REGENXBIO Inc. 10-Q

Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations. You should read the following discussion and analysis of our financial condition and results of operations in conjunction with the financial statements and the notes thereto included elsewhere in this Quarterly Report on Form 10-Q and with our audited financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2025, which we filed with the SEC on March 5, 2026. In addition, you should read the “Risk Factors” and “Information Regarding Forward-Looking Statements” sections of this Quarterly Report on Form 10-Q and our Annual Report on Form 10-K for the year ended December 31, 2025 for a discussion of important factors that could cause actual results to differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis. 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. Overview of Product Candidates We have developed a broad pipeline of gene therapy programs using our proprietary adeno-associated virus (AAV) gene therapy delivery platform (NAV Technology Platform) as a one-time treatment to address an array of diseases. Our lead programs and product candidates are described below: Sura-vec (ABBV-RGX-314) We are developing ABBV-RGX-314 (surabgene lomparvovec, sura-vec) in collaboration with AbbVie as a potential one-time treatment for chronic retinal conditions that cause total or partial vision loss, including wet age-related macular degeneration (wet AMD) and diabetic retinopathy (DR). Sura-vec is currently being evaluated in multiple clinical trials, including two pivotal trials (ATMOSPHERE and ASCENT) where enrollment has been completed, one long-term follow-up study and a fellow eye sub-study in patients with wet AMD, all utilizing subretinal delivery. Additionally, two Phase II clinical trials in patients with wet AMD (AAVIATE) and DR (ALTITUDE) are ongoing along with two corresponding long-term follow-up studies, all utilizing in-office suprachoroidal delivery. Within the Phase II study in DR, we are also evaluating sura-vec in diabetic macular edema (DME). Additionally, we have activated U.S. clinical sites and initiated enrollment of a pivotal trial in DR and expect to dose the first patient in the two-part Phase IIb/III study (NAAVIGATE) in the second quarter of 2026. Sura-vec uses the NAV ® AAV8 vector to deliver a gene encoding a therapeutic antibody fragment to inhibit vascular endothelial growth factor (VEGF). 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. Sura-vec for Treatment of Wet AMD Subretinal Delivery Enrollment in the ATMOSPHERE ® and ASCENT ® pivotal trials for the treatment of patients with wet AMD using subretinal delivery was completed in October 2025. These trials are expected to support global regulatory submissions with the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Topline data from these trials are expected to be shared in the fourth quarter of 2026 in partnership with AbbVie, with global regulatory submissions expected in 2027. Suprachoroidal Delivery The AAVIATE ® trial is a multi-center, open label, randomized, controlled, dose-escalation Phase II trial to evaluate the efficacy, safety and tolerability of suprachoroidal delivery of sura-vec for the treatment of wet AMD. Based on the favorable safety profile observed as of July 29, 2024, the Phase II AAVIATE trial enrolled a cohort to evaluate sura-vec at dose level 4 (1.5x10e12 GC/eye). Patients in this cohort received short course prophylactic steroid eye drops. Enrollment of the AAVIATE trial has been completed. 27 Table of Contents Sura-vec for Treatment of DR and DME The ALTITUDE ® trial is a multi-center, open label, randomized, controlled, dose-escalation Phase II trial to evaluate the efficacy, safety and tolerability of sura-vec using suprachoroidal delivery for the treatment of DR. In November 2023, we announced data showing sura-vec was well tolerated at dose levels 1 and 2 and positive signals of efficacy, including 20.8% of patients exhibiting > 2-step Diabetic Retinopathy Severity Scale (DRSS) improvement without additional DR treatment at one year. In August 2025, we announced positive 2-year data showing sura-vec was well tolerated in subjects with non-proliferative diabetic retinopathy (NPDR) at dose levels 1, 2, and 3. There were no drug-related serious adverse events and no intraocular inflammation was observed through two years at dose level 3 (1.0x10 12 GC/eye) (n = 15) with short-course topical prophylactic steroids. 50% of dose level 3 patients achieved at least a two-step improvement without need for any supplemental treatment. Concurrent with the two-year data announcement in August 2025, we and AbbVie announced an amendment to our collaboration agreement and plans to initiate a pivotal program consisting of a Phase IIb/III trial (NAAVIGATE) as well as a second Phase III trial. NAAVIGATE is a two-part, multicenter, randomized, masked, sham-controlled Phase IIb/III study to evaluate the safety and efficacy of sura-vec in subjects with NPDR without center-involved diabetic macular edema (CI-DME). The primary endpoint is > 2-step improvement on the DRSS at one year. Following an interim analysis of part one (Phase IIb) portion of the NAAVIGATE trial, we and AbbVie will initiate a Phase III expansion, including part two (Phase III) of the U.S. NAAVIGATE trial and a parallel global trial led by AbbVie. We have activated U.S. clinical sites and initiated enrollment of the Phase IIb/III NAAVIGATE trial and expect to dose the first patient in the second quarter of 2026, upon which we are entitled to a $100.0 million milestone payment from AbbVie. RGX-202 for Treatment of Duchenne We are developing RGX-202 as an investigational AAV therapeutic for the treatment of Duchenne muscular dystrophy (Duchenne), using the NAV AAV8 vector to deliver a transgene for a novel microdystrophin that includes the functional elements of the C-Terminal domain as well as a muscle-specific promoter to support a targeted therapy for improved resistance to muscle damage associated with Duchenne. Other differentiating elements of RGX-202 include the proactive immune suppression regimen and in-house, state-of-the-art manufacturing that has demonstrated leading purity levels in Duchenne (>80% full capsids). AFFINITY DUCHENNE ® is an ongoing multicenter, open-label Phase I/II/III trial to evaluate the safety, tolerability and clinical efficacy of a one-time intravenous dose of RGX-202 in ambulatory patients with Duchenne aged 1 to 