the clinical trial process.

Under the FDA’s accelerated approval regulations, the FDA may approve a drug or biologic for a serious or life-

threatening illness that provides meaningful therapeutic benefit to patients over existing treatments based upon a
surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier
than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or
other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of
alternative treatments. In clinical trials, a surrogate endpoint is a measurement of laboratory or clinical signs of a disease
or condition that substitutes for a direct measurement of how a patient feels, functions, or survives. Surrogate endpoints
can often be measured more easily or more rapidly than clinical endpoints. A biologic candidate approved on this basis is
subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical
trials to confirm the effect on the clinical endpoint. Failure to conduct required post-approval trials, or confirm a clinical
benefit during post-marketing trials, will allow the FDA to withdraw the biologic from the market on an expedited basis. All
promotional materials for product candidates approved under accelerated regulations are subject to prior review by the
FDA. The FDA may also grant a full approval to a drug or biologic based on a surrogate endpoint when the surrogate
biomarker is validated, allowing it to be used in place of a clinical outcome. Validated surrogate endpoints must undergo
extensive testing in clinical trials to show they can be relied upon to predict clinical benefit, which is more rigorous than the
testing needed to demonstrate that a surrogate endpoint is reasonably likely to predict clinical benefit to support an
accelerated approval.

Breakthrough therapy designation

The FDA is also required to expedite the development and review of the application for approval of drug or biological

products that are intended to treat a serious or life-threatening disease or condition where preliminary clinical evidence
indicates that the biologic may demonstrate substantial improvement over existing therapies on one or more clinically
significant endpoints. Under the breakthrough therapy program, the sponsor of a new product candidate may request that
the FDA designate the candidate for a specific indication as a breakthrough therapy concurrent with, or after, the filing of
the IND for the biologic candidate. The FDA must determine if the product qualifies for breakthrough therapy designation
within 60 days of receipt of the sponsor’s request. Additionally, the breakthrough therapy designation may be withdrawn
by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process,
including considering any new drug or biologic approvals that later the unmet medical need.

Orphan drug designation

Under the Orphan Drug Act, the FDA may grant orphan drug designation to drug or biological products intended to

treat a rare disease or condition—generally a disease or condition that affects fewer than 200,000 individuals in the United
States, or if it affects more than 200,000 individuals in the United States, there is no reasonable expectation that the cost
of developing and making a product available in the United States for such disease or condition will be recovered from
sales of the product.

Orphan drug designation must be requested before submitting a BLA. After the FDA grants orphan drug designation,

the generic identity of the biological product and its potential orphan use are disclosed publicly by the FDA. Orphan drug
designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.
The first BLA applicant to receive FDA approval for a particular active moiety to treat a particular disease with FDA orphan
drug designation is entitled to a seven-year exclusive marketing period in the United States for that product for that
indication. During the seven-year exclusivity period, the FDA may not approve any other applications to market a
biological product containing the same principal molecular structural features for the same disease, except in limited
circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity. A product is clinically
superior if it is safer, more effective or makes a major contribution to patient care. Orphan drug exclusivity does not

17

prevent the FDA from approving a different drug or biological product for the same disease or condition, or the same
biological product for a different disease or condition. Among the other benefits of orphan drug designation are tax credits
for certain research and a waiver of the BLA user fee.

Rare pediatric disease priority review voucher program

Under the Rare Pediatric Disease Priority Review Voucher program, FDA may award a priority review voucher to the

sponsor of an approved marketing application for a product that treats or prevents a rare pediatric disease. The voucher
entitles the sponsor to priority review of one subsequent marketing application.

A voucher may be awarded only for an approved rare pediatric disease product application. A rare pediatric disease

product application is an NDA or BLA for a product that treats or prevents a serious or life-threatening disease in which
the serious or life-threatening manifestations primarily affect individuals aged from birth to 18 years; in general, the
disease must affect fewer than 200,000 such individuals in the U.S.; the NDA or BLA must be deemed eligible for priority
review; the NDA or BLA must not seek approval for a different adult indication (i.e., for a different disease/condition); the
product must not contain an active ingredient that has been previously approved by FDA; and the NDA or BLA must rely
on clinical data derived from studies examining a pediatric population such that the approved product can be adequately
labeled for the pediatric population. Before NDA or BLA approval, FDA may designate a product in development as a
product for a rare pediatric disease, but such designation is not required to receive a voucher.

To receive a rare pediatric disease priority review voucher, a sponsor must notify FDA, upon submission of the NDA

or BLA, of its intent to request a voucher. If FDA determines that the NDA or BLA is a rare pediatric disease product
application, and if the NDA or BLA is approved, FDA will award the sponsor of the NDA or BLA a voucher upon approval
of the NDA or BLA. FDA may revoke a rare pediatric disease priority review voucher if the product for which it was
awarded is not marketed in the U.S. within 365 days of the product’s approval.

The voucher, which is transferable to another sponsor, may be submitted with a subsequent NDA or BLA and
entitles the holder to priority review of the accompanying NDA or BLA. The sponsor submitting the priority review voucher
must notify FDA of its intent to submit the voucher with the NDA or BLA at least 90 days prior to submission of the NDA or
BLA and must pay a priority review user fee in addition to any other required user fee. FDA must take action on an NDA
or BLA under priority review within six months of receipt of the NDA or BLA.

The Rare Pediatric Disease Priority Review Voucher program was reauthorized in the Creating Hope

Reauthorization Act in December 2020, allowing a product that is designated as a product for a rare pediatric disease
prior to October 1, 2024 to be eligible to receive a rare pediatric disease priority review voucher upon approval of a
qualifying NDA or BLA prior to October 1, 2026.

Disclosure of clinical trial information

Sponsors of clinical trials of FDA-regulated products, including biological products, are required to register and
disclose certain clinical trial information. Information related to the product, patient population, phase of investigation, trial
sites and investigators, and other aspects of the clinical trial is then made public as part of the registration. Sponsors are
also obligated to discuss the results of their clinical trials after completion. Disclosure of the results of these trials can be
delayed in certain circumstances for up to two years after the date of completion of the trial. Competitors may use this
publicly available information to gain knowledge regarding the progress of development programs.

Pediatric information

Under the Pediatric Research Equity Act, or PREA, NDAs or BLAs or supplements to NDAs or BLAs must contain

data to assess the safety and effectiveness of the biological product for the claimed indications in all relevant pediatric
subpopulations and to support dosing and administration for each pediatric subpopulation for which the biological product
is safe and effective. The FDA may grant full or partial waivers, or deferrals, for submission of data. Unless otherwise
required by statute or regulation, PREA generally does not apply to a drug for an indication for which orphan designation
has been granted; however, beginning in 2020, PREA will apply to BLAs for orphan-designated drugs if the drug is a
molecularly targeted cancer product intended for the treatment of an adult cancer and is directed at a molecular target that
the FDA has determined is substantially relevant to the growth or progression of a pediatric cancer.

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Additional controls for biologics

To help reduce the increased risk of the introduction of adventitious agents and related process impurities, the
PHSA emphasizes the importance of manufacturing controls for products whose attributes cannot be precisely defined.
The PHSA also provides authority to the FDA to immediately suspend licenses in situations where there exists a danger
to public health, to prepare or procure products in the event of shortages and critical public health needs, and to authorize
the creation and enforcement of regulations to prevent the introduction or spread of communicable diseases in the United
States and between states.

After a BLA is approved, the product may also be subject to official lot release as a condition of approval. As part of

the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is
released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each
lot of product to the FDA together with a release protocol showing a summary of the history of manufacture of the lot and
the results of all of the manufacturer’s tests performed on the lot. The FDA may also perform certain confirmatory tests on
lots of some products, such as viral vaccines, before releasing the lots for distribution by the manufacturer. In addition, the
FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of
biological products. As with drugs, after approval of biologics, manufacturers must address any safety issues that arise,
are subject to recalls or a halt in manufacturing, and are subject to periodic inspection after approval.

Patent term restoration

After approval, owners of relevant drug or biologic patents may apply for up to a five year patent extension. The

allowable patent term extension is calculated as half of the drug’s testing phase—the time between IND application and
NDA or BLA submission—and all of the review phase—the time between NDA or BLA submission and approval up to a
maximum of five years. The time can be shortened if FDA determines that the applicant did not pursue approval with due
diligence. The total patent term after the extension may not exceed 14 years.

For patents that might expire during the application phase, the patent owner may request an interim patent
extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For
each interim patent extension granted, the post-approval patent extension is reduced by one year. The director of the U.S.
PTO must determine that approval of the drug covered by the patent for which a patent extension is being sought is likely.
Interim patent extensions are not available for a drug or biologic for which an NDA or BLA has not been submitted.

Biosimilars

The Biologics Price Competition and Innovation Act of 2009, or BPCIA, creates an abbreviated approval pathway for

biological products shown to be highly similar to or interchangeable with an FDA-licensed reference biological product.
Biosimilarity sufficient to reference a prior FDA-approved product requires that there be no differences in conditions of
use, route of administration, dosage form, and strength, and no clinically meaningful differences between the biological
product and the reference product in terms of safety, purity, and potency. Biosimilarity must be shown through analytical
trials, animal trials, and a clinical trial or trials, unless the Secretary of Health and Human Services waives a required
element. A biosimilar product may be deemed interchangeable with a prior approved product if it meets the higher hurdle
of demonstrating that it can be expected to produce the same clinical results as the reference product and, for products
administered multiple times, the biologic and the reference biologic may be switched after one has been previously
administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference
biologic. The FDA has approved numerous biosimilar products, and in 2021 approved the first interchangeable product
under the BPCIA. Complexities associated with the larger, and often more complex, structures of biological products, as
well as the process by which such products are manufactured, pose significant hurdles to implementation, which is still
being evaluated by the FDA.

ff

A reference biologic is granted 12 years of exclusivity from the time of first licensure of the reference product, and no

a biosimilar can be submitted for four years from the date of licensure of the reference product. The first

application forff
biologic product submitted under the abbreviated approval pathway that is determined to be interchangeable with the
reference product has exclusivity against a finding of interchangeability for other biologics for the same condition of use
for the lesser of (i) one year after first commercial marketing of the first interchangeable biosimilar, (ii) 18 months after the
first interchangeable biosimilar is approved if there is no patent challenge, (iii) eighteen months after resolution of a
lawsuit over the patents of the reference biologic in favor of the first interchangeable biosimilar applicant, or (iv) 42 months
after the first interchangeable biosimilar’s application has been approved if a patent lawsuit is ongoing within the 42-month
period.

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Post-approval requirements

Once a BLA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA

closely regulates the post-approval marketing and promotion of biologics, including standards and regulations for direct-
to-consumer advertising, off-label promotion, industry-sponsored scientific and educational activities and promotional
activities involving the internet. Biologics may be marketed only for the approved indications and in accordance with the
provisions of the approved labeling.

ff

Adverse event reporting and submission of periodic reports is required following FDA approval of a BLA. The FDA
also may require post-marketing testing, known as Phase 4 testing, REMS, and surveillance to monitor the effects of an
approved product, or the FDA may place conditions on an approval that could restrict the distribution or use of the
product. In addition, quality control, biological product manufacture, packaging, and labeling procedures must continue to
conform to cGMPs after approval. Biologic manufacturers and certain of their subcontractors are required to register their
establishments with the FDA and certain state agencies. Registration with the FDA subjects entities to periodic
unannounced inspections by the FDA, during which the agency inspects manufacturing facilities to assess compliance
with cGMPs. Accordingly, manufacturers must continue to expend time, money, and effort in the areas of production and
quality-control to maintain compliance with cGMPs. Regulatory authorities may withdraw product approvals or request
product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing,
or if previously unrecognized problems are subsequently discovered.

FDA regulation of companion diagnostics

If use of an in vitro diagnostic is essential to safe and effective use of a drug or biologic product, then the FDA
generally will require approval or clearance of the diagnostic, known as a companion diagnostic, at the same time that the
FDA approves the therapeutic product. The FDA has generally required in vitro companion diagnostics intended to select
the patients who will respond to cancer treatment to obtain a pre-market approval, or PMA, for that diagnostic
simultaneously with approval of the therapeutic. The review of these in vitro companion diagnostics in conjunction with the
review of a cancer therapeutic involves coordination of review by the FDA’s Center for Drug Evaluation and Research and
by the FDA’s Center for Devices and Radiological Health. Approval and clearance of a companion diagnostic also
requires a high level of coordination between the drug or biologic manufacturer and device manufacturer, if different
companies.

The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the
FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare
and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device
and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are
subject to a substantial application fee, which is typically increased annually. In addition, PMAs must generally include the
results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness
of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must
demonstrate that the diagnostic has adequate sensitivity and specificity, has adequate specimen and reagent stability,
and produces reproducible results when the same sample is tested multiple times by multiple users at multiple
laboratories. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the
Quality System Regulation, or QSR, which imposes elaborate testing, control, documentation and other quality assurance
requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable

determination based on deficiencies in the application and require additional clinical trial or other data that may be
expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of the PMA
application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific
conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to
secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a
PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can
include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device,
including, among other things, additional testing and/or restrictions on labeling, promotion, sale and distribution.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices
may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must
also register their establishment(s), including payment of an annual establishment registration fee, and list their device(s)
with the FDA. A medical device manufacturer’s manufacturing processes, and the processes of the device specification
developer and repackager/relabeler (if different from the manufacturer) and initial importer (if manufactured outside of the

20

United States), are required to comply with the applicable portions of the QSR, which cover the methods and
documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping
of medical devices. Facility records and manufacturing processes are subject to periodic unscheduled inspections by the
FDA.

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 but not limited to, the Centers for Medicare and Medicaid Services, or CMS, other
divisions of the U.S. Department of Health and Human Services (e.g., the Office of Inspector General), the U.S.
Department of Justice, or DOJ, and individual U.S. Attorney offices within the DOJ, 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 laws, the privacy provisions of the Health Insurance Portability and
Accountability Act, or HIPAA, and similar state laws, each as amended.

The federal Anti-Kickback Statute prohibits, among other things, any person or entity, from knowingly and willfully

offering, paying, soliciting or receiving any remuneration, directly or indirectly, overtly or covertly, in cash or in kind, to
induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any item or service
reimbursable under Medicare, Medicaid or other federal healthcare programs. The term remuneration has been
interpreted broadly to include anything of value. The Anti-Kickback Statute has been interpreted to apply to arrangements
between pharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other.
There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from
prosecution. The exceptions and safe harbors are drawn narrowly and practices that involve remuneration that may be
alleged to be intended to induce prescribing, purchasing or recommending may be subject to scrutiny if they do not qualify
for an exception or safe harbor. Failure to meet all of the requirements of a particular applicable statutory exception or
regulatory safe harbor does not make the conduct per se illegal under the Anti-Kickback Statute. Instead, the legality of
the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all of its facts and
circumstances. Our practices may not in all cases meet all of the criteria for protection under a statutory exception or
regulatory safe harbor.

Additionally, the intent standard under the Anti-Kickback Statute was amended by the Affordable Care Act, or ACA,

to a stricter standard such that a person or entity no longer needs to have actual knowledge of the statute or specific
intent to violate it in order to have committed a violation. In addition, the ACA codified case law that a claim including
items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for
purposes of the federal False Claims Act (discussed below).

The civil monetary penalties statute imposes penalties against any person or entity who, among other things, is

determined to have presented or caused to be presented a claim to a federal health program that the person knows or
should know is for an item or service that was not provided as claimed or is false or fraudulent.

The federal False Claims Act prohibits, among other things, any person or entity from knowingly presenting, or
causing to be presented, a false claim for payment to, or approval by, the federal government or knowingly making, using,
or causing to be made or used a false record or statement material to a false or fraudulent claim to the federal
government. As a result of a modification made by the Fraud Enforcement and Recovery Act of 2009, a claim includes
“any request or demand” for money or property presented to the U.S. government. Recently, several pharmaceutical and
other healthcare companies have been prosecuted under these laws for allegedl
with the expectation that the customers would bill federal programs for the product. Other companies have been
prosecuted for causing false claims to be submitted because of the companies’ marketing of the product for unapproved,
and thus generally non-reimbursable, uses.

y providing free product to customers

ff

HIPAA created new federal criminal statutes that prohibit knowingly and willfully executing, or attempting to execute,

a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or
property owned by, or under the control or custody of, any healthcare benefit program, including private third-party payors
and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, a material fact or making any
materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits,
items or services.

Also, many states have similar fraud and abuse statutes or regulations that apply to items and services reimbursed
under Medicaid and other state programs, or, in several states, apply regardless of the payor. We may be subject to data
privacy and security regulations by both the federal government and the states in which we conduct our business. HIPAA,
as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and its
implementing regulations, imposes requirements relating to the privacy, security and transmission of individually

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identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly
applicable to business associates, independent contractors or agents of covered entities that receive or obtain protected
health information in connection with providing a service on behalf of a covered entity. HITECH also created four new tiers
of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business
associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts
to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions. In
addition, state laws govern the privacy and security of health information in specified circumstances, many of which differ
from each other in significant ways and may not have the same effect, thus complicating compliance efforts.

Additionally, the federal Physician Payments Sunshine Act within the ACA, and its implementing regulations, require

that certain manufacturers of drugs, devices, biological and medical supplies for which payment is available under
Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) to report information related to
certain payments or other transfers of value made or distributed to physicians, physician assistants, certain advanced
care nurses and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the
physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians
and their immediate family members. The reported data are posted in searchable form on a public website on an annual
basis. Failure to submit required information may result in civil monetary penalties.

In order to distribute products commercially, we must comply with state laws that require the registration of

manufacturers and wholesale distributors of drug and biological 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 and biotechnology 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 and biotechnology 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.

If our operations are found to be in violation of any of the federal and state healthcare laws described above or any
other governmental regulations that apply to us, we may be subject to penalties, including without limitation, civil, criminal
and/or administrative penalties, damages, fines, disgorgement, exclusion from participation in government programs, such
as Medicare and Medicaid, injunctions, private “qui tam” actions brought by individual whistleblowers in the name of the
government, or refusal to allow us to enter into government contracts, contractual damages, reputational harm,
administrative burdens, diminished profits and future earnings, and the curtailment or restructuring of our operations, any
of which could adversely affect our ability to operate our business and our results of operations.

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 extent to which third-party payors provide coverage,
and establish adequate reimbursement levels for such products. In the United States, third-party payors include federal
and state healthcare programs, private managed care providers, health insurers and other organizations. The process for
determining whether a third-party payor will provide coverage for a product may be separate from the process for setting
the price of a product or for establishing the reimbursement rate that such a payor will pay for the product. Third-party
payors may limit coverage to specific products on an approved list, also known as a formulary, which might not include all
of the FDA-approved products for a particular indication. Third-party payors are increasingly challenging the price,
examining the medical necessity and reviewing the cost-effectiveness of medical products, therapies and services, in
addition to questioning 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 product does not imply that an adequate reimbursement rate will be approved. Further, one
payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for
the product. 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.

ff

Different pricing and reimbursement schemes exist in other countries. In the EU, governments influence the price of

pharmaceutical products through their pricing and reimbursement rules and control of national health care systems that

22

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 health care costs 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 product candidates for which we receive regulatory approval for commercial sale may suffer

if the government and third-party payors 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 healthcare
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.

Healthcare reform

Healthcare reforms that have been adopted, and that may be adopted in the future, could result in further reductions

in coverage and levels of reimbursement for pharmaceutical products, increases in rebates payable under U.S.
government rebate programs and additional downward pressure on pharmaceutical product prices. On September 9,
2021, the Biden administration published a wide-ranging list of policy proposals, most of which would need to be carried
out by Congress, to reduce drug prices and drug payment. The HHS plan includes, among other reform measures,
proposals to lower prescription drug prices, including by allowing Medicare to negotiate prices and disincentivizing price
increases, and to support market changes that strengthen supply chains, promote biosimilars and generic drugs, and
increase price transparency. Many similar proposals, including the plans to give Medicare Part D authority to negotiate
drug prices, require drug manufacturers to pay rebates on drugs whose prices increase greater than the rate of inflation,
and cap out-of-pocket costs, have already been included in policy statements and legislation currently being considered
by Congress. It is unclear to what extent these and other statutory, regulatory, and administrative initiatives will be
enacted and implemented.

The Foreign Corrupt Practices Act

The Foreign Corrupt Practices Act, or FCPA, prohibits any U.S. individual or business from paying, offering, or
authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate
for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in
obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to
comply with accounting provisions requiring the company to maintain books and records that accurately and fairly reflect
all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of
internal accounting controls for international operations.

Additional regulation

In addition to the foregoing, state and federal laws regarding environmental protection and hazardous substances,

including the Occupational Safety and Health Act, the Resource Conservancy and Recovery Act and the Toxic
Substances Control Act, affect our business. These and other laws govern our use, handling and disposal of various
biological, chemical and radioactive substances used in, and wastes generated by, our operations. If our operations result
in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and
governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued
compliance therewith will not have a material adverse effect on our business. We cannot predict, however, how changes
in these laws may affect our future operations.

Europe / rest of world government regulation

rr

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 of 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 EU, for example, a clinical trial application must be
submitted to each country’s national health authority and an independent ethics committee, much like the FDA and IRB,

23

respectively. Once the clinical trial application is approved in accordance with a country’s requirements, clinical trial
development may proceed. Because biologically sourced raw materials are subject to unique contamination risks, their
use may be restricted in some countries.

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 GCP 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 or biological product under EU regulatory systems, we must

submit a marketing authorization application. The application used to file the BLA in the United States is similar to that
required in the EU, with the exception of, among other things, country-specific document requirements.

For other countries outside of the EU, 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 GCP and the applicable regulatory requirements and the
ethical principles that have their origin in the Declaration of Helsinki.

If we or our potential collaborators 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.

Corporate Information

We were formed as a limited liability company under the laws of the State of Delaware in December 2013 and

converted to a Delaware corporation in March 2015. Our principal executive offices are located at 805 Las Cimas
Parkway, Suite 100, Austin, Texas 78746, and our telephone number is (512) 942-2935. Our website address is
www.aegleabio.com. The information contained on, or that can be accessed through, our website is not part of this Annual
Report, and you should not consider information on our website to be part of this Annual Report.

Human Capital Resources

As of December 31, 2021, we employed 101 people: 94 employees in the United States and 7 employees in

international locations. We also engage temporary employees and consultants to augment our existing workforce. None of
our employees are represented by a labor union, we have not experienced any work stoppages, and we consider our
relations with our employees to be good.

We are committed to providing our employees with a work environment that is free of unlawful discrimination,
including any harassment on the basis of any legally protected status. Accordingly, we will not tolerate any form of
unlawful harassment against our employees, whether by executives, managers, co-workers, or by third parties, such as
vendors, or other third parties with whom our employees interact. In addition, we provide equal employment opportunity to
all employees and applicants for employment and do not discriminate on any basis prohibited by law, including race,
color, sex, gender, sexual orientation, pregnancy, age, religion, national origin, disability, marital status, and veteran
status.

We recognize that attracting, motivating, and retaining talent at all levels is vital to continuing our success. We invest

in our employees through high-quality benefits and various health and wellness initiatives and offer competitive
compensation packages (base salary and incentive plans), ensuring fairness in internal compensation practices. The
principal purposes of our incentive plans (bonus and equity) are to protect the long-term interests of our stakeholders and
stockholders.

To further engage and incentivize our workforce, we offer a wide range of opportunities to support professional
development and growth. For our talent pipeline assessment and development, we work closely with individual business
functional leaders to identify our high-performing and high-potential employees, by conducting a company-wide talent
assessment utilizing a Performance/Potential Matrix assessment tool. This assessment is completed annually to ensure
we tie together our incentives, development, and recognition to retain and attract the people we need to drive our
success.

24

Financial Information

We manage our operations and allocate resources as a single reporting segment. Financial information regarding
our operations, assets and liabilities, including our net loss for the years ended December 31, 2021, 2020 and 2019 and
our total assets as of December 31, 2021 and 2020, is included in our Consolidated Financial Statements in Item 8 of this
AAnnual Report.

Available Information

We file Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other
r
information with the Securities and Exchange Commission (SEC). Our filings with the SEC are available free of charge on
the SEC’s website at www.sec.gov and on our website under the “Investors” tab as soon as reasona
we electronically file such material with, or furnish it to, the SEC.

bly practicable after
r

25

ITEM 1A. RISK FACTORS

Investing in our common stock involves a high degree of risk. You should carefully consider the risks and

uncertainties described below, together with all of the other information in this annual report on Form 10-K, including our
consolidated financial statements and related notes and “Management
iscussion and Analysis of Financial Condition
and Results of Operations,” before investing in our common stock. The risks and uncertainties described below are not
the only ones we fww ace.
Additional risks and uncertainties that we are unaware of, or that we currently believe are not
material, may also become important factors that affect us. If any of the following risks occur, our business, operating
results and prospects could be materially harmed. In that event, the price of our common stock could decline, and you
could lose part or all of your investment.

’s D’

“

ff

Summary Risk Factors

Our business is subject to a number of risks and uncertainties, including those highlighted in the section titled “Risk
Factors” immediately following this summary. Some of these risks are:

•

•

•

•

•

•

•

•

•

•

•

•

•

We have no source of product revenue and we have incurred significant losses since ince
incur losses for the foreseeable future and may never achieve or maintain profitability.

ii

ption. We expect to

We may not be successful in advancing the clinical development of our product candidates.

We will need substantial additional funding. If we are unable to raise capital when needed, we would be
compelled to delay, reduce or eliminate our product development programs or commercialization efforts.

ll

We depend heavily on the success of our most advanced product candidate, pegzilarginase. Existing and
future clinical trials of our product candidates, including pegzilarginase, may not be successful. If we are
unable to commercialize our product candidates or experience significant delays in doing so, our business will
be materially harmed.

The results from our global pivotal PEACE Phase 3 trial may not support marketing approval, and the FDA
tt
may require us to conduct additional clinical trials or evaluate current subjects for an additional follow-up
period.

The outbreak of the novel strain of coronavirus, SARS-CoV-2 and its emerging variants, which causes COVID-
19, has, and may continue to, adversely impact our business, including the timing of our clinical trials and
supply chain interruptions.

Clinical drug development involves a lengthy and expensive process with an uncertain outcome. We may
experience delays in completing, or ultimately be unable to complete, the development and commercialization
of any of our product candidates.

Our engineered human enzyme product candidates represent a novel therapeutic approach, which could result
in heightened regulatory scrutiny, delays in clinical development, or delays in our ability to achieve regulatory
approval or commercialization of our product candidates.

rr

We have only initiated clinical trials f
ff
and have only dl
candidates in humans. Our existing and future planned clinical trials may reveal significant adverse events,
toxicities or other side effects not seen in our nonclinical studies or early stage clinical trials and may result in a
safety profile that could inhibit regulatory approval or market acceptance of any of our product candidates.

osed pegzilarginase and AGLE-177 in humans. We have not dosed any of our other product

ll or pegzilarginase and AGLE-177 for the treatment of certain conditions

If we experience delays or difficulties in the enrollment of patients in our ongoing or planned clinical trials, our
receipt of necessary regulatory approvals could be delayed or prevented.

We contract with third parties for the manufacture of our product candidates for nonclinical studies and our
ongoing and future planned clinical testing and expect to continue to do so for commercialization. This reliance
on third parties increases the risk that we will not have sufficient quantities of our product candidates at an
acceptable cost and quality, which could delay, prevent or impair our development or commercialization efforts.

If we are not able to obtain, or if there are delays in obtaining, required regulatory approvals in the United
States or in foreign jurisdictions, we will not be able to commercialize our product candidates, and our ability to
generate revenue will be materially impaired.

rr

If we are unable to obtain and maintain intellectual property protection for our technology and product
candidates, or if the scope of the intellectual property protection obtained is not sufficiently broad, our
competitors could develop and commercialize technology and product candidates similar or identical to ours,
and our ability to successfully commercialize our technology and product candidates may be impaired.

26

Risks Related to Our Financial Position and Need for Additional Capital

ee
We and our independent auditors have evv

xpressed doubt about our ability to continue as

a going concern.

The independent registered public accounting firm auditors’ report accompanying our financial statements for the
year ended December 31, 2021 contained an explanatory paragraph expressing substantial doubt about our ability to
continue as a going concern. In view of these matters, our ability to continue as a going concern is dependent upon our
ability to raise additional capital through outside sources. We intend to obtain funding through the sale of common stock in
public offerings and/or private placements, debt financings, or through other capital sources, including collaborations with
other companies or other strategic transactions. The failure to obtain sufficient financing or strategic partnerships could
adversely affect our ability to achieve our business objectives and continue as a going concern.

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to
assess our future viability.

We are a clinical-stage biotechnology company. We began operations as a limited liability company in December

2013 and converted to a Delaware corporation in March 2015. Our operations to date have been limited to organizing and
staffing our company, business planning, raising capital, acquiring and developing our technology, identifying potential
product candidates, undertaking nonclinical studies, and preparing for, commencing and conducting clinical trials of our
most advanced product candidates, pegzilarginase and AGLE-177.

Other than the PEACE Phase 3 trial of pegzilarginase, we have not demonstrated our ability to successfully

complete a pivotal clinical trial. We have not yet demonstrated our ability to successfully obtain marketing approvals,
manufacture a commercial scale product or arrange for a third party to do so on our behalf, or conduct sales and
marketing activities necessary for successful product commercialization. Products, on average, take ten to 15 years to be
developed from the time they are discovered to the time they are approved and available for treating patients. Although
we have recruited a team that has experience with clinical trials, as a company we have limited experience in conducting
clinical trials. In part because of this limited experience, we cannot be certain that planned or ongoing clinical trials will
begin or be completed on time, if at all. Consequently, any predictions you make about our future success or viability
based on our short operating history to date may not be as accurate as they could be if we had a longer operating history
or an established track record in commercializing products or conducting clinical trials.

In addition, as a new business, we may encounter unforeseen expenses, difficulties, complications, delays and other

known and unknown factors. We will need to transition from a company with a research focus to a company capable of
supporting commercial activities. We may not be successful in such a transition.

We have no source of product revenue and we have incurred significant losses since inception. We expect to
incur losses for the foreseeable future and may never achieve or maintain profitability.

We have a limited operating history and no approved products. Our ability to generate revenue and become
profitable depends upon our ability to successfully complete the development of any of our product candidates, including
pegzilarginase and AGLE-177, for any of our target indications and to obtain necessary regulatory approvals. To date, we
have recognized revenue from a license and supply agreement and a fully utilized government grant and have not
generated any product revenue. Even if we receive regulatory approval for any of our product candidates, we do not know
when these product candidates will generate revenue for us, if at all.

In addition, since inception, we have incurred significant operating losses. For the years ended December 31, 2021

and 2020, we reported a net loss of $65.8 million and $80.9 million, respectively. As of December 31, 2021, we had an
accumulated deficit of $341.8 million. Based upon our current operating plans, we believe that we have sufficient
resources to fund operations into the first quarter of 2023 with our existing cash, cash equivalents, and marketable
securities. Accordingly, based on recurring losses from operations incurred since inception, the expectation of continued
operating losses, and the need to raise additional capital to finance our future operations, we determined that there is
substantial doubt about our ability to continue as a going concern within twelve months of the issuance date of these
financial statements. We plan to address this condition through the sale of common stock in public offerings and/or private
placements, debt financings, or through other capital sources, including collaborations with other companies or other
strategic transactions. In the past, we have financed our operations primarily through private placements of our preferred
stock, the initial public offering of our common stock, follow-on public offerings of our common stock and pre-funded
warrants, collection of a research grant, and the licensing of our product rights for commercialization of pegzilarginase in
Europe and certain countries in the Middle East. We have devoted substantially all of our efforts to research and
development. Currently, we are conducting clinical development for pegzilarginase for the treatment of Arginase 1
Deficiency and for AGLE-177 for the treatment of Homocystinuria. We have not initiated clinical development of our other
product candidates and none of our product candidates are ready for commercialization. We expect to continue to incur

27

significant expenses and increasing operating losses for the foreseeable future, and the net losses we incur may fluctuate
significantly from quarter to quarter. We anticipate that our expenses will increase substantially if and as we:

•
•
•
•

•

•
•
•

•

continue our research, nonclinical and clinical development of our product candidates;
seek to identify additional product candidates;
conduct additional nonclinical studies and initiate clinical trials for our product candidates;
seek marketing approvals for any of our product candidates that successfully complete clinical trials, including
pivotal trials;
establish a sales, marketing and distribution infrastructure to commercialize any product candidates for which
we may obtain marketing approval;
maintain, expand and protect our intellectual property portfolio;
hire additional executive, clinical, quality control and scientific personnel;
add operational, financial and management information systems and personnel, including personnel to support
our product development; and
acquire or in-license other product candidates and technologies.

We are unable to predict the timing or amount of increased expenses, or when, or if, we will be able to achieve or
maintain profitability because of the numerous risks and uncertainties associated with product development. In addition,
our expenses could increase significantly beyond expectations if we are required by the FDA, EMA, MHRA, or other
relevant regulatory authorities, or the Health Authorities, to modify protocols of our clinical trials or perform studies in
addition to those that we currently anticipate. Even if pegzilarginase, or any of our other product candidates, is approved
for commercial sale, we anticipate incurring significant costs associated with the commercial launch of any product
candidate.

To become and remain profitable, we must develop and eventually commercialize a product candidate or product

candidates with significant market potential. This will require us to be successful in a range of challenging activities,
including completing nonclinical testing, initiating and completing clinical trials of one or more of our product candidates,
obtaining marketing approval for these product candidates, manufacturing, marketing and selling those product
candidates for which we obtain marketing approval and satisfying any post-marketing requirements. We may never
succeed in these activities and, even if we do, we may never generate revenues that are significant or large enough to
achieve profitability. We are currently advancing clinical development for pegzilarginase for the treatment of Arginase 1
Deficiency and have also initiated dosing in our Phase 1/2 clinical trial of AGLE-177 for the treatment of patients with
Homocystinuria. We are in the nonclinical development stages for our remaining product candidates. If we do achieve
profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become
and remain profitable would decrease the value of the company and could impair our ability to raise capital, maintain or
expand our research and development efforts, expand our business or continue our operations. A decline in the value of
our company would also cause you to lose part or even all of your investment.

We will need substantial additional funding. If we are unable to raise capital when needed, we would be
compelled to delay, reduce or eliminate our product development programs or commercialization efforts.

We expect our expenses to increase in parallel with our ongoing activities, particularly as we continue our research

and nonclinical development to identify new clinical candidates and initiate and continue clinical trials of, and seek
marketing approval for, our product candidates. In addition, if we obtain marketing approval for any of our product
candidates, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing
and distribution. Furthermore, we expect to continue to incur additional costs associated with operating as a public
company. Accordingly, we will need to obtain substantial additional funding to support our continuing operations. If we are
unable to raise capital when needed for any reason, including but not limited to a U.S. federal government shutdown, or
on acceptable terms, we would be forced to delay, reduce or eliminate our discovery and nonclinical development
programs, our ongoing clinical development, or any future clinical development or commercialization efforts.

Based upon our planned use of our cash, cash equivalents, marketable securities, and restricted cash as of

December 31, 2021, we estimate such funds will be sufficient for us to (i) to advance the clinical development of
pegzilarginase through our Biologics License Application, or BLA, submission, for the treatment of Arginase 1 Deficiency
(ii) fund our two ongoing extension studies for patients with
AGLE-177 through our Phase 1/2 clinical trial and preparation for a potential Phase 3 trial for the treatment of patients
with Homocystinuria, and (iv) to advance AGLE-325 through IND-enabling studies. Our future capital requirements will
depend on many factors, including:

Arginase 1 Deficiency, (iii) advance the clinical development of

ff

28

•

•

•

•

•

•

•

the costs associated with the scope, progress and results of compound discovery, nonclinical development,
laboratory testing and clinical trials for our product candidates;

ff

the extent to which we enter into partnerships or other arrangements with third parties in order to further
develop our product candidates;

the costs and fees associated with the discovery, acquisition or in-license of product candidates or
technologies;

our ability to establish collaborations on favorable terms, if at all;

the costs of commercialization activities, including product sales, marketing, manufacturing and distribution, for
any of our product candidates for which we receive marketing approval;

revenue, if any, received from commercial sales of our product candidates, should any of our product
candidates receive marketing approval; and

the costs of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual
property rights and defending intellectual property-related claims.

Our product candidates, if approved, may not achieve commercial success. Our commercial revenues, if any, will be

derived from sales of products, none of which have been approved to date. Accordingly, we will continue to rely on
additional financing to achieve our business objectives, which may not be available to us on acceptable terms, or at all.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to
relinquish rights to our technologies or product candidates.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs

through a combination of equity or equity-linked offerings, debt financings, grants from research organizations,
collaborations, and license and development agreements. We do not have any committed external source of funds. To the
extent that we raise additional capital through the sale of equity or convertible debt securities, or if existing holders of
warrants exercise their rights to purchase common stock, your ownership interest will be diluted, and the terms of these
securities may rank senior to our common stock and include liquidation or other preferences, covenants or other terms
that adversely affect your rights as a common stockholder. Further, any future sales of our common stock by us or resale
of our common stock by our existing stockholders could cause the market price of our common stock to decline. Debt
financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting
our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing
arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams,
research programs or product candidates or grant licenses on terms that may not be favorable to us and/or that may
reduce the value of our common stock.

Risks Related to Our Product Development and Regulatory Approval

We may not be successful in advancing the clinical development of our product candidates, including
pegzilarginase and AGLE-177.

