by: Parent Project Muscular Dystrophy
Today, REGENXBIO announced new data from its ongoing Phase I/II AFFINITY DUCHENNE® trial of RGX-202, an investigational gene therapy being developed for individuals with Duchenne muscular dystrophy. RGX-202 is designed to deliver microdystrophin via AAV8 through a one-time IV infusion.
The newly released data comes from boys treated at the higher of two doses (2×1014 GC/kg). Early data indicates positive trends in functional and biopsy data (quantifying microdystrophin expression and biodistribution); functional results showed improved performance on North Star Ambulatory Assessment and timed function tests compared to natural history controls. Additionally, results indicate that RGX-202 is well tolerated with a favorable safety profile.
According to REGENXBIO, the company plans to submit an application for FDA approval in mid-2026 via the accelerated approval pathway and continues to enroll participants in the study. To learn more about the AFFINITY DUCHENNE trial, visit regenxbiodmdtrials.com.
REGENXBIO will be joining us in two weeks at PPMD’s 2025 Annual Conference to connect with families and provide additional updates. View the agenda and register for the event here.
Read REGENXBIO’s press release here.
Read REGENXBIO’s community letter:
Dear Duchenne Community,
We are writing to provide an update on RGX-202*, REGENXBIO’s investigational gene therapy for the treatment of Duchenne muscular dystrophy (Duchenne).
REGENXBIO issued a press release on June 5th sharing new positive interim data from the Phase 1/2 portion of the AFFINITY DUCHENNE® study of RGX-202. AFFINITY DUCHENNE is a Phase 1/2/3 study currently enrolling patients. New data include safety, biomarker, and functional (outcomes) interim results. (REGENXBIO RGX-202 press release – June 5, 2025)
RGX-202 Phase 1/2 AFFINITY DUCHENNE Data Update – as of May 7, 2025
Safety
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- RGX-202 was well tolerated in 13 study participants across both dose levels with no serious adverse events (SAEs) and no AEs of special interest (AESI) reported. Common drug-related AEs included nausea, vomiting and fatigue, all typically anticipated with administration of a gene therapy.
Function
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- Interim functional results were reported for study patients approximately 6 to 12 years of age at dosing who received dose level 2 (our pivotal dose) of RGX-202 and reached their 9-month (n=5) or 12-month (n=4 of the 5) assessments.
- RGX-202 continues to demonstrate evidence of positively impacting the course of Duchenne.
- Dose level 2 patients demonstrated improved performance at 9 and 12 months on the North Star Ambulatory Assessment (NSAA) and timed function tests (Time to Stand, 10 Meter Walk-run, Time to Climb), exceeding available external natural history controls that were matched for both age and baseline function.
Biomarker
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- Biomarker data from the Phase 1/2 study continues to support consistent, robust expression and transduction of RGX-202 microdystrophin.
Program Status
The AFFINITY DUCHENNE trial is enrolling eligible participants in the Phase 3 (pivotal) portion of the trial with study centers in the U.S. and Canada. The trial is expected to enroll approximately 30 patients to support an anticipated U.S. Biologics License Application (BLA) submission using the FDA’s accelerated approval pathway in mid-2026. After the last participant is dosed, enrollment into the confirmatory study is expected to be initiated.
For more information
To learn more about RGX-202 and the AFFINITY DUCHENNE trial, visit https://regenxbiodmdtrials.com/. You may also visit clinicaltrials.gov https://clinicaltrials.gov/study/NCT05693142.
We appreciate the patients, families, clinicians and advocacy organizations who have supported our program and look forward to sharing additional updates.
Warm regards,
The REGENXBIO Team
*RGX-202 is investigational and not approved for use by any regulatory agency.
This letter contains forward-looking statements, which are subject to risks and uncertainties. Actual outcomes may differ. Please refer to our SEC filings for more information.
