rgnx-10k_20211231.htm

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2021

For the transition period from to

Commission file number: 001-37553

REGENXBIO Inc.

(Exact name of registrant as specified in its charter)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading symbol(s) Name of each exchange on which registered

Common Stock, par value $0.0001 per share RGNX The Nasdaq Global Select Market

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such 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 ☒ Accelerated filer ☐

Non-accelerated filer ☐ Smaller reporting company ☐

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards 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 Act). Yes ☐ No ☒

The aggregate market value of common stock held by non-affiliates of the registrant based on the closing price of the registrant’s common stock as reported on The Nasdaq Global Select Market on June 30, 2021, the last business day of the registrant’s most recently completed second quarter, was $1,310,113,569.

As of February 24, 2022, there were 42,949,562 shares of the registrant’s common stock, par value $0.0001 per share, issued and outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Specified portions of the registrant’s definitive proxy statement with respect to the registrant’s 2022 Annual Meeting of Stockholders, which is to be filed pursuant to Regulation 14A within 120 days after the end of the registrant’s fiscal year ended December 31, 2021, are incorporated by reference into Part III of this Annual Report on Form 10-K.

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REGENXBIO INC.

Form 10-K

For the Year Ended December 31, 2021

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Page

Part I

Information Regarding Forward-Looking Statements 1

Industry and Market Data 2

Item 1. Business 3

Item 1A. Risk Factors 29

Item 1B. Unresolved Staff Comments 62

Item 2. Properties 62

Item 3. Legal Proceedings 62

Item 4. Mine Safety Disclosures 62

Part II

Item 6. Reserved 64

Item 7A. Quantitative and Qualitative Disclosures about Market Risk 80

Item 8. Financial Statements and Supplementary Data 80

Item 9A. Controls and Procedures 80

Item 9B. Other Information 81

Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections 81

Part III

Item 10. Directors, Executive Officers and Corporate Governance 82

Item 11. Executive Compensation 82

Item 14. Principal Accountant Fees and Services 82

Part IV

Item 15. Exhibits, Financial Statement Schedules 83

Index to Consolidated Financial Statements 84

Exhibit Index 124

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PART I

INFORMATION REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended (the Securities Act), and Section 21E of the Securities Exchange Act of 1934, as amended (the Exchange Act). These statements express a belief, expectation or intention and are generally accompanied by words that convey projected future events or outcomes such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “assume,” “design,” “intend,” “expect,” “could,” “plan,” “potential,” “predict,” “seek,” “should,” “would” or by variations of such words or by similar expressions. We have based these forward-looking statements on our current expectations and assumptions and analyses in light of our experience and our perception of historical trends, current conditions and expected future developments, as well as other factors we believe are appropriate under the circumstances. However, whether actual results and developments will conform with our expectations and predictions is subject to a number of risks, uncertainties, assumptions and other important factors, including, but not limited to:

• the timely development and launch of new products;

• our anticipated growth strategies;

• our expectations regarding competition;

• our ability to attract or retain key personnel;

• our expectations regarding our expenses and revenue;

• our expectations regarding the outcome of legal proceedings;

You should carefully read the factors discussed in the sections titled “Risk Factors,” “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and elsewhere in this Annual Report on Form 10-K and in our other filings with the U.S. Securities and Exchange Commission (the SEC) for additional discussion of the risks, uncertainties, assumptions and other important factors that could cause our actual results or developments to differ materially and adversely from those projected in the forward-looking statements. The actual results or developments anticipated may not be realized or, even if substantially realized, they may not have the expected consequences to or effects on us or our businesses or operations. Such statements are not guarantees of future performance and actual results or developments may differ materially and adversely from those projected in the forward-

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looking statements. These forward-looking statements speak only as of the date of this report. Except as required by law, we disclaim any duty to update any forward-looking statements, whether as a result of new information, future events or otherwise.

As used in this Annual Report on Form 10-K, the terms “REGENXBIO,” “we,” “us,” “our” or the “Company” mean REGENXBIO Inc. and its subsidiaries, on a consolidated basis, unless the context indicates otherwise.

AAVIATE, NAV, REGENXBIO and the REGENXBIO logos are our registered trademarks. Any other trademarks appearing in this Annual Report on Form 10-K are the property of their respective holders.

INDUSTRY AND MARKET DATA

We obtained the industry, market and competitive position data used throughout this Annual Report on Form 10-K from our own internal estimates and research, as well as from industry and general publications, in addition to research, surveys and studies conducted by third parties. Internal estimates are derived from publicly-available information released by industry analysts and third-party sources, our internal research and our industry experience, and are based on assumptions made by us based on such data and our knowledge of our industry and market, which we believe to be reasonable. We have not independently verified industry, market and competitive position data from third-party sources, but we believe the sources of such information to be reliable. While we believe the industry, market and competitive position data included in this Annual Report on Form 10-K is reliable and is based on reasonable assumptions, such data involves risks and uncertainties and are subject to change based on various factors, including those discussed in “Risk Factors.” These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

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ITEM 1. BUSINESS

Overview

We are a leading clinical-stage biotechnology company seeking to improve lives through the curative potential of gene therapy. Our investigational gene therapies are designed to deliver functional genes to address genetic defects in cells, enabling the production of therapeutic proteins or antibodies that are intended to impact disease. Through a single administration, gene therapy could potentially alter the course of disease significantly and deliver improved patient outcomes with long-lasting effects.

Our investigational gene therapies use adeno-associated virus (AAV) vectors from our proprietary gene delivery platform, which we call our NAV® Technology Platform. AAV vectors are non-replicating viral delivery vehicles that are not known to cause disease. Our NAV Technology Platform consists of exclusive rights to a large portfolio of AAV vectors, including AAV7, AAV8, AAV9, AAVrh10 and more than 100 other novel AAV vectors (NAV Vectors). We believe this platform forms a strong foundation for our current clinical-stage programs and with our ongoing research and development, we expect to continue to expand our platform and pipeline of potential AAV vector-based gene therapies. We refer to commercial and investigational AAV vector-based gene therapies as AAV Therapeutics.

We have developed a broad pipeline of investigational AAV Therapeutics using our NAV Technology Platform as a one-time treatment to address an array of diseases. We are currently focusing our internal development pipeline in three areas: retinal, neuromuscular and neurodegenerative diseases. Our investigational AAV Therapeutics include:

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Our internal pipeline is shown below.

We believe that we have a strong pipeline of AAV Therapeutics with the potential to deliver one-time treatments to patients living with common and rare diseases, and we expect to have more product candidates to come.

We believe our integrated, end-to-end expertise in discovering and developing AAV Therapeutics distinguishes us from other gene therapy companies. We have built a team of experts in research and development, scalable manufacturing and preclinical and clinical development. As a result, we believe we have the resources and capabilities to conduct early research and preclinical testing, advance AAV Therapeutics into clinical development and manufacture new potential therapies for patients.

We believe our history, science, resources, people and values combine to make us an industry leader in gene therapy and the development of potentially ground-breaking AAV Therapeutics. As such, we believe we are well-positioned to achieve our mission to improve lives through the curative potential of gene therapy.

We believe AAV Therapeutics represent a simplified and efficient potential new class of innovative medicines. We believe that our end-to-end capabilities to develop, manufacture and clinically advance AAV Therapeutics will support the achievement of our 2025 goals, such that by the end of 2025, we can grow into a company with multiple AAV Therapeutics that are FDA-approved or in pivotal trials through our internal and partnered programs that can help ensure our continued growth.

AAV Therapeutics

Historically, the primary challenge for gene therapy has been the safe and effective delivery of genes into cells. Genes are made of DNA, which is a large, highly charged molecule that is difficult to transport across a cell membrane and deliver to the nucleus, where it can be transcribed and translated into protein. The genetic material needs to be delivered efficiently and to the desired target tissues and cell types, which will vary depending on the disease to be treated. Based on this need, scientists have designed and developed a variety of gene vectors in order to facilitate gene delivery in cells.

We focus on in vivo gene therapy. Among vectors available for in vivo gene therapy, viral vectors have been adopted frequently due to their demonstrated efficiency in gene delivery to date. Since AAVs are not known to be associated with disease in humans, vectors derived from AAV have promising safety profiles for gene therapy.

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Our NAV Technology Platform

In 2009, we acquired exclusive rights to our NAV Technology Platform. Our NAV Technology Platform includes over 100 NAV Vectors, as well as vectors that are at least 95% identical to any NAV Vector, that provide the foundation for the development of new AAV Therapeutics. We have observed that several of our NAV Vectors demonstrate preferential tropisms for a range of tissues, as well as efficient transgene delivery and expression that may produce a therapeutic effect. Our NAV Technology Platform has enabled the development of a number of AAV Therapeutics being investigated in clinical trials and one that is FDA-approved.

For many years, by sublicensing NAV Vectors from our NAV Technology Platform to other biopharmaceutical companies with disease-specific expertise, which we refer to as our NAV Technology Licensees, we received capital to advance our own research and capabilities. Our NAV Technology Platform is being applied to a number of programs over a broad range of therapeutic areas and disease indications by our NAV Technology Licensees. These partnered programs include Novartis’ Zolgensma®, a gene therapy for the treatment of spinal muscular atrophy (SMA), which was approved by the U.S. Food and Drug Administration in 2019, and has been used to treat over 1,800 patients suffering from SMA, a debilitating and potentially deadly disease. Our partnering strategy provides us the flexibility to sublicense development of treatments designed to address significant unmet medical needs, while remaining focused on our own pipeline of AAV Therapeutics.

We believe we have extensive human safety experience to support the development of our investigational AAV Therapeutics based on data from over 2,000 patients dosed with AAV Therapeutics derived from our NAV Technology Platform in more than 20 different clinical-stage programs and with one FDA approved product. To date, we have observed that AAV Therapeutics derived from our NAV Technology Platform have been generally well tolerated.

Our AAV Therapeutic Platform

Discovery and Development of AAV Therapeutics

We have a team of scientists and engineers dedicated to expanding the understanding and applications of AAV vectors, applying the differentiated capabilities of the NAV Technology Platform and exploring the potential to generate new, innovative AAV Therapeutics. We endeavor to rapidly discover and develop a pipeline of investigational AAV Therapeutics with the potential, through a single administration, to alter the course of disease significantly and deliver improved patient outcomes with long-lasting effects. We believe that we have created a reproducible process and modular platform for the discovery and development of innovative AAV Therapeutics.

Our scientists are continuing to conduct research to evaluate NAV Vectors to identify and characterize more clinically relevant features and benefits. We are also engineering novel capsids by leveraging the natural diversity of our NAV Vectors and our detailed knowledge of AAV structure and function. We are designing additional NAV Vectors with new features that may enhance tissue and cell type specificity, increase potency and potentially improve the safety profile of AAV Therapeutics. Through our internal efforts and collaborations, we are also designing novel vectors to which we add high affinity targeting domains with the goal of enabling them to deliver genes more precisely to specific tissues and cells.

With AAV Therapeutics, the gene is eventually transported to the cell nucleus where it is transcribed into RNA. The production of RNA in the cell is controlled by transcriptional elements called enhancers and promoters that are linked to the gene. We have designed optimized enhancer and promoter combinations with the goal of enabling sustained gene expression and potentially increasing durability of therapeutic effect.

We can design our AAV Therapeutics to deliver genes for a spectrum of therapeutic modalities. Our current pipeline of investigational AAV Therapeutics use NAV Vectors to deliver genes for a therapeutic antibody, or a functional gene to compensate for a missing or non-functional gene.

We also conduct research studying the potential of NAV Vectors to deliver modified RNA, such as microRNA (miRNA) or antisense sequences, which could alter the structure or silence an RNA transcript. We have created a platform for designing efficient miRNAs to address targets of interest while avoiding off-target effects and cellular toxicity. In addition, NAV Vectors have been designed to enable in vivo gene editing, which involves the alteration of a gene via targeted insertion or deletion of DNA base pairs.

In addition to our research evaluating NAV Vectors, we also work on identifying potential indications for the development of new AAV Therapeutics, guided by our expertise and experience in bringing AAV Therapeutics to the clinical stage. Our early evaluation of targets includes scientific rationale and cross-functional analysis of technical feasibility. In our exploratory research, we

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work internally and through collaborations with external researchers to identify and optimize AAV Therapeutics based on AAV vector targeting, gene optimization and evaluation of effective delivery devices. We then execute proof-of-concept research that informs the next steps in our pipeline strategy. While much of our research into potential AAV Therapeutics extends from our clinical expertise in eye diseases, AAV-mediated antibody delivery, neurodegenerative diseases and neuromuscular diseases, we are also able to research potential opportunities to advance AAV Therapeutics for new disease areas.

