Phase 2 Study of EDG-5506 in Children and Adolescents With Duchenne Muscular Dystrophy Previously Treated With Gene Therapy (FOX)

Key Inclusion Criteria: Aged 6 to 14 with a documented mutation on the DMD gene and phenotype consistent with DMD. Prior receipt of an AAV-based gene therapy (≥ 2 years after study drug administration in an open-label study or ≥ 3 years after randomization in a randomized study). Able to complete stand from supine in ≤ 8 seconds at the Screening visit and able to perform the 4-stair climb in < 10 seconds at the Screening visit. Body weight ≤ 20 kg at the Screening visit. Treatment with a stable dose of corticosteroids for a minimum of 6 months prior to the Baseline visit. Key Exclusion Criteria: Medical history or clinically significant physical exam/laboratory result that, in the opinion of the investigator, would render the participant unsuitable for the study. This includes venous access that would be too difficult to facilitate repeated blood sampling. Screening visit cardiac echocardiography showing left ventricular ejection fraction (LVEF) < 40%. Receipt of an investigational drug (other than the AAV-based gene therapy per Inclusion criteria) within 30 days or 5 half-lives (whichever is longer) of the Screening visit in the present study. Receipt of an exon-skipping therapy within 6 months prior to the Screening visit.