Sarepta Therapeutics (SRPT) investor relations material

Study design and methodology

• EMBARK is a global, double-blind, placebo-controlled Phase 3 trial in ambulatory Duchenne muscular dystrophy patients aged 4–7, with 125 participants randomized and a primary readout at one year, followed by crossover and up to five years of follow-up.

• Three-year data were collected from patients initially treated in Part 1 and followed in a long-term extension, using a propensity-weighted external control for comparison.

• Key functional endpoints included North Star Ambulatory Assessment (NSAA), time to arise (TTR), and 10-meter walk/run (10MWR), all pre-specified as co-primary outcomes.

• External controls were rigorously matched from contemporary natural history and placebo-armed studies, ensuring comparability and balanced baseline covariates.

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

Efficacy results

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

• Statistically significant 73% slowing of disease progression on TTR and 70% on 10MWR compared to controls, with a 6.05-second TTR and 2.7-second 10MWR benefit at year 3.

• The functional gap between treated and control groups increased over time, with treated patients, average age nine, remaining above baseline function at three years.

• Only two treated patients lost ambulation over three years, about half the rate seen in external controls.

• Analysis used least squares mean by MMRM for efficacy endpoints.

Safety and tolerability

• No new safety signals or treatment-related serious adverse events were observed in year three; safety profile remains consistent with prior data.

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

• 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.

• Ongoing safety monitoring and planned future publications will keep the community informed.