Our platform capabilities include a team of scientists that develop analytical assays and approaches to support our preclinical and clinical-stage pipeline. The ability to determine dose levels, biodistribution, and target engagement requires an understanding of complex variables that are related to properties of both the NAV Vector and the gene, and dependent on the delivery device. We believe that our analytical capabilities are at the forefront of AAV Therapeutic development.

AAV Therapeutic Manufacturing

Our research team works closely with our manufacturing team, allowing us to evaluate the manufacturability of AAV Therapeutics early in the discovery process. Through our ability to collaborate cross-functionally, we can move quickly from candidate selection to the manufacturing of clinical-grade material, which we believe allows us to accelerate the process of developing AAV Therapeutics.

We have invested in innovative manufacturing process development and analytical capabilities and use a suspension cell culture-based manufacturing process. We have deep in-house knowledge of biologics manufacturing, which we believe will enable us to scale manufacturing of our AAV Therapeutics while ensuring product quality for patients. We have developed systems which we believe will provide robust manufacturing and global supply of AAV Therapeutics to meet quality requirements and anticipated research, clinical, and future commercial demand. Our planned Good Manufacturing Practices (cGMP) production facility, located in our new corporate headquarters in Rockville, Maryland, has been designed to support production of AAV Therapeutics.

We have developed a proprietary, high-yielding manufacturing process platform for NAV vector production that can be applied across multiple AAV Therapeutics. The suspension-based manufacturing platform has demonstrated robust scalability from bench-scale to 500 liter and 1,000-liter cGMP batches with consistent yield and product purity demonstrated via comparability studies. At our manufacturing facility, we expect to scale the manufacturing process to 2,000 liters. We believe this flexibility in manufacturing will support a wide range of potential commercial supply requirements for our AAV Therapeutics.

We have developed product formulations specific to our different delivery devices and routes of administration. We aim to ensure that our formulations are designed and assessed to ensure product stability can be maintained for numerous years and that our AAV Therapeutics can be exposed to a variety of handling and delivery procedures.

We have endeavored to design our platform manufacturing process, formulations and devices to enable efficient transition from research to clinical trials to commercial readiness, while minimizing changes during product development. To support our platform, we have developed a comprehensive set of analytical methods to assess quality and characterize the product. We continue to expand and enhance internal analytical lab capabilities with the aim of improving quality and control and supporting accelerated development of AAV Therapeutics.

We have agreements with several biologics contract development and manufacturing organizations (CDMOs) for production of material under cGMP requirements to support our current and future clinical trials, as well as potential future commercialization of our investigational AAV Therapeutics. We select our CDMOs based on capability, capacity and expertise, and we believe partnering with multiple CDMOs provides us with flexibility and diversity in suppliers, as well as access to future capacity to accommodate clinical trials and commercialization. We have a strategic partnership with FUJIFILM Diosynth Biotechnologies for the manufacture of our investigational AAV Therapeutics. Under the terms of the agreement, we secured capacity for the supply of cGMP NAV Vector drug substance produced at scales up to 2,000 liters. We also have agreements with several CDMOs for cGMP final drug product manufacturing and have produced numerous batches for our clinical trials.

AAV Therapeutic Delivery Devices

We believe that a critical component of AAV Therapeutic development is to deliver treatments safely, effectively and efficiently to the right part of the body. We leverage the differentiated characteristics of NAV Vectors to target different tissues and cells. To further enhance the profile of AAV Therapeutics, we have developed a platform of different devices to assist in the delivery of AAV Therapeutics using multiple routes of administration to tissues and cells.

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We have developed significant expertise in designing delivery device systems for use with AAV Therapeutics and have also developed and in-licensed relevant intellectual property, including know-how, related to delivery devices. Our research and development activities have involved several delivery device advancements for AAV Therapeutics. We focus research on designing features and implementing delivery device solutions that we believe have the potential to improve the effect, patient safety, caregiver usability and cost-of-goods of AAV Therapeutics.

We have advanced image-guided device delivery of AAV Therapeutics into the cerebrospinal fluid to target the brain and central nervous system for neurodegenerative diseases. In 2018, in our clinical trial for the treatment of MPS II, an investigational AAV Therapeutic was delivered to a patient using an intracisternal delivery device for the first time. We have also led the development of two different types of delivery devices of AAV Therapeutics into the eye for targeting the retina of patients. In 2020, in our clinical trial for the in-office treatment of wet AMD, an investigational AAV Therapeutic was delivered to a patient using a novel, suprachoroidal delivery device for the first time. In 2020, we initiated a pivotal phase program for RGX-314 using an automated subretinal delivery device for the treatment of wet AMD. As part of our delivery device expertise, we have created teams of experts to support and train physicians to deliver AAV Therapeutics in operating room and physician office settings.

In recent years, a tremendous amount of progress has been made in the development of AAV Therapeutics, and we believe we have been a leader in these advancements.

Our Investigational AAV Therapeutics

We are currently focusing our internal development pipeline in three areas: retinal diseases, neuromuscular diseases and neurodegenerative diseases.

RGX‐314 for the Treatment of Wet AMD, DR and Other Chronic Retinal Diseases

We are developing RGX‐314 in collaboration with AbbVie as a potential one-time treatment for wet AMD, DR and other chronic retinal diseases. These diseases are characterized by loss of vision due to excess fluid accumulation from new blood vessel formation and treated with anti-vascular endothelial growth factor (anti-VEGF) therapies.

Wet AMD is the leading cause of vision loss in people over 60, affecting more than 2 million patients in the United States, Europe and Japan. The risk for developing wet AMD increases with age and we anticipate that the incidence of new cases will continue to increase significantly with the growth of the aging population. In patients with wet AMD, fluid accumulation can result in physical changes in the structure of the retina and adverse changes in vision. As this process progresses, blindness can result from atrophy and scar formation.

DR is a complication of diabetes and is the leading cause of blindness in adults between 24 and 75 years of age worldwide. It is a progressive retinopathy, and the spectrum of DR severity ranges from non-proliferative diabetic retinopathy (NPDR) to proliferative diabetic retinopathy (PDR). As DR progresses, a large proportion of patients develop vision-threatening complications, including diabetic macular edema (DME) and neovascularization that can lead to blindness. An estimated 27 million patients are affected with DR across the US, Europe and Japan, and of those, there are more than 23 million DR patients without center-involved DME. DR is the leading cause of vision loss in working-age adults and the incidence is expected to continue to grow significantly with the prevalence of diabetes.

Frequent anti-VEGF injections in the eye have been shown to reduce the risk of blindness in randomized controlled clinical trials and are approved for the treatment of wet AMD and DR. The current standard-of-care anti-VEGF treatments require patients to receive injections in the eye every four to 12 weeks for the duration of the disease. Real world evidence shows that patients with wet AMD are severely undertreated, and DR patients with early non-proliferative disease are often not treated due to the unsustainable treatment burden of administering frequent injections required with currently approved anti-VEGF therapies. As a result, the majority of wet AMD patients experience significant vision loss over time and most patients with early non-proliferative DR progress to more severe forms of the proliferative disease, developing common vision-threatening complications such as center-involved DME and proliferative DR.

RGX‐314 is being developed as a novel, one-time treatment that includes the NAV AAV8 vector containing a gene for a monoclonal antibody fragment designed to inhibit VEGF activity, modifying the pathway for formation of new leaky blood vessels and retinal fluid accumulation. After delivery of RGX‐314, we believe retinal cells will continue to produce the anti-VEGF protein. Two separate routes of administration of RGX-314 to the eye are being evaluated: a subretinal delivery procedure as well as a

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targeted, in-office administration to the suprachoroidal space. We have licensed certain exclusive rights to the SCS Microinjector® from Clearside Biomedical, Inc. (Clearside) to deliver gene therapy treatments to the suprachoroidal space of the eye.

Clinical Development of RGX‐314 for the Treatment of Wet AMD

We have initiated two pivotal trials, ATMOSPHERETM and ASCENTTM, for the treatment of wet AMD using RGX-314 delivered subretinally, and we expect these pivotal trials to support a Biologics Licensing Application (BLA) submission in 2024. ATMOSPHERE and ASCENT are multi-center, randomized, active-controlled trials to evaluate the efficacy and safety of a single-administration of RGX-314 versus standard of care in patients with wet AMD. Both trials are active and enrolling patients. We initiated the pivotal program using cGMP material produced from our existing manufacturing process and plan to incorporate our scalable suspension cell culture manufacturing process to support future commercialization, upon completion of a bridging study.

We are also evaluating the efficacy, safety and tolerability of suprachoroidal delivery of RGX-314 through AAVIATE®, a multi-center, open label, randomized, controlled, dose-escalation Phase II trial of RGX-314 for the treatment of wet AMD. Enrollment in AAVIATE is complete in Cohort 4 and expected to be completed in Cohort 5 in the first half of 2022.

In November 2021, we announced additional positive interim data from AAVIATE. As of November 4, 2021, RGX-314 continued to be well tolerated in 50 patients from Cohorts 1-3 with no drug-related serious adverse events (SAEs) in AAVIATE. At six months following one-time administration of RGX-314, stable visual acuity and retinal thickness, as well as a meaningful reduction (>70%) in anti-VEGF treatment burden was observed in patients in Cohort 2, with 40% of patients anti-VEGF injection-free. Mild intraocular inflammation observed on slit-lamp examination was reported at similar incidence across both dose levels in Cohorts 1 and 2, with four out of 15 patients in Cohort 1 and three out of 15 patients in Cohort 2. All cases of inflammation in both cohorts were resolved within days to weeks on topical corticosteroids.

Clinical Development of RGX‐314 for the Treatment of DR

We are evaluating the efficacy, safety and tolerability of suprachoroidal delivery of RGX-314 for the treatment of DR in ALTITUDETM, a multi-center, open label, randomized, controlled, dose-escalation Phase II trial. We expect to complete enrollment in ALTITUDE in Cohorts 2 and 3 in the first half of 2022.

In February 2022, we presented positive interim data from ALTITUDE. As of January 18, 2022, suprachoroidal delivery of RGX-314 continued to be well tolerated in the 15 patients dosed with RGX-314 in Cohort 1, with no drug-related SAEs, and no intraocular inflammation observed. Of the patients dosed with RGX-314 in Cohort 1, 47% demonstrated a two-step or greater improvement from baseline on the Early Treatment Diabetic Retinopathy Study-Diabetic Retinopathy Severity Scale (ETDRS-DRSS) at six months, compared to 0% in the observational control group. One patient (7%) dosed with RGX-314 continued to demonstrate a four-step improvement. The percentage of Cohort 1 patients dosed with RGX-314 achieving at least two-step improvement at six months in RGX-314 treated eyes (47%) increased from the previously reported three-month results (33%).

RGX-202 for the Treatment of Duchenne

RGX-202 is our investigational AAV Therapeutic for the treatment of Duchenne, a rare disease caused by mutations in the gene responsible for making dystrophin, a protein of central importance for muscle cell structure and function. Without dystrophin, muscles throughout the body degenerate and become weak, eventually leading to loss of movement and independence, required support for breathing, cardiomyopathy and premature death. There is presently no cure for Duchenne, and for most patients, there are no satisfactory disease modifying treatments available. Duchenne is one of the most common fatal genetic disorders affecting children, primarily boys. Duchenne is estimated to occur in approximately one in every 3,500-5,000 live male births and has an estimated prevalence of more than 30,000 cases in the U.S., Europe and Japan.

RGX-202 is designed to deliver a transgene for a novel microdystrophin that includes the functional elements of the C-Terminal (CT) domain found in naturally occurring dystrophin. Presence of the CT domain has been shown in preclinical studies to recruit several key proteins to the muscle cell membrane, leading to improved muscle resistance to contraction-induced muscle damage in dystrophic mice. Additional design features, including codon optimization and reduced CpG content, may potentially improve gene expression, increase translational efficiency and reduce immunogenicity. RGX-202 is designed to support the delivery and targeted expression of genes throughout skeletal and heart muscle using the NAV AAV8 vector, and a well-characterized muscle-specific promoter (Spc5-12).

We have received orphan drug product designation and rare pediatric disease designation from the FDA for RGX‐202.

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Planned Clinical Development of RGX-202

We have received clearance of our Investigational New Drug (IND) application by the FDA to evaluate RGX-202 in a first-in-human, Phase I/II clinical trial, named AFFINITY DUCHENNETM, which is expected to initiate in the first half of 2022. This will be a multicenter, open-label dose escalation and dose expansion clinical trial to evaluate the safety, tolerability and clinical efficacy of RGX-202 in patients with Duchenne.