11 years old. Phase I/II results, reported between November 2024 and March 2026, demonstrated RGX-202 to be well tolerated with no serious adverse events or adverse events of special interest among all patients (n=13). Additionally, we reported positive biomarker data showing consistent, high expression and transduction of RGX-202 microdystrophin, with all patients exceeding 10%. Pivotal dose (2x10 14 GC/kg) participants in the Phase I/II exceeded expected disease trajectory on the North Star Ambulatory Assessment (NSAA) and other timed function tests at one year using multiple validated methods to estimate expected disease progression without treatment (n=7). Notably, five participants for whom functional data has been reported were aged eight or older at dosing, when functional decline is expected. In October 2025, we announced that enrollment had completed in the pivotal portion of AFFINITY DUCHENNE, which was designed to enroll approximately 30 patients in the U.S. and Canada, and that we continue to enroll participants in the ongoing confirmatory trial. In May 2026, we announced positive topline results from the pivotal Phase III AFFINITY DUCHENNE trial of RGX-202, including primary endpoint (n=30 at Week 12), interim safety (n=31) and interim functional data (n=9 at 12 months): • The primary endpoint was achieved with high statistical significance; 93% of patients achieved RGX-202 microdystrophin expression above 10% (p<0.0001). • RGX-202 was well-tolerated and continued to demonstrate a favorable interim safety profile. • RGX-202 demonstrated functional improvement and evidence of positively impacting disease trajectory at one year post-treatment, as measured by NSAA and timed function tests (Time to Stand, 10 Meter Walk-run, Time to Climb). • Statistically significant correlation between RGX-202 microdystrophin expression level and functional improvement, supporting validity of surrogate endpoint. As reported in the May 2026 topline data update, we have enrolled over 20 patients in the confirmatory trial (n=30) evaluating RGX-202 in ambulatory patients aged one year and older, and we expect to complete dosing in all 60 patients across the pivotal and confirmatory trials by mid-2026. 28 Table of Contents In recent discussions with the FDA, the agency shared that the use of RGX-202 microdystrophin expression as a surrogate endpoint will be based on the correlation analysis with clinical outcomes, which has been clearly demonstrated in our interim data. While the FDA has recommended a randomized controlled trial, it has guided that externally controlled trials may be adequate for demonstrating substantial evidence of effectiveness, especially when the treatment effect is sufficiently large enough to overcome limitations of externally controlled trials. The FDA offered to review the RGX-202 data and alternative proposals. We plan to discuss this data with the FDA at a future meeting. We are also finalizing the trial design for a study of RGX-202 outside the United States to support global regulatory submissions. Given the positive topline pivotal data, continued favorable safety profile, and statistically significant correlation between microdystrophin and functional improvement, we plan to pursue accelerated approval for RGX-202 and are preparing for a potential commercial launch in 2027. We have completed manufacturing the first batches of RGX-202 intended for commercial supply and manufacturing is ongoing to build commercial inventory in advance of a potential commercial launch. The process performance qualification (PPQ) campaign is also complete. We are also recruiting patients in the AFFINITY BEYOND ® trial, an observational screening study. The primary objective is to evaluate the prevalence of AAV8 antibodies in patients with Duchenne up to 12 years of age. Information collected in this study may be used to identify potential participants for the AFFINITY DUCHENNE trial and potential future trials of RGX-202. RGX-121 for Treatment of MPS II We are developing RGX-121 (clemidsogene lanparvovec) in collaboration with Nippon Shinyaku in the United States and certain countries in Asia as an investigational one-time AAV therapeutic for the treatment of Mucopolysaccharidosis Type II (MPS II), also known as Hunter syndrome, using the NAV AAV9 vector to deliver the gene that encodes the iduronate-2-sulfatase enzyme. A BLA for RGX-121 seeking accelerated approval was submitted to the FDA in March 2025. The FDA subsequently granted priority review of the BLA and successfully completed mid-cycle meeting, Pre-license inspection (PLI) and Bioresearch monitoring information (BIMO) inspections. The PLI and BIMO inspections were completed with no observations. In August 2025, we announced that the FDA review timeline had been extended following submission of 12-month clinical data for all patients in the pivotal study of RGX-121 (n=13) in response to an FDA information request. The longer-term data submitted to the FDA were presented at the International Congress of Inborn Errors of Metabolism (ICIEM) in September 2025. These results showed that in the pivotal phase of the CAMPSIITE trial (n=13), participants through one year sustained an 82% median reduction of cerebrospinal fluid (CSF) levels of HS D2S6. These longer-term data were consistent with previously reported topline pivotal results from the CAMPSIITE trial. The initial Prescription Drug User Fee Act (PDUFA) goal date was extended from November 9, 2025 to February 8, 2026. In January 2026, we announced that the FDA placed the RGX-121 program on partial clinical hold in relation to a serious adverse event in a patient treated in the Phase I/II trial of RGX-111, discussed in further detail below. The FDA cited the similarities in products, study populations, and shared risk between the clinical studies. The partial clinical hold on RGX-121 was lifted by the FDA on April 30, 2026. In February 2026, we announced that the FDA issued a Complete Response Letter (CRL) for the RGX-121 BLA. The FDA stated in the CRL that it had agreed to the study protocol in principle and outlined several reasons for not approving the gene therapy, including uncertainty regarding the study eligibility criteria to adequately define a population with neuronopathic disease (vs. attenuated disease), the comparability of the natural history external control to the study population, and the appropriateness of CSF HS D2S6 as a surrogate endpoint reasonably likely to predict