REGENXBIO Inc. (NASDAQ:RGNX) Q4 2023 Earnings Conference Call February 27, 2024 4:30 PM ET Company Participants Patrick Christmas – Chief Legal Officer Ken Mills – Chief Executive Officer Steve Pakola – Chief Medical Officer Vit Vasista – Chief Financial Officer Conference Call Participants Gena Wang – Barclays Gospel Enyindah-Asonye – Morgan Stanley Alec Stranahan – Bank of America Annabel Samimy – Stifel Lisa Walter – RBC Capital Markets Mani Foroohar – Leerink Partners Operator Good day, and thank you fo ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-37553 Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 1 ...

EXHIBIT 99.1 • ABBV-RGX-314 Subretinal Delivery for the Treatment of Wet AMD o Enrollment is on track in ATMOSPHERE ® and ASCENT™ pivotal trials and these trials are expected to support global regulatory submissions with the U.S. Food and Drug Administration and the European Medicines Agency in late 2025 through the first half of 2026. • ABBV-RGX-314 Suprachoroidal Delivery for Treatment of Wet AMD o REGENXBIO expects to share new program and data updates for the Phase II AAVIATE trial in mid-2024. o In Jan ...

REGENXBIO Inc. (NASDAQ:RGNX) Q3 2023 Earnings Conference Call November 8, 2023 4:30 PM ET Company Participants Patrick Christmas - Chief Legal Officer Ken Mills - Chief Executive Officer Steve Pakola - Chief Medical Officer Vit Vasista - Chief Financial Officer Conference Call Participants Gena Wang - Barclays Dane Leone - Raymond James Alec Stranahan - Bank of America Lisa Walter - RBC Capital Markets Brian Skorney - Baird Mani Foroohar - Leerink Partners Operator Good day, and thank you for standing by. W ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___ to ___ Commission File Number 001-37553 REGENXBIO Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 47-1851754 (S ...

REGENXBIO Inc. (NASDAQ:RGNX) Q2 2023 Earnings Conference Call August 2, 2023 4:30 PM ET Company Participants Patrick Christmas - Chief Legal Officer Ken Mills - Chief Executive Officer Steve Pakola - Chief Medical Officer Vit Vasista - Chief Financial Officer Conference Call Participants Dane Leone - RJF Alec Stranahan - Bank of America Ellie Merle - UBS Lisa Walter - RBC Andreas Argyrides - Wedbush Securities Caroline Palomeque - Berenberg Capital Markets Operator Good day, and thank you for standing by. W ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___ to ___ Commission File Number 001-37553 REGENXBIO Inc. (Exact Name of Registrant as Specified in its Charter) Washington, D.C. 20549 FORM 10-Q (Mark One) (State or other jurisdictio ...

Financial Data and Key Metrics Changes - REGENXBIO ended Q1 2023 with cash, cash equivalents, and marketable securities totaling $474 million, down from $565 million as of December 31, 2022, primarily due to cash used for operating activities [73] - R&D expenses for Q1 2023 were $59 million, an increase from $56 million in Q1 2022, attributed to higher personnel costs and laboratory expenses related to the manufacturing innovation center [74] Business Line Data and Key Metrics Changes - The company is advancing its 5x'25 strategy, aiming to move five AAV therapeutics into pivotal or commercial stages by 2025 [22][25] - The RGX-314 program has dosed over 600 patients across seven trials, demonstrating good tolerability and potential as a one-time treatment for major retinal vascular diseases [29][30] Market Data and Key Metrics Changes - The global market for diabetic retinopathy (DR) is estimated to reach $15 billion in the next decade, with RGX-314 positioned as a potential one-time treatment option [47] - The anti-VEGF market is calculated to be over $14 billion globally, with RGX-314 targeting over 30 million patients with high unmet needs [66] Company Strategy and Development Direction - REGENXBIO is focused on expanding its global reach through collaboration with AbbVie, particularly in the eye care sector, to bring RGX-314 to patients worldwide [44][62] - The company is leveraging its NAVXpress platform for manufacturing, which is operational and designed to meet global regulatory standards [64] Management's Comments on Operating Environment and Future Outlook - Management expressed confidence in the regulatory pathway for RGX-314, anticipating submissions to the FDA and EMA in late 2025 to early 2026 [62] - The company is optimistic about the potential of RGX-314 to address the high unmet need in retinal diseases, particularly given the limitations of current anti-VEGF treatments [63] Other Important Information - The company announced the transfer of INDs for ongoing clinical trials to AbbVie, marking a significant step in their collaboration [23][26] - REGENXBIO's manufacturing innovation center is set to produce commercial-scale GMP material for the RGX-314 clinical program [45] Q&A Session Summary Question: What is the impact of the increased enrollment in ATMOSPHERE and ASCENT on regulatory submissions? - Management indicated that the increased sample size enhances power for both primary and secondary endpoints, which is crucial for regulatory submissions [80][81] Question: Was there an alteration in the agreement with AbbVie regarding regulatory responsibilities? - Management clarified that the transition of regulatory responsibilities was part of the original collaboration agreement and is now being implemented as planned [84][109] Question: How does the decision to expand enrollment impact the registration pathway for suprachoroidal delivery? - Management believes that the expansion will support important milestones for regulatory approvals in both the U.S. and internationally [91][92] Question: What is the expected safety profile for RGX-202 in the Duchenne program? - Management stated that the trial is excluding patients with preexisting AAV8 antibodies to ensure safety and efficacy [95][97] Question: How will the fellow eye study be conducted in relation to the pivotal trials? - The fellow eye study will treat patients at a later time to avoid confounding results, aligning with FDA discussions [120][135]

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___ to ___ Commission File Number 001-37553 REGENXBIO Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 47-1851754 (State ...

REGENXBIO Inc. (NASDAQ:RGNX) Q4 2022 Earnings Conference Call February 28, 2023 4:30 PM ET Company Participants Patrick Christmas - Chief Legal Officer Ken Mills - Chief Executive Officer Steve Pakola - Chief Medical Officer Vit Vasista - Chief Financial Officer Conference Call Participants Dane Leone - Raymond James Lisa Walter - RBC Capital Markets Andreas Argyrides - Wedbush Securities Caroline Palomeque - Berenberg Operator Hello, and thank you for standing by. Welcome to the Q4 and Full Year 2022 REGEN ...