ELEVIDYS demonstrates sustained functional benefit through 3 years in ambulatory Duchenne muscular dystrophy

Sarepta Therapeutics announced positive topline three-year functional results from Part 1–treated patients in the phase 3 EMBARK trial evaluating ELEVIDYS (delandistrogene moxeparvovec-rokl) in ambulatory individuals with Duchenne muscular dystrophy (DMD).¹ The announcement builds on previously published 2-year EMBARK outcomes demonstrating stabilization or slowing of disease progression compared with a propensity-weighted external control cohort.²

EMBARK (Study SRP-9001-301) is a multinational, randomized, placebo-controlled, two-part crossover phase 3 trial assessing a single intravenous dose of delandistrogene moxeparvovec (1.33 × 10^14 vector genomes/kg) in ambulatory boys aged 4 to younger than 8 years at treatment. The primary endpoint was the change from baseline in North Star Ambulatory Assessment (NSAA) total score at week 52. Following completion of the blinded crossover period, longer-term efficacy has been evaluated using a pre-specified external control (EC) comparison because a placebo arm was not maintained beyond 1 year.²

According to the company, 3 years after treatment, patients who received ELEVIDYS in Part 1 of EMBARK demonstrated statistically significant and durable benefit across key motor function measures, including NSAA, Time to Rise (TTR), and 10-meter walk/run (10MWR), compared with a propensity-weighted untreated EC group. At a mean age of approximately 9 years at last assessment, mean NSAA scores in the treated cohort remained above baseline, while EC patients showed the expected age-related decline. The company reported a 73% slowing of disease progression as measured by TTR and a 70% slowing as measured by 10MWR relative to EC patients.

“ELEVIDYS is the first gene therapy for Duchenne to show a dramatic shift in disease trajectory out to 3 years consistent with earlier long-term data extending up to five years,” said Louise Rodino-Klapac, PhD, president of research & development and technical operations at Sarepta Therapeutics, in the press release. “This is long-term data in a robust, controlled clinical dataset that demonstrates the power of a disease-modifying therapy targeting the underlying cause of Duchenne,” she said.

The 3-year topline findings extend the peer-reviewed 2-year EMBARK analysis published in Neurology & Therapy, which reported statistically significant benefit versus the EC cohort for functional outcomes prognostic for delayed loss of ambulation, including NSAA, TTR, and 10MWR. In that analysis, patients treated with delandistrogene moxeparvovec showed stabilization or slowing of disease progression through week 104, while matched EC patients continued to decline. Sustained micro-dystrophin expression and sarcolemmal localization were also observed through 64 weeks, supporting the biologic durability of the therapy.

Safety findings at three years were consistent with earlier EMBARK results. Sarepta reported no new treatment-related safety signals in ambulatory patients, reinforcing what the company described as a manageable safety profile with appropriate monitoring. In the 2-year published analysis, no treatment-related deaths, discontinuations due to adverse events, or clinically significant complement-mediated adverse events were observed between weeks 52 and 104, with adverse events occurring predominantly in the early post-infusion period.

Clinical investigators emphasized the relevance of longer-term functional data for patient care. “As a pediatric neurologist, I spend time with families who are doing everything they can to help their children stay strong in the face of Duchenne,” said Crystal Proud, MD, chief of Neurology and director of Neuromuscular Medicine at Children’s Hospital of The King’s Daughters and an EMBARK investigator. “The EMBARK results give us a clearer picture of how treatment with ELEVIDYS can make a meaningful difference over time, and they reflect what I see in clinical practice–helping boys perform everyday movements, such as standing, walking, and running with greater strength and speed than what we expect as Duchenne progresses without a disease-modifying treatment,” she said.

ELEVIDYS is an adeno-associated virus–based gene transfer therapy designed to address the underlying genetic cause of DMD by delivering a micro-dystrophin transgene. It is currently indicated in the United States for ambulatory patients aged 4 years and older with a confirmed DMD gene mutation. Sarepta reported that more than 1,200 patients have received ELEVIDYS globally in clinical and real-world settings to date

Analysis of the 3-year EMBARK data is ongoing, including outcomes from crossover-treated patients, with additional presentations and publications planned. Together, the three-year topline results and the previously published 2-year EMBARK findings contribute to the growing body of long-term evidence evaluating disease-modifying gene therapy for ambulatory patients with Duchenne muscular dystrophy.

References

1. Sarepta. Sarepta Announces Positive Topline Three-Year EMBARK Results Showing ELEVIDYS Significantly Slows Disease Progression on Key Functional Measures in Ambulatory Duchenne Patients. Sarepta. January 26, 2026. Accessed January 28, 2026. https://investorrelations.sarepta.com/news-releases/news-release-details/sarepta-announces-positive-topline-three-year-embark-results
2. Mendell JR, Muntoni F, McDonald CM, et al. Two-Year Outcomes Following Delandistrogene Moxeparvovec Treatment in Ambulatory Patients with Duchenne Muscular Dystrophy: Phase 3 EMBARK Trial. Neurology and Therapy. Published online January 10, 2026. doi:https://doi.org/10.1007/s40120-025-00879-8