clinical benefit. The CRL lists several potential paths forward, including a new study, treating additional patients and conducting longer-term follow up, and using an untreated control arm. Throughout active discussions during the BLA process, we believed we had addressed the points raised in the CRL through the submission of additional data and responses to numerous information requests. The FDA did not agree the data set provided substantial evidence of effectiveness to support approval of RGX-121 for the treatment of MPS II. 29 Table of Contents Following the CRL, we entered into discussions with FDA senior leadership in March 2026 and filed a Formal Dispute Resolution Request which is pending. We plan to continue to work with the FDA to address the CRL and discuss potential paths forward for the RGX-121 program. Potential approval of the BLA for RGX-121 could result in receipt of a Rare Pediatric Disease Priority Review Voucher (PRV), assuming the statutory criteria are met. If approved, RGX-121 would be the first approved gene therapy and one-time treatment for MPS II. RGX-111 for Treatment of MPS I We are developing RGX-111 in collaboration with Nippon Shinyaku in the United States and certain countries in Asia as an investigational one-time AAV therapeutic for the treatment of Mucopolysaccharidosis Type I (MPS I), also known as Hurler syndrome, using the NAV AAV9 vector to deliver the IDUA gene. In November 2023, future development of RGX-111 was halted as a result of a strategic pipeline prioritization and corporate restructuring. Prior to that announcement, RGX-111 demonstrated to be well tolerated in interim results and indicated encouraging biomarker and neurodevelopmental results in a Phase I/II study. Efforts to continue development of RGX-111 as part of the strategic partnership with Nippon Shinyaku are ongoing. In January 2026, we announced that the FDA placed the RGX-111 program on partial clinical hold following preliminary analysis of a single case of neoplasm (intraventricular CNS tumor) in a participant treated in the Phase I/II study. The case was identified during a routine brain MRI of an asymptomatic five-year-old participant who received intracisternal RGX-111 four years prior. Preliminary genetic analysis of the resected tumor detected an AAV vector genome integration event associated with overexpression of a proto-oncogene (PLAG1), which is known to be susceptible to chromosomal rearrangements. Final analysis of the resected tumor was conducted by an independent third-party lab and, as previously reported, detected an AAV vector genome integration event associated with overexpression of a PLAG1. Clonal integration of AAV vector elements into the PLAG1 gene was detected in the tumor tissue. Analyses supported classification as a PLAG1‑family neuroepithelial tumor and are consistent with the hypothesis that AAV vector integration at the PLAG1 site contributed to tumor formation. Of note, this participant had a background of factors that could have contributed to risk of oncogenic transformation. For example, the participant underwent unsuccessful stem cell transplant at four months of age, with loss of donor chimerism, and he received chemotherapeutics that may have contributed to DNA damage. The report concluded, based on formal neuropsychologic testing and developmental pediatrician assessment, that the patient’s neurocognitive development was above average, which indicated mitigation of MPS I disease, and the patient continued to do well. The analysis was published in The New England Journal of Medicine in May 2026. AbbVie Collaboration for Sura-vec In September 2021, we entered into a collaboration and license agreement with AbbVie Global Enterprises Ltd. (AbbVie), a subsidiary of AbbVie Inc., to jointly develop and commercialize sura-vec (as amended, the AbbVie Collaboration Agreement). Pursuant to the AbbVie Collaboration Agreement, both we and AbbVie are active participants in the development of sura-vec and development expenses are shared between the parties in accordance with the agreement. The Company will lead the manufacturing of sura-vec for clinical development and U.S. commercial supply, and AbbVie will lead the global commercialization of sura-vec. We received an up-front fee of $370.0 million from AbbVie upon the effective date of the AbbVie Collaboration Agreement in November 2021, and we are eligible to receive up to $1.38 billion from AbbVie upon the achievement of specified development and sales-based milestones. Additionally, the parties will share equally in the net profits and net losses associated with the commercialization of sura-vec in the United States, and we are eligible to receive tiered royalties on net sales by AbbVie of sura-vec outside the United States. For additional information regarding the AbbVie Collaboration Agreement, please refer to Note 10, “License and Collaboration Agreements—AbbVie Collaboration and License Agreement” to the accompanying unaudited consolidated financial statements. 30 Table of Contents Nippon Shinyaku Collaboration for RGX-121 and RGX-111 In January 2025, we entered into a collaboration and license agreement with Nippon Shinyaku Co., Ltd. (Nippon Shinyaku) for the development and commercialization of RGX-121 and RGX-111 (the Nippon Shinyaku Collaboration Agreement) in the United States and certain countries in Asia. Pursuant to the Nippon Shinyaku Collaboration Agreement, we are responsible for the development of RGX-121 and RGX-111 in the United States, and Nippon Shinyaku is responsible for development in licensed territories outside the United States. We are responsible for the manufacturing of RGX-121 and RGX-111 for clinical development and commercial supply, and manufacturing expenses will be allocated between the parties in accordance with the terms of the Nippon Shinyaku Collaboration Agreement. Nippon Shinyaku is responsible, at its sole cost, for the commercialization of RGX-121 and RGX-111 in the licensed territories. Under the terms of the Nippon Shinyaku Collaboration Agreement, we received an up-front payment of $110.0 million from Nippon Shinyaku following the effective date of the agreement in March 2025 and are eligible to receive up to $700.0 million from Nippon Shinyaku upon the achievement of specified development and sales-based milestones. We are also eligible to receive double-digit royalties on net sales of RGX-121 and RGX-111 by Nippon Shinyaku, subject to specified offsets and