CAMBRIDGE, Mass., March 16, 2026 — Sarepta Therapeutics announced that screening and enrollment are underway for Cohort 8 of the ENDEAVOR trial (Study SRP-9001-103), evaluating an enhanced immunosuppressive regimen alongside its AAV gene therapy ELEVIDYS in non-ambulatory patients with Duchenne muscular dystrophy (DMD).
The new cohort is designed to assess whether prophylactic treatment with sirolimus can reduce the risk of acute liver injury (ALI) and acute liver failure (ALF)—known safety concerns associated with systemic AAV gene therapy. Approximately 25 non-ambulatory patients in the U.S. are expected to enroll.
Under the updated protocol, patients will receive peri-infusion sirolimus for 14 days prior to ELEVIDYS administration, followed by continued dosing for 12 weeks post-infusion. The study will evaluate key endpoints including the incidence of ALI and micro-dystrophin expression at 12 weeks, providing critical insights into both safety and therapeutic activity.
ENDEAVOR is an open-label Phase 1b study that has enrolled 55 participants across multiple cohorts, including younger ambulatory patients, older ambulatory individuals, and now non-ambulatory patients. The trial aims to better understand how AAV-mediated gene transfer performs across different stages of Duchenne disease progression.
ELEVIDYS is a single-dose AAV-based gene therapy designed to deliver a micro-dystrophin transgene to skeletal muscle, addressing the underlying genetic cause of DMD. To date, the therapy has been administered to over 1,200 patients globally across clinical and real-world settings and remains the only approved gene therapy for Duchenne muscular dystrophy.
Sarepta noted that data from Cohort 8 will help refine safety management strategies, particularly in older, non-ambulatory patients with advanced disease, where treatment options remain limited. The study reflects a broader industry focus on improving the safety profile of systemic AAV therapies, especially through optimized immune modulation approaches.
