Sarepta Therapeutics (NASDAQ:SRPT) released long-term data on Monday that bolsters the clinical case for Elevidys, its pioneering gene therapy for Duchenne muscular dystrophy (DMD).
Three-year results from the Phase 3 EMBARK study showed that patients who received the one-time treatment maintained significantly higher levels of motor function compared to an untreated external control group, potentially quieting long-standing debates regarding the therapy's durability.
The data focused on patients who were aged four to seven at the time of treatment and have now reached an average age of over nine—a period when children with Duchenne typically begin to show visible physical decline.
According to the Cambridge, Massachusetts-based biotech, Elevidys-treated patients demonstrated a 73% slowing of disease progression in "Time to Rise" and a 70% slowing in the "10-meter walk/run" test when compared to the control group.
Most notably, the mean North Star Ambulatory Assessment (NSAA) score—a key metric for motor function in Duchenne—remained above baseline for the treated group three years post-administration.
In contrast, the control group followed the expected natural history of the disease, showing a steady decline below their baseline scores.
Elevidys currently stands as the only approved gene therapy for Duchenne, a rare and fatal muscle-wasting disease that primarily affects boys.
The latest clinical update follows a pivotal label expansion granted by the U.S. Food and Drug Administration at the end of 2025, which opened the therapy to ambulatory individuals aged four and older.
To date, more than 1,200 patients have been treated globally across clinical and real-world settings.
The success of Elevidys is also a major milestone for Swiss pharmaceutical giant Roche, which partnered with Sarepta in 2019.
Under the agreement, Sarepta manages U.S. commercialization and manufacturing, while Roche handles regulatory approvals and distribution across the rest of the world.
In Japan, the therapy is commercialized through Roche subsidiary Chugai Pharmaceuticals.
These findings are likely to strengthen Sarepta's position as it continues to roll out the high-priced therapy globally.