A Study of EDG-5506 in Children With Duchenne Muscular Dystrophy (LYNX)

This is a 2-part, multi-center, Phase 2 study to evaluate the effect of sevasemten (EDG-5506) on safety, pharmacokinetics and biomarkers of muscle damage in approximately 72 children with DMD treated with oral, once-daily sevasemten for up to 48 months. This study will have up to a 4-week Screening period, a 12-week randomized, double-blind, placebo controlled treatment period (Part A), up to a 196-week open-label extension period (Part B), and a 2-week follow up period. Approximately 72 participants aged 4 to 9 years inclusive will be randomized to sevasemten or placebo in a 2:1 ratio. Five dose cohorts (C1, C2, C3, C4 and C5) of approximately 9 participants each will be enrolled sequentially. Approximately 18 total additional participants may be added across Cohorts 2, 3, or 4. An additional cohort, Cohort 2NS, to include participants (aged 4 to 7 years inclusive) not currently treated with corticosteroids, will enroll approximately 9 participants after Cohort 2 safety review and in parallel with the additional cohorts. After review of emerging data, the protocol was amended so all dose cohorts receive the same dose in Part B.