Sarepta's ELEVIDYS Demonstrates Sustained Skeletal Function Preservation in Duchenne Patients Through Three-Year EMBARK Follow-Up

Sarepta Therapeutics has announced remarkable three-year outcomes from its EMBARK clinical trial, revealing that ELEVIDYS significantly decelerates disease progression in ambulatory boys with Duchenne muscular dystrophy. The gene therapy’s sustained efficacy across skeletal muscle function measures marks a transformative milestone for patients facing this severe neuromuscular disorder, offering hope for preserving mobility during critical developmental years.

Duchenne muscular dystrophy represents one of the most challenging pediatric neuromuscular conditions, resulting from mutations in the DMD gene that eliminate dystrophin production. This absence of a critical structural protein leads to progressive skeletal muscle degeneration. Most children experience dramatic functional decline between ages 7 and 10—a vulnerable window when deterioration in walking ability, floor-rising capacity, and daily movement skills can be rapid and devastating.

How ELEVIDYS Protects Skeletal Muscle Function Across Critical Years

The three-year dataset emerges from Part 1 of EMBARK, a global Phase 3 randomized controlled trial enrolling ambulatory boys aged 4-7 at baseline. The primary endpoint measured changes in the North Star Ambulatory Assessment at Week 52, with researchers tracking skeletal muscle performance metrics over an extended three-year observation period. Among 64 patients initially treated with ELEVIDYS, 52 continue participating in ongoing follow-up studies, providing substantial real-world evidence of treatment durability.

ELEVIDYS operates as a single-dose, AAV-based gene therapy that delivers a micro-dystrophin transgene directly to skeletal muscle tissue. This approach restores partial dystrophin function, enabling muscle fibers to resist progressive degeneration more effectively than the natural disease course. The three-year follow-up period captures the critical window when untreated Duchenne typically accelerates dramatically.

Marked Slowing of Disease Progression in Ambulatory Patients

The trial results demonstrate consistent therapeutic advantages across multiple functional assessment tools. When compared to a propensity-weighted external control group, ELEVIDYS-treated patients showed:

• North Star Ambulatory Assessment scores remained above baseline levels at Year 3, while control participants experienced expected declines
• Time to Rise performance deteriorated 73% more slowly in treated patients
• 10-meter walk/run velocity declined 70% more slowly in the treatment group

Notably, the therapeutic benefit diverged increasingly from the expected disease trajectory between Years 2 and 3, suggesting that the protective effect on skeletal muscle strengthens over the treatment period rather than diminishing. Safety monitoring confirmed that the tolerability profile remained consistent with prior experience in ambulatory Duchenne patients, with no unexpected adverse signals emerging through the extended follow-up.

Expanding Global Access to Duchenne Gene Therapy Through Strategic Partnerships

ELEVIDYS achieved FDA approval with an updated label in late 2025 for ambulatory individuals aged 4 and older, following successful Phase 3 trial completion. This represents the first and only gene therapy approved specifically for Duchenne muscular dystrophy, offering a mechanistic breakthrough in an area where treatment options were previously limited to symptom management.

Sarepta’s collaboration with Roche extends ELEVIDYS access beyond the United States, with Roche managing regulatory pathways and commercialization across international markets. This partnership has already enabled administration of ELEVIDYS to more than 1,200 patients in clinical trials and real-world treatment settings globally. The expanded reach accelerates access for families who previously faced limited options for addressing the underlying skeletal muscle degeneration driving Duchenne progression.

What Long-Term Data Means for Duchenne Patients

The three-year EMBARK results carry profound clinical significance. For children in the critical 7-10 age window, maintaining ambulatory function represents the difference between preserved independence and wheelchair dependence. By decelerating skeletal muscle deterioration, ELEVIDYS extends the window of mobility, potentially allowing patients to participate in school, physical activities, and social interactions with greater independence.

Sarepta plans to present comprehensive three-year datasets at upcoming medical conferences and pursue additional peer-reviewed publications detailing mechanistic insights and long-term outcomes. Previous EMBARK interim analyses—including one-year results published in Nature Medicine and two-year data appearing in Neurology and Therapy—have established the therapeutic foundation that these latest data reinforce. Patients enrolled in EMBARK remain eligible for EXPEDITION, a dedicated long-term follow-up study tracking skeletal function preservation and overall health trajectories beyond the initial trial period.

These sustained results underscore gene therapy’s transformative potential for preserving skeletal muscle function in Duchenne, reshaping treatment expectations for patients and families navigating this progressive disorder.