Sarepta Therapeutics (SRPT) Study result summary

Study design and methodology

• EMBARK is a global, double-blind, placebo-controlled Phase 3 trial evaluating ELEVIDYS in ambulatory boys aged 4–7 with Duchenne muscular dystrophy, with 125 patients randomized and a three-year follow-up for functional outcomes.

• After year one, all participants received ELEVIDYS, and comparisons for years two and three used a propensity-weighted external control group matched for baseline characteristics.

• Key inclusion criteria included NSAA score 17–28 and time to rise <5 seconds at screening.

• Over 1,200 patients have been treated with ELEVIDYS across clinical and commercial settings, providing a robust data set.

• The study used least squares mean by MMRM for efficacy endpoints and balanced baseline covariates between treated and control groups.

Efficacy results

• At three years, ELEVIDYS-treated patients maintained mean NSAA scores above baseline, while external controls declined, with a 4.39-point NSAA advantage (p=0.0002).

• Statistically significant 73% slowing of disease progression on time to rise (TTR) and 70% on 10-meter walk/run (10MWR) compared to controls, with a 6.05-second TTR and 2.7-second 10MWR benefit at year three.

• The functional gap between treated and control groups increased over time, with only two treated patients losing ambulation over three years, about half the rate seen in controls.

• MRI data showed stabilization of muscle fat fraction in treated patients over two years, compared to increases in placebo.

• The three-year analysis included pre-specified endpoints: NSAA, time to arise, and 10-meter walk/run, using contemporary natural history and placebo-arm data for external controls.

Safety and tolerability

• No new safety signals or treatment-related serious adverse events were observed in year three; safety profile remained consistent with known risks.

• Common adverse reactions included vomiting, nausea, liver injury, fever, thrombocytopenia, and increased troponin-I.

• Boxed warning for acute serious liver injury and acute liver failure; monitoring and corticosteroid use are required.

• Cardiac function remained within normal range through two years, with year-three data pending analysis.

• No treatment-related deaths reported; one unrelated death disclosed.