reductions. We retain all rights to, and any proceeds related to the sale of, any priority review vouchers that may be issued upon the potential approvals of RGX-121 and RGX-111. For additional information regarding the Nippon Shinyaku Collaboration Agreement, please refer to Note 10, “License and Collaboration Agreements—Nippon Shinyaku Collaboration and License Agreement” to the accompanying unaudited consolidated financial statements. In May 2025, we entered into a loan agreement with entities managed by Healthcare Royalty Management, LLC (collectively and with other affiliated entities, HCR). Pursuant to the terms of the loan agreement, future royalties, sales-based milestone payments and certain development milestone payments earned under the Nippon Shinyaku Collaboration Agreement, along with consideration earned under various other NAV Technology Platform license agreements, shall be used to repay principal and interest owed to HCR. For additional information regarding the May 2025 loan agreement with HCR, please refer to Note 7, “Royalty Monetization Liabilities—2025 Royalty Bond” to the accompanying unaudited consolidated financial statements. NAV Technology Licensing Platform In addition to our internal product development efforts, we also selectively license the NAV Technology Platform and other intellectual property rights to other leading biotechnology and pharmaceutical companies, which we refer to as NAV Technology Licensees. As of March 31, 2026, our NAV Technology Platform was being applied in two commercial products, Zolgensma ® and Itvisma ® , and the preclinical and clinical development of various other licensed products. Licensing the NAV Technology Platform allows us to maintain our internal product development focus on our core disease indications and therapeutic areas while still expanding the NAV gene therapy pipeline, developing a greater breadth of treatments for patients, providing additional technological and potential clinical proof-of-concept for our NAV Technology Platform and creating additional revenue opportunities. Financial Overview Revenues Our revenues to date have been primarily generated from the licensing of our NAV Technology Platform and other intellectual property rights to NAV Technology Licensees and collaborators, as well as from development and manufacturing services performed under such license and collaboration arrangements. We have not generated any revenues from commercial sales of our own products. If we fail to complete the development of our product candidates in a timely manner or obtain regulatory approval and adequate labeling, our ability to generate future revenues will be materially compromised. We license our NAV Technology Platform and other intellectual property rights to other biotechnology and pharmaceutical companies, including collaborators for the joint development and commercialization of our product candidates. The terms of the licenses vary, and licenses may be exclusive or non-exclusive and may be sublicensable by the licensee. Licenses may grant intellectual property rights for purposes of internal and preclinical research and development only, or may include the rights, or options to obtain future rights, to commercialize drug therapies for specific diseases using the NAV Technology Platform and other licensed rights. License agreements generally have a term at least equal to the life of the underlying patents, but are terminable at the option of the licensee. Consideration payable to us under our license and collaboration agreements may include: (i) up-front and annual fees, (ii) milestone payments based on the achievement of certain development and sales-based milestones, (iii) sublicense fees, (iv) royalties on sales of licensed products, (v) fees for services related to the development and manufacturing of licensed products and (vi) other consideration payable upon optional goods and services purchased by licensees and collaborators. 31 Table of Contents Future revenues under our license and collaboration arrangements are dependent on the successful development and commercialization of licensed products, which is uncertain, and revenues may fluctuate significantly from period to period. Additionally, we may never receive consideration under our license or collaboration agreements that is contemplated on optional goods and services, development and sales-based milestones, royalties on sales of licensed products or sublicense fees, given the contingent nature of these payments. Our revenues are concentrated among a low number of licensees and collaborators and the arrangements are terminable at the option of the counterparty. The termination of our license and collaborations arrangements may materially impact the amount of revenue we recognize in future periods. Zolgensma and Itvisma Royalties Royalty revenue to date consists primarily of royalties on net sales of Zolgensma and Itvisma, which are marketed by Novartis Gene Therapies, Inc. (Novartis Gene Therapies), a wholly owned subsidiary of Novartis AG (Novartis), for the treatment of spinal muscular atrophy (SMA). Zolgensma and Itvisma are licensed products under our license agreement with Novartis Gene Therapies (the Novartis License) for the development and commercialization of treatments for SMA using the NAV Technology Platform. In mid-January 2026, licensed patents for Zolgensma under the Novartis License expired in the United States. We are entitled to continued royalties on net sales of Zolgensma in approximately 20 countries where licensed patents remain active. Licensed product made prior to patent expiration but sold after expiration may also be subject to royalties. Patents covering the use of Itvisma have issued in the United States and certain other countries and are licensed to Novartis Gene Therapies under the Novartis License. We are entitled to ongoing royalties on certain net sales of Itvisma in these territories. Operating Expenses Our operating expenses consist primarily of cost of license and royalty revenues, research and development expenses and general and administrative expenses. Personnel costs including salaries, wages, benefits, bonuses and stock-based compensation expense, comprise a significant component of research and development and general and administrative expenses. We allocate indirect expenses associated with our facilities, information technology costs, depreciation and other overhead costs between research and development and general