Regenxbio Reports Positive Functional Outcomes for RGX-202 AAV Gene Therapy in Duchenne

ROCKVILLE, Md., June 5, 2025 /PRNewswire/  Regenxbio announced new functional and biomarker outcomes from its RGX-202 AAV gene therapy for Duchenne muscular dystrophy. The company reported on Thursday that five children treated with the AAV therapy showed improvements in various movement measures on the North Star Ambulatory Assessment (an average four-point gain), as well as in standing, climbing, and walk-run tests, at nine months post-dosing. Four of these patients maintained improvements at one year.

Additionally, biomarker data from nine patients (ages 1-11) who received the RGX-202 AAV gene therapy showed microdystrophin expression ranging from 20.8% to 122.3% of normal levels. These initial results from a small patient group (the five children were 6-12 years old at dosing) were compared to their baseline and natural history studies.

Regenxbio is currently enrolling the pivotal part of its study for RGX-202, having recruited over half of the approximately 30 patients (ages 1+) needed. The company anticipates topline data in early 2026 and plans to apply for FDA approval in mid-2026. If approved, Regenxbio’s AAV gene therapy would be the second commercially available gene therapy for Duchenne, following Sarepta Therapeutics’ Elevidys.

Notably, Regenxbio highlighted the safety profile, reporting no serious adverse events among 13 patients in the Phase 1/2 portion of the study. No patients experienced neurotoxicity, liver injury, low blood platelet counts, or heart muscle inflammation, which contrasts with recent safety concerns in the gene therapy space, including a liver failure death reported by Sarepta in a teenage patient in March.

About RGX-202
RGX-202 is a potential best-in-class investigational gene therapy designed for improved function and outcomes in Duchenne. RGX-202 is the only gene therapy approved or in late-stage development for Duchenne with a differentiated microdystrophin construct that encodes key regions of naturally occurring dystrophin, including the C-Terminal (CT) domain. RGX-202 is designed to support the delivery and targeted expression of microdystrophin throughout skeletal and heart muscle using the  AAV8 vector and a well-characterized muscle-specific promoter (Spc5-12).