Regenxbio’s RGX-202 shows efficacy in Phase 3 Duchenne trial

Regenxbio (RGNX) announced positive topline and interim functional data from the pivotal Phase III portion of the Phase I/II/III AFFINITY DUCHENNE trial of RGX-202, a potential best-in-class gene therapy for Duchenne Muscular Dystrophy. The trial met its primary endpoint with high statistical significance, with 93% of participants reaching at least 10% microdystrophin expression at Week 12. Additionally, RGX-202 demonstrated statistically significant correlation between microdystrophin expression and interim functional improvement. The company expects to have completed dosing in all 60 patients across the pivotal and confirmatory trials by mid-year. 93% of participants achieved greater than10% RGX-202 microdystrophin expression at Week 12. Microdystrophin expression averaged 71.1% across all participants, and 41.6% in older boys, aged greater than8 years. Additionally, 80% of participants achieved greater than40% microdystrophin expression. RGX-202 was appropriately localized to the sarcolemma. RGX-202 was well tolerated and demonstrated a favorable safety profile as of last data cut. Two serious adverse events were reported; both were easily managed and resolved within weeks without sequelae. Participants demonstrated statistically significant improved performance across NSAA and all timed function tests. Regenxbio plans to pursue accelerated approval for RGX-202 and is preparing for a potential commercial launch in 2027.