and administrative categories based on employee headcount and the nature of work performed by each employee or using other reasonable allocation methodologies. Cost of License and Royalty Revenues Our cost of license and royalty revenues consists primarily of upstream fees due to our licensors as a result of revenue generated from the licensing of our NAV Technology Platform and other intellectual property rights, including sublicense fees and royalties on net sales of licensed products. Sublicense fees are based on a percentage of license fees received by us from licensees and are recognized in the period that the underlying license revenue is recognized. Royalties are based on a percentage of net sales of licensed products by licensees and are recognized in the period that the underlying sales occur. Future costs of revenues are uncertain due to the nature of our license agreements and significant fluctuations in cost of license and royalty revenues may occur from period to period. Research and Development Expense Our research and development expenses consist primarily of: • salaries, wages and personnel-related costs, including benefits, travel and stock-based compensation, for our scientific personnel and others performing research and development activities; • costs related to executing preclinical studies and clinical trials; • costs related to acquiring, developing and manufacturing materials for preclinical studies and clinical trials; • fees paid to consultants and other third parties who support our product candidate development; • other costs in seeking regulatory approval of our product candidates; and • direct costs and allocated costs related to laboratories and facilities, depreciation expense, information technology and other overhead. Up-front fees incurred in obtaining technology licenses for research and development activities, as well as associated milestone payments, are charged to research and development expense as incurred if the technology licensed has no alternative future use. 32 Table of Contents We expect to continue to incur significant research and development expenses for the foreseeable future as we continue the development of our product candidates and engage in early research and development for prospective product candidates and new technologies. The following table summarizes our research and development expenses incurred during the three months ended March 31, 2026 and 2025 (in thousands): Three Months Ended March 31, 2026 2025 Direct Expenses ABBV-RGX-314 $ 8,250 $ 8,563 RGX-202 6,966 4,508 RGX-121 715 3,474 Other product candidates 1,194 791 Total direct expenses 17,125 17,336 Unallocated Expenses Platform and early research 9,973 6,681 Personnel 20,018 18,643 Facilities 2,847 2,768 Stock-based compensation 3,760 3,947 Depreciation and amortization 3,616 3,712 Total unallocated expenses 40,214 35,751 Total research and development $ 57,339 $ 53,087 Direct expenses related to the development of ABBV-RGX-314 include $12.6 million and $14.7 million for the three months ended March 31, 2026 and 2025, respectively, in net cost reimbursement from AbbVie under our eye care collaboration, which were recorded as a reduction of research and development expenses. In addition to reimbursement of direct development expenses, net cost reimbursement from AbbVie includes reimbursement of personnel and overhead costs attributable to the development of ABBV-RGX-314, the underlying costs of which are reported as unallocated expenses in the table above. We typically utilize our employee and infrastructure resources across our development programs. As a result, we generally do not allocate personnel and other internal costs, such as facilities and other overhead costs, to specific product candidates or development programs. Platform and early research reported in the table above includes direct costs not identifiable with a specific lead product candidate, including costs associated with our research and development platform used across programs, manufacturing support, process and analytical development, early research and development for prospective product candidates and new technologies, and other costs in support of research and development activities. General and Administrative Expense Our general and administrative expenses consist primarily of salaries, wages and personnel-related costs, including benefits, travel and stock-based compensation, for employees performing functions other than research and development. This includes certain personnel in executive, commercial, corporate development, finance, legal, human resources, information technology, facilities and administrative support functions. Additionally, general and administrative expenses include costs associated with accounting, legal, commercial and other corporate advisory services, obtaining and maintaining patents, insurance, information systems and other general corporate activities, as well as facility-related costs and other corporate overhead costs not otherwise allocated to research and development expense. We expect that our general and administrative expenses will increase as we continue to develop, and potentially commercialize, our product candidates. Specifically, we expect general and administrative costs associated with the potential commercialization of our product candidates to increase in future periods as we and our commercial partners prepare for and carry out product launch efforts, in particular for the potential commercialization of our RGX-202 and ABBV-RGX-314 product candidates. Other Income (Expense) Interest Income from Licensing In accordance with our revenue recognition policy, interest income from licensing consists of imputed interest recognized from significant financing components identified in our license agreements with NAV Technology Licensees. 