REGENXBIO Inc. Q3 FY2024 earnings call

• Curran Simpson recapped business highlights and upcoming milestones, including RGX-202 expected to initiate pivotal phase, RGX-121 BLA filing progress, and RGX-314 End-of-Phase 2 meeting for DR. • Steve Pakola provided clinical updates: RGX-202 dosing in 1-3 year old cohort, RGX-314 progress in DR and wet AMD, RGX-121 CAMPSIITE trial endpoint success. • Mitchell Chan reviewed financials, noting cash balance and R&D expenses.

No specific financial performance data for product segments provided in the transcript.

• Cash balance of $279 million as of Sep 30, 2024 is expected to fund operations into 2026. • Plan to initiate pivotal trial for RGX-202 in Q4 2024. • Complete End-of-Phase 2 meeting with FDA for RGX-314 in DR in Q4 2024. • Continue rolling BLA submission for RGX-121 and expect to complete in Q1 2025.

• Forward-looking statements are subject to risks and uncertainties as described in the company’s annual and quarterly reports with the SEC. No specific operational failure risks detailed in the transcript.

Q: Quick questions on DMD. For the age 1-year-old to 3-year-old cohort, are there any concerns there on durability given the patients are still young and may be growing additional muscle tissue? And then if you all do receive biomarker approval – accelerated approval, would multiple time points be needed for a biopsy versus just one-time point at 3 months? And then also for the data at year-end, how should we think about the magnitude of functional change?

A: Steve Pakola responded on durability noting AAV8 vector has durability in liver-directed hemophilia treatment out beyond 12 years, giving confidence. Curran Simpson said no requests for additional biomarker data beyond protocol. Reiterated excitement about magnitude of effect with benchmarks in mind.

Q: Could you recap for us your latest view on how best to gauge the functional data we are expecting later this month?

A: Steve Pakola mentioned looking at timed function tests, NSAA, caregiver-reported outcomes. Curran Simpson noted use of external controls for natural history assessment.

Q: For RGX-202, when you think about the data we’re going to see from this initial group of patients, is it reasonable to expect that their experience and follow-up and data will be rolled into a larger pool of data collectively for a pivotal data set? Or will a future pivotal data set include being patients recruited in the future, not including these first handful of patients?

A: Curran Simpson said expect to use data from Phase 1/2 study, especially dose level 2 patients. Steve Pakola added primary endpoint for accelerated approval is microdystrophin, so data from Phase 1/2 can be used in pivotal.

Q: For RGX-202, I believe you’ve mentioned previously that you might – you were considering imposing a minimum threshold of microdystrophin expression on your cells in the pivotal trial, even though that might not be something that the agency would necessarily require. I think the number was something maybe like 10% expression for approval. Is that something that you still feel confident in doing? And have you ever discussed that with the FDA?

A: Steve Pakola said concept of 10% threshold is considered, but seeing much higher microdystrophin levels gives flexibility. Details on pivotal design to be shared soon.

Q: For DMD, are you concerned at all about the durability of impact, especially going into younger patients? And are you at all thinking about redosing? And then for wet AMD, can you provide some color on how you think about the Eylea biosimilars from Amgen and potential market impact?

A: Steve Pakola said have evidence of durability in younger patients with AAV8 vector. Reiterated focus on first-time treatment. On Eylea biosimilars, said no impact on branded longer durability products, value proposition of one-time treatment remains.

Q: For RGX-121, what are your latest thoughts are on a potential AdCom for – following the filing. And then secondly, what are the latest, I guess a bit of feedback you are hearing relative to the Denali asset and maybe just how doctors and the physician community are thinking about potentially sequencing these drugs?

A: Curran Simpson said preparing as if there will be an AdCom. Stressed difference between RGX-121 and Denali's approach, with RGX-121 being a one-time gene therapy with better patient benefit.

Q: Just knowing that in general, they are not diagnosed until they are about 4-years-old to 5-years-old, are you having any issues identifying these patients relative to the older cohorts? And do you think there are any efforts there you could make for the potential future market in terms of moving that average age of diagnosis up?

A: Steve Pakola said newborn screening is picking up, will move diagnosis earlier. Confident in finding patients with investigators and compelling nature of the product.

Q: I saw in your press release that you got an approval or authorization to start clinical trial in Canada, which you plan on doing in the first half. Can you share some of the details of that trial and whether the data from that trial will be part of the pivotal data package? And then a question on RGX-314, given recent data from the bilateral study, what are your plans for the fellow eye study for suprachoroidal program, both for – both for Wet AMD MDR?

A: Steve Pakola said Canada approval supports product quality. Data from Canada trial will be relevant for pivotal. On RGX-314, planning to evaluate bilateral treatment with suprachoroidal, excited about safety and opportunity.