In order to execute on our strategy of advancing the clinical development of our product candidates, we completed

the double-blind placebo-controlled portion of our global pivotal PEACE Phase 3 clinical trial and are conducting two long-
term extension studies in the PEACE Phase 3 clinical trial and Phase 1/2 open-label extension study for the treatment of
Arginase 1 Deficiency, and a Phase 1/2 clinical trial of AGLE-177 for the treatment of patients with Homocystinuria. If our
product candidates fail to work as we expect, or if we need to conduct additional studies to better understand the
relationship between our product candidates and clinical activity, our ability to assess the therapeutic effect, seek
regulatory approval or otherwise begin or further clinical development, could be compromised. Although we announced
topline results from the PEACE Phase 3 trial in December 2021 and plan to submit a BLA to the FDA to support approval
for pegzilarginase based on the results of the trial, the FDA may not agree with the adequacy of the trial design or with our
interpretation of the data from the PEACE Phase 3 trial. For example, the study was unable to demonstrate nominal
statistical significance on any prespecified clinical outcome-based endpoints, so the FDA may determine that there is
insufficient direct evidence of effectiveness or inadequate justification to support approval based on the biomarker
endpoint we have chosen. The failure to demonstrate improvement on such clinical endpoints could have been due to an
insufficient duration on treatment to detect such an effect. For example, in preliminary comments from the FDA prior to a
Type B guidance meeting, the FDA indicated that the PEACE Phase 3 trial results described at a high-level do not appear
to provide substantial evidence of effectiveness to support a BLA submission. FDA has raised concerns with the selected

29

primary endpoint and that the duration for our PEACE Phase 3 clinical trial may not be adequate to assess for clinically
meaningful changes. Similarly, our dosing duration for our PEACE Phase 3 clinical trial may not have been adequate to
assess safety and immunogenicity assessment of pegzilarginase. Therefore, while we intend to submit a BLA to the FDA,
the FDA may decide not to file our BLA or approve the BLA in a timely manner, or at all. If the FDA does not approve our
BLA, we may need to conduct additional studies and our expected timing of commercialization of pegzilarginase could be
delayed.

We have in the past had to cease clinical development of product candidates for other indications. We discontinued

clinical development of pegzilarginase for the treatment of the hematological malignancies acute myeloid leukemia, or
AML, and myelodysplastic syndrome, or MDS, in December 2017 due to lack of evidence of clinical benefit. Additionally,
we completed our Phase 1 clinical trial of pegzilarginase for the treatment of advanced solid tumors to study small cell
lung cancer, uveal melanoma, and cutaneous melanoma and our combination trial of pegzilarginase with pembrolizumab
for the treatment of patients with SCLC. We are currently exploring partnership opportunities for further development in
oncology. Such an event may result in longer development times, larger trials and a greater likelihood of terminating the
trial or not obtaining regulatory approval.

We depend heavily on the success of our most advanced product candidate, pegzilarginase. Existing and future
clinical trials of our product candidates, including pegzilarginase, may not be successful. If we are unable to
commercialize our product candidates or experience significant delays in doing so, our business will be
materially harmed.

ll

We have invested a significant portion of our efforts and financial resources in the nonclinical and clinical
development and testing of our most advanced product candidate, pegzilarginase, for the treatment of patients with
Arginase 1 Deficiency and in certain oncology trials. Our ability to generate product revenues, if ever, will depend heavily
on the successful development and commercialization of pegzilarginase. The success of pegzilarginase, AGLE-177, and
our other product candidates will depend on many factors, including the following:

•

•
•

•
•
•

•

•
•

receiving required regulatory approvals for the development and commercialization of our product candidates
as monotherapy or in combination with other products;
establishing commercial manufacturing capabilities or making arrangements with third-party manufacturers;
obtaining and maintaining patent and trade secret protection and non-patent exclusivity for our product
candidates and their components;
enforcing and defending intellectual property rights and claims;
achieving desirable therapeutic properties for our product candidates’ intended indications;
launching commercial sales of our product candidates, if and when approved, whether alone or in collaboration
with third parties;
acceptance of our product candidates, if and when approved, by patients, the medical community and third-
party payors;
effectively competing with other therapies; and
maintaining an acceptable safety profile of our product candidates through clinical trials and following
regulatory approval.

ff

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays

or an inability to successfully commercialize our product candidates, which would materially harm our business.

The results from our global pivotal PEACE Phase 3 trial may not support marketing approval, and th
require us to conduct additional clinical trials to evaluate subjects for an additional follow-up period.

tt

e FDA may

FF

We announced updated data from our ongoing PEACE Phase 3 trial in December 2021 and plan to submit a BLA to

the FDA in the second quarter of 2022 seeking full approval of pegzilarginase. Even though the PEACE Phase 3 trial
achieved statistical significance on its primary endpoint and a positive trend in a secondary endpoint was observed,
nominal statistical significance was not reached on any of the prespecified key secondary or secondary endpoints
evaluating motor assessments. In preliminary comments from the FDA prior to a Type B guidance meeting, the FDA
indicated that the PEACE Phase 3 trial results described at a high-level do not appear to provide substantial evidence of
effectiveness to support a BLA submission. Therefore, while we intend to submit a BLA to the FDA, the FDA may decide
not to file our BLA. Further, even if the FDA files our BLA, the FDA may not conclude that the design of or results seen in
the trial sufficiently demonstrate substantial evidence of effectiveness, including the demonstration of a clinically
meaningful effect. The FDA also weighs the benefits of a product against its risks and the FDA may view the efficacy
results in the context of safety as not being supportive of regulatory approval. We cannot predict whether the BLA that we
plan to submit for pegzilarginase will be filed or approved in a timely manner or at all.

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The outbreak of the novel strain of coronavirus, SARS-CoV-2 and its variants, which causes COVID-19, has, and
may continue to, adversely impact our business, including our clinical trials and nonclinical studies, supply
chain interruptions, and delays for raw materials.

vv

Public health crises such as pandemics or similar outbreaks could adversely impact our business. In response to the

COVID-19 pandemic and the ongoing vaccination campaign, we have reopened our executive offices and research
laboratory in adherence with our COVID-19 protective protocols. While some of our administrative employees continue
their work outside of our offices, a significant portion of our employees, including laboratory personnel, have returned to
the office either full- or part-time.

Timely enrollment in our clinical trials is dependent upon global clinical trial sites which may be adversely affected by

global health matters, such as pandemics. We are currently conducting clinical trials for our product candidates in many
countries, including the United States, Canada, Australia, United Kingdom and throughout the European Union. The
regions in which we operate are currently being or may in the future be affected by COVID-19.

As a result of the COVID-19 outbreak, or similar pandemics, we have experienced and may continue to experience

disruptions that could severely impact our business, clinical trials and nonclinical studies, including:

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delays or difficulties in enrolling patients in our clinical trials;
delays or difficulties in clinical site initiation, including difficulties in recruiting clinical site investigators and
clinical site staff;
delays or disruptions in nonclinical experiments and supplies for such experiments, including animals required
for such experiments;
delays or disruptions in investigational new drug application-enabling good laboratory practice standard
toxicology studies due to unforeseen circumstances in our supply chain;
increased rates of patients missing dosing appointments or withdrawing from our clinical trials following
enrollment as a result of contracting COVID-19, being forced to quarantine, and other travel restrictions, or not
accepting home health visits;
diversion of healthcare resources away from the conduct of clinical trials, including the diversion of hospitals
serving as our clinical trial sites and hospital staff supporting the conduct of our clinical trials, or restricted
access to clinical trial sites for on-site monitoring activities;
interruption of key clinical trial activities, such as clinical assessments at pre-specified timepoints during the
trial and clinical trial site data monitoring, due to limitations on travel imposed or recommended by federal,
state, or foreign governments, employers and others or interruption of clinical trial subject visits and study
procedures (particularly any procedures that may be deemed non-essential), which may impact the integrity of
subject data and clinical study endpoints;
interruption or delays in the operations of the FDA and comparable foreign regulatory agencies, which may
impact feedback and approval timelines;
limitations on employee resources that would otherwise be focused on the conduct of our nonclinical studies
and clinical trials, including because of sickness of employees or their families, the desire of employees to
avoid contact with large groups of people, an increased reliance on working from home or mass transit
disruptions;
interruption of, or delays in receiving, supplies of our product candidates from our CMOs due to staffing
shortages, production slowdowns or stoppages, disruptions in delivery systems and commandeering of
manufacturing facilities for COVID-19 vaccines and treatments;
reduced ability to engage with the scientific, medical and investor communities due to the cancellation of
conferences scheduled throughout the year; and
delays and interruptions to the supply chain, including the raw materials needed for manufacturing.

For example, the timing of our double-blind placebo-controlled portion of our PEACE Phase 3 trial was impacted by
COVID-19 as a result of all of our clinical trial sites temporarily suspending screening. All patients that had initially paused
dosing due to COVID-19 had restarted treatment by September 2020. We completed enrollment and randomization of
patients in the PEACE Phase 3 trial in April 2021 and announced topline data from the trial in December 2021. In addition,
although we are conducting a Phase 1/2 open-label clinical trial of AGLE-177 for the treatment in patients with
Homocystinuria, the protocol requires in-person visits to clinical trial sites. Many of these sites are located in areas that
have experienced significant impacts and may continue to experience more pronounced impacts to their healthcare
systems due to COVID-19 and consequently many previously suspended patient recruitment and may do so again in the
future. While we initiated dosing in our Phase 1/2 clinical trial investigating AGLE-177 for the treatment of Homocystinuria
in June 2021, the timing of continued enrollment may be delayed in the future due to the impact of COVID-19 and local
restrictions. For example, in September 2021, we announced that we believe the emergence of the delta variant and

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lockdowns in Australia, which have slowed trial enrollment, will impact the availability of data for our Phase 1/2 clinical trial
for AGLE-177 and, as a result, we stated that we no longer planned to provide a clinical update relating to this trial in
2021. Additionally, missed doses by patients in the study may adversely affect the usefulness of the data collected in the
trial.

These and other factors arising from the COVID-19 pandemic could worsen in countries that are already afflicted
with COVID-19, could continue to spread to additional countries, or could return to countries where the pandemic has
been partially contained, each of which could further adversely impact our ability to conduct clinical trials and our business
generally, and could have a material adverse impact on our operations and financial condition and results.

In addition, the trading prices for our common stock and other biopharmaceutical companies, as well as the broader

equity and debt markets, have been highly volatile as a result of the COVID-19 pandemic and the resulting impact on
economic activity. As a result, we may face difficulties raising capital when needed, and any such sales may be on
unfavorable terms to us. Further, to the extent we raise additional capital through the sale of equity or convertible debt
securities, the ownership interest of existing stockholders will be diluted.

The COVID-19 outbreak, including the emergence of its variants and their effects, continues to rapidly evolve. The

extent to which the outbreak may impact our business, clinical trials and nonclinical studies will depend on future
developments, which are highly uncertain and cannot be predicted with confidence, such as the ultimate geographic
spread of COVID-19, the duration of the outbreak, the speed and breadth of mass vaccinations and boosters for COVID-
19 and the efficacy of such vaccines and treatments, travel restrictions and actions to contain the outbreak or treat its
impact, such as social distancing and quarantines or lock-downs in the United States and other countries, business
closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain
and treat the disease.

Clinical drug development involves a lengthy and expensive process with an uncertain outcome. We may
experience delays in completing, or ultimately be unable to complete, the development and commercialization of
any of our product candidates.

We have initiated clinical trials with our lead product candidate, pegzilarginase, and AGLE-177. The risk of failure for

all of our product candidates is high. Before obtaining marketing approval from regulatory authorities for the sale of any
product candidate, we must complete nonclinical development and then conduct extensive clinical trials to demonstrate
the safety and efficacy of our product candidates in humans for the respective target indications. Clinical testing is
expensive, difficult to design and implement, can take many years to complete, and its outcome is inherently uncertain.
Failure can occur at any time during the clinical trial process.

The results of nonclinical studies and early clinical trials of our product candidates may not be predictive of the
results of later-stage clinical trials that will likely differ in design and size from early-stage clinical trials, and interim results
of a clinical trial do not necessarily predict final results. For example, while we have observed a reduction in blood arginine
and arginine metabolite levels due to administration of pegzilarginase in patients with Arginase 1 Deficiency, and a
reduction in blood arginine levels due to pegzilarginase in patients with advanced solid tumors, these data may not
necessarily be predictive of the final results of all patients intended to be enrolled in our ongoing or future clinical trials,
and may also not be predictive of pegzilarginase’s ability to reduce arginine or arginine metabolite levels for these patients
over a longer term nor predictive of positive clinical outcomes. In addition, while we intend to announce interim data from
our clinical trials from time to time, such reports may be based on unaudited data provided by our clinical trial
investigators. An audit or subsequent review of this data may change the conclusions drawn from this unaudited data
provided by our clinical trial investigators indicating less promising results than we anticipate. In addition, our observations
of clinical improvements, through clinician and assessor feedback or assessment tools in the Phase 1/2 clinical trial and
Phase 2 open-label study of pegzilarginase in patients with Arginase 1 Deficiency after cumulative doses, may not be
representative of our observations with subsequently dosed patients out to a similar or longer duration of cumulative
dosing.

We completed enrollment in our single, global pivotal PEACE Phase 3 clinical trial to evaluate the safety and
efficacy of pegzilarginase in patients with Arginase 1 Deficiency. Due to COVID-19, all of our clinical trial sites temporarily
suspended screening, limiting patient access, and resulting in some missed dosing appointments for patients. All patients
that had initially paused dosing due to COVID-19 had restarted treatment by September 2020. In addition, while we
initiated dosing in our Phase 1/2 clinical trial investigating AGLE-177 for the treatment of Homocystinuria in June 2021,
the timing of continued enrollment may be delayed in the future due to the impact of COVID-19 and local restrictions.
Additionally, missed doses by patients in the study may adversely affect the usefulness of the data collected in the trial.

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Furthermore, while we have conducted prior clinical trials of pegzilarginase in certain oncology indications, we are

currently exploring partnership opportunities for further development in oncology. It is impossible to predict when or if any
of our product candidates will prove effective or safe in humans or will receive regulatory approval.

We may experience delays in our ongoing and planned clinical trials and we do not know whether planned clinical

trials will begin or enroll subjects on time, whether enrolled subjects will complete trials on time or at all, whether they will
need to be redesigned or whether they will be able to be completed on schedule, if at all. There can be no assurance that
the Health Authorities will allow us to begin clinical trials or that they will not put any of the trials for any of our product
candidates that enter or have entered clinical development on clinical hold in the future. We may experience numerous
unforeseen events during, or as a result of, clinical trials that could delay or prevent our ability to receive marketing
approval or commercialize our product candidates. Clinical trials may be delayed, suspended or prematurely terminated
because costs are greater than we anticipate or for a variety of reasons, such as:

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delay or failure in reaching agreement with the Health Authorities on a trial design that we are able to execute;
delay or failure in obtaining authorization to commence a trial or inability to comply with conditions imposed by
a regulatory authority regarding the scope or design of a clinical trial;
delays in reaching, or failure to reach, agreement on acceptable clinical trial contracts or clinical trial protocols
with planned trial sites;
modifications to our ongoing and planned clinical trial protocols due to regulatory requirements or decisions
made by regulatory authorities;
geographic complexities of managing the design and completion of clinical trials across different Health
Authorities in the United States, Canada, Europe, etc.;
reports of safety issues, side effects or dose-limiting toxicities, or any additional or more severe safety issues in
addition to those observed to date;
inability, delay, or failure in identifying and maintaining a sufficient number of trial sites, many of which may
already be engaged in other clinical programs;
delay or failure in recruiting and enrolling suitable subjects to participate in one or more clinical trials;
delay or failure in having subjects complete a trial or return for post-treatment follow-up. For instance, two
patients previously dosed in our Phase 1/2 clinical trial of pegzilarginase for the treatment of Arginase 1
Deficiency withdrew from the trial due to personal reasons;
clinical sites and investigators deviating from the trial protocol, failing to conduct the trial in accordance with
regulatory requirements, or dropping out of a trial;
a clinical hold for any of our ongoing or planned clinical trials, including for pegzilarginase, where a clinical hold
in a trial in one indication could result in a clinical hold for clinical trials in other indications;
clinical trials of our product candidates may produce negative or inconclusive results, and we may decide, or
regulators may require us, to conduct more clinical trials than we anticipate or abandon product development
programs;
the number of patients required for clinical trials of our product candidates may be larger than we anticipate,
enrollment in these clinical trials may be slower than we anticipate or insufficient or participants may drop out
of these clinical trials at a higher rate than we anticipate;
we may experience delays or difficulties in the enrollment of patients, including the identification of patients
with Arginase 1 Deficiency and Homocystinuria;
our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations
to us in a timely manner, or at all;
we may have difficulty partnering with experienced CROs that can run our clinical trials effectively;
regulators may require that we or our investigators suspend or terminate clinical research for various reasons,
including noncompliance with regulatory requirements or a finding that the participants are being exposed to
unacceptable health risks or privacy concerns;
the supply or quality of our product candidates or other materials necessary to conduct clinical trials of our
product candidates may be insufficient or inadequate; or
there may be changes in governmental regulations or administrative actions.

If we are required to modify our ongoing clinical trial protocols, conduct additional clinical trials or other testing of our

product candidates beyond those that we currently contemplate, if we are unable to successfully initiate or complete
clinical trials of our product candidates or other testing, if the results of these trials or tests do not demonstrate sufficient
clinical benefit or if our product candidates do not have an acceptable safety profile, we may:

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be delayed in obtaining marketing approval for our product candidates;
not obtain marketing approval at all;
cease development of our product candidates;

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obtain approval for indications or patient populations that are not as broad as intended or desired;
obtain approval with labeling that includes significant use or distribution restrictions or safety warnings that
would reduce the potential market for our product candidates or inhibit our ability to successfully commercialize
our product candidates;
be subject to additional post-marketing restrictions and/or testing requirements; or
have the product removed from the market after obtaining marketing approval.

We do not know whether any of our planned or current nonclinical studies, or ongoing or planned clinical trials, will
need to be restructured or will be completed on schedule, or at all. For example, in June 2017, we delayed enrollment of
pediatric patients in our Phase 1/2 clinical trial of pegzilarginase for the treatment of Arginase 1 Deficiency due to a
difference in opinion with the FDA on data required to support inclusion of pediatric patients. Although we reached an
agreement with the FDA in November 2017 and began dosing pediatric patients, the FDA may require additional
information or studies to be conducted, or impose conditions that could further delay or restrict our other planned clinical
activities in the future. We began our global pivotal PEACE Phase 3 clinical trial in which we are studying plasma arginine
reduction from baseline over 24 weeks as our primary endpoint. However, evidence of stabilization or improvement of
clinical signs and symptoms of Arginase 1 Deficiency, such as our secondary endpoints, consisting of clinical outcome
assessments focused primarily on mobility, as well as clinician and caregiver global impressions of effectiveness, may be
required in addition to the primary endpoint to support approval. Certain of our clinical outcome secondary endpoints are
being measured using motor assessments that have not been previously validated for Arginase 1 Deficiency, including the
gross motor function classification system. Such motor assessments have only been validated in ambulatory children with
cerebral palsy. We believe these motor functional assessments are translatable to Arginase 1 Deficiency patients given
the similarities in symptoms of children with cerebral palsy and the Arginase 1 Deficiency populations, however the FDA
or other Health Authorities may disagree.

Significant nonclinical or clinical trial delays also could shorten any periods during which we may have the exclusive

right to commercialize our product candidates or allow our competitors to bring products to market before we do and
impair our ability to successfully commercialize our product candidates and may materially harm our business and results
of operations.

We may not be able to submit INDs, or foreign equivalents outside of the United States, to commence clinical
trials for product candidates on the timeframes we expect, and even if we are able to, the Health Authorities may
not permit us to proceed with planned clinical trials.

We are currently conducting nonclinical development of our product candidates other than our clinical trials for

ff

pegzilarginase for the treatment of patients with Arginase 1 Deficiency and AGLE-177 for the treatment of patients with
Homocystinuria. Progression of any candidate into clinical trials is inherently risky and dependent on the results obtained
in nonclinical programs, and other potential results such as the results of other clinical programs and results of third-party
programs. If results are not available when expected or problems are identified during therapy development, we may
experience significant delays in clinical development. This may also impact our ability to achieve certain financial
milestones and the expected timeframes to market any of our product candidates. Additionally, commencing any future
clinical trials is subject to finalizing the trial design and submitting an IND, CTA or comparable submission in other
jurisdictions. We plan to advance AGLE-325 for the treatment of patients with Cystinuria through IND-enabling studies in
2022 and potential subsequent initiation of clinical development. Even after we submit an IND, CTA or comparable
submission in other jurisdictions, the Health Authorities could disagree that we have satisfied their requirements to
commence our clinical trials, disagree with our study design, or may change their guidance criteria, which may require us
to complete additional nonclinical studies or amend our protocols or impose stricter conditions on the commencement of
clinical trials. Failure to submit or have effective INDs, CTAs or other comparable foreign equivalents and commence
clinical programs will ultimately limit our opportunity to generate revenue.

Our engineered human enzyme product candidates represent a novel therapeutic approach, which could result in
heightened regulatory scrutiny, delays in clinical development, or delays in our ability to achieve regulatory
approval or commercialization of our product candidates.

Engineered human enzyme products are a new category of therapeutics. Because this is a relatively new and
expanding area of novel therapeutic interventions, there can be no assurance as to the length of the trial period, the
manufacturing and quality control standards required to be met by regulators, the number of patients the Health
Authorities will require to be enrolled in the trials in order to establish the safety, efficacy, purity and potency of engineered
human enzyme products, or that the data generated in these trials will be acceptable to the FDA or another applicable
regulatory authority to support marketing approval.

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We have only initiated clinical trials for pegzilarginase and AGLE-177 for the treatment of certain conditions. We
have not dosed any of our other product candidates in humans. Our existing and future planned clinical trials
may reveal significant adverse events, toxicities or other side effects not seen in our nonclinical studies or early
pproval or market acceptance
stage clinical trials and may result in a safety profile that could inhibit regulatory ar
of any of our product candidates.

ee

In order to obtain marketing approval for any of our product candidates, we must demonstrate the safety and
efficacy of the product candidate for the relevant clinical indication or indications through nonclinical studies and clinical
trials as well as additional supporting data. If our product candidates are associated with undesirable side effects in
nonclinical studies or clinical trials, in monotherapy or combination therapy, or have characteristics that are unexpected,
we may need to interrupt, delay or abandon their development or limit development to more narrow uses or
subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more
acceptable from a risk-benefit perspective.

We completed the double-blind placebo-controlled portion of our global pivotal PEACE Phase 3 trial and

pegzilarginase is continuing to be evaluated in two long-term extension studies in the PEACE Phase 3 trial and a Phase
1/2 open-label extension study for the treatment of patients with Arginase 1 Deficiency. We are also conducting a Phase
1/2 AGLE-177 for the treatment of patients with Homocystinuria. Given the nature of the patient populations enrolled in
these trials, we have observed and expect to continue to observe serious adverse events that could be related or
unrelated to pegzilarginase and could impact the safety or efficacy of pegzilarginase and we may observe serious adverse
events that could be related or unrelated to AGLE-177 and could impact the safety or efficacy of AGLE-177. We have also
dosed, and may continue to dose, patients with pegzilarginase following compassionate use requests. While such patients
are not monitored as part of our ongoing clinical trials, the occurrence of significant adverse events in such patients may
negatively impact the prospects of our programs.

In our prior clinical trials of pegzilarginase for the treatment of patients with advanced solid tumors and for the
treatment of the patients with hematological malignancies AML and MDS, we have observed serious adverse events in
some patients, including death. We have reported results from these trials in which we observed serious adverse events
that were considered possibly or probably related to the administration of pegzilarginase including asthenia, fatigue,
failure to thrive, hypertension, diarrhea, nausea, vomiting, dehydration, dizziness, intracranial hemorrhage, and
encephalopathy. In our completed combination trial of pegzilarginase and pembrolizumab in patients with previously-
treated small cell lung cancer, safety observations were consistent with prior studies of pegzilarginase in patients with
cancer.

In a completed Phase 1/2 clinical trial and an ongoing Phase 2 open-label extension study of pegzilarginase for the

treatment of patients with Arginase 1 Deficiency, we have observed serious adverse events in some patients, including
hypersensitivity and hyperammonemia, which were infrequent, expected and manageable. Hyperammonemia is an
important metabolic effect experienced by some patients with Arginase 1 Deficiency. None of the patients in these trials
discontinued due to adverse events, while three patients discontinued for non-medical reasons.

Subjects in our ongoing and planned clinical trials with pegzilarginase and AGLE-177 may suffer minor, significant,

serious, or even life-threatening adverse events, including those that are drug-related. Subjects in our ongoing and
planned clinical trials may also suffer side effects not yet observed in any of our prior and ongoing clinical or nonclinical
studies, including, but not limited to, toxicities to the nervous system, liver, heart, lung, kidney, blood, pulmonary or
immune system. We have not dosed any of our other product candidates in humans.

Testing in animals, such as our primate studies for pegzilarginase and AGLE-177, may not uncover all side effects in

humans or any observed side effects in animals may be more severe in humans. For example, it is possible that patients’
immune systems may recognize our engineered human enzymes as foreign and trigger an immune response. This risk is
heightened in patients with many genetic enzyme deficiencies who lack the target enzyme, including patients with
Arginase 1 Deficiency that we are treating in our global pivotal PEACE Phase 3 trial, our Phase 2 trial open-label
extension study, and any future clinical trials we conduct for this rare genetic disease or in trials in patients with
Homocystinuria with AGLE-177. In addition, our product candidates such as pegzilarginase and AGLE-177 break down
target amino acids, thereby releasing metabolites into the bloodstream. Some patients may be sensitive to these
metabolites, increasing the risk of an adverse reaction due to treatment, which risk may not be able to be mitigated
through dosing. Finally, although our engineered human enzyme product candidates such as pegzilarginase and AGLE-
177 are engineered from the human genome, pegzilarginase and AGLE-177 are produced in E. coli. This manufacturing
process could lead to the products being more likely to trigger an immune response than we expect.

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To the extent significant adverse events or other side effects are observed in any of our clinical trials, we may have

difficulty recruiting patients to the clinical trial, patients may drop out of our trial, or we may be required to abandon the trial
or our development efforts of that product candidate altogether. Some potential therapeutics developed in the
biotechnology industry that initially showed therapeutic promise in early-stage studies have later been found to cause side
effects that prevented their further development. Even if the side effects do not preclude the drug from obtaining or
maintaining marketing approval, undesirable side effects may inhibit market acceptance of the approved product due to its
tolerability versus other therapies. Any of these developments could materially harm our business, financial condition and
prospects.

ff

Further, toxicities associated with our product candidates may also develop after regulatory approval and lead to the

withdrawal of the product from the market. We cannot predict whether our product candidates will cause organ or other
injury in humans that would preclude or lead to the revocation of regulatory approval based on nonclinical studies or early
stage clinical testing.

If we experience delays or difficulties in the enrollment of patients in our ongoing or planned clinical trials, our
receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or continue our ongoing or planned clinical trials if we are unable to locate and enroll a

sufficient number of eligible patients to participate in these trials as required by the Health Authorities. For example,
although we have completed the double-blind placebo-controlled portion of our PEACE Phase 3 trial and are currently
enrolling in our Phase 1/2 clinical trial investigating AGLE-177 for the treatment of Homocystinuria, the timing of each trial
has been impacted by COVID-19. All of our clinical trial sites for the PEACE Phase 3 trial temporarily suspended
screening, limiting patient access, and resulting in some missed dosing appointments for patients. All patients that had
initially paused dosing due to COVID-19 had restarted treatment by September 2020. Additionally, while we initiated
dosing in our Phase 1/2 clinical trial investigating AGLE-177 for the treatment of Homocystinuria in June 2021, the timing
of continued enrollment may be delayed in the future due to the impact of COVID-19 and local restrictions. Furthermore,
many of our product candidates, including pegzilarginase and AGLE-177, initially target indications that may be
characterized as orphan markets, which can prolong the clinical trial timeline if sufficient patients cannot be enrolled in a
timely manner. Arginase 1 Deficiency is a rare disorder, and there are no published reports of disease prevalence.

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We commissioned a genetic prevalence analysis and based on that analysis estimate the Arginase 1 Deficiency

population is greater than 2,500 patients in the global addressable markets and greater than 1,150 patients in the
territories with regulatory and launch plans underway. The genetic prevalence-based methodology is intended to account
for misdiagnosis of the disease and to address limitations in newborn screening methodology, including naturally low
arginine levels in newborns and lack of geographic availability or standardization of testing. Presently, only 34 U.S. states
perform newborn screening for Arginase 1 Deficiency, and newborn screening is not currently widely performed in
European countries. We estimate the patient population for Homocystinuria in global addressable markets may exceed
30,000 patients, including B6-responsive and B6-non-responsive patients, with approximately 15,000 to 18,000 estimated
B6-non-responsive patients (of which approximately 6,000 to 6,600 are estimated in the key commercial markets of the
United States, France, Germany, Italy, Spain, and the United Kingdom), but we may not be able to continue to enroll the
trial as expected or locate and enroll a sufficient number of eligible patients as required by the Health Authorities, and the
necessary regulatory approvals could be delayed or prevented.

Delays in patient enrollment could result in increased costs, delays in advancing our product development, delays in

testing the effectiveness of our technology or termination of the clinical trials altogether.

Patient enrollment is affected by factors including:

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the impact of COVID-19 and related local restrictions;
the severity of the disease under investigation;
the design of the clinical trial protocol;
the novelty of the product candidate and acceptance by physicians;
the patient eligibility criteria for the study in question;
the size of the total patient population;
the design of the clinical trials;
the perceived risks and benefits of the product candidate under study;
the availability and efficacy of competing therapies and clinical trials;
our payments for conducting clinical trials;
the patient referral practices of physicians;
the ability to monitor patients adequately during and after treatment with the product candidate; and
the proximity and availability of clinical trial sites for prospective patients.

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In addition, some patients with Arginase 1 Deficiency suffer from heightened levels of ammonia, or

hyperammonemia. Horizon Therapeutics plc actively markets both RAVICTI (glycerol phenylbutyrate) and BUPHENYL
(sodium phenylbutyrate) to treat patients with urea cycle disorders suffering from hyperammonemia. Some patients who
may be eligible for our ongoing or planned clinical trials may instead pursue treatment for this aspect of their condition by
taking RAVICTI (glycerol phenylbutyrate). Our inability to enroll a sufficient number of patients for any of our clinical trials
could result in significant delays and could require us to abandon one or more clinical trials altogether. Enrollment delays
in our clinical trials may result in increased development costs for our product candidates and in delays to commercially
launching our product candidates, if approved, which would cause the value of our company to decline and limit our ability
to obtain additional financing.

ff

The safety or efficacy profile of pegzilarginase, or any current or future product candidates, may differ in
combination therapy with other existing or future drugs, and therefore may preclude its further development or
approval, which would materially harm our business.

From time to time, our commercialization strategy may include the combination of our product candidates with third-

parties’ products or product candidates. For example, we completed a combination trial with Merck to evaluate the
combination of pegzilarginase with Merck’s anti-PD-1 therapy, KEYTRUDA®AA (pembrolizumab), for the treatment of
patients with small cell lung cancer. Such combination studies involve additional risks due to their reliance on
circumstances outside our control, such as those relating to the availability and marketability of the third-party product
involved in the study. Additionally, we may be unable to secure and maintain a sufficient supply of such third-party
products when needed on commercially reasonably terms. Any such shortages could cause us to delay or terminate our
combination trials.

It is also difficult to predict the way in which pegzilarginase, or any current or future product candidate, will interact

with third-party products used in combination clinical trials. As a result, such combination trials may demonstrate reduced
efficacy, increase or exacerbate side effects that have been seen with pegzilarginase, or any current or future product
candidate, alone, or result in new side effects that have not previously been identified with pegzilarginase, or any current
or future product candidate, alone. In addition, data obtained from any combination trials may be subject to a variety of
interpretations. For instance, positive data may not guarantee the ability to move forward due to changes in the
competitive or regulatory environment for the treatment of targeted indications, and failure to achieve our primary
endpoints may not necessarily preclude a viable commercial path. Any undesirable side effects, lack of efficacy seen in
combination trials, changing regulatory and commercial requirements for approval, differing interpretation of clinical data
or other unforeseen circumstances may affect our ability to continue with and obtain regulatory approval for the
combination therapy, as well as our ability to continue with and obtain regulatory approval for pegzilarginase
monotherapy.

ff

Further, evaluating pegzilarginase, or any current or future product candidate, in combination with other products in

clinical development may require us to establish collaborations, licensing arrangements or alliances with third parties.
There is no assurance that we will be able to enter into such arrangements on favorable terms, or at all.

Even though we have obtained orphan drug designation for pegzilarginase in the United States and Europe for
the treatment of Arginase 1 Deficiency (hyperargininemia), and for AGLE-177 in the United States and Europe for
the treatment of patients with Homocystinuria, we may not obtain or maintain orphan drug exclusivity for
pegzilarginase or AGLE-177 and we may not obtain orphan drug designation or exclusivity for any of our other
product candidates or indications.

UU

Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs or
biologics for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a
product as an orphan drug if it is a drug or biologic intended to treat a rare disease or condition, which is generally defined
as a patient population of fewer than 200,000 individuals in the United States. Similarly, the European Commission may
designate a product as an orphan drug under certain circumstances.

Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for the
indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes
the FDA or the EMA from approving another marketing application for the same drug for the same disease for that time
period. The applicable period is seven years in the United States and ten years in the European Union. The European
exclusivity period can be reduced to six years if a drug no longer meets the criteria for orphan drug designation or if the
drug is sufficiently profitable so that market exclusivity is no longer justified. Orphan drug exclusivity may be lost if the
FDA or EMA determines that the request for designation was materially defective or if the manufacturer is unable to
assure sufficient quantity of the drug to meet the needs of patients with the rare disease or condition.

37

We have obtained orphan drug designation in the United States and Europe for pegzilarginase for the treatment of
patients with Arginase 1 Deficiency. We have also received orphan drug designation in the United States and Europe for
AGLE-177 for the treatment of patients with Homocystinuria. This orphan drug exclusivity prevents the FDA or EMA from
approving another application, including a Biologics License Application, or BLA, in the United States or a MAA in the
European Union, to market a drug containing the same principal molecular structural features for the same orphan
indication, except in very limited circumstances, including when the FDA or the EMA concludes that the later drug is safer,
more effective or makes a major contribution to patient care. In addition, a designated orphan drug may not receive
orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan
designation.

Even though we have received orphan drug designation for pegzilarginase for the treatment of Arginase 1
Deficiency in the United States and Europe, and for AGLE-177 for the treatment of patients with Homocystinuria in the
United States and Europe, we may not be the first to obtain marketing approval for the orphan-designated indication in
these jurisdictions due to the uncertainties associated with developing pharmaceutical product candidates. We may also
seek to obtain orphan drug designations in other international jurisdictions. However, there is no guarantee that we would
be able to do so on a timely basis, or at all. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity
may not effectively protect the product from competition because different drugs with different active moieties can be
approved for the same condition or a drug with the same principal molecular structural features can be approved for a
different indication. Orphan drug designation by FDA or EMA neither shortens the development time or regulatory review
time of a drug nor gives the drug any advantage in the regulatory review or approval process. In addition, even if we
intend to seek orphan drug designation for other product candidates or indications, we may never receive such
designations or obtain orphan drug exclusivity.

A Rare Pediatric Disease designation by the FDA does not guarantee that the NDA or BLA for the
product will
qualify for a priority review voucher upon approval, and it does not lead to a faster development or regulatory
review process, or increase the likelihood that any of our product candidates will rll eceive marketing approval.

FF

rr

ff

Under the Rare Pediatric Disease Priority Review Voucher program, upon the approval of a qualifying BLA or NDA

for the treatment of a rare pediatric disease, the sponsor of such an application would be awarded a transferable rare
pediatric disease priority review voucher that can be used to obtain priority review for a subsequent BLA or NDA. In
September 2018, the FDA notified us that we obtained Rare Pediatric Disease designation for pegzilarginase for the
treatment of patients with Arginase 1 Deficiency, and in November 2020, the FDA notified us that we obtained Rare
Pediatric Disease designation for AGLE-177 for the treatment of Homocystinuria. On December 27, 2020, the Creating
Hope Reauthorization Act extended the Rare Pediatric Disease Priority Review Voucher Program, and after September
30, 2024, the FDA may only award a voucher for an approved rare pediatric disease product application if the sponsor
has rare pediatric disease designation for the drug, and that designation was granted by September 30, 2024. After
September 30, 2026, the FDA may not award any rare pediatric disease priority review vouchers. However, there is no
guarantee that any of our product candidates will be approved by that date, or at all, and, therefore, we may not be in a
position to obtain a priority review voucher prior to expiration of the program, unless Congress further reauthorizes the
program. Additionally, designation of a drug for a rare pediatric disease does not guarantee that a BLA will meet the other
eligibility criteria for a rare pediatric disease priority review voucher at the time the application is approved. Finally, a Rare
Pediatric Disease designation does not lead to faster development or regulatory review of the product, or increase the
likelihood that it will receive marketing approval.

ff

Failure to obtain marketing approval in international jurisdictions would prevent our product candidates from
being marketed abroad.

In order to market and sell our products in the European Union and many other jurisdictions, we or our third-party

collaborators must obtain separate marketing approvals and comply with numerous and varying regulatory requirements.
The approval procedure varies among countries and can involve additional testing and different criteria for approval. The
time required to obtain approval may differ substantially from that required to obtain FDA approval. The regulatory
approval process outside the United States generally includes all of the risks associated with obtaining FDA approval. In
addition, in many countries outside the United States, it is required that the product be approved for reimbursement before
the product can be approved for sale in that country. We, or our third-party collaborators, may not obtain approvals from
regulatory authorities outside the United States on a timely basis, if at all. Approval by the FDA does not ensure approval
by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside the United
States does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. However,
failure to obtain approval in some countries or jurisdictions may compromise our ability to obtain approval elsewhere. We
may not be able to file for marketing approvals and may not receive necessary approvals to commercialize our products in
any market.

