REGENXBIO REPORTS NEW POSITIVE FUNCTIONAL DATA FROM PHASE I/II AFFINITY DUCHENNE® TRIAL OF RGX-202

Core Insights - REGENXBIO Inc. announced positive interim data from the Phase I/II AFFINITY DUCHENNE trial for RGX-202, a gene therapy for Duchenne muscular dystrophy, showing consistent functional benefits and safety [1][2][3] Functional Data - RGX-202 participants at dose level 2 (2x10^14 GC/kg) showed significant functional improvements at both 9 and 12 months, exceeding natural history controls on key measures such as the North Star Ambulatory Assessment (NSAA) [4][5] - At 9 months, participants improved an average of 4 points from baseline on NSAA, and at 12 months, the improvement was 4.5 points from baseline, with a 6.8-point increase compared to natural history [5][6] Biomarker Data - Biomarker data indicated robust microdystrophin expression, with one participant aged 2 showing an expression level of 118.6% compared to control [8][10] - The primary endpoint for the pivotal phase is the proportion of participants with microdystrophin expression ≥10% at Week 12 [8] Safety and Tolerability - RGX-202 demonstrated a favorable safety profile with no serious adverse events reported, and common drug-related adverse events included nausea, vomiting, and fatigue [11][12] - The proactive immune modulation regimen and high product purity levels contributed to the positive safety outcomes [11] Pivotal Trial and Future Plans - REGENXBIO is enrolling participants for the pivotal portion of the AFFINITY DUCHENNE trial, aiming to support a Biologics License Application (BLA) submission under accelerated approval by mid-2026 [14][15] - The company plans to share top-line data in the first half of 2026, including biomarker, functional, and safety data [15] About RGX-202 - RGX-202 is designed to improve function and outcomes in Duchenne muscular dystrophy, utilizing a differentiated microdystrophin construct that encodes key regions of dystrophin [17][18] - The therapy aims to support targeted expression of microdystrophin throughout skeletal and heart muscle using the NAV® AAV8 vector [18] About Duchenne Muscular Dystrophy - Duchenne muscular dystrophy is a severe, progressive muscle disease affecting 1 in 3,500 to 5,000 boys born each year, caused by mutations in the dystrophin gene [19] About REGENXBIO Inc. - REGENXBIO is a biotechnology company focused on gene therapy, with a late-stage pipeline including RGX-202 for Duchenne and other investigational therapies for rare diseases [20]