RGX‐121 for the Treatment of MPS II

RGX‐121 is our investigational AAV Therapeutic for the treatment of MPS II. MPS II, also known as Hunter syndrome, is a rare disease caused by a deficiency of the IDS gene which encodes the I2S enzyme. I2S is responsible for the breakdown of polysaccharides called heparan sulfate (HS) and dermatan sulfate (DS) in lysosomes, which are structures that dispose of waste products inside cells. These polysaccharides, called glycosaminoglycans (GAGs), accumulate in tissues of MPS II patients, resulting in diverse clinical signs and symptoms. HS is a key biomarker of I2S enzyme activity and high amounts of HS accumulate in the central nervous system (CNS) of MPS II patients, which has been shown to correlate with neurocognitive manifestations of the disease. In severe forms of the disease, early developmental milestones may be met during the first year after birth, but developmental delay is readily apparent by 18 to 24 months. Developmental progression begins to plateau between three and five years of age, with regression reported to begin around six and a half years. By the time of death, most patients with CNS involvement are severely mentally handicapped and require constant care. MPS II is estimated to occur in approximately 1 in 100,000 to 1 in 170,000 births worldwide. Based on global population, this equates to approximately 500 to 1,000 MPS II patients born each year worldwide.

Enzyme replacement therapy (ERT), the current standard of care for patients with MPS II, does not treat CNS manifestations of the disease because the enzyme cannot cross the blood-brain barrier. We believe that specific treatment to address the neurological manifestations of MPS II and prevent or stabilize cognitive decline remains a significant unmet medical need.

RGX‐121 is designed to use the NAV AAV9 vector to deliver the human IDS gene to cells in the CNS. Delivery of the gene therapy and expression of the enzyme that is deficient within cells in the CNS could provide a permanent source of secreted I2S on the CNS side of the blood-brain barrier, allowing for long-term cross-correction of cells throughout the CNS. We believe this strategy could provide rapid I2S delivery to the brain, potentially preventing the progression of cognitive deficits that otherwise occur in MPS II patients.

We have received orphan drug product designation, rare pediatric disease designation and Fast Track designation from the FDA, as well as orphan designation and advanced therapy medicinal products (ATMP) classification from the European Medicines Agency (the EMA) for RGX‐121.

Clinical Development of RGX‐121 for the Treatment of MPS II

A Phase I/II clinical trial of RGX‐121 in patients with MPS II under the age of 5 years old to evaluate the safety and tolerability of RGX-121, as well as the effects of RGX-121 on biomarkers of I2S enzyme activity, neurocognitive development and other clinical measures, is ongoing. The primary endpoint is safety. The secondary and exploratory endpoints include the effect of RGX‐121 on biomarkers of I2S activity in the cerebrospinal fluid (CSF), serum and urine, and the effect of RGX‐121 on neurocognitive deficits, as well as other clinical outcome measures.

In February 2022, we announced additional positive interim data from the Phase I/II trial of RGX-121. As of December 20, 2021, RGX-121 continued to be well-tolerated with no drug-related SAEs across three dose levels with preliminary results indicating dose-dependent reductions in key CSF biomarkers with patients in Cohort 3 approaching normal levels of the D2S6 biomarker. Measures of neurodevelopmental function from patients in Cohorts 1 and 2 demonstrated continued developmental skill acquisition up to 2 years after RGX-121 administration. Evidence of systemic enzyme expression and biomarker activity continued to be observed. We plan to initiate a Cohort 3 expansion using commercial-scale cGMP material in the first quarter of 2022.

A second multicenter, open-label Phase I/II trial of RGX-121 for the treatment of pediatric patients with severe MPS II ages 5-18 years old is ongoing. The trial is designed to evaluate the safety of a single administration of RGX-121, the effects of RGX-121 on biomarkers of I2S enzyme activity, and changes in cognitive function, adaptive behavior, daily function and quality of life.

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RGX‐111 for the Treatment of MPS I

RGX-111 is our investigational AAV Therapeutic for the treatment of MPS I, a rare disease caused by deficiency of IDUA, an enzyme required for the breakdown of polysaccharides in lysosomes. Similar to MPS II, many MPS I patients develop symptoms related to GAG accumulation in the CNS, which can include excessive accumulation of fluid in the brain, spinal cord compression and cognitive impairment. MPS I patients span a broad spectrum of disease severity and extent of CNS involvement. The severe form of MPS I is also referred to as Hurler syndrome. Hurler patients have two mutations in the IDUA gene, resulting in no active enzyme. These patients typically present with symptoms before two years of age and universally exhibit severe cognitive decline after an initial period of normal development. MPS I is estimated to occur in approximately 1 in 100,000 births worldwide. Based on global population, this equates to more than 1,000 MPS I patients born each year worldwide.

The current standard of care for patients with an attenuated form of MPS I is a recombinant form of human IDUA, given as a weekly ERT infusion. This has demonstrated improvement in hepatosplenomegaly, growth, mobility and respiratory function. However, as the enzyme cannot cross the blood-brain barrier, ERT does not treat the CNS manifestations of MPS I. Patients are also often treated with hematopoietic stem cell transplantation (HSCT) and, although this approach has demonstrated improvements in survival, growth, cardiac and respiratory function, mobility and intellect, it is also associated with clinically relevant morbidity and an estimated 10% to 20% mortality. Accordingly, the procedure is reserved for patients with severe disease before two years of age because the risk-benefit ratio is thought to be more favorable in younger patients who have not yet experienced advanced cognitive decline. Another critical limitation of HSCT is that cognitive decline continues for up to a year after transplant before stabilizing, leaving permanent cognitive deficits. Overall, we believe the limitations of HSCT and ERT leave a significant unmet need for a method to safely achieve long-term IDUA reconstitution in the CNS for MPS I patients experiencing neurological complications.

RGX‐111 is designed to use the NAV AAV9 vector to deliver the human IDUA gene to the CNS. Delivery of the enzyme that is deficient within cells in the CNS could provide a permanent source of secreted IDUA beyond the blood-brain barrier, allowing for long-term cross-correction of cells throughout the CNS. We believe this strategy could also provide rapid IDUA delivery to the brain, potentially preventing the progression of cognitive deficits that otherwise occurs in MPS I patients.

We have received orphan drug product designation, rare pediatric disease designation and fast track designation from the FDA, as well as orphan designation and ATMP classification from the EMA for RGX‐111.

Clinical Development of RGX‐111 for the Treatment of MPS I

We are currently enrolling patients in a Phase I/II clinical trial of RGX‐111. The trial is a multi-center, open-label, dose escalation trial that is evaluating the safety, tolerability and pharmacodynamics of RGX-111 delivered to patients with MPS I. The primary endpoint of this trial is safety, and the secondary endpoints include the effect of RGX‐111 on biomarkers of IDUA activity in the CSF, serum and urine, neurocognitive development and other outcome measures.

In addition, RGX-111 was administered to a patient with MPS I through a single-patient IND.

In February 2022, we announced positive initial data from the Phase I/II trial, as well as positive interim data from the single patient IND of RGX-111. As of December 20, 2021, RGX-111 was well tolerated across two dose levels in the Phase I/II trial and in the single-patient IND, with no drug-related SAEs. Biomarker and neurodevelopmental assessments indicated an encouraging CNS profile in patients dosed with RGX-111, with emerging evidence of systemic biomarker activity observed. We plan to enroll additional patients in a Cohort 2 expansion of the Phase I/II trial in the first half of 2022.

RGX‐181 and RGX-381 for the Treatment of CLN2 Disease

CLN2 disease, a form of Batten disease, is a rare disease caused by mutations in the tripeptidyl peptidase 1 (TPP1) gene. Mutations in the TPP1 gene and subsequent deficiency in TPP1 enzyme activity result in lysosomal accumulation of storage material and degeneration of tissues, including the brain and retina. CLN2 disease is characterized by seizures, rapid deterioration of language and motor functions, cognitive decline, loss of vision and blindness, and premature death by mid-childhood. Onset of symptoms is generally between two to four years of age, with initial features of recurrent seizures (epilepsy), language delay and difficulty coordinating movements (ataxia). CLN2 disease is estimated to occur in approximately 1 in 250,000 births worldwide. Based on global population, this equates to as many as 500 patients born each year worldwide.

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There is currently no cure for CLN2 disease. Current treatment options include palliative care or ERT. While ERT has been an improvement over palliative care in slowing disease progression, it does not address the ocular manifestations of CLN2 and we believe frequent administration of ERT into the CNS, reliance on limited and specialized infusion centers, the need for and complications associated with a permanently implanted device, and lack of a treatment for the underlying genetic cause of CLN2 disease represent an area of significant unmet medical need.

RGX‐181 is our investigational AAV Therapeutic for the treatment of CLN2 disease. It is designed to use the NAV AAV9 vector to deliver the human TPP1 gene to the CNS. Delivery of the gene that is deficient within cells in the CNS could provide a permanent source of secreted TPP1 enzyme, allowing for long-term cross-correction of cells throughout the CNS. We continue to evaluate RGX-181 in preclinical studies and are working with regulatory agencies on the advancement of our clinical program.

RGX-381 is our investigational AAV Therapeutic targeting the ocular manifestations of CLN2 disease. RGX-381 is designed to use the NAV AAV9 vector to deliver the TPP1 gene directly to the retina. We believe that one-time administration of RGX-381 could provide a durable source of TPP1 activity in the retina, thereby potentially preventing visual decline. There is currently no available treatment for the ocular manifestations of CLN2 disease. We continue to evaluate RGX-381 in preclinical studies and are working with regulatory agencies on the advancement of our clinical program.

We have received orphan drug product designation and rare pediatric disease designation from the FDA, as well as ATMP classification from the EMA for RGX‐181 and RGX-381.

Collaborations, Licensing and Company Formation

Collaborations, licensing and company formation are a key part of our commitment to enable the ongoing development of gene therapy treatments.

AbbVie Eye Care Collaboration

In September 2021, REGENXBIO and AbbVie announced a global strategic partnership to develop and commercialize RGX-314, a potential one-time gene therapy for the treatment of wet AMD, DR and other chronic retinal diseases.

Under the terms of our Collaboration and License Agreement with AbbVie (the AbbVie Collaboration and License Agreement), we received an upfront payment of $370 million. Additionally, we will be eligible to receive up to $1.38 billion in additional development, regulatory and commercial milestone payments.

Through December 31, 2022, we will be responsible for development expenses for certain ongoing trials of RGX-314 and will share additional development expenses related to RGX-314 with AbbVie. Beginning on January 1, 2023, AbbVie will be responsible for the majority of all development expenses.

In the United States, we will participate in commercialization of licensed products to the extent set forth in a commercialization plan to be determined in accordance with the AbbVie Collaboration and License Agreement, and the parties will equally share net profits and net losses associated with commercialization of the licensed products in the United States. Outside the United States, AbbVie will be responsible, at its sole cost, for the commercialization of licensed products. We will also be eligible to receive tiered royalties on net sales by AbbVie of licensed products outside the United States at percentages in the mid-teens to low twenties, subject to specified offsets and reductions.

We will lead the manufacturing of RGX-314 for clinical development and U.S. commercial supply, and AbbVie will lead manufacturing of RGX-314 for commercial supply outside the United States. Manufacturing expenses will be allocated between the parties in accordance with the terms of the AbbVie Collaboration and License Agreement and mutually agreed supply agreements.

NAV Technology Licensees

In addition to our internal product development efforts, we sublicense our NAV Vectors to other leading biotechnology and pharmaceutical companies. As of December 31, 2021, our NAV Technology Licensees are currently applying our NAV Technology Platform to a number of AAV Therapeutics over a broad range of therapeutic areas and disease indications. Over 60 clinical trials utilizing NAV Vectors have been registered in the National Institutes of Health (NIH) clinical trials database since 2015, and one of two FDA-approved AAV Therapeutics in the United States uses a NAV Vector (Novartis’ Zolgensma). As of December 31, 2021, over 2,000 patients have been treated by REGENXBIO and our NAV Technology Licensees using NAV Vectors across the clinical trial, managed access and commercial settings. In 2021, Zolgensma exceeded $1.3 billion in annual sales.

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Our NAV Technology Licensees are shown below.

We have also taken an active role in the formation of several of our NAV Technology Licensees, including being a founding shareholder in Dimension Therapeutics, Inc. (Dimension), Prevail Therapeutics Inc. (Prevail) and Corlieve Therapeutics SAS (Corlieve), all of which have been acquired in strategic transactions since their formation. We entered into a license agreement with each of these NAV Technology Licensees upon their formation, for which we received equity in the NAV Technology Licensee in addition to other consideration. In November 2017, Ultragenyx Pharmaceutical Inc. acquired Dimension for approximately $152 million in cash. In January 2021, Eli Lilly and Company acquired Prevail for up to approximately $1.04 billion. In July 2021, uniQure N.V. (uniQure) acquired Corlieve for up to approximately €250 million in cash and uniQure shares.

NAV Technology licenses have been an important component of our strategy since REGENXBIO’s formation, creating opportunity for the development of additional therapies for patients and potential for additional value generation from the platform. Equity ownership in certain NAV Technology Licensees has generated significant additional return for REGENXBIO shareholders, and we believe the acquisition of these NAV Technology Licensees in strategic transactions by biopharmaceutical companies is an important validation of the NAV Technology Platform.