33 Table of Contents Investment Income Investment income consists of interest income earned and gains and losses realized from our cash equivalents, marketable securities and non-marketable equity securities. Cash equivalents are comprised of money market mutual funds and highly liquid debt securities with original maturities of 90 days or less at acquisition. Marketable securities are comprised of available-for-sale debt securities. Interest Expense Interest expense is primarily associated with our royalty monetization liabilities, including our December 2020 royalty purchase agreement (2020 Royalty Purchase Agreement) and May 2025 loan agreement (2025 Royalty Bond) with HCR. For further information regarding our royalty monetization liabilities and associated interest expense, please refer to Note 7, “Royalty Monetization Liabilities” to the accompanying unaudited consolidated financial statements. Critical Accounting Policies and Estimates This Management’s Discussion and Analysis of Financial Condition and Results of Operations is based on our consolidated financial statements, which we have prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosure of contingent assets and liabilities for the periods presented. We base our estimates on historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities, and other reported amounts, that are not readily apparent from other sources. Actual results may differ materially from these estimates under different assumptions or conditions. Our significant accounting policies are fully described in Note 2 to the accompanying unaudited consolidated financial statements and in Note 2 to our audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025. There have been no significant changes in our critical accounting policies and estimates since December 31, 2025. Results of Operations Our consolidated results of operations were as follows (in thousands): Three Months Ended March 31, 2026 2025 Change Revenues License and royalty revenue $ 5,090 $ 87,049 $ (81,959 ) Service revenue 1,303 1,963 (660 ) Total revenues 6,393 89,012 (82,619 ) Operating Expenses Cost of license and royalty revenues 11,074 3,436 7,638 Research and development 57,339 53,087 4,252 General and administrative 21,306 20,347 959 Other operating expenses 36 15 21 Total operating expenses 89,755 76,885 12,870 Income (loss) from operations (83,362 ) 12,127 (95,489 ) Other Income (Expense) Interest income from licensing 16 25 (9 ) Investment income 2,003 2,501 (498 ) Interest expense (8,708 ) (8,570 ) (138 ) Total other income (expense) (6,689 ) (6,044 ) (645 ) Net income (loss) $ (90,051 ) $ 6,083 $ (96,134 ) 34 Table of Contents Comparison of the Three Months Ended March 31, 2026 and 2025 License and Royalty Revenue. License and royalty revenue decreased by $82.0 million, from $87.0 million for the three months ended March 31, 2025 to $5.1 million for the three months ended March 31, 2026. The decrease was primarily attributable to $70.0 million of upfront license revenue recognized under our collaboration with Nippon Shinyaku in the first quarter of 2025, as well as a decrease in royalty revenues for the first quarter of 2026. Combined Zolgensma and Itvisma royalties decreased by $11.9 million, from $17.0 million for the first quarter of 2025 to $5.1 million for the first quarter of 2026. Novartis reported combined Zolgensma and Itvisma sales of $302 million for the first quarter of 2026, as compared to $327 million for the first quarter of 2025. Zolgensma royalties for the first quarter of 2026 were $4.7 million, a decrease of $12.2 million from the first quarter of 2025. The decrease was primarily attributable to the expiration of licensed patents in the United States in mid-January 2026. We are entitled to continued royalties on net sales of Zolgensma in approximately 20 countries where licensed patents remain active. Itvisma royalties for the first quarter of 2026 were $0.3 million. Itvisma was approved in the United States in the fourth quarter of 2025, with U.S. sales commencing in the first quarter of 2026. Licensed patents covering the use of Itvisma have issued in the United States and certain other countries, and we are entitled to ongoing royalties on certain net sales of Itvisma in these territories. Service Revenue. Service revenue decreased by $0.7 million, from $2.0 million for the three months ended March 31, 2025 to $1.3 million for the three months ended March 31, 2026. The decrease was primarily attributable to service revenue recognized under our collaboration with Nippon Shinyaku, which decreased from $1.8 million for the first quarter of 2025 to $1.0 million for the first quarter of 2026, largely driven by the performance of RGX-121 development and manufacturing services. Cost of License and Royalty Revenues. Cost of license and royalty revenues increased by $7.6 million, from $3.4 million for the three months ended March 31, 2025 to $11.1 million for the three months ended March 31, 2026. The increase was largely driven by a non-recurring charge of $10.0 million in the first quarter of 2026 related to a settlement with GlaxoSmithKline LLC (GSK) to resolve a dispute over sublicense fee obligations under our license agreement with GSK. For further information regarding the settlement agreement with GSK, please refer to Note 8, “Commitments and Contingencies—GlaxoSmithKline—GSK Settlement Agreement” to the accompanying unaudited consolidated financial statements. Research and Development Expense. Research and development expenses increased by $4.3 million, from $53.1 million for the three months ended March 31, 2025 to $57.3 million for the three months ended March 31, 2026. The increase was primarily attributable to the following: • an increase of $1.3 million in costs associated with clinical trials and regulatory activities, largely driven by RGX-202 pivotal trials; • an increase of $1.1 million in personnel-related costs due to increased headcount of development personnel, net of a $0.2 million decrease in stock-based compensation expense; • an increase of $0.9 million in manufacturing-related expenses and other clinical supply costs for our lead product candidates; and • an increase of $0.9 million in costs associated with preclinical activities and other early-stage research and development. General and Administrative Expense. General and administrative expenses increased by $1.0 million, from $20.3 million for the three months ended March 31, 2025 to $21.3 million for the three months ended March 31, 2026. The increase was largely driven by personnel-related costs, consulting and other corporate advisory services. Liquidity and Capital Resources Sources of Liquidity As of March 31, 2026, we had cash, cash equivalents and marketable securities of $150.5 million, which were primarily derived from our royalty monetization with HCR in May 2025 and the up-front payment received under the Nippon Shinyaku Collaboration Agreement in March 2025. At-the-Market Offering Program In December 2024, we entered into a Sales Agreement with Leerink Partners LLC (Leerink) pursuant to which we may offer and