38

We or third parties may not be successful in developing diagnostic assays, or enhanced biomarker approaches,
if required for our product candidates.

ff

In developing a product candidate for some indications, we may decide to use a biomarker-based test to identify
patients for enrollment and, or, monitor patients in clinical trials or in the commercial environment, which could require
development of new and/or modification of existing biochemical monitoring approaches. In such case, the FDA may
require the development and regulatory approval of a companion diagnostic assay as a condition to approval of the
product candidate. Alternatively, there may be clinical benefits for some enzyme-based therapies in enhancing currently
available biochemical monitoring approaches. While we are not aware of any precedents requiring such approaches for
regulatory approval, FDA or other regulatory authorities could request that new biochemical monitoring approaches are
available to support some product candidates. Clinical trials that utilize a biomarker-based test to select patients are likely
to take longer and require additional funding. We do not have experience or capabilities in developing or commercializing
these companion diagnostics and plan to rely in large part on third parties to perform these functions. Some diagnostic
assays are subject to regulation by the FDA as medical devices and require separate regulatory approval prior to the use
of such diagnostic assays with a therapeutic product candidate. If we, or any third parties that we engage to assist us, are
unable to successfully develop companion diagnostic assays for use with our product candidates, or experience delays in
development, we may be unable to identify patients with the specific profile targeted by our product candidates for
enrollment in our clinical trials. Accordingly, further investment may be required to further develop or obtain the required
regulatory approval for the relevant diagnostic assay, which would delay or substantially impact our ability to conduct
further clinical trials or obtain regulatory approval. In addition, if a companion diagnostic is necessary for any of our
product candidates, a delay in the development of the assay, or the delay or failure to obtain regulatory approval of the
companion diagnostic would delay or prevent the approval of the therapeutic product candidate. Alternatively, we may
also make the decision that our therapy does not require a companion diagnostic, however the Health Authorities may
disagree and require the development and regulatory approval of a companion diagnostic assay as a condition of
approval of the product candidate, creating additional costs and a delay in bringing our product candidate to market.

We expect to expand our development and regulatory capabilities and potentially implement commercialization
capabilities, and, as a result, we may encounter difficulties in managing
operations.

our growth, whiww ch could disrupt our

rr

We expect to experience significant growth in the number of our employees and the scope of our operations,
particularly in the areas of product candidate development, regulatory affairs and, if any of our product candidates
receives marketing approval, sales, marketing, access, reimbursement, and distribution.

We currently do not have a fully integrated commercial team to distribute and market our product candidates
following regulatory approval, if approved. In order to commercialize any product candidates, we must build on a territory-
by-territory basis marketing, sales, distribution, managerial and other non-technical capabilities or make arrangements
with third parties to perform these services, and we may not be successful in doing so. If our product candidates receive
regulatory approval, we intend to establish a fully integrated commercial organization with technical expertise and
supporting distribution capabilities to commercialize our product candidates, which will be expensive and time consuming
and will require significant attention of our executive officers to manage. We will also have to compete with other
pharmaceutical and biotechnology companies to recruit, hire, train and retain commercial personnel. Any failure or delay
in the development of our internal sales, marketing, access, reimbursement, and distribution capabilities would adversely
impact the commercialization of any of our product candidates that we obtain approval to market.

ff

With respect to the commercialization of all or certain of our product candidates, we may choose to collaborate,
either globally or on a territory-by-territory basis, with third parties that have direct sales forces and established distribution
systems, either to augment our own sales force and distribution systems or in lieu of our ow
systems. In particular, we have and expect to continue to partner with third parties to commercialize pegzilarginase
outside the United States. For example, in March 2021, we entered into a licensing agreement with Immedica, in which
Immedica acquired the product rights for commercialization of pegzilarginase in the European Economic Area and certain
Middle East jurisdictions. We may have little or no control over the marketing and sales efforts of such third parties and
our revenue from product sales may be lower than if we had commercialized our product candidates ourselves. We also
face competition in our search for third parties to assist us with the sales and marketing efforts of our product candidates.
If we are unable to enter into such arrangements when needed on acceptable terms, or at all, we may not be able to
successfully commercialize any of our product candidates that receive regulatory approval or any such commercialization
may experience delays or limitations. If we are not successful in commercializing our product candidates, either on our
own or through collaborations with one or more third parties, our future product revenue will suffer and we may incur
significant additional losses.

n sales force and distribution

To manage our anticipated future growth, we must continue to implement and improve our managerial, operational

and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our
limited financial resources and the limited experience of our management team in managing a public company with such

39

anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train
additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our
management and business development resources. Any inability to manage growth could delay the execution of our
business plans or disrupt our operations.

We may not be successful in our efforts to identify additional product candidates. Due to our limited resources
and access to capital, we must prioritize development of certain product candidates, which may prove to be
wrong and may adversely affect our business.

vv

Although we intend to explore other therapeutic opportunities, in addition to the product candidates that we are

currently developing, we may fail to identify viable new product candidates for clinical development for a number of
reasons. If we fail to identify additional potential product candidates, our business could be materially harmed.

Research programs to pursue the development of our existing and planned product candidates for additional
indications and to identify new product candidates and disease targets require substantial technical, financial and human
resources whether or not they are ultimately successful. Our research programs may initially show promise in identifying
potential indications and/or product candidates, yet fail to yield results for clinical development for a number of reasons,
including:

•

•

•

•

the research methodology used may not be successful in identifying potential indications and/or product
candidates;
potential product candidates may, after further study, be shown to have harmful adverse effects or other
characteristics that indicate they are unlikely to be effective drugs;
it may take greater human and financial resources than we will possess to identify additional therapeutic
opportunities for our product candidates or to develop suitable potential product candidates through internal
research programs, thereby limiting our ability to develop, diversify and expand our product portfolio; or
alternative research or therapeutic methodologies may be more efficient than the research approaches
provided by Aeglea.

ff

ff

Because we have limited financial and human resources, we intend to initially focus on research programs and
product candidates for a limited set of indications. As a result, we may forego or delay pursuit of opportunities with other
product candidates or for other indications that later prove to have greater commercial potential or a greater likelihood of
success. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable
market opportunities.

Accordingly, there can be no assurance that we will ever be able to identify additional therapeutic opportunities for

our product candidates or to develop suitable potential product candidates through internal research programs, which
could materially adversely affect our future growth and prospects. We may focus our efforts and resources on potential
product candidates or other potential programs that ultimately prove to be unsuccessful.

Risks Related to Commercialization

If the market opportunities for our product candidates are smaller than we believe they are, our future product
revenues may be adversely affected, and our business may suffer.

Our understanding of both the number of people who suffer from conditions such as Arginase 1 Deficiency or
Homocystinuria, as well as the potential subset of those who have the potential to benefit from treatment with our product
candidates, are based on estimates. We expect our product candidates targeting rare diseases to target a smaller subset
of patient populations that suffer from the respective diseases we seek to treat. These estimates may prove to be
incorrect and new studies may reduce the estimated incidence or prevalence of these diseases. The number of patients in
the United States, Europe or elsewhere may turn out to be lower than expected, may not be otherwise amenable to
treatment with our product candidates or patients may become increasingly difficult to identify and access, all of which
would adversely affect our business, financial condition, results of operations and prospects.

40

Further, there are several factors that could contribute to making the actual number of patients who receive our

potential product candidates less than the potentially addressable market. These include the lack of widespread
availability of, and limited reimbursement for, new therapies in many underdeveloped markets. Additionally, our
assumptions regarding the addressable market may be incorrect and the addressable market may change over time,
including from the announcement date of a product candidate to the approval by Health Authorities and
commercialization. Even if we obtain significant market share for our product candidates, because certain of the potential
target populations are small, we may never achieve profitability without obtaining regulatory approval for additional
indications.

Even if any of our product candidates receives marketing approval, it may fail to achieve the degree of market
acceptance by physicians, patients, third-party payors and others in the medical community necessary for
commercial success.

Even if any of our product candidates receives marketing approval, it may nonetheless fail to gain sufficient market

acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial
success. Current treatments for Arginase 1 Deficiency and Homocystinuria include dietary protein restrictions and forff
Arginase 1 Deficiency, in some instances, ammonia-scavenging drugs such as RAVICTI (glycerol phenylbutyrate). If our
product candidates do not achieve an adequate level of acceptance, we may never generate significant product revenues
and we may not become profitable. The degree of market acceptance of our product candidates, if approved for
commercial sale, will depend on a number of factors, including:

•
•
•
•

•

•
•
•
•
•
•

their efficacy, safety and other potential advantages compared to alternative treatments;
our ability to offer them for sale at competitive prices;
their convenience and ease of administration compared to alternative treatments;
the willingness of the target patient population to try new therapies and of physicians to prescribe these
therapies;
the ability of healthcare professionals to accurately identify and diagnose patients with the relevant/indicated
condition;
the strength of marketing and distribution support;
the availability of third-party payor coverage and adequate reimbursement for our product candidates;
the prevalence and severity of their side effects;
any restrictions on the use of our product candidates together with other medications;
interactions of our product candidates with other products patients are taking; and
inability of patients with certain medical histories to take our product candidates.

We face significant competition from other biotechnology and pharmaceutical companies and our operating
results will suffer if we fail to compete effectively.

The biotechnology and pharmaceutical industries are intensely competitive. We have competitors both in the United
States and internationally, including major multinational pharmaceutical companies, biotechnology companies, universities
and other research institutions. Many of our competitors have substantially greater financial, technical and other
resources, such as larger research and development staff and experienced marketing and manufacturing organizations
and well-established sales forces. Competition may increase further as a result of advances in the commercial
applicability of technologies and greater availability of capital for investment in these industries. Our competitors may
succeed in developing, acquiring or licensing, on an exclusive basis, product candidates that are more effective or less
costly than any product candidate that we are currently developing or that we may develop.

There are multiple approved treatments and investigational therapies for the management of hyperammonemia
commonly experienced by patients with urea cycle disorders. While these products – known as ammonia scavengers – do
not target the core metabolic defect of Arginase 1 Deficiency, they can help patients manage their elevated ammonia
levels. Horizon Therapeutics plc actively markets two branded ammonia scavenger therapies (RAVICTI (glycerol
phenylbutyrate) and BUPHENYL (sodium phenylbutyrate)), and at least one generic formulation of sodium phenylbutyrate
is commercially available. From a clinical development perspective, Acer Therapeutics Inc. is developing a taste-masked,
immediate-release formulation of sodium phenylbutyrate (ACER-001) for the treatment of hyperammonemia and in 2021
announced their intent to enter a global development and commercialization agreement with Relief Therapeutics Holding
AG. In October 2021, Acer announced that the FDA has accepted for filing the NDA for ACER-001 and has assigned a
PDUFA target action date of June 5, 2022.

We anticipate a competitive landscape in Homocystinuria. There is currently one FDA-approved therapy for the

treatment of Homocystinuria and multiple medical foods. CYSTADANE® (betaine anhydrous for oral solution) was
approved by the FDA in 1986 and is currently marketed in North America by Recordati Rare Diseases Inc. We are also

41

the treatment of Homocystinuria. Travere Therapeutics

aware of one investigational therapy in clinical development forff
Inc. is focused on the development of pegtibatinase, an enzyme replacement therapy in patients with Homocystinuria due
to cystathionine β-synthase deficiency. Travere released topline data in December 2021 from its Phase 1/2 study of
pegtibatinase which showed a 55% reduction in homocysteine at the highest dose cohort (1.5mg/kg, 2x/week). We are
aware of three other investigational therapies in preclinical stages. The first is Synlogic, studying SYNB1353, an oral
synthetic biotic platform that consumes toxic metabolites in the GI tract. Synlogic presented pre-clinical data on this
molecule at ICIEM in November 2021. The second is Codexis, studying CDX-6512, an oral methionine-gamma-lyase
enzyme therapy. Codexis also presented pre-clinical data on this molecule at ICIEM in November 2021. Additionally,
Erytech Pharma SA has a product candidate for Homocystinuria in preclinical development. It is possible that competitors
may produce, develop, and commercialize therapeutics, or utilize other approaches to treat Homocystinuria.

Our ability to compete successfully will depend largely on our ability to leverage our experience in product candidate

discovery and development to:

•
•
•
•
•
•

discover and develop product candidates that are sufficiently differentiated from other products in the market;
attract qualified management, scientific, product development and commercial personnel;
obtain and maintain patent and/or other proprietary protection for our product candidates and technologies;
obtain required regulatory approvals;
successfully launch and commercialize our approved products; and
successfully collaborate with research institutions or pharmaceutical companies in the discovery, development
and commercialization of new product candidates.

The availability and price of our competitors’ products could limit the demand, and the price we are able to charge,

for any of our product candidates, if approved. We will not achieve our business plan if acceptance is inhibited by price
competition or the reluctance of patients, physicians, or payers to accept our product candidates.

Established biotechnology companies may invest heavily to accelerate discovery and development of products that

could make our product candidates less competitive. In addition, any new product that competes with an approved
product must demonstrate compelling advantages in efficacy, convenience, tolerability and/or safety to establish a
meaningfully differentiated value proposition for patients, physicians, and payers. Accordingly, our competitors may
succeed in obtaining patent protection, receiving FDA or non-U.S. regulatory approval or discovering, developing and
commercializing product candidates before we do, which would have a material adverse impact on our business. Many of
our competitors have greater resources than we do and have established sales, marketing, and market access
capabilities, whether internally or through third parties. We will not be able to successfully commercialize our product
candidates without establishing sales and marketing capabilities internally or through strategic partners.

The insurance coverage and reimbursement status of newly-approved products is uncertain. Failure to obtain or
maintain adequate coverage and reimbursement for new or current product candidates could limit our ability to
market those product candidates and decrease our ability to generate revenue.

tt

The availability and extent of reimbursement by governmental and private payors is essential for most patients to be

able to afford expensive treatments. Sales of any of our product candidates that receive marketing approval will depend
substantially, both in the United States and internationally, on the extent to which the costs of our product candidates will
be paid by health maintenance, managed care, pharmacy benefit and similar healthcare management organizations, or
reimbursed by government health administration authorities, private health coverage insurers and other third-party payors.
If reimbursement is not available, or is available only to limited levels, we may not be able to successfully commercialize
our product candidates. Even if coverage is provided, the approved reimbursement amount may not be high enough to
allow us to establish or maintain pricing sufficient to realize a sufficient return on our investment.

There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In

the United States, the principal decisions about reimbursement for new products are typically made by the Centers for
Medicare & Medicaid Services, or CMS, an agency within the U.S. Department of Health and Human Services since CMS
decides whether and to what extent a new product will be covered and reimbursed under Medicare. Private payors tend to
follow CMS to a substantial degree. It is difficult to predict what CMS will decide with respect to reimbursement for novel
products such as ours since there is no body of established practices and precedents for these new products.
Reimbursement agencies in Europe may be more conservative than CMS. For example, a number of cancer drugs have
been approved for reimbursement in the United States and have not been approved for reimbursement in certain
European countries.

Outside the United States, international operations are generally subject to extensive governmental price controls

and other market regulations, and we believe the increasing emphasis on cost-containment initiatives in Europe, Canada

42

and other countries has and will continue to put pressure on the pricing and usage of therapeutics such as our product
candidates. In many countries, particularly the UK and the countries of the European Union, the prices of medical
products are subject to varying price control mechanisms as part of national health systems. In these countries, 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. In general, the prices of products
under such systems are substantially lower than in the United States. Other countries allow companies to fix their own
prices for products but monitor and control company profits. Additional foreign price controls or other changes in pricing
regulation could restrict the amount that we are able to charge for our product candidates. Accordingly, in markets outside
the United States, the reimbursement for our products may be reduced compared with the United States and may be
insufficient to generate commercially reasonable revenues and profits.

ff

Moreover, increasing efforts by governmental and third-party payors, in the United States and internationally, to cap

or reduce healthcare costs may cause such organizations to limit both coverage and level of reimbursement for new
products approved and, as a result, they may not cover or provide adequate payment for our product candidates. The
U.S. government has similarly expressed concerns over the pricing of pharmaceutical products and there can be no
assurance as to how this scrutiny will impact future pricing of pharmaceutical products generally. We expect to experience
pricing pressures in connection with the sale of any of our product candidates due to the trend toward managed
healthcare, the increasing influence of health maintenance organizations and additional legislative changes. The
downward pressure on healthcare costs in general, particularly prescription drugs and surgical procedures and other
treatments, has become very intense. As a result, increasingly high barriers are being erected to the entry of new
products into the healthcare market.

In addition to CMS and private payors, professional organizations can influence decisions about reimbursement forf
new products by determining standards for care. In addition, many private payors contract with commercial vendors who
sell software that provide guidelines that attempt to limit utilization of, and therefore reimbursement for, certain products
deemed to provide limited benefit to existing alternatives. Such organizations may set guidelines that limit reimbursement
or utilization of our product candidates.

f

Furthermore, some of our target indications, including for Arginase 1 Deficiency for pegzilarginase and

Homocystinuria for AGLE-177, are orphan indications where patient populations are small. In order for therapeutics that
are designed to treat smaller patient populations to be commercially viable, the reimbursement for such therapeutics must
be higher, on a relative basis, to account for the lack of volume. Accordingly, we will need to implement a coverage and
reimbursement strategy for any approved product candidate that accounts for the smaller potential market size. If we are
unable to establish or sustain coverage and adequate reimbursement for any future product candidates from third-party
payors, the adoption of those products and sales revenue will be adversely affected, which, in turn, could adversely affect
the ability to market or sell those product candidates, if approved, and ultimately our financial results.

ff

Our product candidates for which we intend to seek approval as biologic products may face competition sooner
than anticipated.

With the enactment of the Biologics Price Competition and Innovation Act of 2009, or BPCIA, an abbreviated
pathway for the approval of biosimilar biological products (both highly similar and interchangeable biological products)
was created. The abbreviated regulatory pathway establishes legal authority for the FDA to review and approve biosimilar
biologics, including the possible designation of a biosimilar as interchangeable based on its similarity to an existing
reference product. Under the BPCIA, an application for a biosimilar product cannot be approved by the FDA until 12 years
after the first licensure of date of the reference product licensed under a BLA. On March 6, 2015, the FDA approved the
first biosimilar product under the BPCIA and on July 28, 2021, approved the first interchangeable biosimilar. However, the
law is complex and is still being interpreted and implemented by the FDA. As a result, its ultimate impact, implementation,
and meaning are subject to uncertainty. While it is uncertain when the processes intended to implement BPCIA may be
fully adopted by the FDA, any such processes could have a material adverse effect on the future commercial prospects
for our biological products.

43

A biological product submitted for licensure under a BLA is eligible for a period of exclusivity that commences on the

date of its licensure, unless its date of licensure is not considered a date of first licensure because it falls within an
exclusion under the BPCIA. There is a risk that this exclusivity could be shortened due to congressional action or
otherwise, potentially creating the opportunity for biosimilar competition sooner than anticipated. Additionally, this period
of regulatory exclusivity does not apply to companies pursuing regulatory approval via their own traditional BLA, rather
than via the abbreviated pathway. Most states have enacted substitution laws that permit substitution of only
interchangeable biosimilars. The extent to which a biosimilar, once approved, will be substituted for any one of our
reference products that may be approved in a way that is similar to traditional generic substitution for non-biological
products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.

If we fail to develop additional product candidates, our commercial opportunity will be limited.

ii

Developing and obtaining regulatory approval for and commercializing any additional product candidates we identify
will require substantial additional funding and is prone to the risks of failure inherent in medical product development. We
cannot provide you any assurance that we will be able to successfully advance additional product candidates, if any,
through the development process.

Even if we receive FDA approval to market additional product candidates for the treatment of the diseases we target,

we cannot assure you that any such product candidates will be successfully commercialized, widely accepted in the
marketplace or more effective than other commercially available alternatives. If we are unable to successfully develop and
commercialize additional product candidates, our commercial opportunity will be limited. Moreover, a failure in obtaining
regulatory approval of additional product candidates may have a negative effect on the approval process of other product
candidates of ours or result in losing approval of any approved product candidate.

If in the future we are unable to establish U.S. or global sales and marketing capabilities or enter into agreements
with third parties to sell and market our product candidates, we may not be successful in commercializing our
product candidates if they are approved, thus limiting our ability to generate any product revenue.

We do not yet have a fully integrated commercial organization with all of the functions required to market, sell and

distribute our product candidates that may receive regulatory approval. In order to commercialize any product candidates
after approval, we must build on a territory-by-territory basis marketing, sales, distribution, managerial and other non-
technical capabilities or make arrangements with third parties to perform these services, and we may not be successful in
doing so. If our product candidates receive regulatory approval, we may decide to establish an internal sales or marketing
team with technical expertise and supporting distribution capabilities to commercialize our product candidates, which will
be expensive and time-consuming and will require significant attention of our executive officers to manage. Any failure or
delay in the development of our internal sales, marketing and distribution capabilities would adversely impact the
commercialization of any of our product candidates that we obtain approval to market.

ff

With respect to the commercialization of all or certain of our product candidates, we may choose to collaborate,
either globally or on a territory-by-territory basis, with third parties that have direct sales forces and established distribution
systems, either to augment our own sales force and distribution systems or in lieu of our ow
systems. In particular, we have and expect to continue to partner with third parties to commercialize pegzilarginase
outside the United States. In March 2021, we entered into a license and supply agreement with Immedica, in which
Immedica acquired the product rights for commercialization of pegzilarginase for certain territories outside the U.S. If we
are unable to enter into or maintain such arrangements when needed on acceptable terms, or at all, we may not be able
to successfully commercialize any of our product candidates that receive regulatory approval or any such
commercialization may experience delays or limitations. If we are not successful in commercializing our product
candidates, either on our own or through collaborations with one or more third parties, our future product revenue will
suffer and we may incur significant additional losses.

n sales force and distribution

If we obtain approval to commercialize our product candidates outside of the United States, in particular in the
EU, a variety of risks associated with international

operations could materially adversely affect our business.

UU

vv

We expect that we will be subject to additional risks in commercializing our product candidates outside the United

States, including:

44

•
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•

ff

different regulatory requirements for approval of drugs and biologics in foreign countries;
different processes and requirements to obtain adequate reimbursement for our approved therapies;
reduced protection for intellectual property rights;
unexpected changes in tariffs, trade barriers and regulatory requirements;
economic weakness, including inflation, or political instability in particular foreign economies and markets;
compliance with tax, employment, immigration and labor laws for employees living or traveling abroad;
foreign currency fluctuations, which could result in increased operating expenses and reduced revenues, and
other obligations incident to doing business in another country;
workforce uncertainty in countries where labor unrest is more common than in the United States;
production shortages resulting from any events affecting raw material supply or manufacturing capabilities
abroad; and
business interruptions resulting from geopolitical actions, including war and terrorism or natural disasters
including earthquakes, typhoons, floods and fires.

ff

Risks Related to Our Reliance on Third Parties

We currently rely and will rely on third parties to conduct our ongoing and future planned clinical trials, and
those third parties may not perform satisfactorily, including failing to meet deadlines for the completion of such
trials.

We currently rely and will continue to rely on third parties to provide manufacturing and clinical development

capabilities. For example, we currently rely on third party contract manufacturing organizations, to manufacture and
supply nonclinical and clinical trial quantities of our lead product candidate, pegzilarginase, AGLE-177, and for additional
pipeline product candidates. We also expect to continue to rely on such third parties to manufacture and supply
commercial quantities of pegzilarginase, as well as AGLE-177 forff

our Phase 1/2 clinical trial.

We rely on third-party CROs to conduct our ongoing and future planned clinical trials of pegzilarginase and AGLE-

177. We do not plan to independently conduct clinical trials of our other product candidates. These agreements might
terminate for a variety of reasons, including a failure to perform by the third parties. If we need to enter into alternative
arrangements, that would delay our product development activities.

Our reliance on these third parties for research and development activities will reduce our control over these
activities but will not relieve us of our responsibilities. For example, we will remain responsible for ensuring that each of
our ongoing and future planned clinical trials is conducted in accordance with the general investigational plan and
protocols for the trial. Moreover, the FDA requires us to comply with regulatory standards, commonly referred to as good
clinical practices for conducting, recording and reporting the results of clinical trials to assure that data and reported
results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. Other
countries’ regulatory agencies also have requirements for clinical trials with which we must comply. We also will be
required to register ongoing clinical trials and post the results of completed clinical trials on a government-sponsored
database, ClinicalTrials.gov, within specified timeframes. Failure to do so can result in fines, adverse publicity and civil
and criminal sanctions.

Furthermore, these third parties may also have relationships with other entities, some of which may be our

competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or
conduct our ongoing and future planned clinical trials in accordance with regulatory requirements or our stated protocols,
we will not be able to complete our clinical trials, obtain, or may be delayed in obtaining, marketing approvals for our
product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our product
candidates. Further, to meet the demand for COVID-19 vaccine production, manufacturers are required to prioritize rated
orders issued by the Federal Emergency Management Agency pursuant to the U.S. Defense Production Act of 1950, or
the DPA. The potential for manufacturing facilities and materials to be commandeered under the DPA, or equivalent
foreign legislation, could make it more difficult to obtain materials or manufacturing slots for the products needed for our
clinical trials or commercialization of our product candidates, which could lead to delays in these trials and successful
commercialization.

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We also expect to rely on other third parties to store and distribute drug supplies for our clinical trials. Any

performance failure, including due to COVID-19, on the part of our distributors could delay clinical development or
marketing approval of our product candidates or commercialization of our product candidates, producing additional losses
and depriving us of potential product revenue.

We contract with third parties for the manufacture of our product candidates for nonclinical studies and our
ongoing and future planned clinical testing and expect to continue to do so for commercialization. This reliance
on third parties increases the risk that we will nll ot have sufficient quantities of our product candidates at an
acceptable cost and quality, which could delay, prevent or impair our development or commercialization efforts.

We do not own or operate facilities for the manufacture of our product candidates. We currently have no plans to
build our own clinical or commercial scale manufacturing capabilities. We rely, and expect to continue to rely, on third
parties, for the manufacture of our product candidates for nonclinical studies and for our existing and future planned
clinical trials. We also expect to rely on third parties for commercial manufacture if any of our product candidates receive
marketing approval. This reliance on third parties increases the risk that we will not have sufficient quantities of our
product candidates or such quantities at an acceptable cost or quality, which could delay, prevent or impair our
development or commercialization efforts.

Any performance failure, including due to COVID-19, on the part of our existing or future manufacturers could delay

clinical development or marketing approval. We do not currently have arrangements in place for redundant supply or a
source for bulk drug substance. Currently, third party manufacturers are supplying, and are expected to continue to
supply, the drug substance requirements for our ongoing and planned clinical trials with pegzilarginase and AGLE-177. If
such third party manufacturers cannot supply us with sufficient amounts, pursuant to product requirements as agreed, we
may be required to identify alternative manufacturers, which would lead us to incur added costs and delays in identifying
and qualifying any replacement.

The formulation used in early studies may not be a final formulation for commercialization. If we are unable to

demonstrate that our commercial scale product is comparable to the product used in clinical trials, we may not receive
regulatory approval for that product without additional clinical trials. We have contracted with third party manufacturers for
certain studies related to potential commercial scale manufacturing of pegzilarginase, but there is no guarantee that such
studies, the transfer of technology to or any potential manufacturing at such facility, will be completed successfully, on
time, or at all. We also cannot guarantee that we will be able to make any required modifications within currently
anticipated timeframes or that such modifications, if and when made, will obtain regulatory approval or that the new
processes or modified processes will be successfully implemented by or transferred to any third-party contract suppliers
within currently anticipated timeframes. These may require additional studies and may delay our clinical trials and/or
commercialization.

We expect to rely on third-party manufacturers, or third-party strategic partners for the manufacture of commercial
supply of any product candidates for which our strategic partners or we obtain marketing approval. We may be unable to
establish any additional agreements with third-party manufacturers, or to do so on acceptable terms. Even if we are able
to establish agreements with third-party manufacturers on acceptable terms, such third-party manufacturers may have
limited experience manufacturing pharmaceutical drugs for commercialization, and reliance on third-party manufacturers
for the commercial supply of our products may expose us to various risks, including:

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the possible noncompliance by the third party with regulatory requirements and quality assurance;
the possible breach of the manufacturing agreement by the third party;
the operations of such third parties could be disrupted by conditions unrelated to our business or operations,
including the bankruptcy of such party, the issuance of an FDA Form 483 notice or warning letter, or other
enforcement action by the FDA or other regulatory authority;
the possible misappropriation of our proprietary information, including our trade secrets and know-how; and
the possible termination or nonrenewal of the agreement by the third party at a time that is costly or
inconvenient for us.

Third-party manufacturers may not be able to comply with current good manufacturing practices, or cGMP, or similar

regulatory requirements outside the United States. Although we do not have day-to-day control over third-party
manufacturers’ compliance with these regulations and standards, we are responsible for ensuring compliance with such
regulations and standards. Our failure, or the failure of our third-party manufacturers, to comply with applicable regulations
could result in sanctions being imposed on us, including clinical holds, fines, injunctions, civil penalties, delays,
suspension or withdrawal of approvals, license revocation, seizures or recalls of product candidates, operating restrictions
and criminal prosecutions, any of which would significantly and adversely affect supplies of our product candidates and

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our business. If a third-party manufacturer’s facilities do not pass a pre-approval inspection or do not have a cGMP
compliance status acceptable to the FDA or a comparable foreign regulatory agency, our product candidate will not be
approved.

In addition, the process of manufacturing and administering our product candidates is complex and highly regulated.

As a result of the complexities, our manufacturing and supply costs are likely to be higher than those at more traditional
manufacturing processes and the manufacturing process is less reliable and more difficult to reproduce.

We also expect to rely on other third parties to store and distribute drug supplies for our clinical trials. Any

performance failure on the part of our distributors could delay clinical development or marketing approval of our product
candidates or commercialization of our product candidates, producing additional losses and depriving us of potential
product revenue.

Our product candidates and any products that we may develop may compete with other product candidates and
products for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP
regulations and that might be capable of manufacturing for us.

Our current and anticipated future dependence upon others for the manufacture of our product candidates may
adversely affect our future profit margins and our ability to commercialize any product candidates that receive marketing
approval on a timely and competitive basis.

Failure of any future third-party collaborators to successfully commercialize diagnostics or monitoring assays
developed for use with our therapeutic product candidates could harm our ability to commercialize these product
candidates.

We do not plan to internally develop diagnostics or monitoring assays, or Assays. As a result, we are dependent on
the efforts of our third-party strategic partners to successfully commercialize any needed Assays. Our strategic partners:

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may not perform their obligations as expected;
may encounter production difficulties that could constrain the supply of the Assays;
may have difficulties gaining acceptance of the use of the Assays in the clinical community;
may not pursue commercialization of any Assays;
may elect not to continue or renew commercialization programs based on changes in the strategic partners’
strategic focus or available funding, or external factors, such as an acquisition, that divert resources or create
competing priorities;
may not commit sufficient resources to the marketing and distribution of such Assay product candidates; and
may terminate their relationship with us.

If Assays needed for use with our therapeutic product candidates fail to gain market acceptance, our ability to derive
revenues from sales of these therapeutic product candidates could be harmed. If our strategic partners fail to develop and
commercialize these Assays, it could adversely affect and delay the development or commercialization of our therapeutic
product candidates.

We may not be successful in finding strategic partners for continuing development or commercialization of
certain of our product candidates.

We may seek to develop strategic partnerships for developing certain of our product candidates, due to capital costs

required to develop the product candidates or manufacturing constraints. We also have entered into and expect to enter
into future partnership agreements to commercialize pegzilarginase outside the United States, including through our
licensing agreement with Immedica. We may not be successful in our efforts to establish such a strategic partnership or
other alternative arrangements for our product candidates because our research and development pipeline may be
insufficient, our product candidates may be deemed to be at too early of a stage of development for collaborative effort or
third parties may not view our product candidates as having the requisite potential to demonstrate safety and efficacy. In
addition, we may be restricted under existing collaboration or license and development agreements from entering into
future agreements with potential strategic partners. We cannot be certain that, following a strategic transaction or license,
we will achieve an economic benefit that justifies such transaction.

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If we are unable to reach agreements with suitable strategic partners on a timely basis, on acceptable terms or at all,

we may have to curtail the development of a product candidate, reduce or delay its development program, delay its
potential commercialization, reduce the scope of any sales or marketing activities or increase our expenditures and
undertake development or commercialization activities at our own expense. If we elect to fund development or
commercialization activities on our own, or our existing or future partners are not able to adequately fund their
development or commercialization activities pursuant to our arrangements, we may need to obtain additional expertise
and additional capital, which may not be available to us on acceptable terms or at all. If we fail to enter into collaborations
and do not have sufficient funds or expertise to undertake the necessary development and commercialization activities,
we may not be able to further develop our product candidates and our business, financial condition, results of operations
and prospects may be materially and adversely affected.

We may be subject to claims by third parties asserting that our employees or we have misappropriated their
intellectual property, or claiming ownership of what we regard as our own intellectual property.

Many of our employees were previously employed at universities or other biotechnology or pharmaceutical
companies, including our competitors or potential competitors. Although we try to ensure that our employees do not use
the proprietary information or know-how of others in their work for us, we may be subject to claims that these employees
or we have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such
employee’s former employer. Litigation may be necessary to defend against these claims.

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In addition, while it is our policy to require our employees and contractors who may be involved in the development

of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in
executing such an agreement with each party who in fact develops intellectual property that we regard as our own. Our
and their assignment agreements may not be self-executing or may be breached, and we may be forced to bring claims
against third parties, or defend claims they may bring against us, to determine the ownership of what we regard as our
intellectual property.

If we fail in prosecuting or defending any such claims, in addition to paying monetary damages, we may lose

valuable intellectual property rights or personnel. Even if we are successful in prosecuting or defending against such
claims, litigation could result in substantial costs and be a distraction to management.

Risks Related to Government Regulation

If we are not able to obtain, or if there are delays in obtaining, required regulatory approvals in the United States
or in foreign jurisdictions, we will not be able to commercialize our product candidates, and our ability to
generate revenue will be materially impaired.

Our product candidates must be approved by the FDA pursuant to a BLA in the United States, and by the EMA
pursuant to an MAA, and by other comparable regulatory authorities outside the United States prior to commercialization.
The process of obtaining marketing approvals, both in the United States and internationally, is expensive and takes many
years, if approval is obtained at all, and can vary substantially based upon a variety of factors, including the type,
complexity and novelty of the product candidates involved. The approval procedure varies among countries and can
involve additional testing. The time required to obtain approval in Europe or another non-U.S. jurisdiction may differ
substantially from that required to obtain FDA approval. The regulatory approval process outside the United States
generally includes all of the risks associated with obtaining FDA approval. In addition, in many countries outside the
United States, it is required that the product be approved for reimbursement before the product can be approved for sale
in that country. We or our third-party strategic partners may not obtain approvals from regulatory authorities outside the
United States on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other
countries or jurisdictions, and approval by one regulatory authority outside the United States does not ensure approval by
regulatory authorities in other countries or jurisdictions or by the FDA. Furthermore, the implementation of Brexit may
disrupt the operation of any pre-and post-authorization clinical trial infrastructure and regulatory frameworks in Europe, as
discussed further below. We may not be able to file for marketing approvals and may not receive necessary approvals to
commercialize our product candidates in any market.

Failure to obtain marketing approval for a product candidate will prevent us from commercializing the product

candidate. We have not received approval to market any of our product candidates from regulatory authorities in any
jurisdiction. We have limited experience in filing and supporting the applications necessary to gain marketing approvals
and expect to rely on third-party CROs to assist us in this process. Securing marketing approval requires the submission
of extensive nonclinical and clinical data and supporting information to regulatory authorities for each therapeutic
indication to establish the product candidate’s safety and efficacy. Securing marketing approval also requires the
submission of information about the product manufacturing process to, and inspection of manufacturing facilities by, the
regulatory authorities. Our product candidates may not be effective, may be only moderately effective or may prove to

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have undesirable or unintended side effects, toxicities or other characteristics that may preclude our obtaining marketing
approval or prevent or limit commercial use. Regulatory authorities have substantial discretion in the approval process
and may refuse to accept any application or may decide that our data are insufficient for approval and require additional
nonclinical, clinical or other studies. In addition, varying interpretations of the data obtained from nonclinical and clinical
testing could delay, limit or prevent marketing approval of a product candidate. Changes in marketing approval policies
during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory
review for each submitted product application, may also cause delays in or prevent the approval of an application.

Approval of our product candidates may be delayed or refused for many reasons, including the following:

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the Health Authorities may disagree with the design or implementation of our clinical trials;
we may be unable to demonstrate to the satisfaction of the Health Authorities that our product candidates are
safe and effective for any of their proposed indications;
the results of clinical trials may not meet the level of statistical significance required by the Health Authorities
for approval;
we may be unable to demonstrate that our product candidates’ clinical and other benefits outweigh their safety
risks;
the Health Authorities may disagree with our interpretation of data from nonclinical programs or clinical trials;
the data collected from clinical trials of our product candidates may not be sufficient to the satisfaction of the
Health Authorities to support the submission of a BLA, MAA or other comparable submission in other
jurisdictions or to obtain regulatory approval in the United States or elsewhere;
the potential disruptions and uncertainty caused by Brexit implementation, as discussed below;
the facilities of the third-party manufacturers with which we partner may not be adequate to support approval of
our product candidates; and
the approval policies or regulations of the Health Authorities may significantly change in a manner rendering
our clinical data insufficient for approval.

New products for the treatment of cancer frequently are initially indicated only for patient populations that have not

responded to an existing therapy or have relapsed. If any of our product candidates receives marketing approval, the
approved labeling may limit the use of our product candidates in this way, which could limit sales of the product. Also, any
marketing approval we ultimately obtain may be limited or subject to restrictions or post-approval commitments that render
the approved product not commercially viable.

Additionally, the implementation of the United Kingdom’s exit from the European Union, or “Brexit,” may cause
disruptions and uncertainty in the current regulatory framework in Europe. Brexit has resulted in the EMA moving from the
United Kingdom to the Netherlands. In the United Kingdom, this transition may cause disruption in the administrative and
medical scientific links between the EMA and MHRA. Following the United Kingdom’s departure from the European
Union, it no longer automatically complies with the standards of clinical efficacy, safety and chemistry control, and
manufacture as applied by the European Medicines Directive. Applications submitted for marketing authorization under
the centralized EMA procedure will no longer be automatically validated for authorization in the United Kingdom, and the
benefit-risk assessments conducted by the United Kingdom may not be consistent with the EMA conclusions. The
cumulative effects of the disruption to the regulatory framework may add considerably to the development lead time to
marketing authorization and commercialization of products in the European Union and/or the United Kingdom. In view of
the current lack of detail and resolution with regard to the Brexit transition, we are unable to confidently predict the effects
of such disruption to the regulatory framework in Europe, and as to how this may delay or impair any potential regulatory
approvals, commercialization of any of our product candidates, and our ability to generate potential revenues. If we
experience delays in obtaining approval or if we fail to obtain approval of our product candidates, the commercial
prospects for our product candidates may be harmed and our ability to generate revenues will be materially impaired.