Zolgensma License

In March 2014, we entered into an agreement with AveXis, Inc. (AveXis, now Novartis Gene Therapies) for an exclusive, worldwide commercial license, with rights to sublicense, to the NAV AAV9 vector for the treatment of spinal muscular atrophy (SMA). In 2018, we amended the license to include additional intellectual property owned or in-licensed by us, including rights to the NAV Technology Platform beyond NAV AAV9, as well as additional AAV vectors we may discover or license for a certain period of time, for the treatment of SMA. Under the license agreement, as amended, we were entitled to receive over $270 million in fees, development and commercial milestones. In addition, we are entitled to receive mid-single to low double-digit royalties on net sales for Zolgensma or any product developed for the treatment of SMA using the NAV AAV9 vector. For any product developed for the treatment of SMA using a licensed vector other than NAV AAV9, we are entitled to receive a low double-digit royalty on net sales.

Novartis acquired AveXis for $8.7 billion in April 2018, and Zolgensma was subsequently approved by the FDA in May 2019. In December 2020, we sold a portion of our royalty rights from the net sales of Zolgensma to entities managed by Healthcare Royalty Management, LLC (HCR) for a gross purchase price of $200 million. As of December 31, 2021, Zolgensma is approved in 42 countries and over 1,800 patients have been treated.

Platform License Agreements and Other Licenses

Platform Licenses

We have exclusively licensed many of our rights in our NAV Technology Platform from the University of Pennsylvania (Penn) and GlaxoSmithKline LLC (GSK), which together we refer to as our Platform Licenses. We currently use our NAV Technology Platform to develop treatments in the areas of retinal, neuromuscular and neurodegenerative diseases. We also sublicense our NAV Technology Platform to third parties in order to develop and bring to market AAV Therapeutics for a range of severe diseases with significant unmet medical needs outside of our core disease indications and therapeutic areas. For further information regarding our commercial sublicenses, please see “Commercial Licenses to NAV Technology Licensees” located elsewhere in this Annual Report on Form 10-K.

The Trustees of the University of Pennsylvania. In February 2009, we entered into an exclusive, worldwide license agreement with Penn for patent and other intellectual property rights relating to a gene therapy technology platform based on AAVs discovered at Penn in the laboratory of James M. Wilson, M.D., Ph.D. This license was amended in September 2014, April 2016, April 2019 and

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September 2020. In February 2009, we also entered into a sponsored research agreement with Penn (the 2009 SRA) under which we funded the nonclinical research of Dr. Wilson relating to AAV gene therapy and obtained an option to acquire an exclusive worldwide license in certain intellectual property created pursuant to such 2009 SRA. We entered into an additional sponsored research agreement(the 2013 SRA) with Penn in November 2013 which was funded entirely by our NAV Technology Licensee, Dimension Therapeutics, Inc. (since acquired by Ultragenyx Pharmaceutical Inc.) (Dimension). In December 2014, we entered into another SRA with Penn funding related nonclinical research of Dr. Wilson (the 2014 SRA).

Our license agreement with Penn, as amended, provides us with an exclusive, worldwide license under certain patents and patent applications in order to make, have made, use, import, offer for sale and sell products covered by the claims of the licensed patents and patent applications as well as all patentable inventions (to the extent they are or become available for license) that:

• are owned and controlled by Penn.

Prior to entering into the license agreement with us, Penn had previously entered into two license agreements with third parties with respect to certain of the licensed patents and patent applications. Our license from Penn is subject to those preexisting license grants. With respect to the first third party license granted by Penn, our license is non-exclusive with respect to the patents and patent applications licensed to the third party for so long as that preexisting license grant remains in effect and will become exclusive upon the expiration or termination of that existing license agreement. The pre-existing licenses also include a license agreement Penn entered into with GSK in May 2002 granting a license to certain patents and patent applications, of which we subsequently sublicensed certain rights to from GSK in March 2009. For further information regarding our GSK sublicense, please see “Platform License Agreements and Other Licenses—Platform Licenses—GlaxoSmithKline LLC” located elsewhere in this Annual Report on Form 10-K. Our license agreement with Penn provides that should the rights Penn licensed to GSK ever revert to Penn, such rights shall automatically be included in our license agreement with Penn.

The Penn license agreement, as amended, also provides us with certain additional rights, including a non-exclusive, worldwide license to use (i) all data and information that was developed since October 2015 by Dr. Wilson, or other Penn researchers working under his direct supervision at Penn, that is related to Batten disease, owned by Penn, and necessary or useful for the practice of the licensed patent rights in the treatment of CLN2 disease; and (ii) all know-how that:

• is owned by Penn; and

• is necessary or useful for the practice of the licensed patent rights.

Under the terms of the Penn license agreement, we issued equity to Penn and are also obligated to pay Penn:

• reimbursements for ongoing patent prosecution and maintenance expenses.

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Our Penn license agreement, as amended, will terminate with respect to licensed products in a field of use other than the treatment of familial hypercholesterolemia (FH) on a product-by-product and country-by-country basis on the date each particular licensed product ceases to be covered by at least one valid claim, issued or pending, under the licensed patent rights. We can terminate this license agreement by giving Penn prior written notice. Penn has the right to terminate:

• with notice if we are late in paying money due under the license agreement;

• if we or our affiliates experience insolvency; or

Under the 2014 SRA, as amended, we funded research at Penn, paid certain intellectual property legal and filing expenses and received the rights to certain research results. The Penn license agreement, as amended, and the 2014 SRA, as amended, provide that all patentable inventions conceived, created, or conceived and reduced to practice pursuant to the 2014 SRA, together with patent rights represented by or issuing from the U.S. patents and patent applications, including provisional patent applications, automatically become exclusively licensed to us and all research results become automatically licensed to us as know-how. Under the 2009 SRA, as amended, in consideration for our funding of research at Penn, we received an option to acquire a worldwide license on commercially reasonable terms to practice all patentable inventions conceived, created, or reduced to practice pursuant to the 2009 SRA, together with patent rights represented by or issuing from the U.S. patents and patent applications, including provisional patent applications.

GlaxoSmithKline LLC. In March 2009, we entered into a license agreement with GSK, which was amended in April 2009, in order to secure the exclusive rights to patents and patent applications covering NAV Technology that GSK had previously licensed from Penn (subject to certain rights retained by GSK and Penn). Under this GSK license agreement, we receive an exclusive, worldwide sublicense under the licensed patent rights to make, have made, use, import, sell and offer for sale products covered by the licensed patent rights anywhere in the world. Our rights under this GSK license agreement are subject to certain rights retained by GSK for the benefit of itself and other third parties, including rights relating to: domain antibodies; RNA interference and antisense drugs; internal research purposes and GSK’s discovery research efforts with non-profit organizations and GSK collaborators; AAV8 for the treatment of hemophilia B; AAV9 for the treatment of Muscular Dystrophy, congestive heart failure suffered by Muscular Dystrophy patients and cardiovascular diseases by delivery of certain genes; and non-commercial research in the areas of Muscular Dystrophy, hemophilia B, congestive heart failure suffered by Muscular Dystrophy patients, and other cardiovascular disease. Under the terms of the license agreement, we issued equity to GSK and are obligated to pay GSK:

• reimbursements for certain patent prosecution and maintenance expenses.

Under our GSK license agreement, we are required to use commercially reasonable efforts to develop and commercialize licensed products. Our GSK license agreement will terminate upon the expiration, lapse, abandonment or invalidation of the last licensed claim to expire, lapse, become abandoned or unenforceable in all the countries of the world where the licensed patent rights existed. However, if no patent ever issues from patent rights licensed from GSK, this license agreement will terminate a specified number of years after the first commercial sale of the first licensed product in any country. We may terminate this license agreement for any reason upon a specified number of days’ written notice. GSK can terminate this license agreement if:

• we file for bankruptcy.

Other Licenses

Regents of the University of Minnesota. In November 2014, we entered into a license agreement with Regents of the University of Minnesota (Minnesota) for the exclusive rights to Minnesota’s undivided interest in intellectual property jointly owned by

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Minnesota and us relating to the delivery of AAV vectors to the CNS. This license was amended in November 2016 and September 2021. Under this Minnesota license agreement, as amended, we receive an exclusive license under the licensed patent rights to make, have made, use, offer to sell or sell, offer to lease or lease, import or otherwise offer to dispose or dispose of products covered by the licensed patent rights in all fields of use in any country or territory in which a licensed patent has been issued and is unexpired or a licensed patent application is pending until November 2019, after which time the field of use would be limited to all fields of use using our NAV Vectors in addition to certain additional indications and areas. Under the terms of the agreement, we are obligated to pay Minnesota upfront fees, annual maintenance fees, royalties on net sales, if any, sublicense fees and fees upon the achievement of various milestones.

Emory University. In August 2018, we entered into a license agreement with Emory University (Emory) for the exclusive rights to Emory’s undivided interest in intellectual property jointly owned by Emory and us relating to the delivery of AAV vectors to the CNS. Under this Emory license agreement, we receive an exclusive license under the licensed patent rights to make, have made, use, import, offer to sell or sell licensed products in all fields of use in any country. Under the terms of the agreement, we are obligated to pay Emory an upfront fee, annual maintenance fees under certain circumstances, royalties on net sales, sublicense fees, and fees upon the achievement of various milestones for the first licensed product.

Clearside Biomedical, Inc. In August 2019, we entered into an option and license agreement with Clearside Biomedical, Inc. (Clearside) for the option to receive an exclusive, worldwide commercial license, with rights to sublicense, to Clearside’s SCS Microinjector for the delivery of AAV gene therapies for the treatment of wet AMD, DR, and other conditions for which chronic anti-VEGF treatment is currently the standard of care. In October 2019, we exercised the option. Under the terms of the agreement, we are obligated to pay Clearside an upfront fee, royalties on net sales, and fees upon the achievement of various milestones. As between us and Clearside, we will be responsible for all development, regulatory and commercialization activities for our gene therapy product candidates. Clearside will be responsible for supplying the SCS Microinjector in support of our preclinical studies, clinical studies and commercial use.

Intellectual Property

Our patent portfolio includes patents and patent applications that we own, co-own and license from third parties and covers all aspects of our NAV Technology Platform, clinical candidates and programs, formulations, devices, manufacturing and research programs. We believe this patent portfolio enables us to support our development of AAV Therapeutics to address significant unmet medical needs.

NAV Technology Platform

As of December 31, 2021, our patent portfolio included 18 issued U.S. patents and six European patents relating to the AAV7, AAV8, AAV9 and AAVrh10 vectors and their uses. These patents have terms that will expire as late as 2026, not including patent term extensions.

Our Investigational AAV Therapeutics

As of December 31, 2021, in addition to the patents related to our NAV Technology Platform described above, our patent portfolio included a total of five issued U.S. patents, two issued European patents, five pending International Patent applications filed pursuant to the Patent Cooperation Treaty (PCTs) and 22 PCTs that have entered national stage relating to our product candidates, which are described below:

Retinal Diseases

In addition to our NAV Technology Platform patents covering the NAV AAV8 vector and manufacture of NAV AAV8 vectors used in our retinal disease programs, our patent portfolio includes more recent filings relating to our clinical candidate vectors, clinical protocols, routes of administration to the eye (subretinal and suprachoroidal), formulations and target diseases treated by our gene therapy vectors.

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Our patent portfolio relating to RGX-314 includes one issued U.S. patent that will expire in 2037, two pending PCTs and five PCTs that have entered national stage for which any issued U.S. or European patent would expire in 2037, 2038, 2039 or 2040, in each case without taking into account any possible patent term adjustment or extension.

Neuromuscular Diseases

In addition to our NAV Technology Platform patents covering the NAV AAV8 vector and its manufacture, our patent portfolio includes more recent filings relating to RGX-202, the NAV AAV8 capsid carrying our microdystrophin construct used to treat Duchenne and the manufacture of RGX-202. Our patent portfolio also covers other AAV vectors carrying our microdystrophin transgene, as well as intravenous and other modes of administration, and formulations.

Our patent portfolio relating to RGX-202 includes one pending PCT for which any issued U.S. or European patent would expire in 2040, without taking into account any possible patent term adjustment or extension.

Neurodegenerative Diseases

In addition to our NAV Technology Platform patents covering the NAV AAV9 vector and the manufacture of NAV AAV9 vectors used in our neurodegenerative disease programs, our patent portfolio includes more recently filed patents, that cover our clinical candidate vectors, routes of administration used in our neurodegenerative disease clinical-stage programs (intracisternal administration for intrathecal delivery, as well as lumbar puncture and intraventricular administration), formulations and target diseases, including MPS II, MPS I and CLN2 disease.

Manufacturing

Our patent portfolio covers aspects of our manufacturing processes which support our ability to perform large scale manufacturing, increase yield and purity of AAV vector products and meet clinical supply requirements.

