Regenxbio recently announced promising clinical evidence showing improved muscle function in boys with Duchenne muscular dystrophy (DMD) following treatment with their gene therapy, RGX-202.

The FDA has approved a smaller, open-label trial with historical controls for Regenxbio, marking a significant shift that streamlines the approval process for microdystrophin therapies.

The existing Phase 1/2 study has been expanded into a pivotal trial aimed at supporting accelerated approval, which will involve approximately 30 patients aged at least one year.

In consultation with the FDA, Regenxbio is preparing to submit an accelerated approval application for RGX-202 in 2026.

Preliminary results from the trial indicate stabilization or improvement in motor function, as measured by the North Star Ambulatory Assessment (NSAA), with no serious adverse events reported.

Common side effects noted include nausea, vomiting, and fatigue, suggesting a manageable safety profile for RGX-202.

RGX-202 is designed to produce microdystrophin and a larger version of the dystrophin protein, potentially enhancing muscle function in DMD patients.

Early data shows that RGX-202 may achieve higher microdystrophin levels compared to those seen in Sarepta's trials, particularly in children aged eight and older.

Regenxbio is emerging as a significant competitor to Sarepta's Elevidys, especially following setbacks faced by Sarepta and Pfizer in the DMD gene therapy market.

The study design has deprioritized NSAA scores, leading to discussions among analysts about the adequacy of current assessment methods for measuring treatment efficacy.

If approved, RGX-202 could become the second genetic treatment available for DMD, following the accelerated approval of Sarepta Therapeutics’ Elevidys in June 2023.

Following the announcement of positive results, Regenxbio's shares rose approximately 11% in early trading, reflecting investor optimism regarding the new trial path.