Any Fast Track Designation by the FDA, even if granted for any of our product candidates, may not lead to a
faster development or regulatory review or approval process, and does not increase the likelihood that our
product candidates will receive marketing approval.

We have received Fast Track Designation from the FDA for our lead product candidate pegzilarginase for the
treatment of hyperargininemia secondary to Arginase 1 Deficiency and may seek such designation for some or all of our
product candidates. If a drug or biologic is intended for the treatment of a serious or life-threatening condition and the drug
or biologic demonstrates the potential to address unmet medical needs for this condition, the drug or biologic sponsor may
apply for FDA Fast Track Designation. The FDA has broad discretion whether or not to grant this designation. Even if we
believe a particular product candidate is eligible for this designation, we cannot assure you that the FDA would decide to
grant it. Even though we have received Fast Track Designation for pegzilarginase for the treatment of hyperargininemia

49

secondary to Arginase 1 Deficiency, and even if we receive Fast Track Designation for other product candidates or
indications in the future, we may not experience a faster development process, review or approval compared to
conventional FDA procedures. The FDA may withdraw Fast Track Designation if it believes that the designation is no
longer supported by data from our clinical development program. Many drugs or biologics that have received Fast Track
Designation have failed to obtain approval.

FDA may also consider approval of our products through the use of the accelerated approval program, but such
mechanism may not lead to a faster development or regulatory review or approval process. Even if we receive
approval from the FDA under the accelerated approval program, if our confirmatory postmarketing trial does not
verify clinical benefit, or if we do not comply with rigorous postmarketing requirements, the FDA may seek to
withdraw the approval.

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Under the FDA’s accelerated approval program, the FDA may approve a drug or biologic for a serious or life-

threatening illness that provides meaningful therapeutic benefit to patients over existing treatments based upon a
surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that is thought to predict
clinical benefit but is not itself a measure of clinical benefit, or a biomarker that can be measured earlier than irreversible
morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical
benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative
treatments. The FDA bases its decision on whether to accept the proposed surrogate or intermediate clinical endpoint on
the scientific support for that endpoint. Studies that demonstrate a drug’s effect on a surrogate or intermediate clinical
endpoint must be adequate and well controlled as required by the FDC Act.

If FDA were to consider accelerated approval in the review of an application for any product candidates, the FDA
may determine there is inadequate justification to support that our surrogate endpoint is reasonably likely to predict clinical
benefit in patients.

For drugs or biologics granted accelerated approval, post-marketing well-controlled, adequately powered

confirmatory trials of sufficient duration are typically required to describe the anticipated effect on irreversible morbidity or
mortality or other clinical benefit. These confirmatory trials must be completed with due diligence, and the FDA could
require that the trial be designed, initiated, and/or fully enrolled at the time of BLA submission. Moreover, the FDA may
withdraw approval of our product candidate or indication approved under the accelerated approval pathway if, for
example:

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the trial or trials required to verify the predicted clinical benefit of our product candidate fail to verify such
benefit or do not demonstrate sufficient clinical benefit to justify the risks associated with the drug;
other evidence demonstrates that our product candidate is not shown to be safe or effective under the
conditions of use;
we fail to conduct any required post-approval trial of our product candidate with due diligence; or
we disseminate false or misleading promotional materials relating to the relevant product candidate.

A Breakthrough Therapy Designation by the FDA, even if granted for any of our product candidates, may not lead
to a faster development or regulatory review or approval process, and does not increase the likelihood that our
product candidates will receive marketing approval.

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We have received Breakthrough Therapy Designation from the FDA for our lead product candidate pegzilarginase

for the treatment of Arginase 1 Deficiency and may seek such designation for some or all of our product candidates. A
Breakthrough Therapy is defined as a drug or biologic that is intended, alone or in combination with one or more other
drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug or
biologic may demonstrate substantial improvement over existing therapies with respect to one or more clinically significant
endpoints, such as substantial treatment effects observed early in clinical development. For drugs or biologics that have
been designated as Breakthrough Therapies, interaction and communication between the FDA and the sponsor can help
to identify the most efficient path for development.

Designation as a Breakthrough Therapy is within the discretion of the FDA. Accordingly, even if we believe, after
completing early clinical trials, that one of our product candidates meets the criteria for designation as a Breakthrough
Therapy, the FDA may disagree and instead determine not to make such designation. Even though we have received
Breakthrough Therapy Designation for pegzilarginase for the treatment of Arginase
1 Deficiency, or even if we receive
Breakthrough Therapy Designation for other product candidates
or indications in the future, we may not experience a
faster development process, review or approval compared to drugs or biologics considered for approval under

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conventional FDA procedures and such a designation does not assure ultimate approval by the FDA. In addition, even
though we have received Breakthrough Therapy Designation for pegzilarginase for the treatment of Arginase 1
Deficiency, or if one or more of our other product candidates qualify as Breakthrough Therapies, the FDA may later decide
that such product candidates no longer meet the conditions for qualification.

We may seek priority review designation for one or more of our other product candidates, but we might not
receive such designation, and even if we do, such designation may not lead to a faster regulatory review or
approval process.

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If the FDA determines that a product candidate offers a treatment for a serious condition and, if approved, the

product would provide a significant improvement in safety or effectiveness, the FDA may designate the application forff
such product candidate for priority review. A priority review designation means that the goal for the FDA to review an
application is six months, rather than the standard review period of ten months. We plan to request priority review of our
BLA for pegzilarginase. We may request priority review for applications for our other product candidates. The FDA has
broad discretion with respect to whether or not to grant priority review designation to an application, so even if we believe
an application for a particular product candidate is eligible for such designation, the FDA may decide not to grant it.
Moreover, a priority review designation does not necessarily result in an expedited regulatory review or approval process
or confer any advantage with respect to approval compared to conventional FDA procedures. Receiving priority review
from the FDA does not guarantee approval within the six-month review cycle or at all.

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Any product candidate for which we obtain marketing approval will be subject to extensive post-approval
marketing regulatory requirements and could be subject to post-approval marketing restrictions or withdrawal
from the market, and we may be subject to penalties if we fail to comply with regulatory requirements or if we
experience unanticipated problems with our product candidates, when and if any of them are approved.

Our product candidates and the activities associated with their development and commercialization, including their

testing, manufacture, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, are subject
to comprehensive regulation by the FDA and other regulatory authorities. These requirements include submissions of
safety and other post-marketing information and reports, registration and listing requirements, cGMP, requirements
relating to manufacturing, quality control, quality assurance and corresponding maintenance of records and documents,
including periodic inspections by the FDA and other regulatory authorities, requirements regarding the distribution of
samples to physicians and recordkeeping.

The FDA closely regulates the post-approval marketing and promotion of drugs and biologics to ensure drugs and
biologics are marketed only for the approved indications and in accordance with the provisions of the approved labeling.
The FDA imposes stringent restrictions on manufacturers’ communications regarding use of their products and if we
promote our product candidates beyond their approved indications, we may be subject to enforcement action for off-label
promotion. Violations of the Federal Food, Drug, and Cosmetic Act relating to the promotion of prescription drugs may
lead to investigations alleging violations of federal and state healthcare fraud and abuse laws, as well as state consumer
protection laws.

The FDA may also impose requirements for costly post-approval marketing studies or clinical trials and surveillance
to monitor the safety or efficacy of any approved product. In particular, certain of our product candidates, if approved, are
expected to be dosed chronically, and therefore could require follow-up studies and close monitoring of our patients after
regulatory approval has been granted, to establish broader, longer-term understanding of potential for adverse effects
than is plausible for clinical research. These studies may be expensive and time-consuming to conduct and may reveal
side effects or other harmful effects in patients that use our therapeutic products after they are on the market, which may
result in the limitation or withdrawal of our drugs from the market. Alternatively, we may not be able to conduct such
additional clinical trials, which might force us to abandon our efforts to develop or commercialize certain product
candidates. Even if post-approval studies are not requested or required, after our products are approved and on the
market, there might be safety issues that emerge over time that require a change in product labeling or that require
withdrawal of the product from the market, which would cause our revenue to decline. If we fail to comply with any such
post-approval regulatory requirements, approval for our products may be withdrawn, and product sales may be
suspended. We may not be able to regain compliance, or we may only be able to regain compliance after a lengthy delay,
significant expense, lost revenues and damage to our reputation.

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In addition, later discovery of previously unknown adverse events or other problems with our product candidates,
manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yield various results,
including:

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restrictions on such product candidates, manufacturers or manufacturing processes;
restrictions on the labeling or marketing of a product;
restrictions on product distribution or use;
requirements to conduct post-marketing studies or clinical trials;
warning or untitled letters;
withdrawal of any approved product from the market;
refusal to approve pending applications or supplements to approved applications that we submit;
recall of product candidates;
fines, restitution or disgorgement of profits or revenues;
suspension or withdrawal of marketing approvals;
refusal to permit the import or export of our product candidates;
product seizure; or
injunctions or the imposition of civil or criminal penalties.

Non-compliance with European requirements regarding safety monitoring or pharmacovigilance, and with
requirements related to the development of products for the pediatric population, can also result in significant financial
penalties. Similarly, failure to comply with Europe’s requirements regarding the protection of personal information can also
lead to significant penalties and sanctions.

Our relationships with customers and third-party payors 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 will 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
any product candidates for which we obtain marketing approval. Restrictions under applicable U.S. federal and state
healthcare laws and regulations include the following:

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the federal 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, or in
return for, 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 a federal healthcare program 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, or HIPAA, imposes criminal and civil
liability for executing a scheme to defraud any healthcare benefit program or making false statements relating
to healthcare matters;
HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and its
implementing regulations, also imposes obligations, including mandatory contractual terms, with respect to
safeguarding the privacy, security and transmission of individually identifiable health information;
federal law requires applicable manufacturers of covered drugs to report payments and other transfers of value
to physicians and teaching hospitals, which includes annual data collection and reporting obligations, with
reported information disclosed on a searchable website on an annual basis; and
analogous state and foreign 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.

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 and may require
drug manufacturers to report information related to payments and other transfers of value to physicians and other
healthcare providers or marketing expenditures. Other states require reporting of pricing information, including price
increases. State and foreign laws also govern the privacy and security of health information in some circumstances, many
of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance
efforts.

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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, imprisonment, exclusion of product candidates from government funded healthcare programs,
such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any of the physicians or other
healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws,
they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare
programs.

Recently enacted and future legislation may increase the difficulty and cost for us to obtain marketing approval
of and commercialize our product candidates and affect the prices we may obtain.

In the United States and some foreign jurisdictions, there have been a number of legislative and regulatory changes

and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product
l any product candidates for
candidates, restrict or regulate post-approval activities and affect our ability to profitably sel
which we obtain marketing approval.

ff

In the United States, the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, or the MMA,
changed the way Medicare covers and pays for pharmaceutical products. The legislation expanded Medicare coverage
for drug purchases by the elderly and introduced a new reimbursement methodology based on average sales prices for
physician-administered drugs. In addition, this legislation provided authority for limiting the number of drugs that will be
covered in any therapeutic class. Cost reduction initiatives and other provisions of this legislation could decrease the
coverage and price that we receive for any approved product candidates. While the MMA only applies to drug benefits for
Medicare beneficiaries, private payors often follow Medicare coverage policy and payment limitations in setting their own
reimbursement rates. Therefore, any reduction in reimbursement that results from the MMA may result in a similar
reduction in payments from private payors.

The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act,

or collectively the ACA, is a sweeping law intended to broaden access to health insurance, reduce or constrain the growth
of healthcare spending, enhance remedies against fraud and abuse, add transparency requirements for the healthcare
and health insurance industries, impose new taxes and fees on the health industry and impose additional health policy
reforms. The ACA, among other things, also expanded manufacturers’ rebate liability under the Medicaid Drug Rebate
Program and imposed a significant annual, nondeductible fee on companies that manufacture or import certain branded
prescription drug products.

In addition, other legislative changes have been proposed and adopted since the ACA was enacted. These changes
included aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, starting in 2013. While there
was a suspension of the payment reductions as a result of the COVID-19 pandemic, the reductions are being phased
back in and are currently expected to remain in effect through 2030. In January 2013, the American Taxpayer Relief Act of
2012 was signed into law, which, among other things, reduced Medicare payments to several providers, and increased
the statute of limitations period for the government to recover overpayments to providers from three to five years. On
January 20, 2017, federal agencies with authorities and responsibilities under the ACA were directed to waive, defer,
grant exemptions from, or delay the implementation of any provision of the ACA that would impose a fiscal burden on
states or a cost, fee, tax, penalty or regulatory burden on individuals, healthcare providers, health insurers, or
manufacturers of pharmaceuticals or medical devices. More recently, the Tax Cuts and Jobs Act was signed into law,
which eliminated certain requirements of the ACA, including the individual mandate. On June 17, 2021, the United States
Supreme Court held that plaintiffs do not have standing to challenge the constitutionality of the individual mandate. It is
unclear whether there will be additional challenges to the ACA. Additionally, on January 28, 2021, the President of the
United States issued an executive order to initiate a special enrollment period from February 15, 2021 through May 15,
2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also
instructs certain governmental agencies to review and reconsider their existing policies and rules that limit access to
healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work
requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through
Medicaid or the ACA. It is uncertain how other such litigation or the healthcare measures of the United States
administration will impact the ACA and our business.

more rigorous coverage criteria and in additional downward pressure on the price that we receive for any approved
product. For example, on September 9, 2021, the Biden administration published a wide-ranging list of policy proposals,

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most of which would need to be carried out by Congress, to reduce drug prices and drug payment. The Department of
Health and Human Services plan includes, among other reform measures, proposals to lower prescription drug prices,
including by allowing Medicare to negotiate prices and disincentivizing price increases, and to support market changes
that strengthen supply chains, promote biosimilars and generic drugs, and increase price transparency. Many similar
proposals, including the plans to give Medicare Part D authority to negotiate drug prices, require drug manufacturers to
pay rebates on drugs whose prices increase greater than the rate of inflation, and cap out-of-pocket costs, have already
been included in policy statements and legislation currently being considered by Congress. It is unclear to what extent
these and other statutory, regulatory, and administrative initiatives will be enacted and implemented. Any reduction in
reimbursement from Medicare or other government programs may result in a similar reduction in payments from private
payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to
generate revenue, attain profitability, or commercialize our product candidates.

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and

promotional activities for pharmaceutical products. We cannot be sure whether additional legislative changes will be
enacted, or whether FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on
the marketing approvals of our product candidates, if any, may be. In addition, increased scrutiny by the U.S. Congress of
the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent
product labeling and post-marketing testing and other requirements.

Comprehensive tax reform bills could increase the tax burden on our orphan drug programs and adversely affect
our business and financial condition.

New income, sales, use or other tax laws, statutes, rules, regulations or ordinances could be enacted at any time,

which could adversely affect our business and financial condition. Further, existing tax laws, statutes, rules, regulations or
ordinances could be interpreted, changed, modified or applied adversely to us. For example, the 2017 Tax Cuts and Jobs
Act, among others, reduced the orphan drug credit from 50% to 25% of qualifying expenditures. When and if we become
profitable, this reduction in tax credits may result in an increased federal income tax burden on our orphan drug programs.
On March 27, 2020, the Coronavirus Aid, Relief and Economic Security, or CARES Act, was enacted and modified certain
portions of the 2017 Tax Cuts and Jobs Act, including with respect to the carryforward of net operating losses. Future
changes in corporate tax rates, rules relating to the realization of net deferred tax assets, and other tax legislation could
have a material impact on the value of our deferred tax assets, could result in a significant one-time charges, and could
increase our future U.S. tax expense.

Risks Related to Our Intellectual Property

If we are unable to obtain and maintain intellectual property protection fo
r our technology and product
candidates, or if the scope of the intellectual property protection obtained is not sufficiently broad, our
competitors could develop and commercialize technology and product candidates similar or identical to ours,
and our ability to successfully commercialize our technology and product candidates may be impaired.

tt

We rely upon a combination of patents, trade secret protection and confidentiality agreements to protect the

intellectual property related to our technology and product candidates.

In particular, our success depends in large part on our ability, and our licensors’ ability, to obtain and maintain patent

protection in the United States and other countries with respect to our proprietary technology and product candidates,
including any diagnostic developed by us or a third-party strategic partner. We seek to protect our proprietary position by
filing patent applications in the United States and abroad related to our novel technologies and product candidates and
rely on our licensors to obtain patent protection for our licensed intellectual property. Our patent portfolio includes patents
and patent applications we own or we exclusively license from the University of Texas at Austin. This patent portfolio
includes issued patents and pending patent applications covering compositions of matter and methods of use.

ff

The patent prosecution process is expensive and time-consuming, and we may not be able to file, prosecute,
maintain, enforce or license all necessary or desirable patent applications at a reasonable cost or in a timely manner, or in
all jurisdictions. We may choose not to seek patent protection for certain innovations and may choose not to pursue patent
protection in certain jurisdictions, and under the laws of certain jurisdictions, patents or other intellectual property rights
may be unavailable or limited in scope. It is also possible that we will fail to identify patentable aspects of our discovery
and nonclinical and clinical development output before it is too late to obtain patent protection. Moreover, the risks
pertaining to our patents and intellectual property rights also apply to the intellectual property rights that we license from
third parties. In some circumstances, we do not have the right to control the preparation, filing and prosecution of patent
applications, or to maintain the patents, covering technology that we license from third parties. We may also require the
cooperation of our licensors in order to enforce the licensed patent rights, and such cooperation may not be provided.

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Therefore, these patents and applications may not be prosecuted and enforced in a manner consistent with the best
interests of our business and the rights we have licensed may be reduced or eliminated.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex

legal and factual questions and has in recent years been the subject of much litigation. The U.S. Patent and Trademark
Office, or U.S. PTO, has not established a consistent policy regarding the breadth of claims that it will allow in
biotechnology patents. In addition, the laws of foreign jurisdictions may not protect our rights to the same extent as the
laws of the United States. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and
patent applications in the United States and other jurisdictions are typically not published until 18 months after filing, or in
some cases not at all. Therefore, we cannot know with certainty whether we were the first to make the inventions claimed
in our owned or licensed patents or pending patent applications, or that we were the first to file for patent protection of
such inventions, nor can we know whether those from whom we license patents were the first to make the inventions
claimed or were the first to file. As a result, the issuance, scope, validity, enforceability and commercial value of our patent
rights are highly uncertain. Our pending and future patent applications may not result in patents being issued that protect
our technology or product candidates, in whole or in part, or which effectively prevent others from commercializing
competitive technologies and product candidates. Changes in either the patent laws or interpretation of the patent laws in
the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection.
In addition, during prosecution of any patent application, the issuance of any patents based on an application may depend
upon our ability to generate additional nonclinical or clinical data that supports the patentability of our proposed claims.
We may not be able to generate such data on a timely basis, to the satisfaction of the U.S. PTO, or at all.

Moreover, we may be subject to a third-party preissuance submission of prior art to the U.S. PTO or patent offices in
foreign jurisdictions, or become involved in opposition, derivation, reexamination, inter partes review, post-grant review or
interference proceedings challenging our patent rights or the patent rights of others. An adverse determination in any such
submission, proceeding or litigation could reduce the scope of, or invalidate, our patent rights, allow third parties to
commercialize our technology or product candidates and compete directly with us, without payment to us, or result in our
inability to manufacture or commercialize product candidates without infringing third-party patent rights. In addition, if the
breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade
companies from collaborating with us to license, develop or commercialize current or future product candidates.

Even if our owned and licensed patent applications issue as patents, they may not issue in a form that will provide

ff

us with any meaningful protection, prevent competitors from competing with us or otherwise provide us with any
competitive advantage. Our competitors may be able to circumvent our owned or licensed patents by developing similar
or alternative technologies or product candidates in a non-infringing manner.

The issuance of a patent, while given the presumption of validity under the law, is not conclusive as to its
inventorship, scope, validity or enforceability, and our owned and licensed patents may be challenged in the courts or
patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or in patent claims being
narrowed, invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or
commercializing similar or identical technology and product candidates, or limit the duration of the patent protection of our
technology and product candidates. In addition, patents have a limited lifespan. In the United States, the natural expiration
of a patent is generally 20 years after the first non-provisional filing in the patent family. Given the amount of time required
for the development, testing and regulatory review of new product candidates, patents protecting such candidates might
expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio
may not provide us with sufficient rights to exclude others from commercializing product candidates similar or identical to
ours.

Any inability on our part to adequately protect our intellectual property may have a material adverse effect on our

business, operating results and financial position.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document
submission, fee payment and other requirements imposed by governmental patent agencies, and our patent
protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees, renewal fees, annuity fees and various other governmental fees on patents and/or
applications will be due to be paid to the U.S. PTO and various governmental patent agencies outside the United States in
several stages over the lifetime of the patents and/or applications. We have systems in place to remind us to pay these
fees, and we employ an outside firm and rely on our outside counsel to pay these fees. The U.S. PTO and various non-
U.S. governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other
similar provisions during the patent application process. We employ reputable law firms and other professionals to help us
comply, and in some cases, an inadvertent lapse can be cured by payment of a late fee or by other means in accordance
with the applicable rules. However, we also rely on licensors to effect such payments with respect to the patents and
patent applications that we in-license. Moreover, there are situations in which non-compliance can result in abandonment
or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction.

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In such an event, our competitors might be able to enter the market and this circumstance would have a material adverse
effect on our business.

Third parties may initiate legal proceedings alleging that we are infringing their intellectual property rights, the
s of our business.
outcome of which would be uncertain and could have a material adverse effect on the succes

tt

Our commercial success depends upon our ability, and the ability of our collaborators, to develop, manufacture,
market and sell our product candidates and use our proprietary technologies without infringing the proprietary rights of
third parties. There is considerable intellectual property litigation in the biotechnology and pharmaceutical industries. We
may become party to, or threatened with, future adversarial proceedings or litigation regarding intellectual property rights
with respect to our product candidates and technology, including interference or derivation proceedings before the U.S.
PTO and similar bodies in other jurisdictions. Third parties may assert infringement claims against us based on existing
patents or patents that may be granted in the future. We may also institute proceedings in courts or patent offices seeking
decisions regarding the validity or scope of patents owned by third parties. For example, we have filed nullity actions in
the Federal Patent Court in Germany regarding two German patents relating to arginases.

It is also possible that we have failed to identify relevant third-party patents or applications. 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. Moreover, it is difficult for industry participants, including us, to
identify all third-party patent rights that may be relevant to our product candidates and technologies because patent
searching is imperfect due to differences in terminology among patents, incomplete databases and the difficulty in
assessing the meaning of patent claims. We may fail to identify relevant patents or patent applications or may identify
pending patent applications of potential interest but incorrectly predict the likelihood that such patent applications may
issue with claims of relevance to our technology. In addition, we may be unaware of one or more issued patents that
would be infringed by the manufacture, sale or use of a current or future product candidate, or we may incorrectly
conclude that a third-party patent is invalid, unenforceable or not infringed by our activities. Additionally, pending patent
applications that have been published can, subject to certain limitations, be later amended in a manner that could cover
our technologies, our products or the use of our products.

If we are found to infringe a third party’s intellectual property rights, we could be required to obtain a license from

such third party to continue developing and marketing our product candidates and technology. However, we may not be
able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it
could be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. We could be
forced, including by court order, to cease commercializing the infringing technology or product. In addition, we could be
found liable for monetary damages, including treble damages and attorneys’ fees, if we are found to have willfully
infringed a patent. A finding of infringement could prevent us from commercializing our product candidates or force us to
cease some of our business operations, which could materially harm our business. Claims that we have misappropriated
the confidential information or trade secrets of third parties could have a similar negative impact on our business.

We may be subject to claims that our employees, consultants or independent contractors have wrongfully used
or disclosed confidential information or trade secrets of third parties or that our employees, consultants or
independent contractors have wrongfully used or disclosed alleged trade secrets of former or other employers.

Many of our employees, independent contractors and consultants, including our senior management, have been

previously employed or retained by universities or other biotechnology or pharmaceutical companies, including our
competitors or potential competitors. Further, many of our consultants are currently retained by other biotechnology or
pharmaceutical companies and may be subject to conflicting obligations to these third parties. Although we try to ensure
that our employees, consultants and independent contractors do not use the proprietary information or know-how of third
parties in their work for us, and do not perform work for us that is in conflict with their obligations to another employer or
any other entity, we may be subject to claims that we or our employees, consultants or independent contractors have
inadvertently or otherwise improperly used or disclosed confidential information, including trade secrets or other
proprietary information, of a former employer or other third parties. We may also be subject to claims that an employee,
advisor, consultant, or independent contractor performed work for us that conflicts with that person's obligations to a third
party, such as an employer, and thus, that the third party has an ownership interest in the intellectual property arising out
of work performed for us. We are not aware of any threatened or pending claims related to these matters, but in the future
litigation may be necessary to defend against such claims.

ff

In addition, while it is our policy to require our employees, independent contractors and consultants who may be

involved in the development of intellectual property to execute agreements assigning such intellectual property to us, we
may be unsuccessful in timely obtaining such an agreement with each party who in fact develops intellectual property that

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we regard as our own. Even if timely obtained, such agreements may be breached, and we may be forced to bring claims
against third parties, or defend claims they may bring against us, to determine the ownership of what we regard as our
intellectual property.

If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable personnel or

intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property. As a result, we
may also elect to enter into license agreements in order to settle patent infringement claims or to resolve disputes prior to
litigation, and any such license agreements may require us to pay royalties and other fees that could be significant. Such
an outcome could have a material adverse effect on our business. Even if we are successful in defending against such
claims, litigation could result in substantial costs and be a distraction to management.

The illegal distribution and sale by third parties of counterfeit versions of our products or stolen products could
have a negative impact on our reputation and business.

Third parties might illegally distribute and sell counterfeit or unfit versions of our approved products, if any, which do

not meet our rigorous manufacturing and testing standards. A patient who receives a counterfeit or unfit drug may be at
risk for a number of dangerous health consequences. Our reputation and business could suffer harm as a result
of counterfeit or unfit drugs sold under our brand name. In addition, thefts of inventory at warehouses, plants or while in-
transit, which are not properly stored and which are sold through unauthorized channels, could adversely impact patient
safety, our reputation and our business.

Any lawsuits relating to infringement of intellectual property rights necessary to defend ourselves or enforce our
rights will be costly and time consuming, and could be unsuccessful.

Because competition in our industry is intense, competitors may infringe or otherwise violate our issued patents,
patents of our licensors or other intellectual property. To counter infringement or unauthorized use, we may be required to
file infringement claims, which can be expensive and time consuming. Any claims we assert against perceived infringers
could provoke these parties to assert counterclaims against us alleging, among other claims, that we infringe their
patents. In addition, in a patent infringement proceeding there are many grounds upon which a party may assert invalidity
or unenforceability of a patent, and a court may decide that a patent of ours is invalid or unenforceable, in whole or in part,
construe the patent’s claims narrowly or refuse to stop the other party from using the technology at issue on the grounds
that our patents do not cover the technology in question. Litigation is uncertain and we cannot predict whether we would
be successful in any such litigation. Such litigation or proceedings could substantially increase our operating losses and
reduce the resources available for development activities or any future sales, marketing or distribution activities. We may
not have sufficient financial, managerial or other resources to adequately conduct such litigation or proceedings. Some of
our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of
their greater financial, managerial and other resources. Uncertainties resulting from the initiation and continuation of
patent litigation or other proceedings could have a material adverse effect on our business. Furthermore, because of the
substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our
confidential information could be compromised by disclosure.

Intellectual property disputes could cause us to spend substantial resources and distract our personnel from
their normal responsibilities.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause

us to incur significant expenses and could distract our technical and/or management personnel from their normal
responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim
proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a
substantial adverse effect on the market price of our common stock. In some cases, we may choose not to pursue
litigation against those that have infringed on our patents, or used them without authorization, due to the associated
expenses and time commitment of monitoring these activities. If we fail to protect or to enforce our intellectual property
rights successfully, our competitive position could suffer, which could harm our results of operations.

We may not be successful in obtaining or maintaining necessary rights for our development pipeline through
acquisitions and in-licenses.

Presently we have rights to intellectual property to develop our product candidates, including patents and patent
applications we own or exclusively license from the University of Texas at Austin. Because our programs may involve
additional product candidates that may require the use of proprietary rights held by third parties, the growth of our

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business may depend in part on our ability to acquire, in-license or use these proprietary rights. We may be unable to
acquire or in-license any compositions, methods of use, processes or other third-party intellectual property rights from
third parties that we identify as necessary for our product candidates. The licensing and acquisition of third-party
intellectual property rights is a competitive area, and a number of more established companies are also pursuing
strategies to license or acquire third-party intellectual property rights that we may consider attractive. These established
companies may have a competitive advantage over us due to their size, cash resources and greater clinical development
and commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign
or license rights to us. We also may be unable to license or acquire third-party intellectual property rights on terms that
would allow us to make an appropriate return on our investment. If we are unable to successfully obtain rights to required
third-party intellectual property rights, our business, financial condition and prospects for growth could suffer.

If we are not able to prevent disclosure of our trade secrets and other proprietary information, the value of our
technology and product candidates could be significantly diminished.

ff

We rely on trade secret protection to protect our interests in proprietary know-how and in processes that are
unpatentable or for which patents are difficult to obtain or enforce. We may not be able to protect our trade secrets
adequately. We have a policy of requiring our consultants, advisors and strategic partners to enter into confidentiality
agreements and our employees to enter into invention, non-disclosure and non-compete agreements. However, no
assurance can be given that we have entered into appropriate agreements with all parties that have had access to our
trade secrets, know-how or other proprietary information, or that such agreements will provide for a meaningful protection
of our trade secrets, know-how or other proprietary information in the event of any unauthorized use or disclosure of
information. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and
time-consuming, and the outcome is unpredictable. Even if we are successful in prosecuting such claims, any remedy
awarded may be insufficient to fully compensate us for the improper disclosure or misappropriation. Furthermore,
although we seek to preserve the integrity and confidentiality of our data, trade secrets and know-how by maintaining
physical security of our premises and physical and electronic security of our information technology systems, it is also
possible that our trade secrets, know-how or other proprietary information could be obtained by third parties as a result of
breaches of such systems.

Any disclosure of confidential information into the public domain or to third parties could allow our competitors to

learn our trade secrets and use the information in competition against us. In addition, others may independently discover
or develop our trade secrets and proprietary information or substantially equivalent techniques. Any action to enforce our
rights is likely to be time consuming and expensive, and may ultimately be unsuccessful, or may result in a remedy that is
not commercially valuable. These risks are accentuated in foreign countries where laws or law enforcement practices may
not protect proprietary rights as fully as in the United States or Europe. Any unauthorized disclosure of our trade secrets
or confidential information could harm our competitive position.

We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting and defending patents on all of our product candidates throughout the world would be
prohibitively expensive, and our patent rights in some countries outside the United States can be less extensive than
those in the United States. The requirements for patentability may differ in certain countries, particularly developing
countries. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as
federal and state laws in the United States. Consequently, we may not be able to prevent third parties from practicing our
inventions in all countries outside the United States, or from selling or importing products made using our inventions in
and into the United States or other jurisdictions.

As part of ordinary course prosecution and maintenance activities, we determine whether to seek patent protection
outside the United States and in which countries. This also applies to patents we have acquired or in-licensed from third
parties. In some cases, this means that we, or our predecessors in interest or licensors of patents within our portfolio,
have sought patent protection in a limited number of countries for patents covering our product candidates. Competitors
may use our technologies in jurisdictions where we have not pursued and obtained patent protection to develop their own
products and, further, may export otherwise infringing products to territories where we have patent protection but where
enforcement is not as strong as in the United States. These products may compete with our products in jurisdictions
where we do not have any issued patents and, even in jurisdictions where we have or are able to obtain issued patents,
our patent claims or other intellectual property rights may not be effective or sufficient to prevent them from so competing.
Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign
jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the
enforcement of patents and other intellectual property protection, particularly those relating to biopharmaceuticals, which
could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our

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proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial cost
and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or
interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims
against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may
not be commercially meaningful. In addition, certain countries have compulsory licensing laws under which a patent owner
may be compelled to grant licenses to third parties. In those countries, we may have limited remedies if our patents are
infringed or if we are compelled to grant a license to our patents to a third party, which could materially diminish the value
of those patents. In addition, there may be patent law reforms in foreign jurisdictions that could increase the uncertainties
and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents in
those foreign jurisdictions. This could limit our potential revenue opportunities.

Accordingly, our efforts to obtain, register, and enforce our intellectual property rights around the world may be
inadequate to obtain a significant commercial advantage from the intellectual property that we own or license. Moreover,
patent protection must ultimately be sought on a country-by-country basis, which is an expensive and time-consuming
process with uncertain outcomes. Accordingly, we may choose not to seek patent protection in certain countries, and we
will not have the benefit of patent protection in such countries.

If we breach any of the agreements under which we license patent rights to use, develop and commercialize our
product candidates or our technologies from third parties or, in certain cases, we fail to meet certain
development deadlines, we could lose license rights that are important to our business.

We are a party to license agreements under which we are granted rights to intellectual property that are important to

our business and we expect that we may need to enter into additional license agreements in the future.

In December 2013, our wholly owned subsidiaries AECase, Inc. and AEMase, Inc. each entered into an exclusive,

worldwide license agreement, including the right to grant sublicenses, with the University of Texas at Austin for certain
intellectual property owned by the University of Texas at Austin related to our program candidates related to cystinase and
methioninase. In January 2017, we and the University of Texas at Austin entered into an Amended and Restated Patent
License Agreement, or the Restated License, which consolidated the two license agreements, revised certain obligations,
and licensed additional patent applications and invention disclosures to us. The Restated License was amended in August
2017, December 2017, and December 2018 to revise diligence milestones and license additional patent applications,
including our program candidates under the AGLE-177 and cystinuria programs. The intellectual property licensed under
the Restated License includes inventions that were made with U.S. government support. The U.S. government therefore
has certain rights in such inventions under the applicable funding agreements and under applicable law. In addition, we
are subject to a requirement that the products covered by the applicable patents that are sold or used in the United States
must be manufactured substantially in the United States unless a written waiver is obtained in advance from the U.S.
government. The Restated License obligates us to make certain payments at the achievement of certain milestones and
at regular intervals throughout the life of the license. The University of Texas at Austin may terminate the Restated
License under certain circumstances, including for a breach by us that is not cured within 30 or 60 days of notice
(depending on the type of breach), or if we or any of our affiliates or sublicensees participate in any proceeding to
challenge the licensed patent rights (unless, with respect to sublicensees, we terminate the applicable sublicense).

Licensing of intellectual property is of critical importance to our business and involves complex legal, business and

scientific issues. Any other licenses or other intellectual property agreements we may enter into may impose various
diligence, milestone payment, royalty and other obligations on us. If disputes arise between us and our licensor or if we
fail to comply with our obligations under current or future intellectual property agreements, potentially giving our
counterparties the right to terminate these agreements, we might not be able to develop, manufacture or market any
product that is covered by the agreement or face other penalties under the agreement. Such an occurrence could
materially adversely affect the value of the product candidate being developed under any such agreement. Termination of
these agreements or reduction or elimination of our rights under these agreements may result in our having to negotiate
new or reinstated agreements with less favorable terms, or cause us to lose our rights under these agreements, including
our rights to important intellectual property or technology.

The loss of any one of our current licenses, or any other license we may acquire in the future, could prevent or
impair our ability to successfully develop and commercialize the affected product candidates and thus materially harm our
business, prospects, financial condition and results of operations.

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Intellectual property rights do not necessarily address 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, provide a barrier to entry against our competitors or
potential competitors, or permit us to maintain our competitive advantage. Moreover, if a third party has intellectual
property rights that cover the practice of our technology or product candidates, we may not be able to fully exercise or
extract value from our intellectual property rights. The following examples are illustrative:

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•

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 license;
we or our licensors or collaborators might not have been the first to make the inventions covered by an issued
patent or pending patent application that we own or license;
we or our licensors or collaborators might not have been the first to file patent applications covering an
invention;
others may independently develop similar or alternative technologies or duplicate any of our technologies
without infringing or misappropriating our intellectual property rights;
pending patent applications that we own or license may not lead to issued patents;
issued patents that we own or license may not provide us with any competitive advantages, or may be
narrowly construed or held invalid or unenforceable, as a result of legal challenges by our competitors;
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 not develop or in-license additional proprietary technologies that are patentable; and
the patents of others may have an adverse effect on our business.

Any of these events could significantly harm our business, results of operations and prospects.

Changes in patent law could diminish the value of patents in general, thereby impairing our ability to protect our
products, and recent patent legislation could increase the uncertainties and costs surrounding the prosecution
of our patent applications and the enforcement or defense of our issued patents.

As is the case with other biotechnology companies, our success is heavily dependent on patents. Obtaining and
enforcing patents in the biotechnology industry involve both technological and legal complexity, and is therefore costly,
time-consuming and inherently uncertain. In addition, the United States has recently enacted patent reform legislation. In
addition to increasing uncertainty with regard to our ability to obtain patents in the future, this has created greater
uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal
courts, and the U.S. PTO, the laws and regulations governing patents could change in unpredictable ways that would
weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

On September 16, 2011, the Leahy-Smith America Invents Act, or the Leahy-Smith Act, was signed into law. The

U.S. PTO has promulgated regulations and developed procedures to govern administration of the Leahy-Smith Act. The
Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our
patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse
effect on our business and financial condition.

The Leahy-Smith Act also requires an inventor to file a patent application on their invention prior to any other bona
fide independent inventor. Since patent applications in the United States and most other countries are confidential for a
period of time after filing, we cannot be certain that we were the first to either (i) file any patent application related to our
product candidates or (ii) invent any of the inventions claimed in our patents or patent applications.

The Leahy-Smith Act allows a third party to provide evidence in a U.S. PTO proceeding that could invalidate our
patent claims. Accordingly, a third party may use the U.S. PTO procedures to invalidate our patent claims. In such an
event, this circumstance could have a material adverse effect on our business.

