Cambridge, Mass. — Sarepta Therapeutics presented new data showing Elevidys provided durable functional benefits in older ambulatory patients with Duchenne muscular dystrophy, while separate findings showed strong micro-dystrophin expression in younger children.
The data were presented at the 31st Annual Congress of the World Muscle Society and included analyses of patients treated with Elevidys, also known as delandistrogene moxeparvovec, at different stages of Duchenne muscular dystrophy.
In one analysis, patients from the EMBARK and ENDEAVOR studies who were ages 8 to 12 at the time of treatment were compared with a matched external control group. Sarepta said treatment produced durable and clinically meaningful benefits over two years across the North Star Ambulatory Assessment and timed function measures.
Patients treated with Elevidys showed a 3.32-point difference in North Star Ambulatory Assessment scores compared with the external control group, along with improvements in time-to-rise-from-floor velocity and 10-meter walk/run velocity.
The company said clinically meaningful efficacy was observed across all three measures at one and two years after infusion, with nominally statistically significant differences between treated patients and the external control group.
“The period between 8 and 12 years of age represents a critical phase of Duchenne when many boys transition from relative stability to progressive functional decline,” said Louise Rodino-Klapac, Ph.D., President of Research & Development and Technical Operations at Sarepta.
“Results presented at WMS 2026 fit within a broader and increasingly consistent body of evidence generated across the clinical development program. Seeing similar patterns emerge across ambulatory Duchenne populations reinforce that timely treatment with delandistrogene moxeparvovec has the potential to meaningfully change the trajectory of the disease,” she added.
Safety in the older ambulatory patient group was described as manageable and consistent with the known safety profile of Elevidys. The most common treatment-related adverse events were nausea and vomiting.
Sarepta also presented separate data involving children ages 2 to under 3 from the ENDEAVOR and ENVOL studies. The analysis showed robust delandistrogene moxeparvovec-dystrophin expression and sarcolemmal localization 12 weeks after treatment.
Investigators observed higher average and minimum micro-dystrophin expression in these younger patients compared with previously reported results in older ambulatory and non-ambulatory patients. The children will continue to be followed to assess functional outcomes over time.
“The older ambulatory patient data demonstrate that delandistrogene moxeparvovec treatment can provide functional benefit that’s statistically significant at a stage when decline often becomes more pronounced,” said Craig McDonald, M.D., Professor and Chair of the UC Davis Health Department of Physical Medicine and Rehabilitation and an investigator in the EMBARK and ENDEAVOR studies.
“In addition, the findings in younger children help us better understand the biological effects of treatment earlier in the disease course where preserving muscle may offer the greater opportunity for long-term benefit. While measures of expression provide important biological evidence, long-term functional outcomes remain the most meaningful way to understand the impact of treatment for patients and families,” McDonald added.
The safety profile in the younger patients was also described as manageable and consistent with results seen in ambulatory patients ages 4 and older. Sarepta noted that use of delandistrogene moxeparvovec in patients under age 4 remains investigational and has not been evaluated by regulatory authorities for safety and efficacy.
EMBARK was a multinational Phase 3 randomized, placebo-controlled study of Elevidys in patients ages 4 to 7, while ENDEAVOR is an open-label Phase 1b study evaluating safety and micro-dystrophin expression across several groups of patients with Duchenne. ENVOL is an open-label Phase 2 study evaluating Elevidys in young children.
