Phase 2 Study of EDG-5506 in Becker Muscular Dystrophy (GRAND CANYON)

A study of sevasemten (EDG-5506) in Becker muscular dystrophy (known as CANYON) and pivotal cohort (known as GRAND CANYON). The EDG-5506-201 CANYON study was expanded to include an additional 120 adult participants in a cohort called GRAND CANYON, that is a multicenter, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of sevasemten in adults with Becker. CANYON and GRAND CANYON are fully enrolled.

The CANYON Study including the adolescent cohorts are fully enrolled. GRAND CANYON eligibility is listed below. Key Inclusion Criteria: 1. Adults (aged 18 to 50 years, inclusive) with a documented dystrophin mutation and phenotype consistent with Becker muscular dystrophy, and history of being ambulatory beyond 16 years of age without steroids; history of being ambulatory beyond 18 years of age with steroids. 2. Able to complete the 100-meter timed test in \< 200 seconds with or without use of mobility aid devices. 3. Able to perform the North Star Ambulatory Assessment scale and achieve a score of 5 to 32, inclusive. Key Exclusion Criteria: 1. Medical history or clinically significant physical examination/laboratory result that, in the opinion of the investigator, would render the participant unsuitable for the study. This includes contraindications to magnetic resonance imaging such as non-compatible implanted medical devices or severe claustrophobia. 2. Cardiac echocardiogram ejection fraction \< 40% 3. Forced vital capacity predicted \