If we do not obtain patent term extensions under the Hatch-Waxman Act and similar legislation, thereby not
extending the term of our marketing exclusivity for our product candidates, our business may be materially
harmed.

Depending upon the timing, duration and specifics of FDA marketing approval of our product candidates, if any, one

of the U.S. patents covering each of such approved product(s) or the use thereof may be eligible for up to five years of

ff

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patent term restoration. Patent term extension allows a maximum of one patent to be extended per FDA-approved
product. Patent term extension also may be available in certain foreign countries upon regulatory approval of our product
candidates, if any. Nevertheless, we may not be granted patent term extension either in the United States or in any
foreign country because of, for example, failing to apply within applicable deadlines, failing to apply prior to expiration of
relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the term of extension, as well as the
scope of patent protection during any such extension, afforded by the governmental authority could be less than we
request. In addition, if a patent we wish to extend is owned by another party and licensed to us, we may need to obtain
approval and cooperation from our licensor to request the extension.

If we are unable to obtain patent term extension or restoration, or the term or scope of any such extension is less
than we request, the period during which we will have the right to exclusively market our product will be shortened and our
competitors may obtain approval of competing products following our patent expiration, and our revenue could be
reduced, possibly materially.

We have not yet registered our trademarks in a
registrations could adversely affect our business.

kk

ll of our potential markets, and failure to secure those

We attempt to protect our pharmaceutical developments, services, and products under trademark laws. However,

our trademark applications may not be allowed for registration, and registered trademarks may not be maintained or
enforced. During trademark registration proceedings, we may receive rejections. Although we are given an opportunity to
respond to those rejections, we may be unable to overcome such rejections. In addition, in the U.S. Patent and
Trademark Office and in comparable agencies in many foreign jurisdictions, third parties are given an opportunity to
oppose pending trademark applications and to seek to cancel registered trademarks. Opposition or cancellation
proceedings may be filed against our trademarks, and our trademarks may not survive such proceedings. If we do not
secure registrations for our trademarks, we may encounter more difficulty in enforcing them against third parties than we
otherwise would.

Third parties may pursue trademark infringement actions against us, potentially resulting in substantial costs
and material delays.

As our activities grow, we may be subject to an increasing amount of litigation that is common in the pharmaceutical
industry based on allegations of infringement or other alleged violations of trademarks. Any claims of infringement, with or
without merit, could be time consuming, costly, and difficult to defend. Moreover, intellectual property litigation or claims
could require us to redesign packaging and advertising materials associated with our packaging, which could result in
substantial costs and material delays.

Risks Related to Employee Matters, Managing Growth and Other Risks Related to Our Business

Our future success depends on our ability to retain key executives and to attract, retain and motivate qualified
personnel.

We are a clinical-stage biotechnology company with a limited operating history, and, as of December 31, 2021, had
101 employees. We are highly dependent on the research and development, clinical and business development expertise
of our executive officers, as well as the other principal members of our management, scientific and clinical team. Any of
our management team members may terminate their employment with us at any time. We do not maintain “key person”
insurance for any of our executives or other employees.

Recruiting and retaining qualified scientific, clinical, manufacturing and sales and marketing personnel will also be

critical to our success. The loss of the services of our executive officers or other key employees could impede the
achievement of our research, development and commercialization objectives and seriously harm our ability to successfully
implement our business strategy. Furthermore, replacing executive officers and key employees may be difficult and may
take an extended period of time because of the limited number of individuals in our industry with the breadth of skills and
experience required to successfully develop, facilitate regulatory approval of and commercialize product candidates.
Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or motivate these key
personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for
similar personnel. We also experience competition for the hiring of scientific and clinical personnel from universities and
research institutions.

In addition, we rely on consultants and advisors, including scientific and clinical advisors such as our scientific
advisory board, to assist us in formulating our discovery and nonclinical and clinical development and commercialization
strategy. Our consultants and advisors, including members of our scientific advisory board, may be employed by

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employers other than us and may have commitments under consulting or advisory contracts with other entities that may
limit their availability to us. If we are unable to continue to attract and retain high quality personnel, our ability to pursue
our growth strategy will be limited.

Our employees may engage in misconduct or other improper activities, including non-compliance with regulatory
standards and requirements, which could cause significant liability for us and harm our reputation.

We are exposed to the risk of employee fraud or other misconduct, including intentional failures to (i) comply with
FDA regulations or similar regulations of comparable non-U.S. regulatory authorities, (ii) provide accurate information to
the FDA or comparable non-U.S. regulatory authorities, (iii) comply with manufacturing standards we have established,
(iv) comply with the Foreign Corrupt Practices Act and federal and state healthcare fraud and abuse laws and regulations
and similar laws and regulations established and enforced by comparable non-U.S. regulatory authorities, or (v) report
financial information or data accurately or disclose unauthorized activities to us. Employee misconduct could also involve
the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and
serious harm to our reputation. It is not always possible to identify and deter employee misconduct, and the precautions
we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in
protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance
with such laws, standards or regulations. If any such actions are instituted against us, and we are not successful in
defending ourselves or asserting our rights, those actions could have a significant impact on our business and results of
operations, including the imposition of significant fines or other sanctions.

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 testing our product candidates in clinical trials and will face
an even greater risk if we commercialize any products. For example, we may be sued if our product candidates cause or
are perceived to cause injury or are found to be otherwise unsuitable during clinical trials, 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 or 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. Regardless of the merits or eventual outcome, liability
claims may result in:

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inability to bring a product candidate to the market;
decreased demand for our products;
injury to our reputation;
withdrawal of clinical trial participants and inability to continue clinical trials;
initiation of investigations by regulators;
costs to defend the related litigation;
diversion of management's time and our resources;
substantial monetary awards to trial participants or patients;
product recalls, withdrawals or labeling, marketing or promotional restrictions;
loss of revenue;
exhaustion of any available insurance and our capital resources;
the inability to commercialize any product candidate; and
decline in our share price.

Our product liability insurance policies may also have various exclusions, and we may be subject to a product

liability claim for which we have no coverage. We may 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. Even if our agreements with any future corporate collaborators entitle us
to indemnification against losses, such indemnification may not be available or adequate should any claim arise.

Our ability to use our net operating loss carryforwards and certain other tax attributes may be limited.

ff

Under Section 382 of the Internal Revenue Code of 1986, as amended, if a corporation undergoes an “ownership

change,” generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period, the
corporation’s ability to use its pre-change net operating loss carryforwards, or NOLs, and other pre-change tax attributes
(such as research tax credits) to offset its post-change income or taxes may be limited. It is possible that we may have

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triggered an “ownership change” limitation. We may also experience ownership changes in the future as a result of
subsequent shifts in our stock ownership (some of which are outside of our control). As a result, if we earn net taxable
income, our ability to use our pre-change NOLs and other pre-change tax attributes to offset U.S. federal taxable income
or taxes may be subject to limitations, which could potentially result in increased future tax liability to us. Our NOLs and
other tax attributes arising before our conversion from a Delaware limited liability company to a Delaware corporation in
2015 also may be limited by the Separate Return Limitation Year rule, which could increase our U.S. federal tax liability. In
addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited, which
could accelerate or permanently increase state taxes owed.

Risks Related to Our Common Stock

Our executive officers, directors and principal stockholders, if they choose to act together, may continue to have
the ability to control all matters submitted to stockholders for approval.

We have a concentrated stockholder base and our executive officers and directors, combined with our stockholders

who, to our knowledge, each owned more than 5% of our outstanding common stock, in the aggregate, beneficially own
shares representing a substantial number of our capital stock as of December 31, 2021. As a result, if these stockholders
were to choose to act together, they may be able to control all matters submitted to our stockholders for approval, as well
as our management and affairs. For example, these persons, if they choose to act together, would likely control the
election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets. This
concentration of ownership control may:

•
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•

delay, defer or prevent a change in control;
entrench our management and the board of directors; or
impede a merger, consolidation, takeover or other business combination involving us that other stockholders
may desire or may result in you obtaining a premium for your shares.

Failure to achieve and maintain effective internal control over financial reporting in accordance with Section 404
of the Sarbanes-Oxley Act could have a material adverse effect on our business and stock price.

Pursuant to Section 404, we have been required to furnish a report by our management on our internal control over

financial reporting. However, while we remain a non-accelerated filer, we will not be required to include an attestation
report on internal control over financial reporting issued by our independent registered public accounting firm. 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 in accordance with generally accepted accounting principles in the
United States. We may encounter problems or delays in implementing any changes necessary to make a favorable
assessment of our internal control over financial reporting. If we cannot favorably assess the effectiveness of our internal
control over financial reporting, or if our independent registered public accounting firm is unable to provide an unqualified
attestation report on our internal controls when required, investors could lose confidence in our financial information and
the price of our common stock could decline.

Additionally, the existence of any material weakness or significant deficiency would require management to devote
significant time and incur significant expense to remediate any such material weaknesses or significant deficiencies and
management may not be able to remediate any such material weaknesses or significant deficiencies in a timely manner.
The existence of any material weakness in our internal control over financial reporting could also result in errors in our
financial statements that could require us to restate our financial statements causing us to fail to meet our reporting
obligations and cause stockholders to lose confidence in our reported financial information, all of which could materially
and adversely affect us.

Provisions in our corporate charter documents and under Delaware law could make an acquisition of our
company, which may be beneficial to our stockholders, more difficult and may prevent attempts by our
stockholders to replace or remove our current management.

dd

Provisions in our certificate of incorporation and our bylaws may discourage, delay or prevent a merger, acquisition
or other change in control of our company that stockholders may consider favorable, including transactions in which you
might otherwise receive a premium for your 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:

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establish a classified board of directors such that only one of three classes of directors is elected each year;
allow the authorized number of our directors to be changed only by resolution of our board of directors;

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limit the manner in which stockholders can remove directors from our board of directors;
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;
authorize our board of directors to issue 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 two-thirds of the votes that all our stockholders would be entitled
to cast to amend or repeal specified provisions of our certificate of incorporation or bylaws.

Moreover, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which

prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with us for a
period of three 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 of these provisions of our charter documents or Delaware law could, under certain circumstances, depress the

market price of our common stock.

Our amended and restated certificate of incorporation designates the Court of Chancery of the State of Delaware
as the sole and exclusive forum for certain types of actions and proceedings that may be initiated by our
stockholders, and our amended and restated bylaws designates the federal courts of the United States as the
exclusive forum for actions arising under the Securities Act, each of which could limit ou
obtain a favorable judicial forum for disputes with us or our directors, officers, employees or agents.

r stockholders’ ability to

ff

ll

Our amended and restated certificate of incorporation provides that, unless we consent in writing to an alternative

forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or
proceeding brought on our behalf, any action asserting a claim of breach of a fiduciary duty owed by any of our directors,
officers, employees or agents to us or our stockholders, any action asserting a claim arising pursuant to any provision of
the DGCL, our amended and restated certificate of incorporation or our amended and restated bylaws or any action
asserting a claim that is governed by the internal affairs doctrine, in each case subject to the Court of Chancery having
personal jurisdiction over the indispensable parties named as defendants therein and the claim not being one which is
vested in the exclusive jurisdiction of a court or forum other than the Court of Chancery or for which the Court of Chancery
does not have subject matter jurisdiction. Any person purchasing or otherwise acquiring any interest in any shares of our
capital stock shall be deemed to have notice of and to have consented to this provision of our amended and restated
certificate of incorporation.

In March 2020, we amended and restated our restated bylaws to provide that the federal district courts of the United
States of America will, to the fullest extent permitted by law, be the exclusive forum for resolving any complaint asserting a
cause of action arising under the Securities Act (a Federal Forum Provision). Our decision to adopt a Federal Forum
Provision followed a decision by the Supreme Court of the State of Delaware holding that such provisions are facially valid
under Delaware law. While there can be no assurance that federal or state courts will follow the holding of the Delaware
Supreme Court or determine that the Federal Forum Provision should be enforced in a particular case, application of the
Federal Forum Provision means that suits brought by our stockholders to enforce any duty or liability created by the
Securities Act must be brought in federal court and cannot be brought in state court.

These choice of forum provisions may limit our stockholders’ ability to bring a claim in a judicial forum that it finds
favorable for disputes with us or our directors, officers, employees or agents, which may discourage such lawsuits against
us and our directors, officers, employees and agents even though an action, if successful, might benefit our stockholders.
Stockholders who do bring a claim in the specified courts could face additional litigation costs in pursuing any such claim.
The specified courts may also reach different judgments or results than would other courts, including courts where a
stockholder considering an action may be located or would otherwise choose to bring the action, and such judgments or
results may be more favorable to us than to our stockholders. Alternatively, if a court were to find these provisions of our
governance documents inapplicable to, or unenforceable in respect of, one or more of the specified types of actions or
proceedings, we may incur additional costs associated with resolving such matters in other jurisdictions, which could have
a material adverse effect on our business, financial condition or results of operations.

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The price of our common stock has been and may be volatile and fluctuate substantially, which could result in
substantial losses for purchasers of our common stock.

Our stock price is volatile. The stock market in general and the market for smaller biotechnology companies in

particular have experienced extreme volatility that has often been unrelated to the operating performance of particular
companies. The market price for our common stock may be influenced by many factors, including:

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the success or failure of competitive products or technologies;
results of ongoing or planned clinical trials of our product candidates or those of our competitors;
regulatory or legal developments in the United States and other countries;
developments or disputes concerning patent applications, issued patents or other proprietary rights;
the recruitment or departure of key personnel;
the level of expenses related to any of our product candidates or clinical development programs;
the results of our efforts to discover, develop, acquire or in-license additional product candidates or products;
actual or anticipated changes in estimates as to financial results, development timelines or recommendations
by securities analysts;
operating results that fail to meet expectations of securities analysts that cover our company;
variations in our financial results or those of companies that are perceived to be similar to us;
changes in the structure of healthcare payment systems;
market conditions in the pharmaceutical and biotechnology sectors;
general economic and market conditions; and
the other factors described in this “Risk Factors” section.

We have broad discretion in the use of the net proceeds from our public offerings and may not use them
effectively.

Our management has broad discretion in the application of the net proceeds from our public offerings, and you will

not have the opportunity as part of your investment decision to assess whether the net proceeds are being used
appropriately. Our management could spend the net proceeds from our public offerings in ways that do not improve our
results of operations or enhance the value of our common stock. The failure by our management to apply these funds
effectively could result in financial losses that could have a material adverse effect on our business, cause the price of our
common stock to decline and delay the development of our product candidates. Pending their use, we may invest the net
proceeds from our public offerings in a manner that does not produce income or that loses value.

Future sales 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, 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 and
make it more difficult for you to sell your common stock at a time and price that you deem appropriate.

Moreover, we have also registered under the Securities Act shares of common stock that we may issue under our

equity compensation plans.

In addition, in April 2020, we entered into an “at-the-market” offering of our common stock pursuant to a sales

agreement between us and JonesTrading Institutional Services LLC, or JonesTrading, under a shelf registration
statement on Form S-3. Subject to certain limitations in the sales agreement and compliance with applicable law, we have
the discretion to deliver a placement notice to JonesTrading at any time throughout the term of the sales agreement,
which has a term equal to the term of the registration statement on Form S-3 unless otherwise terminated earlier by us or
JonesTrading pursuant to the terms of the sales agreement. The number of shares that are sold by JonesTrading after
delivering a placement notice will fluctuate based on the market price of our common stock during the sales period and
limits we set with JonesTrading. Because the price per share of each share sold will fluctuate based on the market price
of our common stock during the sales period, it is not possible at this stage to predict the number of shares that will be
ultimately issued. Issuances of any shares sold pursuant to the sales agreement will have a dilutive effect on our existing
stockholders. In February 2022, the registration statement on Form S-3, which the at-the-market offering was registered
under, expired and no sales under this registration statement will occur going forward.

In July 2020, we filed a new shelf registration statement on Form S-3 that was declared effective in July 2020 by the
SEC for the potential offering, issuance and sale by us of up to $400.0 million of our common stock, preferred stock, debt
securities, warrants to purchase common stock, preferred stock and debt securities, subscription rights to purchase
common stock and units consisting of all or some of these securities. If we sell common stock, preferred stock, convertible
securities and other equity securities in other transactions pursuant to our shelf registration statements on Form S-3,

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existing investors may be materially diluted by such subsequent sales and new investors could gain rights superior to our
existing stockholders. In May 2021, we filed a shelf registration statement on Form S-3, that was declared effective on
June 8, 2021 by the SEC, registering up to 19,020,434 shares of our common stock held by 667, L.P., or 667, and Baker
Brothers Life Sciences, L.P., or Life Sciences, and together with 667, the Baker Funds, which includes 15,610,328 shares
of common stock issuable upon the exercise of pre-funded warrants held by the Baker Funds, for resale or other
disposition from time to time as described in the registration statement.

In addition, in the future, we may issue additional shares of common stock or other equity or debt securities convertible

into common stock in connection with a financing, acquisition, litigation settlement, employee arrangements or otherwise,
including upon exercise of our pre-funded warrants. For example, in April 2020, we sold an aggregate of 15,442,303 shares
of common stock and pre-funded warrants to purchase up to 13,610,328 shares of common stock in an underwritten
public offering. Any such issuance could result in substantial dilution to our existing stockholders and could cause our stock
price to decline.

WWe will not receive a s
warrants; however,
market and result in substantial dilution to our stockholders.

ignificant amount, or potentially any, additional funds upon the exercise of our pre-funded
t, or potentially any, additional funds upon the exercise of our pre-funded

any exercise would increase the number of shares eligible for future resale in the public

To date, we have issued pre-funded warrants to purchase a total of 17,610,328 shares of our common stock, of
which 1,000,000 have been exercised and 16,610,328 are currently outstanding. Each pre-funded warrant is exercisable
for $0.0001 per share of common stock underlying such pre-funded warrant, which may be paid by way of a cashless
exercise, meaning that the holder may not pay a cash purchase price upon exercise, but instead would receive upon such
exercise the net number of shares of common stock determined according to the formula set forth in the pre-funded
warrant. Accordingly, we will not receive a s
pre-funded warrants.
issued for nominal or no additional consideration, which will result in substantial dilution to the then existing holders of our
common stock and will increase the number of shares eligible for resale in the public market. Sales of substantial
numbers of such shares in the public market could adversely affect the market price of the common stock, causing our
stock price to decline.

, or potentially any,
To the extent such pre-funded warrants are exercised, additional shares of common stock will be

ignificant amount, or potentially any, additional funds upon the exercise of the

There is no public market for our pre-funded warrants.

rr

There is no public trading market for our pre-funded warrants issued in the February 2019 and April 2020 public

offerings, and we do not expect a market to develop. In addition, we do not intend to apply to list the pre-
funded warrants on any securities exchange or nationally recognized trading system, including the Nasdaq Global Market.
Without an active market, the liquidity of the pre-funded warrants will be limited and their value may be adversely
impacted.

Additionally, each holder of pre-funded warrants will not be entitled to exercise any portion of any pre-funded
warrant, which, upon giving effect to such exercise, would cause (i) the aggregate number of shares of our common stock
beneficially owned by the holder (together with its affiliates) to exceed 4.99%, or 9.99% for certain holders, of the number
of shares of our common stock outstanding immediately after giving effect to the exercise, or (ii) the combined voting
power of our securities beneficially owned by the holder (together with its affiliates) to exceed 4.99%, or 9.99% for certain
holders, of the combined voting power of all of our securities then outstanding immediately after giving effect to the
exercise. However, any holder may increase or decrease such percentage to any other percentage (not in excess of
19.99% for the majority of such warrants) upon at least 61 days’ prior notice from the holder to us.

We are a “smaller reporting company,
companies may make okk

“

ur common stock less attractive to investors.

” and the reduced disclosure requirements applicable to smaller reporting

We are a “smaller reporting company,” under the Exchange Act. For so long as we remain a smaller reporting
company, we are permitted and intend to rely on exemptions from certain disclosure requirements that are applicable to
other public companies that are not smaller reporting companies. These exemptions include:

•

•

being permitted to provide only two years of audited financial statements, in addition to any required unaudited
interim financial statements, with correspondingly reduced “Management’s Discussion and Analysis of
Financial Condition and Results of Operations” disclosure;
not being required to comply with the auditor attestation requirements in the assessment of our internal control
over financial reporting of Section 404(b) of the Sarbanes-Oxley Act; and

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•

reduced disclosure obligations regarding executive compensation.

We may continue to take advantage of these exemptions until we are no longer a smaller reporting company. We
will remain a smaller reporting company if we have either (i) less than $250 million in market value of our shares held by
non-affiliates as of the last business day of our second fiscal quarter or (ii) less than $100 million of annual revenues in
our most recent fiscal year and a market value of our shares held by non-affiliates less than $700 million as of the last
business day of our second fiscal quarter. We may choose to take advantage of some but not all of these scaled
disclosure requirements. Therefore, the information that we provide stockholders may be different than one might get from
other public companies. Further, if some investors find our shares of common stock less attractive as a result, there may
be a less active trading market for our shares of common stock and the market price of such shares of common stock
may be more volatile.

We will continue to incur incre
be required to devote substantial time to new compliance initiatives and corporate governance practices.

ased costs as a result of operating as

a public company, and our management will

rr

ii

As a public company, and particularly now that we are no longer an emerging growth company, we incur significant

legal, accounting and other expenses that we did not incur as a private company. The Sarbanes-Oxley Act of 2002, the
Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of The Nasdaq Global Market and
other applicable securities rules and regulations impose various requirements on public companies, including
establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our
management and other personnel will need to devote a substantial amount of time to these compliance initiatives.
Moreover, these rules and regulations will continue to increase our legal and financial compliance costs and will make
some activities more time-consuming and costly. For example, we expect that these rules and regulations may make it
more difficult and more expensive for us to obtain and maintain director and officer liability insurance, which in turn could
make it more difficult for us to attract and retain qualified members of our board of directors.

We are evaluating these rules and regulations, and cannot predict or estimate the amount of additional costs we
may incur or the timing of such costs. These rules and regulations are often subject to varying interpretations, in many
cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is
provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters
and higher costs necessitated by ongoing revisions to disclosure and governance practices.

Pursuant to Section 404, we are required to furnish a report by our management on our internal control over
financial reporting. As discussed above, if we cease to be a non-accelerated filer, we will be required to include an
attestation report on internal control over financial reporting issued by our independent registered public accounting firm
as required by Section 404(b). To achieve compliance with Section 404 within the prescribed period, we will be engaged
in a process to document and evaluate our internal control over financial reporting, which is both costly and challenging. In
this regard, we will need to continue to dedicate internal resources, potentially engage outside consultants and adopt a
detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to
improve control processes as appropriate, validate through testing that controls are functioning as documented and
implement a continuous reporting and improvement process for internal control over financial reporting. Despite our
efforts, there is a risk that we will not be able to conclude, within the prescribed timeframe or at all, that our internal control
over financial reporting is effective as required by Section 404. If we identify one or more material weaknesses, it could
result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of our consolidated
financial statements.

Since we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, stock price
appreciation, if any, will be your sole source of gain.

ff

We have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future

earnings, if any, to finance the growth and development of our business. In addition, the terms of any future debt
agreements may preclude us from paying dividends. As a result, appreciation, if any, in the market price of our common
stock will be your sole source of gain for the foreseeable future.

General Risk Factors

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 harm 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 and biological materials. Our
operations also produce hazardous waste products. We generally contract with third parties for the disposal of these

67

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, 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 for failure to comply with such laws and regulations.

Although we maintain workers’ compensation insurance that we believe is consistent with industry norms to cover us

for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, we
cannot assure you that it will be sufficient to cover our liability in such cases. 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
biological, hazardous or radioactive materials.

In addition, 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 discovery, nonclinical and clinical
development or production efforts. Our failure to comply with these laws and regulations also may result in substantial
fines, penalties or other sanctions.

Our information technology systems, or those used by our CROs, third-party vendors, contractors or
consultants, may fail or suffer security breaches, cyber-attacks, and loss of data, which could harm our
business, reputation, financial condition, and operations.

Cyber-attacks are increasing in their frequency, sophistication and intensity, and have become increasingly difficult

to detect. Despite the implementation of security measures, our information technology systems and those of our strategic
partners and third parties on whom we rely are vulnerable to cyber-attacks, security breaches, damage from computer
viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. Cyber-
attacks could include the deployment of harmful malware, ransomware, denial-of-service attacks, social engineering and
other means to affect service reliability and threaten the confidentiality, integrity and availability of information. Cyber-
attacks also could include phishing attempts or e-mail fraud to cause payments or information to be transmitted to an
unintended recipient. Furthermore, we have little or no control over the security measures and computer systems of third
parties including any CROs we may work with in the future. While we and, to our knowledge, our third-party strategic
partners have not experienced any such material system failure, accident or security breach to date, if such an event were
to occur, it could result in material negative consequences for us including interruptions in our operations, the operations
of our strategic partners, or our manufacturers or suppliers, misappropriation of confidential business information and
trade secrets, disclosure of corporate strategic plans, and result in material disruptions of our product candidate
development programs. Additionally, the costs to us or our CROs, third-party vendors, or other contractors or consultants
we may utilize to mitigate network security problems, bugs, viruses, worms, malicious software programs and security
vulnerabilities could be significant, and while we have implemented security measures to protect our data security and
information technology systems, our efforts to address these problems may not be successful, and these problems could
result in unexpected system failures, interruptions, delays, cessation of service and other harm to our business and our
competitive position. For example, the loss of clinical trial data from completed or ongoing or planned clinical trials could
result in delays in our regulatory approval efforts, and we may incur substantial costs to attempt to recover or reproduce
the data. If any disruption or security breach resulted in a loss of or damage to our data or applications, or inappropriate
disclosure of confidential or proprietary information, including personal information or health information, we could incur
liability, or the further development of our product candidates could be delayed.

Moreover, if a security breach affects our systems or results in the unauthorized access, use or disclosure of
personal information, our reputation could be materially damaged. In addition, such a breach may require notification to
governmental agencies, the media and/or affected individuals pursuant to various federal, state and international privacy
and security laws, if applicable, including HIPAA or HITECH and its implementing rules and regulations, as well as
regulations promulgated by the Federal Trade Commission and state breach notification laws. We would also be exposed
to a risk of loss or litigation and potential liability under laws, regulations and contracts that protect the privacy and security
of personal information. For example, the California Consumer Privacy Act, or the CCPA, imposes a private right of action
for security breaches that could lead to some form of remedy including regulatory scrutiny, fines, private right of action
settlements, and other consequences. The financial exposure from the events referenced above could either not be
insured against or not be fully covered through any insurance that we may maintain, and there can be no assurance that
the limitations of liability in any of our contracts would be enforceable or adequate or would otherwise protect us from
liabilities or damages as a result of the events referenced above. Any of the foregoing could have a material adverse
effect on our business, reputation, results of operations, financial condition and prospects.

We depend on our information technology and infrastructure, and disruptions could compromise sensitive
information related to our business or other personal information or prevent us from accessing critical

68

information, which could adversely affect our business, reputation, results of operations, financial condition and
prospects.

We rely on the efficient and uninterrupted operation of information technology systems to manage our operations, to

process, transmit, and store electronic and financial information, and to comply with regulatory, legal and tax
requirements. We also depend on our information technology infrastructure for communications among our personnel,
contractors, consultants and suppliers. System failures or outages could materially compromise our ability to perform
these functions in a timely manner, which could harm our ability to conduct business or delay our financial reporting, and
could otherwise compromise the security of sensitive information, including personal information and health information. In
addition, our remediation efforts for system failures, outages, or security breaches may not be successful. If we do not
allocate and effectively manage the resources necessary to build and sustain the proper technology and cybersecurity
infrastructure, we could suffer significant business disruption, including transaction errors, supply chain or manufacturing
interruptions, processing inefficiencies, data loss or the loss of or damage to intellectual property or other proprietary
information, including personal information and health information. In addition, we depend on third parties to operate and
support our information technology systems. Failure by these providers to adequately deliver the contracted services
could have an adverse effect on our business, which in turn may materially adversely affect our operating results and
financial condition.

We are subject to a variety of stringent and changing privacy and data security laws, regulations and standards,
as well as contractual obligations related to data privacy and security, and our actual or perceived failure to
comply with them could harm our business and reputation and subject us to significant fines and liability.

vv

We maintain a quantity of sensitive information, including confidential business and patient health information in

connection with our clinical trials, and are subject to laws and regulations governing the privacy and security of such
information. In the United States, there are numerous federal and state privacy and data security laws and regulations
governing the collection, use, disclosure and protection of personal information, including federal and state health
information privacy laws, federal and state security breach notification laws, and federal and state consumer protection
laws. Each of these laws is subject to varying interpretations and constantly evolving. In May 2018, a new privacy regime,
the General Data Protection Regulation, or GDPR, took effect in the European Economic Area, or EEA. The GDPR
increases our obligation with respect to clinical trials conducted in the EEA by expanding the definition of “personal data”
and requiring changes to informed consent practices, as well as more detailed notices for clinical trial subjects and
investigators. The GDPR authorizes fines for certain violations of up to 4% of global annual revenue or €20 million,
whichever is greater, and other administrative penalties. In addition, the GDPR increases the scrutiny of transfers of
personal information from clinical trial sites located in the EEA to the United States. For example, on July 16, 2020, the
Court of Justice of the European Union (the Court of Justice) invalidated the European Union-United States (EU-U.S.)
Privacy Shield on the grounds that the EU-U.S. Privacy Shield failed to offer adequate protections to EU personal
information transferred to the United States. While the Court of Justice upheld the use of other data transfer mechanisms,
such as the Standard Contractual Clauses, or SCCs, the decision has led to some uncertainty regarding the use of such
mechanisms for data transfers to the United States, and the court made clear that reliance on SCCs alone may not
necessarily be sufficient in all circumstances. The use of SCCs for the transfer of personal information specifically to the
United States also remains under review by a number of European data protection supervisory authorities. For example,
German and Irish supervisory authorities have indicated that the SCCs alone provide inadequate protection for EU-U.S.
data transfers. Use of the data transfer mechanisms must now be assessed on a case-by-case basis taking into account
the legal regime applicable in the destination country, in particular applicable surveillance laws and rights of individuals.
The European Data Protection Board, or the EDPB, issued additional guidance regarding the Court of Justice’s decision
on November 11, 2020 which imposes higher burdens on the use of data transfer mechanisms, such as the SCCs, for
cross-border data transfers. To comply with this guidance, we may need to implement additional safeguards to further
enhance the security of data transferred out of the EEA, which could increase our compliance costs, expose us to further
regulatory scrutiny and liability, and adversely affect our business. Further, the European Commission adopted two new
sets of SCCs on June 4, 2021 and set timelines for when they became effective. These obligations may be interpreted
and applied in a manner that is inconsistent from one jurisdiction to another and may conflict with other requirements or
our practices.

Furthermore, Brexit has caused some uncertainty in this regulatory framework. For example, since the transition

period for Brexit ended December 31, 2020, there remains some uncertainty regarding cross-border data transfers from
the EEA to the United Kingdom. With respect to transfers of personal data from the EEA to the United Kingdom, on June
28, 2021, the European Commission issued an adequacy decision in respect of the United Kingdom’s data protection
framework, enabling data transfers from EU member states to the United Kingdom to continue without requiring
organizations to put in place contractual or other measures in order to lawfully transfer personal data between the
territories. While it is intended to last for at least four years, the European Commission may unilaterally revoke the

69

adequacy decision at any point, and if this occurs it could lead to additional costs and increase our overall risk exposure.
Additionally, the United Kingdom implemented the Data Protection Act effective in May 2018 and statutorily amended in
2019, that substantially implements the GDPR and contains provisions, including UK-specific derogations, for how GDPR
is applied in the United Kingdom. Since the end of the Brexit transition period ended, we have to continue to comply with
the GDPR and also the Data Protection Act, with each regime having the ability to fine up to the greater of €20 million
(£17 million) or 4% of global turnover. Compliance with these privacy and data security laws and regulations is a rigorous
and time-intensive process and if we fail to comply with any such laws or regulations, we may face significant fines and
penalties that could adversely affect our business, financial condition and results of operations.

In the United States, in addition to HIPAA, various federal and state regulators have adopted, or are considering

adopting, laws and regulations concerning personal information and data security. Certain state laws may be more
stringent or broader in scope, or offer greater individual rights, with respect to personal information than federal,
international or other state laws, and such laws may differ from each other, all of which may complicate compliance
efforts. For example, the CCPA, which increases privacy rights for California residents and imposes obligations on
companies that process their personal information, came into effect on January 1, 2020, and became enforceable by the
California Attorney General on July 1, 2020, along with related regulations which came into force on August 14, 2020.
Additionally, although not effective until January 1, 2023, the California Privacy Rights Act, or the CPRA, which expands
upon the CCPA, was passed in the recent election on November 3, 2020. Among other things, the CCPA requires
covered companies to provide new disclosures to California consumers about their data collection, use and sharing
practices and provide such consumers new data protection and privacy rights, including the ability to opt out of certain
sales of personal information, right to request correction, access, and deletion of their personal information, the right to opt
out of certain personal information sharing, and the right to receive detailed information about how their personal
information is processed. The CCPA provides for civil penalties for violations, as well as
breaches that result in the loss of personal information, as mentioned above. This private right of action may increase the
likelihood of, and risks associated with, data breach litigation. The CPRA significantly modifies the CCPA, including by
expanding consumers’ rights with respect to certain personal information and creating a new state agency to oversee
implementation and enforcement efforts. The CCPA and CPRA may increase our compliance costs and potential liability,
particularly in the event of a data breach, and could have a material adverse effect on our business, including how we use
personal information, our financial condition, the results of our operations or prospects. State laws are changing rapidly
and there is discussion in the U.S. of a new comprehensive federal data privacy law to which we would become subject if
it is enacted.

a private right of action for data

ff

All of these evolving compliance and operational requirements impose significant costs, such as costs related to

In addition, such requirements may require us to modify our data processing

organizational changes, implementing additional protection technologies, training employees and engaging consultants,
which are likely to increase over time.
practices and policies, distract management or divert resources from other initiatives and projects, all of which could have
a material adverse effect on our business, financial condition, results of operations and prospects. Any failure or
perceived failure by us to comply with any applicable federal, state or similar foreign laws and regulations relating to data
privacy and security could result in damage to our reputation, as well as proceedings or litigation by governmental
agencies or other third parties, including class action privacy litigation in certain jurisdictions, which would subject us to
significant fines, sanctions, awards, injunctions, penalties or judgments. Any of the foregoing could have a material
adverse effect on our business, results of operations, financial condition and prospects.

We and our strategic partners that we rely on may be adversely affected by natural disasters, and our business
continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Natural disasters could severely disrupt our operations or the operations of our third party manufacturers’ facilities
and have a material adverse effect on our business, financial condition, results of operations and prospects. If a natural
disaster, power outage, global epidemic, pandemic or contagious disease, or other event occurred that prevented us from
using all or a significant portion of our headquarters or research laboratory, that damaged critical infrastructure, such as
our third party manufacturers’ facilities, or that otherwise disrupted operations, it may be difficult or, in certain cases,
impossible for us to continue our business for a substantial period of time. The disaster recovery and business continuity
plans we have in place currently are limited and may not prove adequate in the event of a serious disaster or similar
event. Substantially all of our current supply of product candidates are located at a single third party manufacturer’s
facilities, and we do not have any existing back-up facilities in place or plans for such back-up facilities. We may incur
substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which could
have a material adverse effect on our business, financial condition, results of operations and prospects.

70

We may be subject to securities litigation, which is expensive and could divert management attention.

Our stock price is volatile, and in the past companies that have experienced volatility in the market price of their
stock have been subject to an increased incidence of securities class action litigation. We may be the target of this type of
litigation in the future. Securities litigation against us could result in substantial costs and divert our management’s
attention from other business concerns, which could seriously harm our business.

If securities or industry analysts do not publish research or reports about our business, or publish negative reports

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. We do not have any control over these analysts. There can be no assurance
that analysts will cover us or provide favorable coverage. If one or more of the analysts who cover us downgrade our
stock or change their opinion of our stock, our stock price would likely decline. If one or more of these analysts cease
coverage of our company or fail to regularly publish reports on us, we could lose visibility in the financial markets, which
could cause our stock price or trading volume to decline.

71

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

ITEM 2. PROPERTIES

In April 2019, we entered into a lease agreement (the “Las Cimas Lease”) for corporate headquarters and laboratory

space located in Austin, Texas. The Las Cimas Lease includes approximately 30,000 square feet and commenced on
April 30, 2019, with an expiration date of April 30, 2028. Moreover, we lease approximately 4,560 square feet of additional
laboratory space in Austin, Texas. The lease for the additional laboratory space will expire in September 2021. We intend
to lease additional space if we add employees and expand geographically. We believe that our facilities are adequate to
meet our needs for the immediate future, and that, should it be needed, suitable additional space will be available on
commercially reasonable terms to accommodate any such expansion of our operations.

ITEM 3. LEGAL PROCEEDINGS

From time to time, we may become involved in legal proceedings arising in the ordinary course of our business.
Regardless of outcome, litigation can have an adverse impact on us due to defense and settlement costs, diversion of
management resources, negative publicity and reputational harm, and other factors.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

72

PART II

ITEM 5. MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER
PURCHASES OF EQUITY SECURITIES

Market Information and Holders

Our common stock is traded on The Nasdaq Global Market under the symbol “AGLE.”

As of February 24, 2022, there were approximately 20 stockholders of record of our common stock based on

information provided by our transfer agent. The actual number of stockholders is greater than this number of record
holders, and includes stockholders who are beneficial owners, but whose shares are held in street name by brokers and
other nominees. This number of holders of record also does not include stockholders whose shares may be held in trust
by other entities.

Stock Price Performance Graph

This graph shall not be deemed “soliciting material” or be deemed “filed” for purposes of Section 18 of the Exchange
Act, or otherwise subject to the liabilities under that Section, and shall not be deemed to be incorporated by reference into
any of our filings under the Securities Act whether made before or after the date hereof and irrespective of any general
incorporation language in any such filing.

