REGENXBIO Inc. (NASDAQ: RGNX) reported interim data from its Phase I/II trial of RGX-202, an investigational gene therapy for Duchenne muscular dystrophy. The company presented the data at the Muscular Dystrophy Association Clinical and Scientific Conference.

Seven participants treated with the pivotal dose of 2x10^14 GC/kg showed improved performance on functional measures at one year compared to external controls. Participants improved an average of 4.9 points on the North Star Ambulatory Assessment compared to the cTAP disease progression model. Five participants aged 8 years and older at dosing improved an average of 5.2 points.

The participants demonstrated cardiac stability at one year post-treatment based on MRI endpoints. Mean left ventricular ejection fraction remained at 61.7% at baseline and 61.6% at 12 months. Global circumferential strain measured -20.4% at baseline and -20.9% at 12 months.

Safety data showed no serious adverse events or adverse events of special interest in the Phase I/II study of 13 participants. Common drug-related adverse events included vomiting, fatigue, and nausea. Liver safety measures including gamma-glutamyl transferase and total bilirubin did not exceed the upper limit of normal up to two years post-treatment.

Biomarker data indicated microdystrophin expression levels, with one additional patient aged 3.6 at dosing showing 51.2% expression at Week 12. The primary endpoint in the pivotal phase requires microdystrophin expression greater than 10% at Week 12.

REGENXBIO expects to report topline pivotal data in early Q2 2026 and plans to request a pre-BLA meeting with the FDA in mid-2026. The company continues enrolling approximately 30 participants aged 1 year and older in the confirmatory trial.

The information is based on a company press release statement.