Our patent portfolio also includes protection for novel validation and potency assays that further support and streamline our manufacturing processes.

Customers

Our revenues for the years ended December 31, 2021, 2020 and 2019 consisted solely of license and royalty revenue. Two customers (AbbVie and Novartis Gene Therapies) accounted for approximately 99% of our total revenues for the year ended December 31, 2021. One customer (Novartis Gene Therapies) accounted for approximately 94% of our total revenues for the year ended December 31, 2020. Three customers (Novartis Gene Therapies and two other customers) accounted for approximately 92% of our total revenues for the year ended December 31, 2019. We expect future license and royalty revenue to continue to be derived from a limited number of licensees. Future license and royalty revenue is uncertain due to the contingent nature of our licenses granted to third-parties and may fluctuate significantly from period to period.

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Competition

We are aware of a number of companies focused on developing gene therapies in various disease indications, including 4D Molecular Therapeutics, Inc., Adverum Biotechnologies, Inc., Amicus Therapeutics, Inc., BioMarin Pharmaceutical, Inc., Homology Medicines, Inc., MeiraGTx Limited, Novartis AG, Passage Bio, Inc., PTC Therapeutics, Inc., Roche, Sanofi, Sarepta Therapeutics, Inc., Solid Biosciences, Inc., Taysha Gene Therapies, Inc., Tenaya Therapeutics, Inc. and uniQure N.V., as well as a number of companies addressing other methods for modifying genes and regulating gene expression. Additionally, we have sublicensed our NAV Technology Platform for developing gene therapies in various disease indications to our NAV Technology Licensees. Not only must we compete with other companies that are focused on gene therapy products using earlier generation AAV technology and other gene therapy platforms, but any products that we may commercialize will have to compete with existing therapies and new therapies that may become available in the future.

There are other organizations working to improve existing therapies or to develop new therapies for our initially selected disease indications. Depending on how successful these efforts are, it is possible they may increase the barriers to adoption and success for our product candidates, if approved. These efforts include the following:

Many of our competitors, either alone or with their strategic partners, have substantially greater financial, technical and human resources than we do. Our competitors may be more successful than us in obtaining approval for treatments and achieving widespread market acceptance. Our competitors’ treatments may be more effective, or more effectively marketed and sold, than any treatment we may commercialize and may render our treatments obsolete or non-competitive before we can recover the expenses of developing and commercializing any of our treatments.

Mergers and acquisitions in the biotechnology and pharmaceutical 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.

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We anticipate that we will face intense and increasing competition as new drugs and treatments enter the market and advanced technologies become available. We expect any treatments that we develop and commercialize to compete on the basis of, among other things, efficacy, safety, convenience of administration and delivery, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.

Government Regulation

In the United States, biological products, including gene therapy products, are subject to regulation under the Federal Food, Drug, and Cosmetic Act (FD&C Act), and the Public Health Service Act (PHS Act) and other federal, state, local and foreign statutes and regulations. Both the FD&C Act and the PHS Act and their corresponding regulations govern, among other things, the testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, advertising and other promotional practices involving biological products. Applications to the FDA are required before conducting clinical testing of biological products, and each clinical study protocol for a gene therapy product is reviewed by the FDA.

Within the FDA, the Center for Biologics Evaluation and Research (CBER) regulates gene therapy products. The FDA has published guidance documents related to, among other things, gene therapy products in general, their preclinical assessment, observing subjects involved in gene therapy studies for delayed adverse events, potency testing, and chemistry, manufacturing and control information in gene therapy INDs.

Ethical, scientific, social and legal concerns about gene therapy, genetic testing and genetic research could result in additional regulations restricting or prohibiting the processes we may use. Federal and state agencies, congressional committees and foreign governments have expressed interest in further regulating biotechnology. More restrictive regulations or claims that our products are unsafe or pose a hazard could prevent us from commercializing any products. New government requirements may be established that could delay or prevent regulatory approval of our product candidates under development. It is impossible to predict whether legislative changes will be enacted, regulations, policies or guidance changed, or interpretations by agencies or courts changed, or what the impact of such changes, if any, may be.

U.S. Biological Products Development Process

The process required by the FDA before a biological product may be marketed in the United States generally involves the following:

• FDA review and approval, or licensure, of the BLA.

The clinical study sponsor must submit the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and a proposed clinical protocol, to the FDA as part of the IND. Some preclinical testing may continue even after the IND is submitted. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA places the clinical study on a clinical hold within that 30-day time period. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before the clinical study can begin. The FDA may also impose clinical holds on a biological product

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candidate at any time before or during clinical studies due to safety concerns or non-compliance. If the FDA imposes a clinical hold, studies may not recommence without FDA authorization and then only under terms authorized by the FDA. Accordingly, we cannot be sure that submission of an IND will result in the FDA allowing clinical studies to begin, or that, once begun, issues will not arise that suspend or terminate such studies.

Clinical studies involve the administration of the biological product candidate to healthy volunteers or patients under the supervision of qualified investigators, generally physicians not employed by or under the study sponsor’s control. Clinical studies are conducted under protocols detailing, among other things, the objectives of the clinical study, dosing procedures, subject selection and exclusion criteria, and the parameters to be used to monitor subject safety, including stopping rules that assure a clinical study will be stopped if certain adverse events should occur. Each protocol and any amendments to the protocol must be submitted to the FDA as part of the IND. Clinical studies must be conducted and monitored in accordance with the FDA’s regulations imposing the GCP requirements, including the requirement that all research subjects provide informed consent. Further, each clinical study must be reviewed and approved by an independent institutional review board (IRB) at or servicing each institution at which the clinical study will be conducted. An IRB is charged with protecting the welfare and rights of study participants and considers such items as whether the risks to individuals participating in the clinical studies are minimized and are reasonable in relation to anticipated benefits. The IRB also approves the form and content of the informed consent that must be signed by each clinical study subject or his or her legal representative and must monitor the clinical study until completed. Clinical studies generally also must be reviewed by an institutional biosafety committee (IBC), a local institutional committee that reviews and oversees basic and clinical research conducted at that institution. The IBC assesses the safety of the research and identifies any potential risk to public health or the environment. Some studies also employ a Data and Safety Monitoring Board (DSMB), which operates with independence from the study sponsor and has access to unblinded study data during the course of the study and may halt a study for ethical reasons such as undue safety risks.

Human clinical studies are typically conducted in three sequential phases that may overlap or be combined:

During all phases of clinical development, regulatory agencies require extensive monitoring and auditing of all clinical activities, clinical data, and clinical study investigators. Annual progress reports detailing the results of the clinical studies must be submitted to the FDA. Written IND safety reports must be promptly submitted to the FDA and the investigators for serious and unexpected adverse events, any findings from other studies, tests in laboratory animals or in vitro testing that suggest a significant risk for human subjects, or any clinically important increase in the rate of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. The sponsor must submit an IND safety report within 15 calendar days after the sponsor determines that the information qualifies for expedited reporting. The sponsor also must notify the FDA of any unexpected fatal or life-threatening suspected adverse reaction within seven calendar days after the sponsor’s initial receipt of the information. Phase I, Phase II and Phase III clinical studies may not be completed successfully within any specified period, if at all. The FDA or the sponsor or its DSMB may suspend a clinical study at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical study at its institution if the clinical study is not being conducted in accordance with the IRB’s requirements or if the biological product has been associated with unexpected serious harm to patients.

Human gene therapy 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 study period, the number of patients the FDA will require to be enrolled in the studies in order to establish the safety, efficacy, purity and potency of human gene therapy products, our ability to recruit sufficient numbers of study subjects for any trial, or that the data generated in these studies will be acceptable to the FDA to support marketing approval.

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Concurrent with clinical studies, companies usually complete additional animal studies and must also develop additional information about the physical characteristics of the biological product as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. To help reduce the risk of the introduction of adventitious agents with use of biological products, the PHS Act emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of the final biological product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the biological product candidate does not undergo unacceptable deterioration over its shelf life.

U.S. Review and Approval Processes

After the completion of clinical studies of a biological product, FDA approval of a BLA must be obtained before commercial marketing of the biological product. The BLA must include results of product development, laboratory and animal studies, human studies, information on the manufacture and composition of the product, proposed labeling and other relevant information. Under the Prescription Drug User Fee Act (PDUFA), the BLA must be accompanied by a substantial user fee payment unless an exception or waiver applies. In addition, under the Pediatric Research Equity Act (PREA), a BLA or supplement to a BLA 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 product is safe and effective. The FDA may grant deferrals for submission of pediatric data or full or partial waivers of pediatric requirements. Unless otherwise required by regulation, PREA does not apply to any biological product for an indication for which orphan designation has been granted. The testing and approval processes require substantial time and effort and there can be no assurance that the FDA will accept the BLA for filing and, even if filed, that any approval will be granted on a timely basis, if at all.

Within 60 days following submission of the application, the FDA reviews a BLA submitted to determine if it is substantially complete before the agency accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA. The FDA reviews the BLA to determine, among other things, whether the proposed product is safe and potent, including whether it is effective, for its intended use, and has an acceptable purity profile, and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity, strength, quality, potency and purity as those factors relate to the safety or effectiveness of the product. The FDA may refer applications for novel biological products or biological products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions. During the biological product approval process, the FDA also will determine whether a Risk Evaluation and Mitigation Strategy (REMS) is necessary to assure the safe use of the biological product upon marketing. If the FDA concludes a REMS is needed, the sponsor of the BLA must submit a proposed REMS; the FDA will not approve the BLA without a REMS, if required.

Before approving a BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. For a gene therapy product, the FDA also will not approve the product if the manufacturer is not in compliance with GTP. These are FDA regulations that govern the methods used in, and the facilities and controls used for, the manufacture of human cells, tissues, and cellular and tissue based products (HCT/Ps) which are human cells or tissue intended for implantation, transplant, infusion, or transfer into a human recipient. The primary intent of the GTP requirements is to ensure that cell and tissue based products are manufactured in a manner designed to prevent the introduction, transmission and spread of communicable disease. FDA regulations also require tissue establishments to register and list their HCT/Ps with the FDA and, when applicable, to evaluate donors through screening and testing. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure that the clinical studies were conducted in compliance with IND study requirements and GCP requirements. To assure cGMP, GTP and GCP compliance, an applicant must incur significant expenditure of time, money and effort in the areas of training, record keeping, production, and quality control.

Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the BLA does not satisfy its regulatory criteria for approval and deny approval. Data obtained from clinical studies are not always conclusive and the FDA may interpret data differently than we interpret the same data. If the agency decides not to approve the BLA in its present form, the FDA will issue a complete response letter that usually describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical studies. Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application.

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If a product receives regulatory approval, the approval may be significantly limited to specific diseases and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form of a REMS, or otherwise limit the scope of any approval. In addition, the FDA may require post marketing clinical studies designed to further assess a biological product’s safety and effectiveness, and testing and surveillance programs to monitor the safety of approved products that have been commercialized.

One of the performance goals agreed to by the FDA under PDUFA is to review 90% of standard BLAs in 10 months of the 60-day filing date and 90% of priority BLAs in six months of the 60-day filing date, whereupon a review decision is to be made. Two months are added to these time periods for new molecular entities. The FDA does not always meet its PDUFA goal dates for standard and priority BLAs and its review goals are subject to change from time to time. The review process and the PDUFA goal date may be extended by three months if the FDA requests or the BLA sponsor otherwise provides additional information, or clarification regarding information already provided in the submission, constituting a major amendment to the BLA.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biological product intended to treat a rare disease or condition, which is defined under the FD&C Act as a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making a drug or biological product available in the United States for this type of disease or condition will be recovered from sales of the product. Orphan product designation must be requested before submitting a BLA. After the FDA grants orphan product designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product that has orphan designation subsequently receives the first FDA approval for that product for the disease or condition for which it has such designation, the product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same drug or biological product for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity. Competitors, however, may receive approval of different products for the indication for which the orphan product has exclusivity or obtain approval for the same product but for a different indication for which the orphan product has exclusivity. Orphan product exclusivity also could block the approval of one of our products for seven years if a competitor obtains approval of the same biological product as defined by the FDA or if our product candidate is determined to be contained within the competitor’s product for the same indication or disease. If a drug or biological product designated as an orphan product receives marketing approval for an indication broader than what is designated, it may not be entitled to orphan product exclusivity. Orphan drug status in the European Union (EU) has similar, but not identical, benefits.

Orphan drug products are also eligible for Rare Pediatric Disease Designation if greater than 50% of patients living with the disease are under age 18. A priority review voucher will be given to the sponsor of a product with a Rare Pediatric Disease Designation at the time of product approval that is transferable to another company.