The following stock performance graph compares our total stock return with the total return for (i) the Nasdaq
Composite Index and the (ii) the Nasdaq Biotechnology Index for the period from December 31, 2016 through December
31, 2021. The figures represented below assume an investment of $100 in our common stock at the closing price of $4.35
on December 31, 2016 and in the Nasdaq Composite Index and the Nasdaq Biotechnology Index on December 31, 2016
and the reinvestment of dividends into shares of common stock. The comparisons in the table are required by the SEC
and are not intended to forecast or be indicative of possible future performance of our common stock.

73

Comparison of Cumulative Return

$350

$300

$250

$200

$150

$100

$50

$0
Dec-16

Dec-17

Dec-18

Dec-19

Dec-20

Dec-21

AGLE

IXIC

NBI

*$100 invested on 12/31/16 in stock or index, including reinvestment of dividends.
Fiscal year ending December 31.

Ticker
$100 investment in stock or index
AAGLE
AAeglea Biotherapeutics, Inc.
Nasdaq Composite Index
IXIC
Nasdaq Biotechnology Index NBI

Dividends

December 31,
2016
100.00 $
100.00 $
100.00 $

December 31,
2017
124.37 $
129.64 $
121.63 $

December 31,
2018
172.18 $
125.96 $
110.85 $

December 31,
2019
175.63 $
172.17 $
138.69 $

December 31,
2020
180.92 $
249.51 $
175.33 $

December 31,
2021
109.20
304.85
175.37

$
$
$

We have never declared or paid any cash dividends on our capital stock. We currently intend to retain all available

funds and any future earnings to support our operations and finance the growth and development of our business. We do
not intend to pay cash dividends on our common stock for the foreseeable future.

Securities Authorized for Issuance under Equity Compensation Plans

The information required by this item will be included in an amendment to this Annual Report on Form 10-K or

incorporated by reference from our definitive proxy statement to be filed pursuant to Regulation 14A.

74

Recent Sales of Unregistered Securities

None.

Purchases of Equity Securities by the Issuer and Affiliated Purchasers

None.

ITEM 6. [RESERVED]

75

ITEM 7. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF
OPERATIONS

You should read the following discussion and analysis of our financial condition and results of operations together

tt

with our financial statements and related notes appearing in this Annual Report. Some of the information contained in this
discussion and analysis or set forth elsewhere in this Annual Report, including information with respect to our plans and
strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties.
As a result of many factors, including those factors set forth in the
results could differ materially from the results described in or implied by the forward-looking statements contained in the
following discussion and analysis. As used in this report, unless the context suggests otherwise, “we““
Company” or “Aeglea

” section of this Annual Report, our actual

” refers to Aeglea BioTherapeutics, Inc.

“
“Risk Factors

“
’, “our

’, “the““

’, “us“

rr

“

Overview

We are a clinical-stage biotechnology company redefining the potential of human enzyme therapeutics to benefit

people with rare metabolic diseases with limited treatment options. We believe our expertise in enzyme science,
bioengineering and rare disease drug development coupled with an approach focused on diseases with unmet medical
needs enables us to develop medicines with the potential to transform the lives of patients and families with rare
metabolic diseases.

We employ a distinctive platform to fuel our innovative pipeline of human enzymes, which we believe reduces key

risks throughout the development process and provides a greater likelihood of clinical success and commercial adoption.

Our mission is to provide transformative therapies to patient communities who have inadequate or no therapeutic

options available to address these debilitating diseases. Driven by this purpose and urgent patient need, we have taken a
focused approach to the selection and development of novel assets into clinical evaluation that is guided by defined
strategic considerations:

-

-

-

-

-

Clear, urgent unmet medical need

Rigorous preclinical data and strong scientific rationale

Mechanistic opportunity to create or enhance enzymatic activity through novel engineering

Meaningful and sustainable commercial opportunities

Potential to be first in class or best in class, with little competition

Our lead product candidate, pegzilarginase, is a recombinant human arginase 1 that enzymatically degrades the
amino acid arginine to lower arginine levels in patients with Arginase 1 Deficiency. We engineered pegzilarginase with
modifications that enhance the stability and arginine-degrading activity of the enzyme in human plasma. For Arginase 1
Deficiency, which is a rare progressive disease, that presents in early childhood and results in severe complications and
early mortality, we believe pegzilarginase may reduce the harmful metabolic effects caused by the accumulation of high
levels of arginine and other arginine-derived metabolites. We are currently evaluating pegzilarginase in the open-label
extension portion of the global pivotal PEACE Phase 3 trial and in a Phase 2 open-label extension study for patients with
Arginase 1 Deficiency.

Our second product candidate, AGLE-177, is a novel PEGylated, or polyethylene glycol modified, human enzyme

engineered to degrade free homocysteine and homocystine in patients with Homocystinuria, a serious metabolic disorder
characterized by elevated plasma homocysteine which leads to a wide range of life-altering complications and reduced life
expectancy. We engineered AGLE-177 by directed mutagenesis of amino acids within cystathionine γ-lyase, resulting in a
molecule that has high substrate specificity for homocysteine and homocystine but not for the native substrate,
cystathionine. For Homocystinuria due to cystathionine β-synthase, or CBS, enzyme deficiency, which is the most
common form of an inherited disorder of methionine metabolism that results in elevated homocysteine and homocystine,
we believe AGLE-177 may reduce the adverse impact of CBS enzyme deficiency in the transsulfuration pathway by
providing an alternate pathway for enzymatic degradation of high plasma total homocysteine levels. We are currently
conducting a Phase 1/2 clinical trial for the treatment of patients with Homocystinuria.

Cystinuria is a rare genetic disease characterized by frequent and recurrent kidney stone formation requiring
multiple procedural interventions, and by an increased risk of chronic kidney disease. Cystinuria occurs due to genetic
mutations in an amino acid transporter that leads to increased amounts of cystine in the urine. This results in high cystine
concentrations in the urine and formation of kidney stones. As such, we engineered our Cystinuria program candidate to
reduce plasma cystine and cysteine levels with accompanying reductions in urine cystine concentrations as an approach
to inhibit both cystine crystal and kidney stone formation.

76

We have incurred net losses in each year since inception. Our net losses were $65.8 million, $80.9 million, and

$78.3 million for the years ended December 31, 2021, 2020, and 2019, respectively, and have resulted from costs
incurred in connection with our research and development programs and from general and administrative expenses
associated with our operations. As of December 31, 2021, we had an accumulated deficit of $341.8 million. We expect to
continue to incur operating losses over the next several years. Our net losses may fluctuate significantly from quarter to
quarter and from year to year. We anticipate that our expenses will increase as we continue our clinical development
activities for our product candidates and prepare for the potential commercialization of our lead product candidate,
pegzilarginase; concurrently develop our pipeline product candidates; expand and protect our intellectual property
portfolio; hire additional personnel; and continue to operate as a public company.

Components of Operating Results

Revenue

We have recognized license and development revenue from a license and supply agreement, or Immedica

Agreement, with Immedica, and expect to continue to recognize revenue as we satisfy our performance obligations under
the agreement. We may also be entitled to receive additional milestone payments pursuant to the Immedica Agreement
upon achievement of specified milestones. As the recognition of future license and development revenue will be based on
costs incurred to date relative to total estimated costs at completion and the uncertainty of when the events underlying
various milestones are resolved, we expect our license and development revenue will fluctuate from period to period.

We have not generated any revenue from commercial product sales. Our ability to generate product revenues in the
future will depend on the successful development, regulatory approval, and commercialization of our product candidates.
In the future, we may also seek to generate revenue from a combination of research and development payments, license
fees and other upfront or milestone payments, including under the Immedica Agreement.

Research and development expenses

Research and development expenses consist primarily of costs incurred for the discovery and development of our

product candidates, including, our lead product candidate, pegzilarginase, and AGLE-177. In addition to operating an
internal research laboratory, we contract with external providers for nonclinical studies and clinical trials. Our research and
development expenses include:

•

•

•

costs from acquiring clinical trial materials and services performed for contracted services with contract
manufacturing organizations, or CMOs;

fees paid to clinical trial sites, clinical research organizations, or CROs, CMOs, nonclinical research
companies, and academic institutions; and

employee and consultant-related expenses incurred, which include salaries, benefits, travel and stock-based
compensation.

Research and development costs are expensed as incurred. Advance payments for goods or services to be
rendered in the future for use in research and development activities are deferred and capitalized. The capitalized
amounts are expensed as the related goods are delivered or the services are performed.

Research and development expenses have historically represented the largest component of our total operating

expenses.

Our expenditures on current and future nonclinical and clinical development programs are subject to numerous
uncertainties in timing and cost to completion. The duration, costs, and timing of clinical trials and development of our
product candidates will depend on a variety of factors, including:

•

•

•

•

•

the scope, rate of progress, and expenses of our ongoing research activities as well as any additional clinical
trials and other research and development activities;

future clinical trial results;

uncertainties in clinical trial enrollment rates or drop-out or discontinuation rates of patients;

changes in the competitive drug development environment;

potential safety monitoring or other studies requested by regulatory agencies;

77

•

•

•

significant and changing government regulation;

the timing and receipt of regulatory approvals, if any; and

developments relating to the COVID-19 global pandemic.

The process of conducting the necessary clinical research to obtain FDA and other regulatory approval is costly and
time consuming and the successful development of our product candidates is highly uncertain. The risks and uncertainties
associated with our research and development projects are discussed more fully in Part I, Item 1A of this Annual Report
titled “Risk Factors.” As a result of these risks and uncertainties, we are unable to determine with any degree of certainty
the duration and completion costs of our research and development projects, or if, when, or to what extent we will
generate revenues from the commercialization and sale of any of our product candidates that obtain regulatory approval.
We may never succeed in achieving regulatory approval for any of our product candidates.

General and administrative expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based

ff

compensation, for personnel in executive, finance, accounting, legal, commercial development, operations, and human
resources functions. Other significant costs include legal fees relating to corporate matters and fees for insurance,
accounting, consulting, facilities, and recruiting services.

We expect that our general and administrative expenses will increase in the future to support our continued research

and development activities and ramp up of commercialization capabilities for pegzilarginase. These increases will likely
include higher costs related to the hiring of additional personnel and fees to outside consultants, lawyers and accountants,
among other expenses. Additionally, we have incurred and expect to continue to incur increased costs associated with
being a public company, including expenses related to services associated with maintaining compliance with Nasdaq
listing rules and SEC requirements, insurance, and investor relations costs.

Interest income

Interest income consists of interest earned on our cash, cash equivalents, marketable securities, and restricted

cash.

Income taxes

We serve as a holding company for our ten wholly owned subsidiary corporations in the United States, United

Kingdom, and European Union. We file a consolidated U.S. corporate federal income tax return with our eight United
States subsidiaries. Additionally, we operate in the U.K. and our income tax return is subject to audit and adjustment by
local tax authorities. We use the asset and liability method of accounting for income taxes. Under this method, deferred
tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the
financial statements and the tax bases of assets and liabilities. A valuation allowance is established against the deferred
tax assets to reduce their carrying value to an amount that is more likely than not to be realized. The deferred tax assets
and liabilities are classified as noncurrent along with the related valuation allowance. Due to our lack of earnings history,
the net deferred tax assets have been fully offset by a valuation allowance.

We recognize benefits of uncertain tax positions if it is more likely than not that such positions will be sustained upon

examination based solely on the technical merits, as the largest amount of benefits that is more likely than not to be
realized upon the ultimate settlement. Our policy is to recognize interest and penalties related to the unrecognized tax
benefits as a component of income tax expense.

Critical Accounting Policies and Estimates

Our consolidated financial statements are prepared in accordance with generally accepted accounting principles in

the United States, or GAAP. The preparation of these consolidated financial statements requires us to make estimates
and assumptions that affect the reported amounts of assets, liabilities, revenue, costs and expenses, and related
disclosures. These estimates form the basis for judgments we make about the carrying values of our assets, liabilities and
equity and the amount of revenues and expenses, which are not readily apparent from other sources. We base our
estimates on historical experience and on various other assumptions that we believe are reasonable under the
circumstances. On an ongoing basis, we evaluate our estimates and assumptions. Our actual results may differ materially
from these estimates under different assumptions or conditions.

ff

78

Our critical accounting policies are those policies which require the most significant judgments and estimates in the
preparation of our consolidated financial statements. We believe that the assumptions and estimates associated with our
most critical accounting policies are those relating to accrued research and development costs.

We define our critical accounting policies as those accounting principles generally accepted in the United States that

require us to make subjective estimates and judgments about matters that are uncertain and are likely to have a material
impact on our financial condition and results of operations, as well as the specific manner in which we apply those
principles. Our significant accounting policies are more fully described in Note 2 to our audited consolidated financial
statements appearing elsewhere in this annual report.

Revenue recognition

We enter into license agreements related to our technologies that we have determined are within the scope of
Accounting Standards Codification 606. Based on the terms and conditions of our agreements, we identify the goods and
services that we promise to transfer to the customer, which may consist of the licensing of technologies, the performance
of research and development activities, and/or the supply of products related to our technologies. Based on the nature of
the goods and services provided and the customer’s intended benefit of the arrangement, we evaluate which of the
promised goods and services are distinct and, therefore, represent a performance obligation, which may require us to
combine certain promised goods and services that are determined to not be distinct from one another. We also evaluate
whether an agreement provides the customer an option to purchase future goods or services at a discounted price, or a
material right, which would also represent a performance obligation.

In exchange for the performance obligations, we estimate the amount of consideration promised by the customer, or

transaction price, which may include both fixed and variable consideration. Variable consideration, which may consist of
various milestone payments based upon the achievement of certain events or conditions, sales-based royalties, or
payments contingent on the performance of research and development services, are included in the transaction price only
if we expect to receive such consideration and determine it is probable that the inclusion of the variable consideration will
not result in a significant reversal in the cumulative amount of revenue recognized under the arrangement. Sales-based
royalty and milestone payments that we determine are predominantly related to the license of our intellectual property are
excluded from the transaction price we expect to receive until the underlying sales occur.

We allocate the estimated transaction price to the identified performance obligations based on the relative estimated
stand-alone selling price, or SSP, of each performance. SSP is based on the observable price of our goods and services,
or when SSP is not directly observable, we estimate SSP based on factors such as forecasted revenues or costs,
development timelines, discount rates, probabilities of technical and regulatory success, and considerations such as
market conditions and entity-specific factors. We recognize revenue allocated to each performance obligation either at a
point-in-time or over time in a manner that depicts the transfer of control of the promised goods and services to the
customer. For performance obligations that are recognized over time, we estimate the measure of progress associated
with the satisfaction of the performance obligation based on an input or output method, which may be based on factors
such as costs incurred, labor hours expended, time elapsed, among other measures based on the nature of the
performance obligation. The estimates made on an input or output method are subject to change and may result in
material changes to revenue that could materially affect our results of operations. Please refer to Note 9, Strategic
License Agreements, to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K.

Accrued research and development costs

We record the costs associated with research nonclinical studies, clinical trials, and manufacturing development as
incurred. These costs are a significant component of our research and development expenses, with a substantial portion
of our on-going research and development activities conducted by third-party service providers, including CROs and
CMOs.

We accrue for expenses resulting from obligations under agreements with CROs, CMOs, and other outside service

providers for which payment flows do not match the periods over which materials or services are provided to us. We
record accruals based on estimates of services received and efforts expended pursuant to agreements established with
CROs, CMOs, and other outside service providers. These estimates are typically based on contracted amounts applied to
the proportion of work performed and determined through analysis with internal personnel and external service providers
as to the progress or stage of completion of the services. We make significant judgments and estimates in determining the
accrual balance in each reporting period. In the event advance payments are made to a CRO, CMO, or outside service
provider, the payments will be recorded as a prepaid asset which will be amortized as the contracted services are
performed. As actual costs become known, we adjust our accruals. Inputs, such as the services performed, the number of
patients enrolled, or the study duration, may vary from our estimates, resulting in adjustments to research and

79

development expense in future periods. Changes in these estimates that result in material changes to our accruals could
materially affect our results of operations.

Results of Operations

Comparison of the Years Ended December 31, 2021 and 2020

A discussion and analysis of our financial condition and results of operations for the year ended December 31, 2019
is included in Item 7 of Part II, “Management’s Discussion and Analysis of Financial Condition and Results of Operations”
in our Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 18, 2021.

The following table summarizes our results of operations for the years ended December 31, 2021 and 2020,

together with the changes in those items in dollars and as a percentage:

Year Ended December 31,

2021

Dollar
2020
Change
(dollars in thousands)

Revenue:

License
Development fee
Total revenue

Research and development
General and administrative

Total operating expenses

Loss from operations
Interest income
Other expense, net

Loss before income tax expense

Income tax expense

Net loss

*

Percentage not meaningful

$

12,000 $

6,739
18,739

— $
—
—

12,000
6,739
18,739

57,069
27,319
84,388
(65,649)
111
(122)
(65,660)
(141)

59,638
21,843
81,481
(81,481)
593
(5)
(80,893)
—

$ (65,801) $ (80,893) $

(2,569)
5,476
2,907
15,832
(482)
(117)
15,233
(141)
15,092

% Change

*
*
*

4%
25%
4%
19%
81%
*
19%
*
19%

License and Development Fee Revenue. For the year ended December 31, 2021, we recognized $18.7 million of
license and development fee revenue in connection with the Immedica Agreement. The total revenue generated of $18.7
million was attributable to $12.0 million allocated to the license and $6.7 million allocated to the PEACE Phase 3 trial and
BLA package. We did not recognize any revenue for the year ended December 31, 2020. Please refer to Note 9, Strategic
License Agreements, to the consolidated financial statements included elsewhere in this Annual Report on Form 10-K for
additional disclosures around revenue recognition.

Research and Development Expenses

EE

. Research and development expenses decreased by $2.6 million, or 4%, to

$57.1 million for the year ended December 31, 2021 from $59.6 million for the year ended December 31, 2020. The
change in research and development expenses was due to:

•

•

•

•

lower manufacturing expenses, which decreased by $12.4 million as a result of completing certain pre-
commercial manufacturing activities for pegzilarginase and formulation, characterization, and stability studies
for AGLE-177; offset by

higher clinical development expenses, which increased by $5.1 million as a result of ramping-up and
completing enrollment in our PEACE Phase 3 trial of pegzilarginase for the treatment of patients with Arginase
1 Deficiency, and preparing and initiating dosing in our Phase 1/2 trial of AGLE-177 for the treatment of
Homocystinuria;

higher nonclinical development expenses, which increased by $2.5 million as a result of additional laboratory
costs, BLA development activities, and toxicology costs incurred to support our Phase 1/2 trial of AGLE-177 for
the treatment of patients with Homocystinuria; and

higher personnel-related expenses, which increased by $2.2 million as a result of changes to employee
headcount and additional compensation to support our clinical and research development capabilities.

80

General and Administrative Expenses. General and administrative expenses increased by $5.5 million, or 25%, to

$27.3 million for the year ended December 31, 2021 from $21.8 million for the year ended December 31, 2020. The
increase in general and administrative expenses was primarily due to a $3.6 million increase in compensation and other
personnel expenses, including $1.3 million in non-cash stock compensation, driven by additional headcount to establish
and execute our commercial planning activities, and $1.9 million of expenses to ramp-up our commercial infrastructure
and capabilities.

Liquidity and Capital Resources

Sources of liquidity

We are a clinical-stage biotechnology company with a limited operating history, and due to our significant research

and development expenditures, we have generated operating losses since our inception and have not generated any
revenue from the sale of any products. Since our inception and through December 31, 2021, we have funded our
operations primarily by raising an aggregate of $461.0 million of gross proceeds from the sale and issuance of convertible
preferred and common equity securities, pre-funded stock warrants, the collection of grant proceeds, and the licensing of
our product rights for the commercialization of pegzilarginase in Europe and certain countries in the Middle East.

In March 2021, we entered into the Immedica Agreement, pursuant to which Immedica licensed the product rights

for commercialization of pegzilarginase in the European Economic Area, United Kingdom, Switzerland, Andorra, Monaco,
San Marino, Vatican City, Turkey, Saudi Arabia, United Arab Emirates, Qatar, Kuwait, Bahrain, and Oman. In April 2021,
we received an upfront payment of $21.5 million from Immedica. Under the terms of the Immedica Agreement, we are
also eligible to receive additional payments of up to approximately $125.0 million in regulatory and commercial milestone
payments, assuming an exchange rate of $1.13 to €1.00. Additionally, we are entitled to receive royalties in the mid-20
percent range on the net sales of the product in countries included in the Immedica Agreement. In July 2021, the
Immedica Agreement was modified to include additional development services, up to $3.0 million, to support the PEACE
Phase 3 trial and BLA package performance obligation.

During the year ended December 31, 2020, we raised $163.3 million of gross proceeds through an underwritten

public offering and an at-the-market offering program. We sold 15,442,303 shares of common stock and pre-funded
warrants to purchase up to 13,610,328 shares of common stock in an underwritten public offering, or the 2020 Public
Offering, for gross proceeds of $138.0 million, resulting in net proceeds of $129.0 million after deducting underwriting
discounts, commissions, and offering costs. Additionally, we sold an aggregate of 3,245,077 shares of common stock
under an at-the-market offering program, or the 2020 ATM, for gross proceeds of $25.3 million, resulting in net proceeds
of $24.6 million, after deducting underwriting discounts, commissions, and offering costs.

The shares of common stock and pre-funded warrants sold in the 2020 Public Offering were pursuant to a shelf

registration statement on Form S-3, declared effective in February 2019 by the SEC for the potential offering, issuance
and sale by us of up to $200.0 million of our common stock, warrants to purchase common stock, and other security types
and subscription rights. The shares of common stock sold under the 2020 ATM were pursuant to an April 2020 sales
agreement with JonesTrading Institutional Services LLC, as sales agent, to issue and sell shares of our common stock for
an aggregate offering price of $60.0 million. In February 2022, the shelf registration statement the 2020 ATM was
registered under expired and no sales under this registration statement will occur going forward.

In July 2020, we filed a shelf registration statement on Form S-3 that was declared effective by the SEC for the

potential offering, issuance and sale by us of up to $400.0 million of our common stock, preferred stock, debt securities,
warrants to purchase common stock, preferred stock and debt securities, subscription rights to purchase common stock
and units consisting of all or some of these securities.

Our primary use of cash is to fund the development of our product candidates, prepare for the potential
commercialization of our lead product candidate, pegzilarginase and advance our pipeline. This includes both the
research and development costs and the general and administrative expenses required to support those operations.
Since we are a clinical-stage biotechnology company, we have incurred significant operating losses since our inception
and we anticipate such losses, in absolute dollar terms, to increase as we continue clinical development of our product
candidates, prepare for the potential commercialization of pegzilarginase, and expand our development efforts in our
pipeline of nonclinical candidates.

81

Future funding requirements and operational plan

Our operational plan for the near future is to continue clinical trials for our lead product candidate pegzilarginase in

Arginase 1 Deficiency and for our AGLE-177 product candidate for the treatment of Homocystinuria, prepare for the
potential commercialization of pegzilarginase, and to advance development activities for our Cystinuria program. As such,
we plan to focus our research and development expenditures and general and administrative expenditures on nonclinical
studies, clinical trials, manufacturing, and commercial development. We expect our principal expenditures during this time
period to include expenses for the following:

•

•

•

•

funding the continuing development of pegzilarginase and AGLE-177;

funding the establishment of commercial operations;

funding the advancement of additional product candidates; and

funding working capital, including general operating expenses.

Due to our significant research and development expenditures, we have generated substantial losses in each period

since inception. We have an accumulated deficit of $341.8 million as of December 31, 2021. We anticipate that we will
continue to generate losses into the foreseeable future as we develop our product candidates, seek regulatory approval of
those candidates and begin to commercialize any approved products. Until such time as we can generate substantial
product revenue, we expect to finance our cash needs through a combination of equity or debt financings, collaborations,
license and development agreements, or other sources. We currently have no debt, credit facility or additional committed
capital. To the extent that we raise additional equity, the ownership interest of our stockholders will be diluted.

Based on our available cash, cash equivalents, marketable securities, and restricted cash of $95.0 million as of
December 31, 2021, we believe that we have sufficient resources to fund our operations into the first quarter of 2023.
Accordingly, based on recurring losses from operations incurred since inception, the expectation of continued operating
losses, and the need to raise additional capital to finance our future operations, we determined that there is substantial
doubt about our ability to continue as a going concern within one year after the date that these financial statements are
issued. As a result, in order to continue to operate our business beyond that time, we will need to raise additional funds.
However, there can be no assurance that we will be able to generate funds on terms acceptable to us, on a timely basis,
or at all. In addition, we have based this estimate on assumptions that may prove to be wrong, and we could deplete our
capital resources sooner than we currently anticipate.

Cash flows

A discussion and analysis of our financial condition and cash flows for the year ended December 31, 2019 is
included in Item 7 of Part II, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in
our Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 18, 2021.

The following table summarizes our cash flows for the periods indicated (in thousands):

Net cash and cash equivalents (used in) provided by:

Operating activities
Investing activities
Financing activities
Effect of exchange rate on cash, cash equivalents, and

restricted cash

Net (decrease) increase in cash and cash equivalents

Year Ended December 31,

2021

2020

$

$

(53,716) $
(22,619)
1,393

(75,775)
(7,604)
154,512

(15)
(74,957) $

51
71,184

82

Cash used in operating activities

Cash used in operating activities for the year ended December 31, 2021 was $53.7 million and reflected a net loss of

$65.8 million. The cash impact of our net loss was offset by non-cash expenses of $8.0 million for stock-based
compensation, $1.6 million for depreciation and amortization, $0.4 million for operating lease expense, and $0.2 million for
net premium purchase and amortization on marketable securities. The net change in operating assets and liabilities of
$1.8 million was primarily related to a $3.6 million increase in deferred revenue due to receiving a $21.5 million upfront
payment under the Immedica Agreement offset by the recognition of revenue allocated to the license, PEACE Phase 3
trial and BLA filing. Additional offsets included a $1.2 million increase in prepaid expenses and other assets due to
advance payments for the Phase 1/2 trial of AGLE-177 and manufacturing activities for the Arginase 1 Deficiency
program, a $0.8 million increase in license and development receivable for incremental services provided to Immedica
and not yet paid, and a $0.4 million decrease in operating lease liabilities due to lease payments made during the year.

Cash used in operating activities for the year ended December 31, 2020 was $75.8 million and reflected a net loss of

$80.9 million. The cash impact of our net loss was offset by non-cash expenses of $6.3 million for stock-based
compensation, $1.0 million for depreciation and amortization, and $0.6 million for operating lease expense. The net
change in operating assets and liabilities of $2.5 million was primarily related to a $1.7 million decrease in accrued
liabilities and accounts payable due to payments for manufacturing and a $1.1 million increase in prepaid expenses and
other assets due to advanced payments associated with manufacturing for Arginase 1 Deficiency and nonclinical studies
for Homocystinuria.

Cash used in investing activities

Cash used in investing activities for the year ended December 31, 2021 was $22.6 million and consisted of $133.1

million in purchases of marketable securities and $0.5 million in purchases of property and equipment offset by $111.0
million in maturities of marketable securities.

Cash used in investing activities for the year ended December 31, 2020 was $7.6 million and consisted of $129.0
million in purchases of marketable securities and $4.3 million in purchases of property and equipment offset by $125.7
million in maturities of marketable securities.

Cash provided by financing activities

Cash provided by financing activities for the year ended December 31, 2021 was $1.4 million, which consisted of

$1.9 million in stock option exercises and sale of common stock under our 2016 Employee Stock Purchase Plan offset by
$0.5 million in principal payments made on finance lease obligations.

Cash provided by financing activities for the year ended December 31, 2020 was $154.5 million, which consisted of
$138.0 million from the public offering of our common stock, offset by $9.0 million in paid underwriting and offering costs,
$25.3 million from the sale of our common stock under an at-the-market program, offset by $0.7 million in paid
underwriting and offering costs, and $0.8 million in proceeds received from stock option exercises and sale of common
stock under our 2016 Employee Stock Purchase Plan.

Contractual Obligations and Other Commitments

In April 2019, the Company entered into a lease agreement, or the Las Cimas Lease, for its corproate headquarters
and laboratory space located in Austin, TX. Future minimum lease commitments under the Las Cimas Lease through April
2028 are $7.0 million. Please refer to Note 7, Leases, to the consolidated financial statements included elsewhere in this
Annual Report on Form 10-K for additional disclosures.

We have entered into agreements in the normal course of business with contract research organizations for clinical
trials and contract manufacturing organizations, and with vendors for nonclinical research studies and other services and
products for operating purposes. These contractual obligations are cancelable at any time by us, generally upon 30 to 60
days’ prior written notice to the vendor.

83

Contingent contractual obligations

The terms of the Grant Contract require that we pay CPRIT tiered royalties in the low- to mid-single digit

percentages on revenues from sales and license of products or services that are based upon, utilize, are developed from
or materially incorporate the intellectual property resulting from the grant-funded activities for pegzilarginase. Such
royalties reduce to less than one percent after a mid-single digit multiple of the grant funds have been repaid to CPRIT in
royalties. Such royalties are payable for so long as we have marketing exclusivity or patents covering the applicable
product or service (or twelve years from commercial sale of product or service in certain countries if there is no such
exclusivity or patent protection).

In December 2013, our wholly owned subsidiaries AECase, Inc. and AEMase, Inc. each entered into an exclusive,

worldwide license agreement, including the right to grant sublicenses, with the University of Texas at Austin, or the
University, for certain intellectual property owned by the University related to our program candidates for cystinase and
methioninase. In January 2017, we and the University entered into an Amended and Restated Patent License Agreement,
or the Restated License, which consolidated the two license agreements, revised certain obligations, and licensed
additional patent applications and invention disclosures to us. The Restated License was amended in August 2017,
December 2017, and December 2018 to revise diligence milestones and license additional patent applications, including
our program candidates under our AGLE177 and Cystinuria programs.

With respect to each program candidate covered by the Restated License, we could be required to pay the

University up to $6.4 million in milestone payments based on the achievement of certain development milestones,
including clinical trials and regulatory approvals, the majority of which are due upon the achievement of later development
milestones, including a $5.0 million payment due on regulatory approval of a product and a $0.5 million payment payable
on final regulatory approval of a product for a second indication. In addition, we are required to pay the University a low
single digit royalty on worldwide-net sales of products covered under the Restated License, together with a revenue share
on non-royalty consideration received from sublicensees. The rate of the revenue share ranges from 6.5% to 25%
depending on the date the sublicense agreement is signed. The University may terminate the agreement under certain
circumstances, including for a breach by us that is not cured within 30 or 60 days of notice (depending on the type of
breach), or if we or any of our affiliates or sublicensees participate in any proceeding to challenge the licensed patent
rights (unless, with respect to sublicensees, we terminate the applicable sublicense).

ITEM 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

We are exposed to market risks in the ordinary course of our business. Our primary exposure to market risk is
interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates, particularly because our
investments are in marketable securities. Our marketable securities are subject to interest rate risk and could fall in value
if market interest rates increase. However, we believe that our exposure to interest rate risk is not significant as the
majority of our investments are short-term in duration and due to the low risk profile of our investments, a 10% change in
interest rates would not have a material effect on the total market value of our investment portfolio. We have the ability to
hold our marketable securities until maturity, and therefore we would not expect our operating results or cash flows to be
affected to any significant degree by the effect of a change in market interest rates on our investments.

As of December 31, 2021, we held $95.0 million in cash, cash equivalents, marketable securities, and restricted
cash, all of which was denominated in U.S. dollar assets, and consisting primarily of investments in money market funds,
commercial paper, and corporate bonds.

We are also exposed to market risk related to changes in foreign currency exchange rates, as a result of entering

into transactions denominated in currencies other than U.S. dollars. Due to the uncertain timing of expected payments in
foreign currencies, we do not utilize any forward exchange contracts. All foreign transactions settle on the applicable spot
exchange basis at the time such payments are made. For the year ended December 31, 2021, a majority of our
expenditures were denominated in U.S. dollars. A hypothetical 10% change in foreign exchange rates during any of the
periods presented would not have had a material impact on our consolidated financial statements.

84

ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

AEGLEA BIOTHERAPEUTICS, INC.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Audited Consolidated Financial Statements

Report of Independent Registered Public Accounting Firm........................................................................................
Consolidated Balance Sheets.....................................................................................................................................
Consolidated Statements of Operations .....................................................................................................................
Consolidated Statements of Comprehensive Loss.....................................................................................................
Consolidated Statements of Changes in Stockholders’ Equity...................................................................................
Consolidated Statements of Cash Flows....................................................................................................................
Notes to Consolidated Financial Statements..............................................................................................................

Page

86
88
89
90
91
92
93

85

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Stockholders of Aeglea BioTherapeutics, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Aeglea BioTherapeutics, Inc. and its subsidiaries (the
“Company”) as of December 31, 2021 and 2020, and the related consolidated statements of operations, of
comprehensive loss, of changes in stockholders’ equity and of cash flows for each of the three years in the period ended
December 31, 2021, including the related notes (collectively referred to as the “consolidated financial statements”). In our
opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company
as of December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the
period ended December 31, 2021 in conformity with accounting principles generally accepted in the United States of
America.

Substantial Doubt about the Company’s A’

bility to Continue as a Going Concern

The accompanying consolidated financial statements have been prepared assuming that the Company will continue as a
going concern. As discussed in Note 1 to the consolidated financial statements, the Company has not generated any
product revenues and has not achieved profitable operations. These conditions raise substantial doubt about the
Company’s ability to continue as a going concern. Management's plans in regard to these matters are also described in
Note 1. The consolidated financial statements do not include any adjustments that might result from the outcome of this
uncertainty

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to
express an opinion on the Company’s consolidated financial statements based on our audits. We are a public accounting
firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be
independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and
regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these consolidated financial statements in accordance with the standards of the PCAOB.
Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the
consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not
required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our
audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of
expressing an opinion on the effectiveness of the Company's internal control over financial reporting. Accordingly, we
express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial
statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures
included examining, on a test basis, evidence regarding the amounts and 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. We believe that our
audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial
statements that was communicated or required to be communicated to the audit committee and that (i) relates to accounts
or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging,
subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the
consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below,
providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Revenue Recognition

As described in Notes 2 and 9 to the consolidated financial statements, the Company’s revenue is generated from
licensing their product, completion of the global pivotal Pegzilarginase Effect on Arginase 1 Deficiency Clinical Endpoints

86

Phase 3 trial (“PEACE Trial”) and related Biologics License Application (“BLA”) package and performance of a Pediatric
Investigation Plan trial (“PIP Trial”) in connection with the exclusive license and supply agreement entered into with
Immedica Pharma AB. Total revenue was $18.7 million for the year ended December 31, 2021. The Company
recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when
(or as) each performance obligation is satisfied at a point in time or over time, and if over time, recognition is based on the
use of an output or input method. The development fee allocated to the PEACE Trial, BLA package and PIP Trial
performance obligations will be recognized over time using an input method of costs incurred related to the performance
obligations. Revenue allocated to the License performance obligation is recognized at a point in time and upon transfer of
the License to Immedica Pharma AB. Management assesses whether the goods or services promised within each
contract are distinct to identify those that are performance obligations. This assessment involves subjective
determinations and requires management to make judgments about the individual promised goods or services and
whether such are separable from the other aspects of the contractual relationship. The transaction price is determined
and allocated to the identified performance obligations in proportion to their stand-alone selling prices (“SSP”) on a
relative SSP basis. SSP is based on observable prices of the performance obligations or, when such prices are not
observable, are estimated. If an arrangement includes development, regulatory or commercial milestone payments,
management evaluates whether the milestones are considered probable of being reached and estimates the amount to
be included in the transaction price using the most likely amount method. If it is probable that a significant revenue
reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are
not within the Company’s control or the licensee’s control, such as regulatory approvals, are generally not considered
probable of being achieved until those approvals are received.

The principal considerations for our determination that performing procedures relating to revenue recognition is a critical
audit matter are the significant judgment by management when identifying the individual performance obligations,
estimating the SSP and determining the transaction price allocated to the identified performance obligations. This in turn
led to a high degree of auditor judgment, subjectivity, and effort in performing procedures and evaluating audit evidence
related to the identification of the individual performance obligations, estimation of the SSP and the allocation of the
transaction price to the identified performance obligations.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our
overall opinion on the consolidated financial statements. These procedures included, among others (i) reading the
executed agreement entered into with Immedica Pharma AB; (ii) evaluating management’s identification of the individual
performance obligations based on the terms and conditions of the agreement; (iii) evaluating and testing management’s
process for estimating the SSP and allocation to the individual performance obligations; (iv) vouching the cash for the
upfront fixed payment; and (v) testing actual costs incurred and their eligibility for billing under the development
performance obligations for a sample of costs. Testing the estimation of SSP involved testing the completeness and
accuracy of the data utilized by management.

/s/ PricewaterhouseCoopers LLP
Austin, Texas
March 3, 2022

We have served as the Company’s auditor since 2014.

87

Aeglea BioTherapeutics, Inc.
Consolidated Balance Sheets

(In thousands, except share and per share amounts)

ASSETS

December 31,

2021

2020

CURRENT ASSETS

Cash and cash equivalents
Marketable securities
License and development receivable
Prepaid expenses and other current assets

Total current assets

Restricted cash
Property and equipment, net
Operating lease right-of-use assets
Other non-current assets
TOTAL ASSETS

$

$

LIABILITIES AND STOCKHOLDERS’ EQUITY

CURRENT LIABILITIES
Accounts payable
Operating lease liabilities
Deferred revenue
Accrued and other current liabilities

Total current liabilities

Non-current operating lease liabilities
Deferred revenue, net of current portion
Other non-current liabilities
TOTAL LIABILITIES
Commitments and Contingencies (Note 9)

’ EQUITY

Preferred stock, $0.0001 par value; 10,000,000 shares authorized as of
December 31, 2021 and 2020; no shares issued and outstanding as of
December 31, 2021 and 2020

Common stock, $0.0001 par value; 500,000,000 shares authorized as of

December 31, 2021 and 2020, 49,355,130 shares and 47,959,086
shares issued and outstanding as of December 31, 2021 and 2020,
respectively

Additional paid-in capital
Accumulated other comprehensive (loss) income
Accumulated deficit

TOTAL STOCKHOLDERS’ EQUITY
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY

$

$

$

$

$

15,142
77,986
815
4,948
98,891
1,838
4,549
3,806
842
109,926

3,319
436
2,359
14,030
20,144
4,608
1,217
16
25,985

90,095
56,178
—
3,516
149,789
1,842
5,642
4,230
115
161,618

2,254
319
—
13,870
16,443
5,129
—
214
21,786

—

—

5
425,765
(20)
(341,809)
83,941
109,926

$

5
415,824
11
(276,008)
139,832
161,618

The accompanying notes are an integral part of these consolidated financial statements.