sell shares of our common stock having an aggregate offering price of up to $150.0 million from time to time through Leerink, acting as our sales agent (the Leerink ATM Program). As of March 31, 2026, no shares of common stock had been sold under the 35 Table of Contents Leerink ATM Program. We intend to use proceeds obtained from the sale of shares under the Leerink ATM Program, if any, for general corporate purposes. Future Liquidity and Ability to Continue as a Going Concern We intend to devote the majority of our current capital to preclinical research, clinical development, seeking regulatory approval of our product candidates and, if approved, commercialization of our product candidates, as well as additional capital expenditures needed to support these activities. Because of the numerous risks and uncertainties associated with the development and commercialization of gene therapy product candidates, we are unable to estimate the total amount of operating expenditures and capital outlays necessary to complete the development and commercialization of our product candidates. We expect that our cash, cash equivalents and marketable securities of $150.5 million as of March 31, 2026 will enable us to fund our operating expenses and capital expenditure requirements, and are sufficient to meet our financial commitments and obligations into early 2027. This estimate is based on our current operating plan, and excludes the potential effects of any future financings or material milestone payments that may be received under our licensing and collaboration arrangements. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our capital resources sooner than expected. These conditions raise substantial doubt about our ability to continue as a going concern within 12 months from the issuance date of our consolidated financial statements for the three months ended March 31, 2026, which accompany this Quarterly Report on Form 10-Q. Our ability to continue as a going concern will depend heavily on the successful development, approval and commercialization of our product candidates and our ability to raise additional capital to fund operations. If we are unable to raise capital sufficient to meet our working capital needs in the future, we may be forced to delay expenditures, reduce the scope of our development activities or make other changes to our operating plans. Cash Flows Our consolidated cash flows were as follows (in thousands): Three Months Ended March 31, 2026 2025 Net cash provided by (used in) operating activities $ (76,186 ) $ 33,629 Net cash provided by investing activities 70,588 44,743 Net cash used in financing activities (13,639 ) (5,794 ) Net increase (decrease) in cash and cash equivalents and restricted cash $ (19,237 ) $ 72,578 Cash Flows from Operating Activities Our net cash used in operating activities for the three months ended March 31, 2026 increased by $109.8 million from the three months ended March 31, 2025, largely driven by the $110.0 million up-front fee received from Nippon Shinyaku in March 2025 and an increase in operating expenses in the first quarter of 2026. We expect to continue to incur regular net cash outflows from operations for the foreseeable future as we continue the development and advancement of our product candidates and other research programs. For the three months ended March 31, 2026, our net cash used in operating activities of $76.2 million consisted of a net loss of $90.1 million and unfavorable changes in operating assets and liabilities of $1.5 million, offset by adjustments for non-cash items of $15.4 million. The changes in operating assets and liabilities include a decrease in accrued expenses and other current liabilities of $16.7 million, which was driven largely by decreases in accrued personnel-related expenses, royalties and sublicense fees, and external research and development services. The unfavorable changes in operating assets and liabilities were partially offset by a decrease in accounts receivable of $18.2 million, which was driven largely by royalties receivable on net sales of Zolgensma. Other changes in operating working capital occurred in the normal course of business. Adjustments for non-cash items primarily consisted of stock-based compensation expense of $8.6 million, depreciation and amortization expense of $3.9 million and non-cash interest expense of $3.8 million. For the three months ended March 31, 2025, our net cash provided by operating activities of $33.6 million consisted of net income of $6.1 million, adjustments for non-cash items of $11.1 million and favorable changes in operating assets and liabilities of $16.4 million. Adjustments for non-cash items primarily consisted of stock-based compensation expense of $8.5 million and depreciation and amortization expense of $4.0 million, partially offset by the accretion of discounts on marketable debt securities during the period. The changes in operating assets and liabilities include an increase of $39.8 million in deferred revenue, which was driven primarily by the deferred portion of the $110.0 million up-front payment received under our collaboration with Nippon Shinyaku in the first quarter of 2025. The favorable changes in operating assets and liabilities were partially offset by a decrease in 36 Table of Contents total accounts payable and accrued expenses and other current liabilities of $18.1 million, which was driven largely by decreases in accrued personnel-related expenses, royalties and external research and development services, as well as a total increase in prepaid expenses and other current assets of $4.3 million, which was driven primarily by increases in prepaid software licenses and net cost reimbursement due from AbbVie under our ABBV-RGX-314 collaboration. Other changes in operating working capital occurred in the normal course of business. Cash Flows from Investing Activities For the three months ended March 31, 2026, our net cash provided by investing activities consisted of $81.7 million in maturities of marketable debt securities, offset by $9.8 million used to purchase marketable debt securities and $1.2 million used to purchase property and equipment. For the three months ended March 31, 2025, our net cash provided by investing activities consisted of $64.9 million in maturities of marketable debt securities, offset by $19.2 million used to purchase marketable debt securities and $1.0 million used to purchase property and equipment. Cash Flows from