Part 1: Randomized, placebo-controlled dose-titration to assess safety, tolerability and pharmacokinetics of 4 dose levels of SRP-4053 in genotypically-confirmed DMD patients with deletions amenable to exon 53 skipping.~Part 2: Open-label evaluation of SRP-4053 in patients from Part 1, along with newly enrolled DMD patients with deletions amenable to exon 53 skipping and an untreated group of DMD patients with deletions not amenable to exon 53 skipping.~Safety, including adverse event monitoring and routine laboratory assessments, will be followed on an ongoing basis for all patients.~Clinical efficacy, including functional tests such as the six-minute walk test (6MWT), will be assessed at regularly scheduled study visits. Patients in the treated groups will undergo one baseline and one follow-up muscle biopsy. Patients in the untreated group will not undergo biopsies and will follow an abbreviated schedule of study assessments.
This is a first-in-human, multiple-dose 2-part study to assess the safety, tolerability, efficacy, and pharmacokinetics of SRP-4053 in Duchenne muscular dystrophy (DMD) patients with deletions amenable to exon 53 skipping.