88

Aeglea BioTherapeutics, Inc.
Consolidated Statements of Operations

(In thousands, except share and per share amounts)

Revenue:

License
Development fee
Total revenue

Operating expenses:

Research and development
General and administrative

Total operating expenses

Loss from operations

Other income (expense):

Interest income
Other expense, net

Total other income (expense)

Loss before income tax expense

Income tax expense

Net loss

Net loss per share, basic and diluted
Weighted-average common shares outstanding, basic and diluted

2021

Year Ended December 31,
2020

2019

$

12,000
6,739
18,739

— $
—
—

—
—
—

57,069
27,319
84,388
(65,649)

59,638
21,843
81,481
(81,481)

111
(122)
(11)
(65,660)
(141)
(65,801) $

593
(5)
588
(80,893)
—
(80,893) $

64,600
15,734
80,334
(80,334)

2,143
(63)
2,080
(78,254)
—
(78,254)

(1.00) $

(1.52) $

65,744,611

53,371,730

(2.45)
31,949,633

$

$

$

The accompanying notes are an integral part of these consolidated financial statements.

89

Aeglea BioTherapeutics, Inc.
Consolidated Statements of Comprehensive Loss

(In thousands)

Net loss
Other comprehensive income (loss):

Foreign currency translation adjustment
Unrealized (loss) gain on marketable securities

Total comprehensive loss

2021

Year Ended December 31,
2020

2019

(65,801) $

(80,893) $

(78,254)

(1)
(30)
(65,832) $

19
(59)
(80,933) $

—
78
(78,176)

$

$

The accompanying notes are an integral part of these consolidated financial statements.

90

Aeglea BioTherapeutics, Inc.
Consolidated Statements of Changes in Stockholders’ Equity

(In thousands)

Common
Stock

Shares

Amount

Additional
Paid-in
Capital
2 $ 184,314 $

Accumulated
Other

Comprehensive Accumulated
(Loss) Income

Deficit

Total
Stockholders’
Equity

Balances—December 31, 2018
Issuance of common stock in connection with employee

24,140 $

stock purchase plan

Issuance of common stock in connection with exercise

of stock options

Issuance of common stock and pre-funded warrants in
connection with public offering, net of offering costs

Stock-based compensation expense
Unrealized gain on marketable securities
Net loss
Balances—December 31, 2019

Issuance of common stock in connection with employee

stock purchase plan

Issuance of common stock in connection with exercise

of stock options

Issuance of common stock and pre-funded warrants in

connection with public and at-the-market offerings, net
of offering costs

Stock-based compensation expense
Foreign currency translation adjustment
Unrealized loss on marketable securities
Net loss
Balances—December 31, 2020

Issuance of common stock in connection with employee

stock purchase plan

Issuance of common stock in connection with exercise

of stock options

Issuance of common stock in connection with exercise

of pre-funded warrants

Stock-based compensation expense
Foreign currency translation adjustment
Unrealized loss on marketable securities
Net loss
Balances—December 31, 2021

45

274

—

—

307

1,143

4,625
—
—
—
29,084 $

64,502
4,876
—
—

1
—
—
—
3 $ 255,142 $

60

127

—

—

366

490

18,688
—
—
—
—
47,959 $

153,570
6,256
—
—
—

2
—
—
—
—
5 $ 415,824 $

83

313

—

—

454

1,449

1,000
—
—
—
—
49,355 $

—
—
—
—
—
5 $ 425,765 $

—
8,038
—
—
—

(27) $

(116,861) $

67,428

—

—

—
—
78
—
51 $

—

—

—
—
19
(59)
—
11 $

—

—

—
—
(1)
(30)
—
(20) $

—

—

—
—
—
(78,254)
(195,115) $

—

—

—
—
—
—
(80,893)
(276,008) $

—

—

—
—
—
—
(65,801)
(341,809) $

307

1,143

64,503
4,876
78
(78,254)
60,081

366

490

153,572
6,256
19
(59)
(80,893)
139,832

454

1,449

—
8,038
(1)
(30)
(65,801)
83,941

The accompanying notes are an integral part of these consolidated financial statements.

91

Aeglea BioTherapeutics, Inc.
Consolidated Statements of Cash Flows

(In thousands)

CASH FLOWS FROM OPERATING ACTIVITIES
Net loss
AAdjustments to reconcile net loss to net cash used in operating activities:

Depreciation and amortization
Purchase net (premium) discount on marketable securities
Net amortization of premium (accretion of discount) on marketable
securities
Stock-based compensation
Non-cash operating lease expense
Other

Changes in operating assets and liabilities:
License and development receivable
Prepaid expenses and other assets
Accounts payable
Operating lease liabilities
Deferred revenue
Accrued and other liabilities

Net cash used in operating activities

CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment
Purchases of marketable securities
Proceeds from maturities and sales of marketable securities

Net cash used in investing activities

CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock and pre-funded warrants in public

and at-the-market offerings, net of offering costs

Proceeds from employee stock plan purchases and stock option

exercises

Principal payments on finance lease obligation

Net cash provided by financing activities

Effect of exchange rate on cash, cash equivalents, and restricted cash
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS, AND

RESTRICTED CASH

2021

Year Ended December 31,
2020

2019

$

(65,801) $

(80,893) $

(78,254)

1,576
(344)

548
8,038
425
9

(815)
(1,216)
1,065
(404)
3,576
(373)
(53,716)

996
(286)

73
6,256
628
(9)

—
(1,101)
(544)
251
—
(1,146)
(75,775)

(573)
(133,079)
111,033
(22,619)

(4,280)
(129,000)
125,676
(7,604)

418
504

(818)
4,876
483
(5)

—
(346)
2,583
(258)
—
5,125
(65,692)

(1,492)
(91,926)
91,679
(1,739)

—

153,716

64,298

1,903
(510)
1,393
(15)

816
(20)
154,512
51

1,450
(25)
65,723
—

(74,957)

71,184

(1,708)

CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Beginning of period
End of period

Supplemental Disclosure of Non-Cash Investing and Financing

Information:

Leased assets obtained in exchange for lease obligations
Unpaid amounts related to purchase of property and equipment

91,937
16,980

$

20,753
91,937

872

$
— $

172
224

22,461
20,753

5,294
356

$

$
$

$

$
$

The accompanying notes are an integral part of these consolidated financial statements.

92

Aeglea BioTherapeutics, Inc.
Notes to Consolidated Financial Statements

1. The Company and Basis of Presentation

Aeglea BioTherapeutics, Inc. (“Aeglea” or the “Company”) is a clinical-stage biotechnology company redefining the

potential of human enzyme therapeutics to benefit people with rare metabolic diseases with limited treatment options. The
Company was formed as a Limited Liability Company (LLC) in Delaware on December 16, 2013 under the name Aeglea
BioTherapeutics Holdings, LLC and was converted from a Delaware LLC to a Delaware corporation on March 10, 2015.
The Company operates in one segment and has its principal offices in Austin, Texas.

Liquidity

As of December 31, 2021, the Company had working capital of $78.7 million, an accumulated deficit of $341.8

million, and cash, cash equivalents, marketable securities, and restricted cash of $95.0 million. The Company has not
generated any product revenues and has not achieved profitable operations. There is no assurance that profitable
operations will ever be achieved, and, if achieved, could be sustained on a continuing basis. In addition, development
activities, clinical and nonclinical testing, and commercialization of the Company’s products will require significant
additional financing.

The Company is subject to a number of risks similar to other life science companies, including, but not limited to,
risks related to the successful discovery, development, and commercialization of product candidates, raising additional
capital, development of competing drugs and therapies, protection of proprietary technology and market acceptance of the
Company’s products. As a result of these and other factors and the related uncertainties, there can be no assurance of
the Company’s future success.

In accordance with ASC 205-40, Going Concern, the Company has evaluated whether there are conditions and

events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going
concern within one year after the date the financial statements are issued. Based upon the Company’s current operating
plans, the Company believes that it has sufficient resources to fund operations into the first quarter of 2023 with its
existing cash, cash equivalents, and marketable securities. Accordingly, based on its recurring losses from operations
incurred since inception, the expectation of continued operating losses, and the need to raise additional capital to finance
its future operations, the Company determined that there is substantial doubt about the Company’s ability to continue as a
going concern within twelve months of the issuance date of these financial statements. The accompanying consolidated
financial statements do not include any adjustments that might result from the outcome of this uncertainty and assumes
the Company will continue as a going concern through the realization of assets and satisfaction of liabilities and
commitments in the ordinary course of business. The Company plans to address this condition through the sale of
common stock in public offerings and/or private placements, debt financings, or through other capital sources, including
collaborations with other companies or other strategic transactions.

Although the Company has been successful in raising capital in the past, there is no assurance that it will be
successful in obtaining such additional financing on terms acceptable to the Company, if at all, nor is it considered
probable under the accounting standards. If the Company is unable to obtain sufficient funding on acceptable terms, it
could be forced to delay, reduce or eliminate some or all of its research and development programs or commercialization
activities, which could materially adversely affect its business prospects or its ability to continue operations.

Basis of Presentation

The consolidated financial statements have been prepared in conformity with generally accepted accounting

principles in the United States (“U.S. GAAP”) as defined by the Financial Accounting Standards Board (“FASB”) and
include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have
been eliminated in consolidation.

2. Summary of Significant Accounting Policies

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and

assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes.
Management bases its estimates on historical experience and on various other market-specific and relevant assumptions

93

that management believes to be reasonable under the circumstances, the results of which form the basis for making
judgements about the carrying value of assets, liabilities, and equity and the amount of revenues and expenses. Actual
results could differ significantly from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less from the date of

purchase to be cash equivalents. Cash equivalents consist of money market funds and debt securities and are stated at
fair value.

Marketable Securities

All investments have been classified as available-for-sale and are carried at estimated fair value as determined

based upon quoted market prices or pricing models for similar securities. Management determines the appropriate
classification of its investments in debt securities at the time of purchase. The Company may hold securities with stated
maturities greater than one year until maturity. All available-for-sale securities are considered available to support current
operations and are classified as current assets. The Company presents credit losses as an allowance rather than as a
reduction in the amortized cost of the available-for-sale securities.

For available-for-sale debt securities in an unrealized loss position, the Company first assesses whether it intends to

sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If
either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair
value and recognized in other income (expense) in the results of operations. For available-for-sale debt securities that do
not meet the aforementioned criteria, the Company evaluates whether the decline in fair value has resulted from credit
losses or other factors. In making this assessment, management considers the extent to which fair value is less than
amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to
the security, among other factors. If this assessment indicates that a credit loss exists, an allowance is recorded for the
difference between the present value of cash flows expected to be collected and the amortized cost basis of the security.
Impairment losses attributable to credit loss factors are charged against the allowance when management believes an
available-for-sale security is uncollectible or when either of the criteria regarding intent or requirement to sell is met.

Any unrealized losses from declines in fair value below the amortized cost basis as a result of non-credit loss factors

is recognized as a component of accumulated other comprehensive (loss) income, along with unrealized gains. Realized
gains and losses and declines in fair value, if any, on available-for-sale securities are included in other income (expense)
in the results of operations. The cost of securities sold is based on the specific-identification method.

Restricted Cash

Restricted cash consists of money market accounts held by financial institutions as collateral for the Company’s

obligations under a credit agreement and a facility lease for the Company’s corporate headquarters in Austin, TX.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash
equivalents, marketable securities, and restricted cash. The Company’s investment policy limits investments to high credit
quality securities issued by the U.S. government, U.S. government-sponsored agencies, highly rated banks, and
corporate issuers, subject to certain concentration limits and restrictions on maturities. The Company’s cash, cash
equivalents, marketable securities, and restricted cash are held by financial institutions that management believes are of
high credit quality. Amounts on deposit may at times exceed federally insured limits. The Company has not experienced
any losses on its deposits of cash, cash equivalents, and restricted cash and its accounts are monitored by management
to mitigate risk. The Company is exposed to credit risk in the event of default by the financial institutions holding its cash,
cash equivalents, and restricted cash, and bond issuers.

Property and Equipment

Property and equipment are stated at cost, net of accumulated depreciation and amortization. Depreciation and

amortization are computed using the straight-line method over the estimated useful lives of the assets. Repairs and
maintenance that do not extend the life or improve an asset are expensed as incurred. Upon retirement or sale, the cost
of disposed assets and their related accumulated depreciation and amortization are removed from the balance sheet. Any
gain or loss is credited or charged to operations.

94

The useful lives of the property and equipment are as follows:

Laboratory equipment
Furniture and office equipment
Computer equipment
Software
Leasehold improvements

5 years
5 years
3 years
3 years
Shorter of remaining lease term or estimated useful life

Impairment of Long-Lived Assets

Long-lived assets are reviewed for indications of possible impairment whenever events or changes in circumstances

indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the
carrying amounts to the future undiscounted cash flows attributable to these assets. An impairment loss is recognized to
the extent an asset group is not recoverable, and the carrying amount exceeds the projected discounted future cash flows
arising from these assets. There were no impairments of long-lived assets for the years ended December 31, 2021, 2020,
and 2019.

Accrued Research and Development Costs

The Company records the costs associated with research nonclinical studies, clinical trials, and manufacturing

development as incurred. These costs are a significant component of the Company’s research and development
expenses, with a substantial portion of the Company’s on-going research and development activities conducted by third-
party service providers, including contract research and manufacturing organizations.

The Company accrues for expenses resulting from obligations un

ff

der agreements with contract research

organizations (“CROs”), contract manufacturing organizations (“CMOs”), and other outside service providers for which
payment flows do not match the periods over which materials or services are provided to the Company. Accruals are
recorded based on estimates of services received and efforts expended pursuant to agreements established with CROs,
CMOs, and other outside service providers. These estimates are typically based on contracted amounts applied to the
proportion of work performed and determined through analysis with internal personnel and external service providers as to
the progress or stage of completion of the services. The Company makes significant judgments and estimates in
determining the accrual balance in each reporting period. In the event advance payments are made to a CRO, CMO, or
outside service provider, the payments will be recorded as a prepaid asset which will be amortized as the contracted
services are performed. As actual costs become known, the Company adjusts its accruals. Inputs, such as the services
performed, the number of patients enrolled, or the study duration, may vary from the Company’s estimates, resulting in
adjustments to research and development expense in future periods. Changes in these estimates that result in material
changes to the Company’s accruals could materially affect the Company’s results of operations. Historically, the Company
has not experienced any material deviations between accrued and actual research and development expenses.

Leases

The Company determines if an arrangement is a lease at inception. Right-of-use ("ROU") assets represent the

f

Company's right to use an underlying asset for the lease term
and lease liabilities represent the Company's obligation to
make lease payments arising from the lease. The classification of the Company's leases as operating or finance leases
along with the initial measurement and recognition of the associated ROU assets and lease liabilities is performed at the
lease commencement date. The measurement of lease liabilities is based on the present value of future lease payments
over the lease term. As the Company's leases do not provide an implicit rate, the Company uses its incremental borrowing
rate based on the information available at the lease commencement date in determining the present value of future lease
payments. The ROU asset is based on the measurement of the lease liability and also includes any lease payments made
prior to or on lease commencement and excludes lease incentives and initial direct costs incurred, as applicable. The
lease terms may include options to extend or terminate the lease when it is reasonably certain the Company will exercise
any such options. Rent expense for the Company's operating leases is recognized on a straight-line basis over the lease
term. Amortization expense for the ROU asset associated with its finance leases is recognized on a straight-line basis
over the term of the lease and interest expense associated with its finance leases is recognized on the balance of the
lease liability using the effective interest method based on the estimated incremental borrowing rate.

The Company has lease agreements with lease and non-lease components. As allowed under Topic 842, the

Company has elected to not separate lease and non-lease components for any leases involving real estate and office
equipment classes of assets and, as a result, accounts for the lease and non-lease components as a single lease

95

component. The Company has also elected to not apply the recognition requirement of Topic 842 to leases with a term of
12 months or less for all classes of assets.

Fair Value of Financial Instruments

The Company uses fair value measurements to record fair value adjustments to certain financial and non-financial

assets and liabilities and to determine fair value disclosures. The accounting standards define fair value, establish a
framework for measuring fair value, and require disclosures about fair value measurements. Fair value is defined as the
price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market
participants at the measurement date. When determining the fair value measurements for assets and liabilities required to
be recorded at fair value, the principal or most advantageous market in which the Company would transact are considered
along with assumptions that market participants would use when pricing the asset or liability, such as inherent risk,
transfer restrictions, and risk of nonperformance.

The accounting standard for fair value establishes a fair value hierarchy based on three levels of inputs, the first two

of which are considered observable and the last unobservable, that requires an entity to maximize the use of observable
inputs and minimize the use of unobservable inputs when measuring fair value. A financial instrument’s categorization
within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

The three levels of inputs that may be used to measure fair value are as follows:

Level 1: Observable inputs, such as quoted prices in active markets for identical assets or liabilities.

Level 2: Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, or other
inputs that are observable or can be corroborated by observable market data for substantially the full term
of the assets or liabilities.

Level 3: Valuations based on unobservable inputs to the valuation methodology and including data about
assumptions that market participants would use in pricing the asset or liability based on the best
information available under the circumstances.

Financial instruments carried at fair value include cash, cash equivalents, marketable securities, and restricted cash.

The carrying amounts of accounts payable and accrued liabilities approximate fair value due to their relatively short
maturities.

Revenue Recognition

Under ASC Topic 606, “Revenue from Contracts with Customers” (“Topic 606”), an entity recognizes revenue when

its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity
expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an
entity determines are within the scope of Topic 606, the entity performs the following five steps: (i) identify the contract(s)
with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price, including
variable consideration, if any; (iv) allocate the transaction price to the performance obligations in the contract; and (v)
recognize revenue when (or as) the entity satisfies a performance obligation.

The Company assesses its license arrangements within the scope of Topic 606 in accordance with this framework

as follows:

License revenue

The Company assesses whether the goods or services promised within each contract are distinct to identify those

that are performance obligations. This assessment involves subjective determinations and requires management to make
judgments about the individual promised goods or services and whether such are separable from the other aspects of the
contractual relationship. In assessing whether a promised good or service is distinct, and therefore a performance
obligation, the Company considers factors such as the research, stage of development of the licensed product,
manufacturing and commercialization capabilities of the customer and the availability of the associated expertise in the
general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised
good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct,
the Company is required to combine that good or service with other promised goods or services until it identifies a bundle
of goods or services that is distinct. Arrangements that include rights to additional goods or services that are exercisable
at a customer’s discretion are generally considered options. The Company assesses if these options provide a material
right to the customer and if so, they are considered performance obligations.

96

The transaction price is determined and allocated to the identified performance obligations in proportion to their

stand-alone selling prices (“SSP”) on a relative SSP basis. SSP is based on observable prices of the performance
obligations or, when such prices are not observable, are estimated. The estimation of SSP may include factors such as
forecasted revenues or costs, development timelines, discount rates, probabilities of technical and regulatory success,
and considerations such as market conditions and entity-specific factors. In certain circumstances, the Company may
apply the residual method to determine the SSP of a good or service if the SSP is considered highly variable or uncertain.
The Company validates the SSP for performance obligations by evaluating whether changes in the key assumptions used
to determine the SSP will have a significant effect on the allocation of arrangement consideration between multiple
performance obligations.

If the consideration promised in a contract includes a variable amount, the Company estimates the amount of
consideration to which it will be entitled in exchange for transferring the promised goods or services to a customer. The
Company determines the amount of variable consideration by using the expected value method or the most likely amount
method. The Company includes the amount of estimated variable consideration in the transaction price to the extent that it
is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent
reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any
related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are
recorded on a cumulative catch-up basis in the period of adjustment.

If an arrangement includes development, regulatory or commercial milestone payments, the Company evaluates

whether the milestones are considered probable of being reached and estimates the amount to be included in the
transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur,
the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s
control or the licensee’s control, such as regulatory approvals, are generally not considered probable of being achieved
until those approvals are received.

In determining the transaction price, the Company adjusts consideration for the effects of the time value of money if

the timing of payments provides the Company with a significant benefit of financing. The Company does not assess
whether a contract has a significant financing component if the expectation at contract inception is such that the period
between payment by the licensee and the transfer of the promised goods or services to the licensees will be one year or
less. For arrangements with licenses of intellectual property that include sales-based royalties, including milestone
payments based on the level of sales, and if the license is deemed to be the predominant item to which the royalties
relate, the Company recognizes royalty revenue and sales-based milestones at the later of (i) when the related sales
occur, or (ii) when the performance obligation to which the royalty has been allocated has been satisfied.

The Company recognizes as revenue the amount of the transaction price that is allocated to the respective
performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over
time, recognition is based on the use of an output or input method.

The Company’s contracts may be modified for changes in the customer’s requirements. If contract modifications are

for additional goods and services that are distinct from the existing contract, the modification will be accounted for as
either a separate contract or a termination of the existing contract, depending on whether the additional goods or services
reflects the SSP.

If the additional goods or services in a contract modification are not distinct from the existing contract, they are
accounted for as if they were part of the original contract. The effect of the contract modification on the transaction price
and the measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenue
on a cumulative catch-up basis. The cumulative catch-up adjustment is calculated using an updated measure of progress
applied to the sum of (1) the remaining consideration allocated to the partially satisfied performance obligation and (2) the
revenue already recognized on that performance obligation. The revenue recognized for fully satisfied goods or services
and distinct from the remaining performance obligations is not altered by the modification.

Collaborative arrangements

The Company analyzes its license arrangements to assess whether such arrangements involve joint operating

activities performed by parties that are both active participants in the activities and exposed to significant risks and
rewards dependent on the commercial success of such activities and therefore within the scope of ASC Topic 808,
Collaborative Arrangements (“Topic 808”). This assessment is performed throughout the life of the arrangement based on
changes in the responsibilities of all parties in the arrangement. For arrangements within the scope of Topic 808 that
contain multiple elements, the Company first determines which elements of the collaboration are deemed to be within the

97

scope of Topic 808 and which elements of the collaboration are more reflective of a vendor-customer relationship and
therefore within the scope of Topic 606. For elements of collaboration arrangements that are accounted for pursuant to
Topic 808, an appropriate recognition method is determined and applied consistently, either by analogy to authoritative
accounting literature or by applying a reasonable and rational policy election. For those elements of the arrangement that
are accounted for pursuant to Topic 606, the Company applies the five-step model described above.

Research and Development Costs

Research and development costs are expensed as incurred. Research and development costs include, but are not

limited to, salaries, benefits, travel, stock-based compensation, consulting costs, contract research service costs,
laboratory supplies and facilities, contract manufacturing costs, and costs paid to other third parties that conduct research
and development activities on the Company’s behalf. Amounts incurred in connection with license agreements are also
included in research and development expense.

Advance payments for goods or services to be rendered in the future for use in research and development activities

are recorded as a prepaid asset and expensed as the related goods are delivered or the services are performed.

Stock-Based Compensation

The Company recognizes the cost of stock-based awards granted to employees and non-employees based on the
estimated grant-date fair values of the awards. The fair values of stock options are estimated on the date of grant using
the Black-Scholes option pricing model. The fair values of restricted stock units (“RSUs”) are based on the fair value of the
Company’s common stock on the date of the grant. The value of the award is recognized as compensation expense on a
straight-line basis over the requisite service period. Forfeitures are recognized when they occur, which may result in the
reversal of compensation costs in subsequent periods as the forfeitures arise. Compensation expense for employee and
non-employee share-based payment awards with performance conditions is recognized when the performance condition is
deemed probable.

Income Taxes

The Company and its ten wholly owned subsidiary corporations use the asset and liability method of accounting for

income taxes. Under this method, deferred tax assets and liabilities are recognized for the expected future tax
consequences of temporary differences between the financial statements and the tax bases of assets and liabilities.
Additionally, any changes in income tax laws are immediately recognized in the year of enactment.

A valuation allowance is established against the deferred tax assets to reduce their carrying value to an amount that

is more likely than not to be realized. The deferred tax assets and liabilities are classified as noncurrent along with the
related valuation allowance. Due to a lack of earnings history, the net deferred tax assets have been fully offset by a
valuation allowance.

The Company recognizes benefits of uncertain tax positions if it is more likely than not that such positions will be
sustained upon examination based solely on the technical merits, as the largest amount of benefits that is more likely than
not to be realized upon the ultimate settlement. The Company’s policy is to recognize interest and penalties related to the
unrecognized tax benefits as a component of income tax expense, if applicable. As of December 31, 2021 and 2020, the
Company had no unrecognized tax benefits and there was no interest or penalties incurred by the Company in the years
ended December 31, 2021, 2020, or 2019.

Comprehensive Loss

Comprehensive loss is the change in stockholders’ equity from transactions and other events and circumstances

other than those resulting from investments by stockholders and distributions to stockholders. The Company’s other
comprehensive income (loss) is currently comprised of changes in unrealized losses and gains on available-for-sale
securities and foreign currency translation adjustments reflecting the cumulative effect of changes in exchange rates
between the foreign entity’s functional currency and the reporting currency.

98

3. Fair Value Measurements

The Company measures and reports certain financial instruments as assets and liabilities at fair value on a recurring

basis. The following tables sets forth the fair value of the Company’s financial assets and liabilities at fair value on a
recurring basis based on the three-tier fair value hierarchy (in thousands):

Financial Assets

Money market funds
Commercial paper
Corporate bonds
Total financial assets

Financial Assets

Money market funds
U.S. treasury securities
U.S. government agency securities
Corporate bonds
Total financial assets

$

$

$

Level 1

Level 2

Level 3

Total

December 31, 2021

8,888 $
—
—
8,888 $

— $

65,412
12,574
77,986 $

— $
—
—
— $

8,888
65,412
12,574
86,874

Level 1

Level 2

Level 3

Total

December 31, 2020

6,700 $
—
—
—

— $

57,181
66,893
3,001

$

6,700 $ 127,075 $

— $
6,700
—
57,181
—
66,893
3,001
—
— $ 133,775

The Company measures the fair value of money market funds on quoted prices in active markets for identical asset

or liabilities. The Level 2 assets include U.S. treasury securities, U.S. government agency securities, commercial paper,
and corporate bonds and are valued based on quoted prices for similar assets in active markets and inputs other than
quoted prices that are derived from observable market data.

The Company evaluates transfers between levels at the end of each reporting period. There were no transfers

between Level 1 and Level 2 during the periods presented.

4. Cash Equivalents and Marketable Securities

The following tables summarize the estimated fair value of the Company’s cash equivalents and marketable

securities and the gross unrealized gains and losses (in thousands):

Cash equivalents:

Money market funds
Commercial paper
Total cash equivalents

Commercial paper
Corporate bonds

Total marketable securities

Amortized
Cost

December 31, 2021

Gross
Unrealized
Gains

Gross
Unrealized
Losses

Estimated
Fair Value

$

$

8,888 $
—
8,888

65,443
12,581
78,024 $

— $
—
—

3
—
3 $

— $
—
—

8,888
—
8,888

(34)
(7)
(41) $

65,412
12,574
77,986

99

Cash equivalents:

Money market funds
U.S. treasury securities
U.S. government agency securities

Total cash equivalents

U.S. treasury securities
Corporate bonds

Total marketable securities

Amortized
Cost

December 31, 2020

Gross
Unrealized
Gains

Gross
Unrealized
Losses

Estimated
Fair Value

$

6,700 $
4,005
66,895
77,600

53,183
3,000

$

56,183 $

— $
—
—
—

1
1
2 $

— $
(1)
(2)
(3)

6,700
4,004
66,893
77,597

(7)
—
(7) $

53,177
3,001
56,178

The following table summarizes the available-for-sale securities in an unrealized loss position for which an

allowance for credit losses has not been recorded as of December 31, 2021 and 2020, aggregated by major security type
and length of time in a continuous unrealized loss position:

Less Than 12 Months

12 Months or Longer

Total

December 31, 2021

Commercial paper
Corporate bonds
Total marketable securities

Fair Value
$ 47,425
12,573
$ 59,998

Unrealized
Losses

Fair Value

Unrealized
Losses

$

$

(34) $
(7)
(41) $

— $
—
— $

Fair Value
— $ 47,425
12,573
—
— $ 59,998

Unrealized
Losses

$

$

(34)
(7)
(41)

Less Than 12 Months

12 Months or Longer

Total

December 31, 2020

U.S. treasury securities
U.S. government agency securities
Total marketable securities

Fair Value
$ 43,183
66,893
$ 110,076

Unrealized
Losses

Fair Value

Unrealized
Losses

$

$

(8) $
(2)
(10) $

$

—
— $

Fair Value
$ 43,183
66,893
—
— $ 110,076

Unrealized
Losses

$

$

(8)
(2)
(10)

As of December 31, 2021 and 2020, the Company held 29 and 16 debt securities, respectively, that were in an
unrealized loss position. The Company evaluated its securities for credit losses and considered the decline in market
value to be primarily attributable to current economic and market conditions and not to a credit loss or other factors.
Additionally, the Company does not intend to sell the securities in an unrealized loss position and does not expect they
will be required to sell the securities before recovery of the unamortized cost basis. As of December 31, 2021 and 2020,
an allowance for credit losses had not been recognized. Given our intent and ability to hold such securities until recovery,
and the lack of significant change in credit risk of these investments, we do not consider these marketable securities to be
impaired as of December 31, 2021 and 2020.

There were no realized gains or losses on marketable securities for the years ended December 31, 2021 and 2020.
A realized gain is included in other expense, net for the year ended December 31, 2019. Interest on marketable securities
is included in interest income. Accrued interest receivable on available-for-sale debt securities totaled $0.1 million and
$0.2 million as of December 31, 2021 and 2020, respectively, and is excluded from the estimate of credit losses.

The following table summarizes the contractual maturities of the Company's marketable securities at estimated fair

value (in thousands):

Due in one year or less
Due in 1 - 2 years

Total marketable securities

December 31,

2021

2020

$

$

77,986 $
—
77,986 $

56,178
—
56,178

100

The Company may sell investments at any time for use in current operations even if they have not yet reached

maturity. As a result, the Company classifies marketable securities, including securities with maturities beyond twelve
months as current assets.

5. Property and Equipment, Net

Property and equipment, net consist of the following (in thousands):

Laboratory equipment
Furniture and office equipment
Computer equipment
Software
Leasehold improvements
Property and equipment, gross
Less: Accumulated depreciation and amortization

Property and equipment, net

December 31,

2021

2020

$

$

2,245 $
520
54
139
4,393
7,351
(2,802)
4,549 $

1,916
747
56
132
4,774
7,625
(1,983)
5,642

Depreciation and amortization expense for the years ended December 31, 2021, 2020, and 2019 was $1.4 million,

$1.0 million, and $0.4 million, respectively. All of the Company’s long-lived assets are located in the United States.

6. Accrued and Other Current Liabilities

Accrued and other current liabilities consist of the following (in thousands):

AAccrued compensation
AAccrued contracted research and development costs
AAccrued professional and consulting fees
Other

Total accrued and other current liabilities

December 31,

2021

2020

4,988 $
5,995
2,264
783
14,030 $

3,712
8,620
1,074
464
13,870

$

$

7. Leases

The Company leases certain office space, laboratory facilities, and equipment. These leases require monthly lease

payments that may be subject to annual increases throughout the lease term. Certain of these leases also include
renewal options at the election of the Company to renew or extend the lease for an additional three to five years. These
optional periods have not been considered in the determination of the right-of-use-assets or lease liabilities associated
with these leases as the Company did not consider it reasonably certain it would exercise the options. The Company
performed evaluations of its contracts and determined it has both operating and finance leases. Variable lease expense
for these leases primarily consists of common area maintenance and other operating costs.

In April 2019, the Company entered into a lease agreement (the “Las Cimas Lease”) for its corporate headquarters

and laboratory space located in Austin, TX. The Las Cimas Lease includes approximately 30,000 square feet and
commenced on April 30, 2019, with an expiration on April 30, 2028. The Company posted a customary letter of credit in
the amount of $1.5 million as security, which is subject to automatic reductions per the terms of the Las Cimas Lease. A
tenant allowance of up to $1.0 million was provided by the lessor and fully reimbursed to the Company.

101

The following table summarizes the Company’s recognition of its operating and finance leases (in thousands):

Assets

Operating
Finance

Total leased assets

Leases
Current

Operating
Finance
Non-current
Operating
Finance

Total lease liabilities

Classification

December 31,

2021

2020

Operating lease right-of-use assets
Other non-current assets

Operating lease liabilities
Accrued and other current liabilities

Non-current operating lease liabilities
Other non-current liabilities

$

$

$

3,806
798
4,604

436
418

4,608
16
5,478

$

4,230
68
4,298

319
27

5,129
45
5,520

The following table summarizes the weighted-average remaining lease term and discount rates for the Company’s

operating and finance leases:

Lease term (years)
Operating leases
Finance leases

Discount rate

Operating leases
Finance leases

December 31,

2021

2020

6.3
0.5

7.3
2.6

10.7%
6.7%

10.7%
10.2%

The following table summarizes the lease costs pertaining to the Company’s operating leases (in thousands):

Operating lease cost
Variable lease cost
Total lease cost

Year Ended December 31,

2021

2020

2019

991
519
1,510

$

$

1,258
665
1,923

$

$

946
331
1,277

$

$

Cash paid for amounts included in the measurement of operating lease liabilities during the years ended

December 31, 2021 and 2020 was $1.1 million and $1.3 million, respectively, and was included within net cash used in
operating activities in the cash flows.

The maturities of the Company’s operating and finance lease liabilities as of December 31, 2021 were as follows (in

thousands):

2022
2023
2024
2025
2026
Thereafter

Total lease payments

Less:

Imputed interest

Total

Operating Leases

Finance Leases

$

$

$

948
1,064
1,096
1,129
1,163
1,602
7,002

(1,958)
5,044

$

424
16
—
—
—
—
440

(6)
434

102

8. Stockholders’ Equity

The Company is authorized to issue 510,000,000 shares of capital stock of which 500,000,000 shares are
designated as common stock and 10,000,000 shares are designated as preferred stock, all with a par value of $0.0001
per share. Each holder of common stock is entitled to one vote for each share of common stock held. The Company’s
common stock is not entitled to preemptive rights, and is not subject to conversion, redemption or sinking fund provisions.
Subject to preferences that may apply to any shares of preferred stock outstanding at the time, the holders of common
stock are entitled to receive dividends out of funds legally available if the board of directors, in its discretion, determines to
issue dividends and then only at the times and in the amounts that the board of directors may determine. As of
December 31, 2021 and 2020, no common stock dividends had been declared by the board of directors and there were
no shares of preferred stock outstanding.

Follow-on Public Offerings

In February 2019, the Company issued and sold 4,625,000 shares of common stock at a public offering price of

$8.00 per share and pre-funded warrants to purchase up to 4,000,000 shares of common stock at a public offering price
of $7.9999 per warrant in an underwritten public offering pursuant to a shelf registration statement on Form S-3. This
includes the full exercise by the underwriters of their option to purchase up to 1,125,000 additional shares of common
stock. The net proceeds to the Company from this public offering were $64.5 million, after deducting underwriting
discounts and commissions of $4.1 million and offering costs of $0.4 million.

In April 2020, the Company issued and sold 15,442,303 shares of common stock at a public offering price of $4.75

per share and pre-funded warrants to purchase up to 13,610,328 shares of common stock at a public offering price of
$4.7499 per warrant in an underwritten public offering pursuant to a shelf registration statement on Form S-3. This
includes the full exercise by the underwriters of their option to purchase up to 3,789,473 additional shares of common
stock. The net proceeds to the Company from this public offering were $129.0 million, after deducting underwriting
discounts and commissions of $8.2 million and offering costs of $0.8 million.

The public offering price for the pre-funded warrants sold in February 2019 and April 2020 was equal to the public

offering price of the common stock, less the $0.0001 per share exercise price of each warrant. The warrants were
recorded as a component of stockholders’ equity within additional paid-in capital and have no expiration date. Per the
terms of the warrant agreements, the outstanding warrants to purchase shares of common stock may not be exercised if
the holder’s ownership of the Company’s common stock would exceed 4.99% (“Maximum Ownership Percentage”) or
9.99% for certain holders. By written notice to the Company, each holder may increase or decrease the Maximum
Ownership Percentage to any other percentage (not in excess of 19.99% for the majority of such warrants). The revised
Maximum Ownership Percentage would be effective 61 days after the notice is received by the Company.

As of December 31, 2021, the following pre-funded warrants to purchase common stock were issued and

outstanding:

Issue Date

Expiration Date

Exercise Price

February 8, 2019
AApril 30, 2020

Total pre-funded warrants

None
None

$
$

0.0001
0.0001

Number of Warrants
Outstanding

3,750,000
12,860,328
16,610,328

At-The-Market Offering

In April 2020, the Company entered into a new sales agreement with JonesTrading Institutional Services LLC, as

sales agent, to issue and sell shares of its common stock for an aggregate offering price of $60.0 million under an at-the-
market (“2020 ATM”) offering program. In the fourth quarter of 2020, the Company issued and sold 3,245,077 shares of
common stock under the 2020 ATM for gross proceeds of $25.3 million, resulting in net proceeds of $24.6 million, after
deducting underwriting discounts, commissions, and offering costs.

103

9. Strategic License Agreements

Immedica Pharma AB License and Development Agreement

On March 21, 2021, the Company entered into an exclusive license and supply agreement with Immedica Pharma

AB (“Immedica”). By entering into this agreement, the Company agreed to provide Immedica the following goods and
services:

i.

ii.

iii.