Expedited Development and Review Programs

The FDA has a Fast Track program that is intended to expedite or facilitate the process for reviewing new drugs and biological products, including precision drugs or biological products, that meet certain criteria. Specifically, new drugs and biological products are eligible for Fast Track designation if they are intended to treat a serious or life-threatening condition and demonstrate the potential to address unmet medical needs for the condition. Fast Track designation applies to the combination of the product and the specific indication for which it is being studied. The sponsor of a new drug or biologic may request the FDA to designate the drug or biologic as a Fast Track product at any time during the clinical development of the product. Also under the Fast Track program, the FDA may consider for review sections of the marketing application on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the application, the FDA agrees to accept sections of the application and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the application.

Any product submitted to the FDA for marketing, including under a Fast Track program, may be eligible for other types of FDA programs intended to expedite development and review, such as Breakthrough Therapy designation, priority review, and accelerated approval. Under the Breakthrough Therapy program, products intended to treat a serious or life-threatening disease or condition may be eligible for additional benefits when preliminary clinical evidence demonstrates that such product may have substantial improvement on one or more clinically significant endpoints over existing therapies. The FDA will seek to ensure the sponsor of a breakthrough therapy product receives timely advice and interactive communications to help the sponsor design and conduct a

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development program as efficiently as possible. In addition, gene therapies, including genetically modified cells, that lead to a durable modification of cells or tissues, may be eligible for regenerative medicine advanced therapy (RMAT) designation. Products with an RMAT designation are eligible for the benefits of Breakthrough Therapy in addition to allowing the sponsor the ability to participate in meetings with the FDA to discuss whether accelerated approval would be appropriate based on surrogate or intermediate endpoints reasonably likely to predict long-term clinical benefit. Any product is eligible for priority review if it has the potential to provide safe and effective therapy where no satisfactory alternative therapy exists or a significant improvement in the treatment, diagnosis or prevention of a serious or life-threatening disease or condition compared to marketed products. Specific priority review programs exist for material threat medical countermeasures, rare pediatric diseases and tropical diseases. The FDA will attempt to direct additional resources to the evaluation of an application for a new drug or biological product designated for priority review in an effort to facilitate the review, in accordance with FDA guidance. Additionally, a product may be eligible for accelerated approval. Drug or biological products studied for their safety and effectiveness in treating serious or life-threatening illnesses and that provide meaningful therapeutic benefit over existing treatments may receive accelerated approval, which means that they may be approved on the basis of adequate and well-controlled clinical studies establishing that the product has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit, or on the basis of an effect on a clinical endpoint other than survival or irreversible morbidity. As a condition of approval, the FDA will require that a sponsor of a drug or biological product receiving accelerated approval perform adequate and well-controlled post-marketing clinical studies to confirm the clinical benefit of the medicine. In addition, the FDA currently requires as a condition for accelerated approval pre-submission of promotional materials, which could adversely impact the timing of the commercial launch of the product. Fast Track designation, Breakthrough Therapy or RMAT designation, priority review and accelerated approval do not change the standards for approval. Rather, these programs are intended to expedite the development and approval process, but do not necessarily accomplish that intent.

Post-Approval Requirements

Maintaining substantial compliance with applicable federal, state, and local statutes and regulations requires the expenditure of substantial time and financial resources. Rigorous and extensive FDA regulation of biological products continues after approval, particularly with respect to cGMP. We will rely, and expect to continue to rely, on third parties for the production of clinical and commercial quantities of any products that we may commercialize. Manufacturers of our products are required to comply with applicable requirements in the cGMP regulations, including quality control and quality assurance and maintenance of records and documentation. Other post-approval requirements applicable to biological products, include reporting of cGMP deviations that may affect the identity, strength, quality, potency, or purity of a distributed product in a manner that may impact the safety or effectiveness of the product, record-keeping requirements, reporting of adverse effects, reporting updated safety and efficacy information, and complying with electronic record and signature requirements. After a BLA is approved, the product also may be subject to official lot release. 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 also may 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.

We also must comply with the FDA’s advertising and promotion and related medical communication requirements, such as those related to direct-to-consumer advertising, the prohibition on promoting products for uses or in patient populations that are not described in the product’s approved labeling (known as “off-label use”), the requirement to balance promotion information on efficacy with important safety information and limitations on use, industry-sponsored scientific and educational activities, and promotional activities involving the internet. Discovery of previously unknown problems or the failure to comply with the applicable regulatory requirements may result in restrictions on the marketing of a product or withdrawal of the product from the market as well as possible civil or criminal sanctions. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or after approval, may subject an applicant or manufacturer to administrative or judicial civil or criminal sanctions and adverse publicity. FDA sanctions could include refusal to approve pending applications, withdrawal of an approval, clinical hold, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, mandated corrective advertising or communications with doctors, debarment, restitution, disgorgement of profits, or civil or criminal penalties. Any agency or judicial enforcement action could have a material adverse effect on us.

Biological product manufacturers and other entities involved in the manufacture and distribution of approved biological products are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMP and other laws. Accordingly, manufacturers must continue to expend time, money, and effort in the area of production and quality control to maintain cGMP compliance. Discovery of problems with a product after approval may result in restrictions on a product, manufacturer, or holder of an approved BLA, including

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withdrawal of the product from the market. In addition, changes to the manufacturing process or facility generally require prior FDA approval before being implemented and other types of changes to the approved product or conditions of approval, such as adding new indications and additional labeling claims, are also subject to further FDA review and approval.

U.S. Patent Term Restoration and Marketing Exclusivity

Depending upon the timing, duration and specifics of the FDA approval of the use of our product candidates, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly referred to as the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent restoration term of up to five years as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. The patent term restoration period is generally one-half the time between the effective date of an IND and the submission date of a BLA plus the time between the submission date of a BLA and the approval of that application. Only one patent applicable to an approved biological product is eligible for the extension and the application for the extension must be submitted prior to the expiration of the patent. The U.S. Patent and Trademark Office, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we may apply for restoration of patent term for one of our currently owned or licensed patents to add patent life beyond its current expiration date, depending on the expected length of the clinical studies and other factors involved in the filing of the relevant BLA.

A biological product can obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted in the case of a biologic approved under a BLA, adds six months to existing exclusivity periods. This six-month exclusivity, which runs from the end of other exclusivity protection, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study.

The Patient Protection and Affordable Care Act (PPACA) signed into law on March 23, 2010, includes a subtitle called the Biologics Price Competition and Innovation Act of 2009, which created an abbreviated approval pathway for biological products shown to be similar to, or interchangeable with, an FDA-licensed reference biological product. This amendment to the PHS Act attempts to minimize duplicative testing. Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate 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. However, complexities associated with the larger, and often more complex, structure of biological products, as well as the process by which such products are manufactured, pose significant hurdles to interchangeability approval.

A reference biologic is granted 12 years of exclusivity from the time of first licensure of the reference product. The first biologic product submitted under the abbreviated approval pathway that is determined to be interchangeable with the reference product has exclusivity against other biologics submitting under the abbreviated approval pathway for the lesser of (i) one year after the first commercial marketing, (ii) 18 months after approval if there is no legal challenge, (iii) 18 months after the resolution in the applicant’s favor of a lawsuit challenging the biologics’ patents if an application has been submitted, or (iv) 42 months after the application has been approved if a lawsuit is ongoing within the 42-month period.

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. Equivalent laws have been adopted in other countries that impose similar obligations.

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Other U.S. Healthcare Laws and Regulations

Healthcare providers, physicians and third-party payors play a primary role in the recommendation and use of pharmaceutical products that are granted marketing approval. Arrangements with third-party payors, existing or potential customers and referral sources are subject to broadly applicable fraud and abuse and other healthcare laws and regulations, and these laws and regulations may constrain the business or financial arrangements and relationships through which manufacturers market, sell and distribute the products for which they obtain marketing approval. Such restrictions under applicable federal and state healthcare laws and regulations include the following:

Violation of any of the laws described above or any other governmental laws and regulations may result in penalties, including civil and criminal penalties, damages, fines, the curtailment or restructuring of operations, the exclusion from participation in federal and state healthcare programs and imprisonment. Furthermore, efforts to ensure that business activities and business arrangements comply with applicable healthcare laws and regulations can be costly for manufacturers of branded prescription products.

Coverage and Reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of any products for which we may obtain regulatory approval. In the United States and markets in other countries, sales of any product candidates for which regulatory approval for commercial sale is obtained will depend in part on the availability of coverage and reimbursement from third-party payors. Third-party payors include government authorities, managed care providers, private health insurers and other organizations. The process for determining whether a payor will provide coverage for a drug product may be separate from the process for setting the reimbursement rate that the payor will pay for the drug product. Third-party payors may limit coverage to specific drug products on an approved list, or formulary, which might not include all FDA-approved drugs for a particular indication. Moreover, a payor’s decision to provide coverage for a drug product does not imply that an adequate reimbursement rate will be approved.

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Third-party payors are increasingly challenging the price and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. New metrics frequently are used as the basis for reimbursement rates, such as average sales price, average manufacturer price and actual acquisition cost. In order to obtain coverage and reimbursement for any product that might be approved for sale, it may be necessary to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the products, in addition to the costs required to obtain regulatory approvals. If third-party payors do not consider a product to be cost-effective compared to other available therapies, they may not cover the product after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow a company to sell its products at a profit. Health Technology Assessment which is intended to take account of medical, social, economic and ethical issues when determining the suitability of a medicinal product for reimbursement has increasingly become an element of the pricing and reimbursement decisions of the competent authorities in EU Member States.

The U.S. government, state legislatures and foreign governments have shown significant interest in implementing cost containment programs to limit the growth of government-paid health care costs, including price controls, restrictions on reimbursement and requirements for substitution of generic products for branded prescription drugs. By way of example, PPACA contains provisions that may reduce the profitability of drug products, including, for example, increasing the minimum rebates owed by manufacturers under the Medicaid Drug Rebate Program, extending the rebate program to individuals enrolled in Medicaid managed care plans, addressing a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected and establishing annual fees based on pharmaceutical companies’ share of sales to federal health care programs. Adoption of government controls and measures, and tightening of restrictive policies in jurisdictions with existing controls and measures, could limit payments for pharmaceuticals.

U.S. Foreign Corrupt Practices Act

The U.S. Foreign Corrupt Practices Act (FCPA), to which we are subject, prohibits corporations and individuals from engaging in bribery and corruption when dealing with foreign government officials. It is illegal to pay, offer to pay, promise or authorize the payment of money or anything of value, directly or indirectly, to any foreign government official, political party or political candidate in an attempt to secure an improper advantage in order to obtain or retain business or to otherwise improperly influence a foreign official in his or her official capacity. Comparable laws have been adopted in other countries that impose similar obligations. We are also subject to the FCPA’s accounting provisions, which require us to keep accurate books and records and to maintain a system of internal accounting controls sufficient to assure management’s control, authority, and responsibility over our assets. The failure to comply with the FCPA and similar laws could result in civil or criminal sanctions or other adverse consequences.

Government Regulation Outside of the United States

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 studies and any commercial sales and distribution of our products. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries.

Whether or not we obtain FDA approval for a product, we must obtain the requisite approvals from regulatory authorities in foreign countries prior to the commencement of clinical studies or marketing of the product in those countries. Many countries outside of the United States have a similar process that requires the submission of a clinical study application much like the IND prior to the commencement of human clinical studies. In the EU, for example, clinical trials are governed by the new EU Regulation on Clinical Trials (Reg. EU No. 536/2014), or CTR, which became applicable in January 2022 and stipulates the process of obtaining competent authority approval for clinical trials in the EU. Under the CTR, trial sponsors submit their application for approval via an EU Portal. The approvals will still need to be granted by the competent authorities of the EU Member States where a trial takes place; however, the procedure for approval will be conducted in a coordinated manner among the concerned EU Member States as provided under the CTR. While the process for the application and granting of the approvals was streamlined, it remains a complex process that can significantly delay the start of a multinational clinical trial.

To obtain regulatory approval of a biological medicinal product under EU regulatory systems, we must submit a marketing authorization application. The grant of marketing authorization in the EU for products containing viable human tissues or cells such as gene therapy medicinal products is governed by Regulation 1394/2007/EC on advanced therapy medicinal products, read in combination with Directive 2001/83/EC of the European Parliament and of the Council, commonly known as the Community code on medicinal products and Regulation (EC) No 726/2004 of the European Parliament and of the Council of 31 March 2004 laying down Community procedures for the authorization and supervision of medicinal products for human and veterinary use and establishing the European Medicines Agency (the EMA), commonly referred to as the EMA Regulation. Regulation 1394/2007/EC lays down specific rules concerning the authorization, supervision and pharmacovigilance of gene therapy medicinal products, somatic cell therapy medicinal products and tissue engineered products. The EMA’s Committee for Advanced Therapies (CAT) is responsible for assessing the quality, safety and efficacy of advanced therapy medicinal products (ATMP). ATMP include gene therapy medicinal

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products, somatic cell therapy medicinal products and tissue engineered products. The role of the CAT is to prepare a draft opinion on an application for marketing authorization for an ATMP candidate that is submitted to the EMA. The EMA then provides a final opinion regarding the application for marketing authorization. The European Commission grants or refuses marketing authorization after the EMA has delivered its opinion.

