Cambridge, Mass. — Sarepta Therapeutics (NASDAQ: SRPT) has released new data from its ongoing ENDEAVOR clinical trial, highlighting strong protein expression and a consistent safety profile for ELEVIDYS (delandistrogene moxeparvovec-rokl), its gene therapy treatment for Duchenne muscular dystrophy (DMD) in very young children.
In the latest update from Cohort 6 of the trial, six participants who were 2 years old at the time of treatment showed an average of 93.87% protein expression, measured via western blot, and nearly 80% dystrophin-positive fibers (PDPF), based on immunofluorescence analysis. These results were based on muscle biopsies taken 12 weeks after treatment.
The safety data from this youngest cohort was consistent with previous ELEVIDYS studies and real-world usage. The most commonly reported side effects were nausea and vomiting, with two cases of elevated liver enzymes that were successfully managed using steroids.
“These biomarker results in younger patients are extremely encouraging,” said Dr. Louise Rodino-Klapac, Sarepta’s Chief Scientific Officer and Head of R&D. “We’re preparing to meet with the FDA next month to discuss a potential label expansion to include these younger age groups.”
The company previously reported data from Cohort 4, which included 3-year-old participants. That group showed even higher mean protein expression of 99.64%, also measured 12 weeks post-treatment. To date, over 25 children under age 4 have received ELEVIDYS in clinical studies, further supporting the therapy’s safety and effectiveness in early childhood.
The ENDEAVOR study (Study 9001-103) is a multi-cohort clinical trial evaluating ELEVIDYS in boys with DMD, a rare and progressive genetic disorder characterized by muscle degeneration and weakness. Sarepta is aiming to expand access to the therapy, particularly for younger patients, where early intervention may yield the greatest benefit.
ELEVIDYS is Sarepta’s gene therapy designed to deliver a shortened, functional version of the dystrophin gene—mutations of which cause Duchenne muscular dystrophy. The therapy received accelerated FDA approval in 2023 for ambulatory DMD patients aged 4 to 5 years. Sarepta is now seeking to broaden that indication based on continued clinical progress.