Deliver an exclusive, sublicensable, license and know-how (the “License”) to develop and commercialize
pegzilarginase (the “Product”), in the territory comprising the members states of the European Economic Area,
United Kingdom, Switzerland, Andorra, Monaco, San Marino, Vatican City, Turkey, Saudi Arabia, United Arab
Emirates, Qatar, Kuwait, Bahrain, and Oman (the “Territory”);

Complete the global pivotal PEACE (Pegzilarginase Effect on Arginase 1 Deficiency Clinical Endpoints) Phase
3 trial (“PEACE Trial”) and related Biologics License Application (“BLA”) package to file with the United States
Food and Drug Administration (“FDA”), which will be leveraged by Immedica in obtaining the necessary
regulatory approvals in the Territory; and

Perform a Pediatric Investigation Plan trial (“PIP Trial”) in order for Immedica to be able to receive certain
regulatory approvals within the Territory.

In addition, the Company and Immedica formed a Joint Steering Committee (“JSC”) to provide oversight to the

activities performed under the agreement; however, the substance of the Company’s participation in the JSC does not
represent an additional promised service, but rather, a right of the Company to protect its own interests in the
arrangement.

Further, the Company agreed to supply to Immedica, and Immedica agreed to purchase from the Company,

substantially all commercial requirements of the Product. The terms of the agreement do not provide for either (i) an
option to Immedica to purchase the Product from the Company at a discount from the standalone selling price or (ii)
minimum purchase quantities. Finally, Immedica will bear (i) all costs and expenses for any development or
commercialization of the Product in the Territory subject to the License exclusive of the Company’s promised goods and
services summarized above and (ii) all costs and fees associated with applying for regulatory approval of the Product in
the Territory.

The Company received a non-refundable payment of $21.5 million and Immedica agreed to provide payment of 50%

of the Company’s costs incurred in performing the PIP Trial up to a maximum of $1.8 million. In addition, the Company
has the ability to receive additional payments under the agreement of up to approximately $125.0 million in regulatory and
commercial milestone payments, assuming an exchange rate of $1.13 to €1.00. The Company is also entitled to receive
royalties in the mid-20 percent range on net sales of the Product in the Territory.

The Company concluded that Immedica meets the definition to be accounted for as a customer because the
Company is delivering intellectual property and other services within the Company’s normal course of business, in which
the parties are not jointly sharing the risks and rewards. Therefore, the Company concluded that the promises
summarized above represent transactions with a customer within the scope of ASC 606. The Company determined that
the following promises represent distinct promised services, and therefore, performance obligations: (i) the License, (ii)
the PEACE Trial and BLA package, and (iii) the PIP Trial.

Specifically, in making these determinations, the Company considered the following factors:

-

-

-

As of inception of the agreement, the Company had completed the Phase 1/2 clinical trial related to the Product
and were conducting the ongoing PEACE Trial. Accordingly, the Company is not promising, nor expecting, to
perform additional research and development activities pursuant to the agreement that would either significantly
modify, customize or be considered highly interdependent or interrelated with pegzilarginase.

The License represents functional intellectual property given the functionality of the License is not expected to
change substantially as a result of the company’s ongoing activities.

The services necessary to complete the PEACE Trial, BLA package and PIP Trial could be performed by other
parties.

Given that Immedica is not obligated to purchase any minimum amount or quantities of the Product, the supply of
f
the Product for commercial use to Immedica was determined to be an option for Immedica, rather than a performance
obligation of the Company at contract inception and will be accounted for if and when exercised. The Company also

104

determined that Immedica’s option to purchase the Product does not create a material right as the expected pricing is not
at a discount.

The Company determined that the upfront fixed payment amount of $21.5 million must be included in the transaction
price. Additionally, the Company determined that 50% of the probable estimated costs to be incurred in relation to the PIP
Trial exceeds $1.8 million and, as such, it is probable that a significant reversal of such revenue will not occur in a future
period. Therefore, the Company included an estimated $1.8 million that will be due in relation to the PIP Trial in the
transaction price. In total, the transaction price was determined to be $23.3 million at inception of the arrangement.

The Company allocated $7.2 million and $4.1 million of the transaction price to the PEACE Trial and BLA package
and PIP Trial performance obligations, respectively, based on the SSP, which was based on the estimated costs that a
third-party would charge in performing such services on a stand-alone basis. The SSP for the License was established
using a residual value approach due to the uniqueness of and lack of observable data related to the License and without a
specific analog from which to make reliable estimates, resulting in an allocation of $12.0 million.

The potential regulatory milestone payments that the Company is eligible to receive were excluded from the
transaction price, as the milestone amounts were fully constrained based on the probability of achievement, since the
milestones relate to successful achievement of certain regulatory approvals, which might not be achieved. The Company
determined that the royalties and commercial milestone payments relate predominantly to the license of intellectual
property and are therefore excluded from the transaction price under the sales- or usage-based royalty exception of ASC
606. The Company will reevaluate the transaction price, including all constrained amounts, at the end of each reporting
period and as uncertain events are resolved or other changes in circumstances occur, the Company will adjust its
estimate of the transaction price as necessary. The Company will recognize the royalties and commercial milestone
payments as revenue when the associated sales occur, and relevant sales-based thresholds are met. The Company
assessed the arrangement with Immedica and concluded that a significant financing component does not exist.

The Company recognized revenue allocated to the License performance obligation at a point in time and upon
transfer of the License. The Company completed the transfer of the know-how necessary for Immedica to benefit from the
License in June 2021 and recognized $12.0 million of revenue at that time. The development fee allocated to the PEACE
Trial, BLA package and PIP Trial performance obligations will be recognized over time using an input method of costs
incurred related to the performance obligations.

In July 2021, the Company entered into a memorandum of understanding with Immedica to provide certain

additional services in relation to the PEACE Trial and BLA package performance obligation in exchange for the
reimbursement of up to $3.0 million of the actual costs incurred in relation to such incremental services. The Company
accounted for this as a modification of the existing contract as the incremental services were determined to be not distinct
from the PEACE Trial and BLA package performance obligation. The Company calculated the remaining transaction price
and allocated the consideration over the remaining performance obligations. The impact of the cumulative catch-up
adjustment related to the modification and recorded in the year ended December 31, 2021 was not material to the
Company’s financial statements.

December 31, 2021

For the year ended

Dece

mber 31, 2021, the Company recognized revenue of $6.7 million related to the PEACE Trial

and BLA package performance obligation and $12.0 million related to the transfer of the License. The Company
recognized no revenue for the years ended December 31, 2020 a
recorded deferred revenue of $3.6 million associated with the license and supply agreement with Immedica, of which $2.4
million is classified as current. The Company had no deferred revenue recorded as of December 31, 2020.

nd 2019. As of December 31, 2021, the Company has

2019. As of December 31, 2021

Contract Balances from Customer Contract

The timing of revenue recognition, billings and cash collections results in contract assets and contract liabilities on
the balance sheets. The Company recognizes license and development receivables based on billed services, which are
derecognized upon reimbursement. When consideration is received, or such consideration is unconditionally due, from a
customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is
recorded. Contract liabilities are recognized as revenue after control of the goods or services is transferred to the
customer and all revenue recognition criteria have been met.

105

The following table presents changes in the Company’s contract liabilities for the periods presented (in thousands):

YYear Ended December 31, 2021
Contract liabilities:

December 31,
2020

Additions

Deductions

December 31,
2021

e

$

— $

22,315

$

(18,739) $

3,576

The Company had no contract assets during the years ended December 31, 2021, 2020 and 2019 and no contract

December 31, 2021, 2020 and 2019

liabilities during the years ended December 31, 2020 and

2019.

University of Texas at Austin License Agreement

In December 2013, two of the Company’s wholly owned subsidiaries AECase, Inc. and AEMase, Inc. each entered

into an exclusive, worldwide license agreement, including the right to grant sublicenses, with the University of Texas at
Austin (the “University”) for certain intellectual property owned by the University related to cystinase and methioninase. In
January 2017, the Company and the University entered into an Amended and Restated Patent License Agreement (the
“Restated License”), which consolidated the two license agreements, revised certain obligations, and licensed additional
patent applications and invention disclosures to us. The Restated License was amended in August 2017, December 2017,
and December 2018 to revise diligence milestones and license additional patent applications, including our program
candidates under the AGLE177 and Cystinuria Programs.

Pursuant to the terms of the Restated License, the Company may be required to pay the University up to $6.4 million

in milestone payments based on the achievement of certain development milestones, including clinical trials and
regulatory approvals, the majority of which are due upon the achievement of later development milestones, including a
$5.0 million payment due on regulatory approval of a product and a $0.5 million payment payable on final regulatory
approval of a product for a second indication. In addition, the Company is required to pay the University a low single-digit
royalty on worldwide-net sales of products covered under the Restated License, together with a revenue share on non-
royalty consideration received from sublicensees. The rate of the revenue share ranges from 6.5% to 25% depending on
the date the sublicense agreement is signed.

For the years ended December 31, 2021, 2020 and 2019, the Company paid $0.1 million in license fees annually.

10. Stock-Based Compensation

2015 Equity Incentive Plan

In March 2015, the Company adopted the 2015 Equity Incentive Plan (“2015 Plan”), administered by the board of
directors, and provides for the Company to sell or issue common stock or restricted common stock, or to grant 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. Under the terms of the 2015 Plan, the exercise prices, vesting and other
restrictions may be determined at the discretion of the board of directors, or their committee if so delegated, except that
the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common
stock on the date of grant, the term of stock options may not be greater than ten years for all grants, and for grantees
holding more than 10% of the total combined voting power of all classes of stock, the term may not be greater than five
years.

The Company granted options under the 2015 Plan until April 2016 when it was terminated as to future awards,

although it continues to govern the terms of options that remain outstanding under the 2015 Plan.

As of December 31, 2021, a total of 136,560 shares of common stock are subject to options outstanding under the

2015 Plan and will become available under the 2016 Equity Incentive Plan (“2016 Plan”) to the extent the options are
forfeited or lapse unexercised.

2016 Equity Incentive Plan

The 2016 Plan became effective in April 2016 and serves as the successor to the 2015 Plan. Under the 2016 Plan,

the Company may grant stock options, stock appreciation rights, restricted stock awards, restricted stock units,
performance awards, and stock bonuses. The 2016 Plan provides for an initial reserve of 1,100,000 shares of common
stock, plus 509,869 shares of common stock remaining under the 2015 Plan, and any share awards that subsequently are

106

forfeited or lapse unexercised under the 2015 Plan. The shares reserved exclude shares of common stock reserved for
issuance under the 2015 Plan.

In October 2018, the 2016 plan was amended to increase the number of shares of common stock reserved for
issuance thereunder by 1,759,602 shares, extend the term of the 2016 Plan through August 7, 2028, and provide for an
automatic increase in the number of shares reserved for issuanc
term of the plan equal to (a) 4.0% of the number of issued and outstanding shares of common stock on December 31 of
the immediately preceding year, or (b) a lesser amount as approved by the board each year. The superseded 2016 Plan
provision to provide an annual increase in the number of shares available for issuance required the Company’s board of
directors to approve the increase, up to 4%, prior to January 1 of each relevant year. As a result of the operation of each
of these provisions, on January 1, 2021, 2020, and 2019, an additional 1,918,363, 1,163,377, and 965,603 shares,
respectively, became available for issuance under the 2016 Plan.

e thereunder on January 1 of each year for the remaining

ff

ff

As of December 31, 2021, the total number of shares reserved for issuance under the 2016 Plan was 8,802,022, of

which 6,317,069 shares were subject to outstanding option awards and restricted unit awards.

2018 Equity Inducement Plan

In February 2018, the board of directors approved and adopted the 2018 Equity Inducement Plan (“2018 Plan”),

which became effective on the same date. The board of directors approved an initial reserve of 1,100,000 shares of
common stock to be used exclusively for individuals who were not previously employees or directors, or following a bona
fide period of non-employment, as an inducement material to the individual entering into employment with the Company.
Nonqualified stock options or restricted stock units may be granted under the 2018 Plan at the discretion of the
Compensation Committee or the board of directors. The Company did not seek stockholder approval of the 2018 Plan
pursuant to Nasdaq Rule 5635(c)(4).

As of December 31, 2021, the total number of shares reserved for issuance under the 2018 Plan was 1,100,000, of

which 343,958 shares were subject to outstanding option awards.

Under the 2016 Plan and 2018 Plan, the Company may grant stock-based awards with service conditions (“service-
based” awards), performance conditions (“performance-based” awards), and market conditions (“market-based” awards).
Service-based awards granted under the 2018 Plan, 2016 Plan, and 2015 Plan generally vest over four years and expire
after ten years, although awards have been granted with vesting terms less than four years.

2016 Employee Stock Purchase Plan

The 2016 Employee Stock Purchase Plan (“2016 ESPP”) became effective in April 2016. A total of 165,000 shares

of common stock were reserved for issuance under the 2016 ESPP. Eligible employees may purchase shares of common
stock under the 2016 ESPP at 85% of the lower of the fair market value of the Company’s common stock as of the first or
the last day of each offering period. Employees are limited to contributing 15% of the employee’s eligible compensation
and may not purchase more than $25,000 of stock during any calendar year or more than 2,000 shares during any one
purchase period or a lesser amount determined by the board of directors. The 2016 ESPP will terminate ten years from
the first purchase date under the plan, unless terminated earlier by the board of directors.

In June 2018, the 2016 ESPP was amended to provide for an automatic annual increase in the number of shares
reserved for issuance thereunder on January 1 of each year for the remaining term of the year equal to (a) 1.0% of the
number of issued and outstanding shares of common stock on December 31 of the immediately preceding year, or (b) a
lesser amount as approved by the board of directors each year. As a result of the operation of this provision, on January
1, 2021, 2020 and 2019, an additional 479,590, 290,844, and 241,400 shares, respectively, became available for
issuance under the 2016 ESPP. As of December 31, 2021, the reserve remaining and available for future issuance under
the 2016 ESPP was 874,923 shares.

107

The following table summarizes employee and non-employee stock option activity for the year ended December 31,

2021:

Outstanding as of December 31, 2020
Granted
Exercised
Forfeited
Outstanding as of December 31, 2021
Options vested and expected to vest as of

December 31, 2021

Options exercisable as of December 31, 2021

Shares
Issuable
Under
Options

Weighted
Average
Exercise
Price

5,357,844 $
2,757,600
(313,095)
(1,194,762)
6,607,587 $

6,291,349 $
3,181,979 $

7.64
7.11
4.63
7.67
7.56

7.64
7.64

Weighted
Average
Remaining
Contractual
Term
(in years)

Aggregate
Intrinsic
Value
(in thousands)
3,788

7.92 $

7.90 $

6.99 $
6.99 $

328

326
231

The aggregate intrinsic value of options outstanding, exercisable, vested and expected to vest were calculated as

the difference between the exercise price of the options and the fair value of the Company’s common stock as of the
reporting date.

For the years ended December 31, 2021, 2020, and 2019, the weighted-average grant date fair value of options

granted was $4.96, $4.68, and $8.09, respectively. The total intrinsic value of options exercised during the years ended
December 31, 2021, 2020, and 2019 was $0.7 million, $0.4 million and $1.0 million, respectively.

There were no stock options issued to non-employees during the years ended December 31, 2021, 2020, and 2019.

For the year ended December 31, 2020, 1,663 non-employee stock options vested in the period. For the years ended
December 31, 2021 and 2019, no non-employee stock options vested in the period.

Restricted Common Stock Units

The Company granted 228,200 restricted stock units (“RSUs”) during the year ended December 31, 2020 to certain

employees with regulatory, commercial, and clinical milestones in addition to a service condition. There were no RSUs
granted for the years ended December 31, 2021 and 2019.

As of December 31, 2021, the performance conditions of the granted RSUs were not probable of being achieved. If

and when the performance milestones are deemed probable of being achieved within the required time frame, the
Company may recognize up to $1.6 million of stock-based compensation for the remaining unvested RSUs as of
December 31, 2021.

The following table summarizes employee restricted stock activity for the year ended December 31, 2021:

Unvested restricted stock units as of December 31, 2020
Granted
Vested
Forfeited
Unvested restricted stock units as of December 31, 2021

Shares

Weighted
Average Grant
Date Fair Value

228,200
—
—
(38,200)
190,000

$

$

8.13
—
—
8.13
8.13

There were no RSUs granted to non-employees during the years ended December 31, 2021, 2020, and 2019.

108

Stock-Based Compensation Expense

Total stock-based compensation expense recognized from the Company’s equity incentive plans, 2018 Plan, and

the 2016 ESPP for the years ended December 31, 2021, 2020, and 2019 was as follows (in thousands):

2021

Year Ended December 31,
2020

2019

Research and development
General and administrative

Total stock-based

Employees
2,723
$
5,315

Non-
Employees
$

Employees
2,168
4,052

— $
—

Non-
Employees
36
$
—

Employees
1,828
$
3,048

Non-
Employees
$
—
—

compensation expense

$

8,038

$

— $

6,220

$

36

$

4,876

$

—

No related tax benefits were recognized for the years ended December 31, 2021, 2020, and 2019 (see Note 11).

The employee and non-employee awards contain both performance and service-based vesting conditions. No
expense was recognized for the unvested employee and non-employee awards with only a performance condition for the
years ended December 31, 2021, 2020, and 2019. The performance-based vesting conditions represent specific
performance targets. Compensation expense for employee and non-employee share-based payment awards with
performance conditions is recognized when the performance condition is deemed probable of achievement.

As of December 31, 2021, the Company had an aggregate of $15.1 million of unrecognized stock-based

compensation expense for options outstanding, which is expected to be recognized over a weighted average period of 2.6
years.

In determining the fair value of the stock-based awards, the Company uses the Black-Scholes option-pricing model

and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to
determine.

Expected Term

The Company’s expected term represents the period that the Company’s stock-based awards are expected to be

outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end
of the contractual term). The Company utilizes this method due to lack of historical exercise data and the plain-vanilla
nature of the Company’s stock-based awards.

Expected Volatility

Since the Company was privately held through April 2016, it alone does not have the relevant company-specific
historical data to support its expected volatility. As such, the Company has used an average of expected volatilities based
on the volatilities of a representative group of publicly traded biopharmaceutical companies over a period equal to the
expected term of the stock option grants. Subsequent to the Company’s initial public offering, it began to consider the
Company’s own historic volatility. However, due to its limited history as a public company, the Company still uses peer
company data to assist in this analysis. For purposes of identifying comparable companies, the Company selected
companies with comparable characteristics to it, including enterprise value, risk profiles, position within the industry, and
with historical share price information sufficient to meet the expected life of the stock-based awards. The historical
volatility data was computed using the daily closing prices for the selected companies’ shares during the equivalent period
of the calculated expected term of the stock-based awards. The Company intends to consistently apply this process using
the same or similar comparable entities until a sufficient amount of historical information regarding the volatility of the
Company’s own share price becomes available.

Risk-Free Interest Rate

The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods

corresponding with the expected term of option.

109

Expected Dividend

The Company has never paid dividends on its common stock and has no plans to pay dividends on its common

stock. Therefore, the Company used an expected dividend yield of zero.

The fair value of the stock options granted under the 2018 Plan, 2016 Plan, and 2015 Plan and the shares available

for purchase under the 2016 ESPP were determined using the Black-Scholes option-pricing model. The following table
summarizes the weighted-average assumptions used in calculating the fair value of the awards:

2018 Plan, 2016 Plan, and 2015 Plan

Expected term (in years)
Expected volatility
Risk-free interest
Dividend yield

2016 ESPP

Expected term (in years)
Expected volatility
Risk-free interest
Dividend yield

11. Defined Contribution Plan

Year Ended December 31,
2020

2019

2021

5.99

83%
0.88%
0%

0.50

86%
0.08%
0%

6.10

76%
1.06%
0%

0.50

76%
0.75%
0%

6.01

80%
2.32%
0%

0.50

70%
2.11%
0%

The Company sponsors a 401(k) retirement plan in which substantially all of its full-time employees are eligible to

participate. Participants may contribute a percentage of their annual compensation to this plan, subject to statutory
limitations. During the years ended December 31, 2021, 2020, 2019, the Company provided $0.6 million, $0.5 million, and
$0.3 million, respectively, in contributions to the plan.

12. Income Taxes

The following table summarizes the (loss) income before income tax expense by jurisdiction for the periods

indicated:

Domestic
Foreign
Loss before income tax expense

2021

Year Ended December 31,
2020
$ (65,940) $ (80,893) $ (78,254)
—
$ (65,660) $ (80,893) $ (78,254)

280

2019

—

For the year ended December 31, 2021, the Company recognized an income tax expense of $0.1 million, related to
foreign subsidiaries income tax expense and the Texas margins tax. For the years ended December 31, 2020 and 2019,
the Company recognized no provision or benefit from income taxes. The difference between the Company’s provision for
income taxes and the amounts computed by applying the statutory federal income tax rate to income before income taxes
is as follows (in thousands):

Tax provision derived by applying the federal statutory

rate to income before income taxes

Permanent differences and other
Federal tax credits
State tax credits
Effect of tax rate on foreign jurisdiction
Change in the valuation allowance
Income tax expense

Year Ended December 31,
2020

2019

2021

$

$

(13,789) $
1,002
(3,815)
(152)
(5)
16,900
141

$

(16,988) $
482
(3,905)
(251)
—
20,662

— $

(16,433)
(98)
(3,599)
(229)
—
20,359
—

110

The components of the deferred tax assets and liabilities consist of the following (in thousands):

Deferred tax assets

Net operating loss carryforward
Intangible assets
Accrued expense
Stock-based compensation
Federal tax credits
State tax credits
Other
Total deferred tax assets

Deferred tax liabilities
Depreciable assets
Total deferred tax liabilities
Less: Valuation allowance
Deferred tax assets, net

December 31,

2021

2020

$

64,531 $
57
846
2,767
18,579
991
220
87,991

51,708
51
598
2,087
14,764
839
299
70,346

(948)
(948)
(87,043)

$

— $

(203)
(203)
(70,143)
—

The Company has established a full federal and state valuation allowance equal to the net deferred tax assets due
to uncertainties regarding the realization of the deferred tax asset based on the Company’s lack of earnings history. The
valuation allowance increased by $16.9 million, $20.7 million, and $20.4 million during the years ended December 31,
2021, 2020, and 2019, respectively, primarily due to continuing loss from operations.

As of December 31, 2021 and 2020, the Company had U.S. net operating loss carryforwards (“NOL”) of $307.3

million and $246.2 million, respectively. As of December 31, 2021 and 2020, the Company had U.S. tax credit
carryforwards of $18.6 million and $14.8 million, respectively, and state tax credit carryforwards of $1.0 million and $0.8
million, respectively. The net operating loss and tax credit carryforwards of $58.4 million, respectively, will begin to expire
in 2033, if not utilized. The net operating loss and credit carryforwards are subject to Internal Revenue Service
adjustments until the statute closes on the year the net operating loss or tax credits are utilized.

The Company has not completed a study to assess whether an ownership change has occurred or whether there
have been multiple ownership changes since the Company’s formation due to the complexity and cost associated with
such a study, and the fact that there may be additional such ownership changes in the future. If the Company has
experienced an ownership change at any time since its formation, utilization of the NOL or R&D credit carryforwards
would be subject to an annual limitation under Section 382 or 383 of the Internal Revenue Code, which is determined by
first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term, tax-
exempt rate, and then could be subject to additional adjustments, as required. Additionally, the separate return limitation
year (“SRLY”) rules may apply to losses of the Company’s eight wholly owned U.S. subsidiary corporations. The SRLY
rules limit the consolidated group’s use of a subsidiary corporation’s net operating losses to the amount of income
generated by the subsidiary corporation after it becomes a member of the group. Any limitation may result in expiration of
a portion of the NOL or R&D credit carryforwards before utilization. Further, until a study is completed and any limitation
known, no amounts are being considered as an uncertain tax position or disclosed as an unrecognized tax benefit.
Additionally, the Company does not expect any unrecognized tax benefits to change significantly over the next twelve
months. Due to the existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will
not impact its effective tax rate. Any carryforwards that will expire prior to utilization as a result of such limitations will be
removed from deferred tax assets with a corresponding reduction of the valuation allowance.

The Company is subject to examination by taxing authorities in its significant jurisdictions for the 2017 and

subsequent years. However, due to NOL and tax attribute carryovers, the taxing authorities have the ability to adjust the
NOLs and other tax attributes related to closed years. As of December 31, 2021 and 2020, there were no amounts
recorded for uncertain tax positions. As of December 31, 2021, undistributed earnings of the Company’s newly
incorporated foreign subsidiaries are immaterial. Under the Global Intangible Low-Taxed Income (“GILTI”) provisions of
the 2017 Tax Cuts and Jobs Act, U.S. income taxes have been incurred on the undistributed earnings of the foreign
subsidiaries and therefore, the tax impact upon distribution is limited to state income and withholding taxes and is not
material.

111

13. Net Loss Per Share

Basic and diluted net loss per share is computed by dividing net loss by the weighted-average number of common

stock and pre-funded warrants outstanding during the period. The pre-funded warrants are included in the computation of
basic net loss per share as the exercise price is negligible and they are fully vested and exercisable. For periods in which
the Company generated a net loss, the Company does not include the potential impact of dilutive securities in diluted net
loss per share, as the impact of these items is anti-dilutive.

The following weighted-average equity instruments were excluded from the calculation of diluted net loss per share

because their effect would have been anti-dilutive for the periods presented:

Options to purchase common stock
Unvested restricted stock units

Year Ended December 31,
2020

2021

6,621,457
199,379

5,049,435
105,995

2019

3,874,817
—

112

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL
DISCLOSURE

None.

ITEM 9A. CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our principal executive officer and our principal financial officer,
evaluated, as of the end of the period covered by this Annual Report on Form 10-K, the effectiveness of our disclosure
controls and procedures. Based on that evaluation of our disclosure controls and procedures as of December 31, 2021,
our principal executive officer and principal financial officer concluded that our disclosure controls and procedures as of
such date are effective at the reasonable assurance level. The term “disclosure controls and procedures,” as defined in
Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act, means
controls and other procedures of a company that are designed to ensure that information required to be disclosed by a
company in the reports that it files or submits under the Exchange Act are recorded, processed, summarized and reported
within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without
limitation, controls and procedures designed to ensure that information required to be disclosed by us in the reports we file
or submit under the Exchange Act is accumulated and communicated to our management, including our principal
executive officer and principal financial officer, as appropriate to allow timely decisions regarding required disclosure.
Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only
reasonable assurance of achieving their objectives and our management necessarily applies its judgment in evaluating
the cost-benefit relationship of possible controls and procedures.

Management’s Annual Report on Internal Control Over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting.
Internal control over financial reporting is defined in Rules 13a-15(f) and 15d-15(f) promulgated under the Exchange Act
as a process designed by, or under the supervision of, our principal executive and principal financial officers and effected
by our board of directors, management and other personnel to provide reasonable assurance regarding the reliability of
financial reporting and the preparation of financial statements for external purposes in accordance with U.S. GAAP. Our
internal control over financial reporting includes those policies and procedures that:

•

•

•

pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect our transactions
and dispositions of our assets;

provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial
statements in accordance with U.S. GAAP, and that our receipts and expenditures are being made only in
accordance with authorizations of our management and directors; and

provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or
disposition of our assets that could have a material effect on our 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.

Our management, with the participation of our principal executive officer and principal financial officer, assessed the

effectiveness of our internal control over financial reporting as of December 31, 2021. 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 our assessment, our management has concluded
that, as of December 31, 2021, our internal control over financial reporting is effective based on those criteria.

113

This Annual Report on Form 10-K does not include an attestation report of our registered public accounting firm

regarding internal control over financial reporting. For as long as we remain a “smaller reporting company” as defined by
Rule 12b-2 of the Exchange Act and report less than $100 million of annual revenues in our most recent fiscal year, we
intend to take advantage of the exemption permitting us not to comply with the requirement that our independent
registered public accounting firm provide an attestation on the effectiveness of our internal control over financial reporting.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting that occurred during the quarter ended
December 31, 2021 that have materially affected, or are reasonably likely to materially affect, our internal control over
financial reporting.

ITEM 9B. OTHER INFORMATION

None.

ITEM 9C. DISCLOSURE REGARDING FOREIGN JURISDICTIONS THAT PREVENT INSPECTIONS

None.

114

PART III

ITEM 10. DIRECTORS, EXECUTIVE OFFICERS AND CORPORATE GOVERNANCE

The information required by this item is incorporated herein by reference to our Proxy Statement with respect to our
2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the end of the fiscal year covered by this
Annual Report on Form 10-K.

ITEM 11. EXECUTIVE COMPENSATION

The information required by this item is incorporated herein by reference to our Proxy Statement with respect to our
2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the end of the fiscal year covered by this
Annual Report on Form 10-K.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT AND RELATED
STOCKHOLDER MATTERS

The information required by this item is incorporated herein by reference to our Proxy Statement with respect to our
2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the end of the fiscal year covered by this
Annual Report on Form 10-K.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS, AND DIRECTOR INDEPENDENCE

The information required by this item is incorporated herein by reference to our Proxy Statement with respect to our
2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the end of the fiscal year covered by this
Annual Report on Form 10-K.

ITEM 14. PRINCIPAL ACCOUNTANT FEES AND SERVICES

The information required by this item is incorporated herein by reference to our Proxy Statement with respect to our
2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days of the end of the fiscal year covered by this
Annual Report on Form 10-K.

115

ITEM 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

The following documents are filed as part of this report:

PART IV

1.

Financial Statements

See Index to Financial Statements at Item 8 herein.

2.

Financial Statement Schedules

All schedules are omitted because they are not applicable or the required information is shown in the financial

statements or notes thereto.

3.

Exhibits

Exhibit
Number

Description of Document

Incorporate by Reference
Date of
Filing

File No.

Form

Exhibit
No.

Filed
Herewith

3.1

3.2

4.1

4.2

4.3

4.4

4.5

10.1

10.2‡

10.3‡

10.4‡

Restated Certificate of Incorporation

S-1/A 333-205001 9/14/2015

AAmended and Restated Bylaws

8-K

001-37722

4/3/2020

Form of Common Stock Certificate

S-1/A 333-205001 9/14/2015

Form of Pre-Funded Warrants 2019

8-K

001-37722

2/7/2019

Description of the Registrant's securities

10-K

001-37722

3/18/2021

Form of Pre-Funded Warrants 2020

8-K

001-37722

4/28/2020

3.2

3.1

4.1

4.1

4.3

4.1

Registration Rights Agreement, dated March 16, 2021, by
and among the Registrant and Baker Brothers Life
Sciences, L.P. and 667, L.P.

10-K

001-37722

3/18/2021 4.5

Form of Amended and Restated Indemnification
AAgreement

2015 Equity Incentive Plan and forms of award
agreements

2016 Equity Incentive Plan and forms of award
agreements, as amended

10Q

001-37722

8/9/2018

10.1

S-1

333-205001 6/16/2015

10.2

10Q

001-37722

11/8/2018

10.2

2016 Employee Stock Purchase Plan and forms of award
agreements, as amended

10-K

001-37722

3/7/2019

10.4

10.5‡

2018 Equity Inducement Plan

10.6‡

Form of Stock Restriction Agreement

10.7‡

Form of Severance Agreement

S-8

S-1

8-K

333-223614 3/13/2018

99.2

333-205001 6/16/2015

10.5

001-37722

4/16/2018

10.1

10.8†

Sponsored Research Agreement No. UTA13-001113,
dated December 24, 2013, between The University of
Texas at Austin (“UT-Austin”) and Aeglea
BioTherapeutics, Inc., Aeglea Development Company,
Inc., AERase, Inc., AEMase, Inc., AECase, Inc., AE4ase,
Inc., AE5ase, Inc. and AE6ase., Inc., as amended

10-Q 001-37722

11/7/2017

10.3

116

Exhibit
Number

10.9

10.10

10.11†

10.12†

10.13‡

10.14‡

10.15†

Description of Document

Incorporate by Reference
Date of
Filing

File No.

Form

Exhibit
No.

Filed
Herewith

Office Lease, dated November 24, 2014, between Barton
Oaks Office Center, LLC and the Registrant

S-1

333-205001 6/16/2015 10.11

First Amendment to Office Lease and Assignment and
AAssumption of Lease dated September 20, 2016 to Office
Lease dated November 24, 2014, between Barton Oaks
Office Center, LLC, Aeglea Development Company, Inc.,
and Aeglea BioTherapeutics, Inc.

AAmended and Restated Patent License Agreement No.
PM1401501, dated January 31, 2017, between the
Registrant and The University of Texas at Austin on
behalf of the Board of Regents of the University of Texas
system

Cancer Research Grant Contract, dated June 15, 2015,
between AERase, Inc. and the Cancer Prevention
Research Institute of Texas

Offer Letter, dated July 18, 2018, by and between the
Registrant and Anthony G. Quinn

Severance Agreement, dated July 18, 2018, by and
between the Registrant and Anthony G. Quinn

Master Services Agreement, dated November 26, 2018,
between the Registrant, Fujifilm Diosynth Biotechnologies
UK Limited, Fujifilm Diosynth Biotechnologies Texas,
LLC, and Fujifilm Diosynth Biotechnologies U.S.A, Inc.

10-Q 001-37722

11/9/2016

10.1

10-K

001-37722

3/7/2019

10.12

S-1

333-205001 6/16/2015 10.15

8-K

001-37722

7/23/2018

10.1

8-K

001-37722

7/23/2018

10.2

10-K

001-37722

3/9/2019

10.18

10.16

Lease Agreement dated April 30, 2019, between Las
Cimas Owner LP and the Registrant

10-Q 001-37722

5/7/2019

10.1

10.17‡

Offer Letter, dated March 13, 2020 issued by the
Registrant to Dr. Leslie Sloan

10-Q 001-37722

5/7/2020

10.1

10.18‡

Severance Agreement dated August 7, 2019 by and
between the Registrant and Dr. Leslie Sloan

10-Q 001-37722

5/7/2020

10.2

10.19‡

10.20‡

10.21‡

21.1

23.1

24.1

License and Supply Agreement, dated March 21, 2021,
by and between the Registrant and Immedica Pharma AB

10-Q 001-37722

5/10/2021

10.1

Offer Letter, dated June 14, 2021 issued by the Registrant
to Mr. Jonathan Alspaugh

Severance Agreement dated July 6, 2021 by and between
the Registrant and Mr. Jonathan Alspaugh

Subsidiaries of the Registrant

Consent of independent registered public accounting firm

Power of Attorney. Reference is made to the signature
page hereto

117

X

X

X

X

X

Exhibit
Number

Description of Document

Certification of the Principal Executive Officer pursuant to
Rule 13a-14(a) or 15d-14(a) of the Securities Exchange
AAct of 1934

Certification of the Principal Financial Officer pursuant to
Rule 13a-14(a) or 15d-14(a) of the Securities Exchange
AAct of 1934

Certification of the Principal Executive Officer pursuant to
18 U.S.C. Section 1350, as adopted pursuant to Section
906 of the Sarbanes-Oxley Act of 2002

Certification of the Principal Financial Officer pursuant to
18 U.S.C. Section 1350, as adopted pursuant to Section
906 of the Sarbanes-Oxley Act of 2002

Inline XBRL Instance Document - the instance document
does not appear in the Interactive Data File because its
XBRL tags are embedded within the Inline XBRL
document

Inline XBRL Taxonomy Extension Schema Document

31.1

31.2

32.1(1)

32.2(1)

101.INS

101.SCH

101.CAL

Inline XBRL Taxonomy Extension Calculation Linkbase
Document

101.DEF

Inline XBRL Taxonomy Extension Definition Linkbase
Document

101.LAB

Inline XBRL Taxonomy Extension Labels Linkbase
Document

101.PRE

Inline XBRL Taxonomy Extension Presentation Linkbase
Document

104

The cover page of this Annual Report on Form 10-K for
the year ended December 31, 2020, formatted in Inline
XBRL and contained in Exhibit 1010

Incorporate by Reference
Date of
Filing

File No.

Form

Exhibit
No.

Filed
Herewith

X

X

X

X

X

X

X

X

X

X

† Confidential treatment has been granted for portions of this exhibit pursuant to Rule 406 of the Securities Act, or Rule
24b-2 of the Exchange Act. The Registrant has omitted and filed separately with the SEC the confidential portions of
this exhibit.

‡

Indicates management contract or compensatory plan.

(1) The certifications on Exhibit 32 hereto are deemed not “filed” for purposes of Section 18 of the Exchange Act or

otherwise subject to the liability of that Section. Such certifications will not be deemed incorporated by reference into
any filing under the Securities Act or the Exchange Act.

ITEM 16. FORM 10-K SUMMARY

None.

118

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly

caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: March 8, 2022

AEGLEA BIOTHERAPEUTICS, INC.

By:

/s/ Anthony G. Quinn, M.B Ch.B, Ph.D.
Anthony G. Quinn, M.B Ch.B, Ph.D.
President, Chief Executive Officer and Director
(Principal Executive Officer)

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and

appoints Anthony G. Quinn, M.B. Ch.B, Ph.D. and Jonathan Alspaugh, jointly and severally, his attorneys-in-fact, each
with the power of substitution, for him in any and all capacities, to sign any amendments to this Report on Form 10-K and
to file same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said attorneys-in-fact, or his substitutes, may do or cause to
be done by virtue hereof.

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 Registrant and in the capacities and on the dates indicated.

Signature

Title

/s/ Anthony G. Quinn, M.B Ch.B, Ph.D.
Anthony G. Quinn, M.B. Ch.B, Ph.D.

President, Chief Executive Officer and Director
(Principal Executive Officer)

/s/ Jonathan Alspaugh
Jonathan Alspaugh

Chief Financial Officer
(Principal Financial Officer)

/s/ Steven Weber
Steven Weber

/s/ Russell J. Cox
Russell J. Cox

/s/ Sandesh Mahatme, LLM
Sandesh Mahatme, LLM

/s/ Armen Shanafelt, Ph.D.
Armen Shanafelt, Ph.D.

/s/ Ivana Magovcevic-Liebisch, Ph.D.
Ivana Magovcevic-Liebisch, Ph.D.

/s/ Bryan Lawlis, Ph.D.
Bryan Lawlis, Ph.D.

/s/ Alison Lawton
Alison Lawton

/s/ Marcio Souza, M.B.A.
Marcio Souza, M.B.A.

/s/ Hunter C. Smith, M.B.A.
Hunter C. Smith, M.B.A.

Vice President and Corporate Controller
(Principal Accounting Officer)

Director

Director

Director

Director

Director

Director

Director

Director

119

Date

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022

March 8, 2022