REGENXBIO (NASDAQ:RGNX) shared positive interim data from its Phase I/II AFFINITY DUCHENNE trial on Wednesday, bolstering the case for its gene therapy candidate, RGX-202.
The data, reflecting a cutoff of Jan. 5, 2026, focused on participants receiving the pivotal dose of 2x10^14 GC/kg, a cohort that has demonstrated significant functional improvements compared to external natural history controls.
Clinical outcomes measured by the North Star Ambulatory Assessment (NSAA) showed a mean improvement of +4.9 points at one year compared to the cTAP external control group.
Notably, the effect was even more pronounced in older participants (aged 8 and above), who saw a +5.2 point improvement.
Cardiac MRI measures remained stable across the cohort, a critical metric for Duchenne patients who often face progressive heart muscle weakening.
The safety profile for RGX-202 appears increasingly robust.
The company reported no serious adverse events (SAEs) or adverse events of special interest (AESIs).
Liver markers—frequently a point of concern in high-dose AAV gene therapies—remained below thresholds that would necessitate clinical intervention.
On the biomarker front, REGENXBIO reported consistent microdystrophin expression across treated patients.
New data highlighted one specific patient reaching 51.2% expression by Week 12.
These biological markers, combined with the functional gains, suggest the therapy is successfully delivering its genetic payload to the targeted muscle tissues.
The company remains on an aggressive regulatory trajectory.
Topline pivotal data is expected in Q2 2026, with a pre-Biologics License Application (BLA) meeting with the FDA planned for mid-2026.
If the data holds, REGENXBIO could emerge as a major competitor in a gene therapy landscape currently led by Sarepta Therapeutics.