Innovative medicinal products are authorized in the EU on the basis of a full marketing authorization application (as opposed to an application for marketing authorization that relies, in whole or in part, on data in the marketing authorization dossier for another, previously approved medicinal product). Applications for marketing authorization for innovative medicinal products must contain the results of pharmaceutical tests, preclinical tests and clinical trials conducted with the medicinal product for which marketing authorization is sought. Innovative medicinal products for which marketing authorization is granted are entitled to eight years of data exclusivity. During this period, applicants for approval of generics or biosimilars of these innovative products cannot rely on data contained in the marketing authorization dossier submitted for the innovative medicinal product to support their application. Innovative medicinal products for which marketing authorization is granted are also entitled to ten years of market exclusivity. During these ten years of market exclusivity, no generic or biosimilar medicinal product may be placed on the EU market even if a marketing authorization application for approval of a generic or biosimilar of the innovative product has been submitted to the EMA or to the competent regulatory authorities in the EU Member States and marketing authorization has been granted. The ten years of market exclusivity will be extended to a maximum of eleven years if, during the first eight years of those ten years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. However, there is no guarantee that a product will be considered by the EU’s regulatory authorities to be an innovative medicinal product which is eligible for the relevant periods of data and market exclusivity.

Products authorized as “orphan medicinal products” in the EU are entitled to benefits additional to those granted in relation to innovative medicinal products. In accordance with Article 3 of Regulation (EC) No. 141/2000 of the European Parliament and of the Council of 16 December 1999 on orphan medicinal products, a medicinal product may be designated as an orphan medicinal product if (1) it is intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition; (2) either (a) such condition affects no more than five in 10,000 persons in the EU when the application is made, or (b) the product, without the incentives derived from orphan medicinal product status, would not generate sufficient return in the EU to justify investment; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such condition authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected by the condition. Further guidance on such criteria is provided in European Commission Regulation (EC) No. 847/2000 of 27 April 2000 laying down the provisions for implementation of the criteria for designation of a medicinal product as an orphan medicinal product and definitions of the concepts “similar medicinal product” and “clinical superiority”. Orphan medicinal products are eligible for financial incentives such as reduction of fees or fee waivers and following grant of a marketing authorization, the EMA and the EU Member States’ competent authorities are not permitted to accept another application for a marketing authorization, or grant a marketing authorization or accept an application to extend an existing marketing authorization, for the same therapeutic indication of a similar medicinal product for ten years following grant or authorization. The application for orphan drug designation must be submitted before the application for marketing authorization. The applicant may receive a fee reduction for the marketing authorization application if the orphan drug designation has been granted, but not if the designation is still pending at the time the marketing authorization is submitted. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

The 10-year market exclusivity that an orphan drug enjoys may be reduced to six years if, at the end of the fifth year, it is established that the product no longer meets the criteria for orphan designation, for example, if the product is sufficiently profitable not to justify maintenance of market exclusivity. Additionally, marketing authorization may be granted to a similar product during the 10-year period of market exclusivity for the same therapeutic indication at any time if:

Similar to obligations imposed in the United States, medicinal products authorized in the EU may be subject to post-authorization obligations, including the obligation to conduct Post Marketing Safety Studies (PASS) or Post Marketing Efficacy Studies (PAES).

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Reimbursement for medicinal products is still an area that is not harmonized in the EU andis largely governed by EU Member States’ laws. However, there are some EU level legal frameworks that must be taken into account, including Council Directive 89/105/EEC (the Price Transparency Directive). The aim of the Price Transparency Directive is to ensure that pricing and reimbursement mechanisms established in EU Member States are transparent and objective, do not hinder the free movement and trade of medicinal products in the EU and do not hinder, prevent or distort competition on the market. The Price Transparency Directive does not, however, provide any guidance concerning the specific criteria on the basis of which pricing and reimbursement decisions are to be made in individual EU Member States. Neither does it have any direct consequence for pricing or levels of reimbursement in individual EU Member States. The national authorities of the individual EU Member States are free to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices and/or reimbursement of medicinal products for human use. Individual EU Member States adopt policies according to which a specific price or level of reimbursement is approved for the medicinal product. Other EU Member States adopt a system of reference pricing, basing the price or reimbursement level in their territory either, on the pricing and reimbursement levels in other countries, or on the pricing and reimbursement levels of medicinal products intended for the same therapeutic indication. Furthermore, some EU Member States impose direct or indirect controls on the profitability of the company placing the medicinal product on the market.

In 2011, Directive 2011/24/EU was adopted at the EU level. This Directive concerns the application of patients’ rights in cross-border healthcare. The Directive is intended to establish rules for facilitating access to safe and high-quality cross-border healthcare in the EU.

Health Technology Assessment (HTA) of medicinal products is becoming an increasingly common part of the pricing and reimbursement procedures in some EU Member States. HTA is the procedure according to which the assessment of the public health impact, therapeutic impact and the economic and societal impact of the use of a given medicinal product in the national healthcare systems of the individual country is conducted. HTA generally focuses on the clinical efficacy and effectiveness, safety, cost, and cost-effectiveness of individual medicinal products as well as their potential implications for the national healthcare system. Those elements of medicinal products are compared with other treatment options available on the market.

The outcome of HTA may influence the pricing and reimbursement status for specific medicinal products within individual EU member states. The extent to which pricing and reimbursement decisions are influenced by the HTA of a specific medicinal product vary between the EU Member States.

A new Regulation on HTA on EU level was adopted in December 2021: Regulation (EU) 2021/2282 of the European Parliament and of the Council of 15 December 2021 on health technology assessment and amending Directive 2011/24/EU (the HTA Regulation). The HTA Regulation covers new medicines and certain new medical devices. Member states will be able to use common HTA tools, methodologies and procedures across the EU, working together in four main areas: 1) joint clinical assessments focusing on the most innovative health technologies with the most potential impact for patients; 2) joint scientific consultations whereby developers can seek advice from HTA authorities; 3) identification of emerging health technologies to identify promising technologies early; and 4) continuing voluntary cooperation in other areas. Individual member states will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technology, and making decisions on pricing and reimbursement. The HTA Regulation will become applicable in January 2025. For other countries outside of the EU, such as countries in Eastern Europe, Latin America or Asia, the requirements governing the conduct of clinical studies, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical studies are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki.

The United Kingdom (UK) formally left the EU on January 31, 2020 and a transitional period applied until the UK’s withdrawal from the EU became fully effective on December 31, 2020. As of January 1, 2021, the UK is a “third country” with respect to the EU (subject to the terms of the EU UK Trade Agreement), and EU law ceased to apply directly in the UK. However, the UK has retained the EU regulatory regime with certain modifications as standalone UK legislation. Therefore, the UK regulatory regime is currently similar to EU regulations, but under proposed legislation, the Medicines and Medical Devices Act, the UK may adopt changed regulations that may diverge from the EU legislative regime for medicines, including their research, development and commercialization, and has issued a consultation document with respect to future changes. For a two-year period, which started in January 2021, the UK has adopted transitional provisions that apply to the importation of medicines into the UK and decision reliance procedures with respect to certain EMA marketing authorization application procedures.

If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

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Human Capital Resources

As of February 24, 2022, we employed 372 full-time employees, of which 295 were engaged in research and development activities, including preclinical, manufacturing and clinical study related functions, and 77 were engaged in general administrative activities, including commercial, corporate development, finance, legal, human resources, information technology, facilities and other general and administrative functions. We have never had a work stoppage, and none of our employees are represented by a labor organization or under any collective bargaining arrangements. We consider our relationship with our employees to be good.

Talent, Growth and Retention

We appreciate the importance of retention, growth and development of our employees. We seek and value employees who have substantial experience in the discovery, development, manufacture and commercialization of innovative therapies in a complex regulatory environment. For certain key functions, especially in research and development and manufacturing activities, we require specialized scientific and gene therapy expertise. To attract and retain the talent we require, we believe we offer competitive compensation, including salary, cash incentive awards and equity awards, along with competitive benefits packages, including medical, dental, vision and life insurance, flexible spending accounts, short- and long-term disability and matching contributions to a 401(k) tax-deferred savings plan. All full-time employees are eligible to participate in the same health and welfare and retirement savings plans. Additionally, we provide professional development programs and on-demand learning opportunities to cultivate talent at all levels throughout our company.

Diversity, Equity and Inclusion

We believe that a diverse, equitable and inclusive culture fosters innovation, which is integral to our mission of improving lives through the curative potential of gene therapy. We are firmly committed to providing equal opportunity in all aspects of employment and aim for appropriate representation of gender, race and ethnicity at every level of our company. We have emphasized diversity, equity and inclusion as part of our company culture, as set out in our Code of Business Conduct and Ethics, and we are determined to support further progress in this area.

Health and Safety

We prioritize the health and safety of our employees and have implemented policies to minimize the spread of COVID-19 in our workplace. At various times during the COVID-19 pandemic, we have implemented work-from-home policies for all employees who are not essential to be onsite, as well as policies relating to testing, vaccination, facial coverings, social distancing and contact tracing. Additionally, we have provided employees with resources to help persevere through the pandemic, including work-from-home technology packages and personal protective equipment.

Available Information

Our principal offices are located at 9804 Medical Center Drive, Rockville, MD 20850, and our telephone number is (240) 552-8181. Our website address is www.regenxbio.com. The information contained in, or that can be accessed through, our website is not a part of, or incorporated by reference in, this Annual Report on Form 10-K. We file annual, quarterly, and current reports, proxy statements, and other documents with the SEC under the Exchange Act. You may obtain any reports, proxy and information statements, and other information that we file electronically with the SEC at www.sec.gov.

You also may view and download copies of our SEC filings free of charge at our website as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. The information contained on, or that can be accessed through, our website will not be deemed to be incorporated by reference in, and is not considered part of, this Annual Report on Form 10-K. Investors should also note that we use our website, as well as SEC filings, press releases, public conference calls and webcasts, to announce financial information and other material developments regarding our business. We use these channels, as well as any social media channels listed on our website, to communicate with investors and members of the public about our business. It is possible that the information that we post on our social media channels could be deemed material information. Therefore, we encourage investors, the media and others interested in our company to review the information that we post on our social media channels.

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ITEM 1A. RISK FACTORS

You should carefully consider the risk factors set forth below as well as the other information contained in this Annual Report on Form 10-K and in our other public filings in evaluating our business. Any of the following risks could materially and adversely affect our business, financial condition or results of operations. In addition, these risks could cause actual results and developments to differ materially and adversely from those projected in the forward-looking statements contained in this Annual Report on Form 10-K (please read the Information Regarding Forward-Looking Statements appearing at the beginning of this Form 10-K). Additional risks and uncertainties not currently known to us or that we currently view to be immaterial may also materially adversely affect our business, financial condition or results of operations. In these circumstances, the market price of our common stock would likely decline and you could lose all or part of your investment.

Risk Factor Summary

Risks Related to Our NAV Technology Platform and the Development of Our Product Candidates

• We have limited clinical results for most of our product candidates.

Risks Related to Our Financial Position

Risks Related to Third Parties

Risks Related to Manufacturing

• We are required to comply with ongoing manufacturing regulatory requirements.

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Risks Related to the Commercialization of Our Product Candidates

Risks Related to Our Business Operations

• We may face product liability lawsuits.

Risks Related to Our Intellectual Property

• We may be subject to intellectual property claims.

Risks Related to Ownership of Our Common Stock

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Risks Related to our NAV Technology Platform and the Development of Our Product Candidates

Our business, operations and preclinical and clinical development timelines and plans could be adversely affected by the effects of the COVID-19 pandemic, including further resurgences or multiple waves of infections, and other public health crises.

The COVID-19 pandemic and other public health crises in regions where we have clinical trial sites or other business operations could have a material adverse effect on our business, operations and preclinical and clinical development timelines and plans, and could significantly constrain or disrupt the operations of third parties upon which we rely, including contract research organizations (CROs) and contract manufacturing organizations (CMOs).

In response to the COVID-19 pandemic, federal, state, local and foreign governments have put in place quarantines, executive orders, shelter-in-place orders, guidelines and other similar orders and restrictions intended to control the spread of the disease. Such orders and restrictions have resulted in business closures, work stoppages, delays, work-from-home policies, travel restrictions and cancellations of events, among other effects that could negatively impact productivity and disrupt our business and operations. Our offices, laboratories, clinical trial sites, prospective clinical trial sites, CROs, CMOs and other collaborators and partners are located in jurisdictions where such orders and restrictions have been enforced, and further resurgences or waves of infections may lead to similar orders and restrictions in the future. At various times during the COVID-19 pandemic, we have implemented work-from-home policies for all employees who are not essential to be onsite, as well as policies relating to testing, vaccination, facial coverings, social distancing and contact tracing, and we may take further actions that alter our operations, as may be required by federal, state or local authorities or which we determine are in the best interests of our employees. The increase in remote working may result in increased cybersecurity, privacy and fraud risks.