Financing Activities For the three months ended March 31, 2026, our net cash used in financing activities primarily consisted of $13.4 million of royalties paid, net of interest, under our royalty monetization liabilities. For the three months ended March 31, 2025, our net cash used in financing activities primarily consisted of $5.6 million of royalties paid, net of interest, under our royalty monetization liabilities. Additional Capital Requirements Our material capital requirements from known contractual and other obligations primarily relate to our vendor service contracts and purchase commitments, in-license agreements, operating lease agreements and royalty monetization agreements. Our material commitments and obligations are further described in Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of our Annual Report on Form 10-K for the year ended December 31, 2025, and in the notes to the audited consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2025. Other than the changes described in the notes to the unaudited consolidated financial statements accompanying this Quarterly Report on Form 10-Q, including Note 8, “Commitments and Contingencies,” there have been no material changes to our commitments and obligations since December 31, 2025. Future Funding Requirements We have incurred cumulative losses since our inception and had an accumulated deficit of $1.22 billion as of March 31, 2026. Our transition to recurring profitability is dependent upon achieving a level of revenues adequate to support our cost structure, which depends heavily on the successful development, approval and commercialization of our product candidates. We do not expect to achieve such revenues, and expect to continue to incur losses, for at least the next several years. We expect to continue to incur significant research and development and general and administrative expenses for the foreseeable future as we continue the development of, and seek regulatory approval for, our product candidates. Subject to obtaining regulatory approval for our product candidates, we expect to incur significant commercialization expenses for product sales, marketing, manufacturing and distribution. Additionally, we expect to continue to incur capital expenditures associated with building out additional laboratory and manufacturing capacity to further support the development of our product candidates and potential commercialization efforts. As a result, we will need significant additional capital to fund our operations, which we may obtain through one or more equity offerings, debt financings or other third-party funding, including potential strategic alliances and licensing or collaboration arrangements. Our future capital requirements will depend on many factors, including: • the timing of enrollment, commencement and completion of our clinical trials; • the results of our clinical trials; • the results of our preclinical studies for our product candidates and any subsequent clinical trials; • the scope, progress, results and costs of drug discovery, laboratory testing, preclinical development and clinical trials for our product candidates; 37 Table of Contents • delays or costs due to a clinical hold or CRL, including BLA resubmission; • whether we receive a PRV and are able to monetize or otherwise realize any potential value associated with such a voucher; • the value of any PRV received diminishes including any decreases due to demand for these vouchers; • the costs associated with building out additional laboratory and manufacturing capacity; • the costs, timing and outcome of regulatory review of our product candidates; • the impact of any government-imposed tariffs on cost of goods and services, particularly related to partnered product candidates; • the costs of future product sales, medical affairs, marketing, manufacturing and distribution activities for any of our product candidates for which we receive marketing approval; • revenue, if any, received from commercial sales of our products, should any of our product candidates receive marketing approval; • revenue received from commercial sales of Zolgensma and Itvisma, and the timing and amount of Zolgensma and Itvisma royalties paid to HCR under our royalty monetization agreements; • revenue received from other commercial sales of our licensees’ and collaborators’ products, should any of their product candidates receive marketing approval, other revenue received under our licensing agreements and collaborations, and the timing and amount of any such revenues payable to HCR under our royalty monetization agreements; • the costs of preparing, filing and prosecuting patent applications, maintaining and enforcing our intellectual property rights, including against Sarepta Therapeutics, Inc., and defending any intellectual property-related claims; • our current licensing agreements or collaborations remaining in effect, including the AbbVie Collaboration Agreement relating to ABBV-RGX-314 and the Nippon Shinyaku Collaboration Agreement relating to RGX-121 and RGX-111, and our ability to timely achieve any milestones set forth in such agreements or collaborations; • our ability to establish and maintain additional licensing agreements or collaborations on favorable terms, if at all; and • the extent to which we acquire or in-license other product candidates and technologies. The issuance of additional securities, whether equity or debt, by us, including through our at-the-market program, or the possibility of such issuance, may cause the market price of our common stock to decline. Adequate additional financing may not be available to us on acceptable terms, or at all. We also could be required to seek funds through arrangements with partners or otherwise that may require us to relinquish rights to our intellectual property, our product candidates or otherwise agree to terms unfavorable to us. Off-Balance Sheet Arrangements We did not have any off-balance sheet arrangements during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined in the rules and regulations of the SEC. 38 Table of Contents Item 3. Quantitative and Qualitati ve Disclosures about Market Risk. For information regarding market risk, refer to Item 7A, “Quantitative and Qualitative Disclosures About Market Risk,” included in our Annual Report on Form 10-K for the year ended December 31, 2025. There have been no material changes to our exposure to market risk during the three months ended March 31, 2026.