A Randomized, Double-blind, Placebo-controlled Study of Delandistrogene Moxeparvovec (SRP-9001) for Duchenne Muscular Dystrophy (DMD)

A Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial for Duchenne Muscular Dystrophy Using SRP-9001

The purpose of this study is to evaluate the safety and efficacy of exogenous gene transfer in DMD participants by measuring biological and clinical endpoints in three parts: two 48-week randomized, double-blinded, placebo-controlled periods (Part 1 and Part 2), and an open-label follow-up period (Part 3). Participants who are randomized to placebo in Part 1 will have the opportunity for treatment with delandistrogene moxeparvovec in Part 2.

In order to provide a uniform approach to monitoring long-term safety and efficacy in participants who received SRP-9001 in a clinical trial, the Sponsor has amended Study Completion for this study to occur at Week 130. Therefore, participants have transitioned and will complete the remainder of the Part 3 follow up visits in a long-term extension study, SRP-9001-305 (NCT05967351).

Inclusion Criteria:

• Established clinical diagnosis of DMD and documented dystrophin gene mutation of DMD phenotype.
• Indication of symptomatic muscular dystrophy by protocol-specified criteria.
• Ability to cooperate with motor assessment testing.
• Stable dose equivalent of oral corticosteroids for at least 12 weeks.
• A frameshift mutation contained between exons 18 and 58 (inclusive).

Exclusion Criteria:

• Impaired cardiovascular function on echocardiogram.
• Prior or ongoing medical condition on physical examination, electrocardiogram, or laboratory findings that could adversely affect participant safety, compromise completion of follow-up, or impair assessment of study results.
• Exposure to another investigational drug or exon skipping medication within 6 months of screening.
• Exposure to an investigational or commercial gene therapy product.
• Abnormal liver or renal function by protocol-specified criteria.

Other inclusion/exclusion criteria apply.