RGX-202 Gene Therapy Shows Promise for‍ Duchenne ⁤muscular⁤ Dystrophy

‍ Updated june 13, 2025

An interim analysis of the phase 1/2 AFFINITY‍ DUCHENNE trial indicates that RGX-202, an experimental gene therapy, demonstrates consistent efficacy for Duchenne muscular dystrophy (DMD). REGENXBIO, the therapy’s developer, reported the findings, which are based on ⁢functional and biomarker data.

The interim results, gathered from the first five participants in ⁤the dose level 2 cohort (2×10¹⁴ ‍GC/kg), revealed consistent⁤ benefits at both 9 and 12 months following treatment with RGX-202, when compared to natural history controls. researchers expected that four of the five participants, aged 6 to 12 years at the start of the trial, would experience a decline in their condition. however, those receiving RGX-202 showed improvements⁤ in the north Star Ambulatory Assessment (NSAA) and in timed function tests, such as time to stand, 10-meter walk-run, and time to ‍climb.

REGENXBIO’s chief medical officer, Dr.⁢ Steve Pakola, stated that the findings suggest RGX-202 has the potential⁤ to alter the course of Duchenne and provide significant benefits to patients.He noted the striking outperformance of RGX-202 participants compared to natural history across key measures, including the North Star Ambulatory Assessment, particularly in older patients. The company plans to⁤ submit a Biologics License Request under accelerated approval in mid-2026.

Today’s findings support the potential of RGX-202 to positively change the ‍disease course for Duchenne and meaningfully benefit patients living with this degenerative disease. We are particularly encouraged by the outperformance observed in older patients.

Patients treated with RGX-202 showed⁢ functional ‍advancement across all measures. At 9 months ‍post-dosing, the average improvement in‍ NSAA among treated patients was⁤ 4 points from baseline and 4.8⁢ points compared with natural history⁢ controls. Results at 12 months post-dosing among ⁢four of five patients were similar to the 9-month results, ⁤with improvement in all timed function tests vs baseline. Patients improved an average of 4.5 points from baseline in the NSAA⁢ and 6.8 points compared with natural history controls.

Changes in timed task velocity also surpassed minimal clinically important ⁢difference ⁤benchmarks at 12 months in the RGX-202 cohort.

Biomarker data has demonstrated consistent and high expression of RGX-202 microdystrophin. The primary endpoint in the pivotal phase of the AFFINITY DUCHENNE study is the⁤ proportion of participants whose RGX-202 microdystrophin expression is at least 10% at week‍ 12. One ‍patient, who was 2 ⁤years old at dosing, showed a microdystrophin expression ⁤level of 118.6% compared to the natural history control.

No serious adverse events (AEs) or AEs of⁣ special interest were reported. The ⁤most common drug-related AEs were nausea, ‍vomiting, and fatigue, all typical with gene therapy administration. REGENXBIO suggests that a proactive,⁢ short-course immune modulation regimen, combined with a differentiated construct and high product purity‍ levels, ⁢may contribute to RGX-202’s favorable safety profile.

These findings suggest ⁣that the microdystrophin expression observed with RGX-202 is leading to meaningful ⁤functional improvements, even in individuals with DMD who are expected to experience functional decline. I’m enthusiastic about the continued progress of RGX-202 and the promise⁣ it holds for the⁣ Duchenne community.

The pivotal phase 3 portion of the‍ AFFINITY‍ DUCHENNE TRIAL,aiming to enroll approximately 30 participants,is ongoing.

What’s next

The ongoing phase 3 trial will further evaluate the efficacy and safety of RGX-202 gene therapy for⁢ Duchenne muscular dystrophy. Researchers hope to confirm these promising early results and bring a new treatment option to patients.