Sarepta Therapeutics Advances Safety Protocol in Duchenne Gene Therapy Trial

Sarepta adds sirolimus regimen to its ENDEAVOR study for DMD, aiming to reduce liver injury risk in non-ambulatory patients and strengthen the therapy's safety profile.

Sarepta Therapeutics is refining the safety profile of its gene therapy, ELEVIDYS, through a strategic update to its ongoing clinical program. The company has initiated screening for an eighth cohort in its ENDEAVOR study, placing a heightened emphasis on managing potential risks for patients with Duchenne muscular dystrophy (DMD).

Study Design Targets Liver Safety

At the core of this new phase is a modified treatment regimen. The cohort, for which patient screening began on March 16, will enroll approximately 25 non-ambulatory participants in the United States. This patient population frequently has limited therapeutic options, making enhanced safety measures a critical priority.

The revised protocol introduces the immunosuppressant sirolimus. Administration will start 14 days prior to the ELEVIDYS infusion and continue for a total of twelve weeks post-treatment. This approach is designed to mitigate the risk of acute liver injury, a recognized challenge associated with adeno-associated virus (AAV)-delivered gene therapies. Following the twelve-week period, researchers will also measure dystrophin expression to assess the therapy's efficacy under the new supportive medication.

Competitive Landscape and Strategic Implications

ELEVIDYS has already been administered to more than 1,200 patients. The expansion of the ENDEAVOR trial underscores Sarepta's effort to strengthen its market position within a competitive field where multiple firms are pursuing genetic treatments for DMD. Clinical differentiation, particularly regarding safety and tolerability, remains a decisive factor.

For industry observers, the proactive management of safety risks is a key component in evaluating the long-term potential of a therapeutic platform. Successfully minimizing liver-related adverse events could significantly improve the therapy's therapeutic index—the balance between its efficacy and safety.

The outcomes from this cohort, focusing on safety data and protein expression, will help determine the regulatory pathway for ELEVIDYS in non-ambulatory patients. By targeting this group, Sarepta is addressing an area of high unmet medical need where clinical progress and additional safety assurances are especially urgent.