REGENXBIO Inc. Q1 FY2026 earnings call

• RGX202 (Duchenne Muscular Dystrophy Gene Therapy) Pivotal Trial Results:
  • Met the primary endpoint (proportion of patients with >10% microdystrophin expression at week 12) with high statistical significance: 93% (28/30) of patients exceeded 10% expression, 80% exceeded 40% expression, and the average expression across all patients was 71.1%, with 41.6% average expression in patients aged 8 and older — the highest reported for this age group across all DMD gene therapy programs.
  • Demonstrated a strong, statistically significant correlation (>0.9) between microdystrophin expression and 12-month functional improvement, a first for the DMD gene therapy field. Interim 12-month functional data for 9 patients aged 4+ showed improved outcomes compared to external control disease trajectories across all measured functional domains, even in patients aged 8+ who are typically in a disease decline phase.
  • Favorable safety profile: only 2 treatment-related serious adverse events (SAEs), both resolved fully without sequelae; no cases of drug-related thrombocytopenia, myositis, or neurotoxicity reported. The proactive, short-course immune suppression regimen implemented from the program's start is credited for the positive safety profile.
• Other Pipeline Updates:
  • The partial clinical hold on RGX121 for Hunter syndrome has been fully lifted; the company has filed an appeal of the RGX121 Complete Response Letter (CRL) and continues to engage the FDA on a path forward.
  • For the retinal disease program partnered with AbbVie, the company is on track to dose the first patient in the phase 2B trial for diabetic retinopathy in Q2 2026, which will trigger a $100 million milestone payment from AbbVie. Topline data from subretinal pivotal trials is expected to be reported in Q4 2026.
  • More than 50 patients have been dosed across RGX202's pivotal and confirmatory studies, with line of sight to 60 dosed patients by mid-2026.
• Strategic Positioning: Management remains confident the company is positioned to achieve three product approvals over the next few years, including two potential blockbuster opportunities.

This webcast focused primarily on clinical trial data for Regenexx Bio's pipeline candidates, with no detailed financial segment performance data released for Q1 2026. Only high-level operational updates were provided across the firm's product pipeline.

• Management reaffirms its plan to pursue potential accelerated approval of RGX202 in the U.S. with a goal of approval in 2027, requiring a BLA filing in the first half of 2027. The company is on track to meet this timeline.
• By the time of the planned early 2027 BLA filing, the company expects to have at least 50 patients in the safety database and 15 to 20 patients aged 4+ who have completed their 12-month functional assessment.
• Additional 12-month functional data updates for RGX202 are expected to be released in fall 2026 as more patients reach the 12-month timepoint post-dosing.
• The company plans to initiate a pre-designed randomized controlled trial (RCT) for RGX202 outside of the U.S. in 2026 as part of a global development approach, in case the FDA requires an RCT as the confirmatory study for accelerated approval.

• The FDA has not yet reviewed the complete topline RGX202 data released in this call, and there is uncertainty around whether the agency will accept the external control trial design and strong biomarker-functional outcome correlation to support accelerated approval without requiring a new RCT conducted prior to approval, which would delay approval to ~2030.
• While the observed safety profile for RGX202 is highly favorable to date with only two resolved SAEs, longer-term safety data across a larger patient population is still being collected.
• FDA is currently undergoing a leadership transition, which creates uncertainty around regulatory policy flexibility for rare disease accelerated approval pathways.

Q: What were the circumstances around the asymptomatic liver SAE reported in the RGX202 trial, and how does this impact the overall liver safety profile? / A: The patient was hospitalized solely for administrative reasons: the elevation was detected on a Friday, and an outpatient infusion center was not available over the weekend to administer a planned pulse of steroids. The SAE designation was triggered by the hospitalization requirement, not the severity of the liver enzyme elevation, which was mild and resolved fully without sequelae. Across all 31 dosed patients, including this case, mean liver enzyme levels remained stable and below the upper limit of normal, resulting in a far lower liver injury rate than seen with existing approved DMD gene therapy.

Q: What is the company's timeline for regulatory engagement and BLA filing, and what is the range of potential outcomes from upcoming FDA discussions about the need for a randomized controlled trial? / A: Management maintains a high sense of urgency given that current approved treatment volume is lower than annual new patient incidence, leaving significant unmet need. The company plans to wait for the FDA leadership transition to settle before scheduling a data meeting with the agency in the second half of 2026, and remains on track to file in the first half of 2027 for 2027 approval. Management notes that requiring a new RCT prior to approval would delay approval to ~2030, which is untenable for the Duchenne community. If FDA requires an RCT as the post-approval confirmatory study for accelerated approval, the company is prepared to pivot its ongoing confirmatory study (or run a new study) mostly outside the U.S. where equipoise for a placebo-controlled trial still exists.

Q: Is there a minimum threshold of microdystrophin expression required to achieve functional benefit, and how will the functional data set mature as more patients reach 12 months? / A: The nine patients with available 12-month functional data have a demographic and age distribution that matches the overall 31-patient pivotal cohort, so management is confident the positive results will replicate as more patients reach the 12-month timepoint. Investigators note that the trial's primary endpoint threshold of 10% expression was selected because prior data shows functional improvement can occur at that level, and it is too early to establish a required 40% threshold based on the current small data set. Additional data updates will be shared in fall 2026.

Q: What do investigators think about the proactive immune suppression regimen used for RGX202, including the addition of eculizumab? / A: Initially, investigators had concerns about the intensity of the multi-drug regimen including eculizumab, but clinical experience across multiple dosed patients has shown the regimen is generally well tolerated by patients, and families have been able to manage the additional monitoring and infusion requirements. No complement-mediated side effects like thrombotic microangiopathy have been observed, and investigators credit the proactive regimen for the program's strong observed safety profile.