The COVID-19 pandemic has caused delays to our clinical trials and may further delay or prevent us from proceeding with our clinical trials. Our clinical trial site initiation and subject enrollment has been delayed, and may be further delayed or suspended, due to site closures, personnel turnover and prioritization of resources toward the COVID-19 pandemic. In addition, some subjects have been, and may continue to be, disinterested in participating in trials with regular follow-up visits during a pandemic, and some subjects have been, and may continue to be, unable or unwilling to comply with clinical trial protocols. Further, some clinical trial vendors have experienced significant delays in providing necessary equipment, supplies and services during the COVID-19 pandemic, and our ability to obtain clinical samples may be adversely affected. Our ability to conduct follow-up visits with treated subjects may be limited if travel or healthcare services are impeded. Similarly, our ability to recruit and retain principal investigators and other clinical trial personnel could be adversely affected.

The COVID-19 pandemic may impact our ability to procure resources, raw materials or components necessary for our research studies and preclinical and clinical development, and prices have escalated due to limited supplies of such resources, raw materials and components. For instance, our supply chain may be disrupted or our CMOs may be required to dedicate their facilities, personnel and resources to support vaccine production. Additionally, required inspections and reviews by regulatory authorities may be delayed due to a focus of resources on COVID-19 as well as continued travel and other restrictions. Significant delays in the timing and completion of our research studies and preclinical and clinical development would increase our costs and could adversely affect our ability to obtain marketing approval from regulatory authorities for the commercialization of our product candidates. Further, meetings with regulatory authorities that would be important in progressing our programs may be delayed or impeded in connection with the COVID-19 pandemic.

The construction of our new headquarters, including our current good manufacturing practice (cGMP) production facility, has been delayed from our original estimates, and may be delayed further, due to various government orders and restrictions relating to the COVID-19 pandemic. The potential impact of any such delay is unpredictable but may includesignificantadditional costsanddisruptionstoouroperations.

The spread of COVID-19 has caused a broad impact globally and may materially affect our business, financial condition and results of operations, as well as continue to increase the volatility and adversely affect the value of our common stock. While the full extent of the economic impact and duration of the COVID-19 pandemic may be difficult to assess or predict, the continuation of prolonged adverse economic conditions (including due to further resurgences or waves of COVID-19 infections) may reduce our ability to access capital and adversely affect our liquidity. In addition, if the business and operations of our licensees or collaborators are adversely affected by the COVID-19 pandemic, our revenuescouldinturnbeadverselyaffected.

Scientific and economic analyses of the COVID-19 pandemic, including the expected impact of variants, vaccinations and therapeutics, continue to evolve and we will continue to monitor the situation closely. The ultimate impact of the COVID-19 pandemic and other public health crises is highly unpredictable and subject to change. We are not yet certain about the full extent of the potential impact of COVID-19 on our business, operations and preclinical and clinical development. To the extent COVID-19adversely affectsourbusiness,financialconditionandresultsofoperations,aswellas global economic conditions more generally, it may also heighten many of the other risk factors described in this Annual Report on Form 10-K.

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Our gene therapy product candidates are based on a novel technology that makes it difficult to predict the time and cost of development and of subsequently obtaining regulatory approval. Only a few gene therapy products have been approved in the United States, the European Union or elsewhere.

We have concentrated our research and development efforts on our proprietary adeno-associated virus (AAV) gene delivery platform (our NAV Technology Platform), and we have granted licenses to certain intellectual property related to our NAV Technology Platform to licensees (our NAV Technology Licensees). Our future success depends on our and our NAV Technology Licensees’ successful development and commercialization of viable gene therapy product candidates. There can be no assurance that we or our NAV Technology Licensees will not experience problems or delays in developing current or future product candidates or that such problems or delays will not cause unanticipated costs, or that any such development problems can be solved. We also may experience unanticipated problems or delays in expanding our manufacturing capacity, and this may prevent us from completing our clinical trials, meeting the obligations of our collaborations or commercializing our products on a timely or profitable basis, if at all. For example, we, a partner or another group may uncover one or more previously unknown risks associated with AAV or our NAV Technology Platform, and this may prolong the period of observation required for obtaining regulatory approval, necessitate additional clinical testing or invalidate our NAV Technology.

In addition, the clinical trial requirements of the U.S. Food and Drug Administration (the FDA), the European Medicines Agency (the EMA) and other regulatory authorities and the criteria these regulators use to determine the quality, safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of such product candidates. The regulatory approval process for novel product candidates such as ours can be significantly more expensive and take longer than for other, better known or more extensively studied product candidates. Only a few gene therapy products have been approved in the United States, the European Union or elsewhere. It is difficult to determine how long it will take or how much it will cost to obtain regulatory approvals for our product candidates in the United States, the European Union or elsewhere, or how long it will take to commercialize our product candidates. Furthermore, approvals by one regulatory authority may not be indicative of what other regulatory authorities may require for approval, and approvals of ex vivo gene therapy products may not be indicative of what may be required for approval of in vivo gene therapy products.

Regulatory requirements governing gene and cell therapy products have changed frequently and may continue to change in the future. Additionally, we may seek regulatory approval in territories outside the United States and the European Union, which may have their own regulatory authorities along with frequently changing requirements or guidelines. The regulatory review committees and advisory groups in the United States, the European Union and elsewhere, and any new guidelines they promulgate, may lengthen the regulatory review process, require us to perform additional studies, increase our development costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and commercialization of our product candidates or lead to significant post-approval limitations or restrictions. As we advance our product candidates, we will be required to consult with these regulatory and advisory groups, and comply with applicable guidelines. If we fail to do so, we may be required to delay or discontinue development of certain of our product candidates. These additional processes may result in a review and approval process that is longer than we otherwise would have expected. Delay or failure to obtain, or unexpected costs in obtaining, the regulatory approval necessary to bring a potential product to market could decrease our ability to generate product revenue, and our business, financial condition, results of operations and prospects would be materially harmed.

Our business depends substantially on the success of our lead product candidates. If we are unable to obtain regulatory approval for, or successfully commercialize, our lead product candidates, our business will be materially harmed.

Several of our lead product candidates are in the early stages of development and all of our lead product candidates will require substantial clinical development and testing, manufacturing bridging studies and process validation and regulatory approval prior to commercialization. Successful continued development and ultimate regulatory approval of our lead product candidates is critical for our future business success and our ability to generate product revenue. We have invested, and will continue to invest, a significant portion of our financial resources in the development of our lead product candidates. We will need to raise sufficient funds for, and successfully complete, our clinical trials of our lead product candidates in appropriate subjects. The future regulatory and commercial success of these product candidates is subject to a number of risks, including the following:

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• we may not successfully establish commercial manufacturing capabilities;

Of the large number of biologics and drugs in development in the biopharmaceutical industry, only a small percentage result in the submission of a Biologics License Application (BLA) to the FDA or marketing authorization application (MAA) to the EMA and even fewer are approved for commercialization. Due to several of the risk factors identified in this Annual Report on Form 10-K, we may not achieve our goal to have multiple AAV vector-based gene therapies that are approved or in pivotal trials through our internal and partnered programs by the end of 2025. Furthermore, even if we do receive regulatory approval to market our lead product candidates, any such approval may be subject to limitations on the indicated uses for which we may market the product. Accordingly, even if we are able to obtain the requisite financing to continue to fund our development programs, we cannot assure you that our lead product candidates will be successfully developed or commercialized. If we or any of our future development partners are unable to develop, or obtain regulatory approval for, or, if approved, successfully commercialize, our lead product candidates, we may not be able to generate sufficient revenue to continue our business.

We have limited clinical results for most of our product candidates and success in preclinical studies or early clinical trials may not be indicative of results obtained in later trials.

Gene therapy development has inherent risks. Most of our lead product candidates have limited clinical and preclinical results and we may experience unexpected results in the future. We or any of our future development partners will be required to demonstrate through adequate and well-controlled clinical trials that our product candidates containing our proprietary vectors are safe and effective, with a favorable benefit-risk profile, for use in their target indications before we can seek regulatory approvals for their commercial sale. Drug development is a long, expensive and uncertain process, and delay or failure can occur at any stage of development, including after commencement of any of our clinical trials.

The results of preclinical studies and early clinical trials are not always predictive of future results. Any product candidate we or any of our future development partners advance into clinical trials, including our lead product candidates, may not have favorable results in later clinical trials, if any, or receive regulatory approval. There is a high failure rate for drugs and biologic products proceeding through clinical trials. Data obtained from preclinical and clinical activities are subject to varying interpretations that may delay, limit or prevent regulatory approval. In addition, we may experience regulatory delays or rejections as a result of many factors, including due to changes in regulatory policy during the period of our product candidate development. Any such delays could materially harm our business, financial condition, results of operations and prospects.

Because we are developing product candidates for the treatment of certain diseases in which there is little clinical experience and we are using new endpoints or methodologies, there is increased risk that the FDA, the EMA or other regulatory authorities may not consider the endpoints of our clinical trials to provide clinically meaningful results and that these results may be difficult to analyze.

During the FDA review process, we will need to identify success criteria and endpoints such that the FDA will be able to determine the clinical efficacy and safety profile of our product candidates. As we are developing novel treatments for diseases in which there is little clinical experience with new endpoints and methodologies, there is heightened risk that the FDA, the EMA or other regulatory bodies may not consider the clinical trial endpoints to provide clinically meaningful results (reflecting a tangible benefit to patients). In addition, the resulting clinical data and results may be difficult to analyze. Even if the FDA does find our

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success criteria to be sufficiently validated and clinically meaningful, we may not achieve the pre-specified endpoints to a degree of statistical significance. Further, even if we do achieve the pre-specified criteria, we may produce results that are unpredictable or inconsistent with the results of the non-primary endpoints or other relevant data. 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. The EMA and other regulatory authorities in the European Union and other countries may make similar comments with respect to these endpoints and data.

The results from our preclinical studies or clinical trials for our product candidates may not support as broad a marketing approval as we seek, and the FDA, the EMA or other regulatory authorities may require us to conduct additional clinical trials or evaluate subjects for an additional follow-up period.

While we believe our product candidates should be applicable for the treatment of patients with certain conditions, the results from our preclinical and planned clinical trials may not support as broad of a marketing approval as we seek. Even if we obtain regulatory approval for our product candidates, we may be required by the FDA, the EMA or other regulatory bodies to conduct additional clinical trials to support approval of our product candidates for patients diagnosed with different mutations of the respective diseases to which our product candidates relate. This could result in our experiencing significant increases in costs and substantial delays in obtaining, or never obtaining, marketing approval for our product candidates to treat patients. The inability to market our product candidates to treat patients for the intended indications would materially harm our business, financial condition, results of operations and prospects.

We may encounter substantial delays in our planned clinical trials, or we may fail to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities.

Before obtaining marketing approval from regulatory authorities for the sale of our product candidates, we must conduct extensive clinical trials to demonstrate the safety and efficacy of the product candidates. Clinical testing is expensive, time-consuming and uncertain as to outcome. A failure of one or more clinical trials can occur at any stage of testing. Events that may prevent successful or timely commencement and completion of preclinical and clinical development include:

• delays in reaching a consensus with regulatory authorities on trial design;

• clinical trial sites or subjects dropping out of a trial;

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Any inability to successfully complete research studies, preclinical and clinical development could result in additional costs to us or impair our ability to generate revenues from product sales, regulatory and commercialization milestones and royalties. In addition, if we make manufacturing or formulation changes to our product candidates, we may need to conduct additional studies to bridge our modified product candidates to earlier versions. 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, which could impair our ability to successfully commercialize our product candidates and may harm our business, financial condition, results of operations and prospects.

Additionally, if the results of our planned clinical trials are inconclusive or if there are safety concerns or serious adverse events associated with our product candidates, we may:

• be subject to changes in the way the product is administered;

• be sued; or

• experience damage to our reputation.

Our NAV Technology Platform, our product candidates or our licensees’ or collaborators’ product candidates, and the process for administering such product candidates, may cause undesirable side effects or have other properties that could delay or prevent regulatory approval of product candidates, limit the commercial potential or result in significant negative consequences following any potential marketing approval.

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RGNX · 10-K · period ended 2021-12-31

ITEM 1. BUSINESS

ITEM 1A. RISK FACTORS

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RGNX · 10-K · period ended 2021-12-31

ITEM 1. BUSINESS

ITEM 1A. RISK FACTORS

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