Phase I/II Study of SRP-4053 in DMD Patients

A 2-Part, Randomized, Double-Blind, Placebo-Controlled, Dose-Titration, Safety, Tolerability, and Pharmacokinetics Study (Part 1) Followed by an Open-Label Efficacy and Safety Evaluation (Part 2) of SRP-4053 in Patients With Duchenne Muscular Dystrophy Amenable to Exon 53 Skipping

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.

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.

Inclusion Criteria:

• Diagnosed with DMD, genotypically confirmed.
• Intact right and left biceps muscles or an alternative upper arm muscle group.
• Stable pulmonary and cardiac function.
• Minimum performance on 6MWT, North Star Ambulatory Assessment, and rise (Gowers) test as specified in the study protocol.
• On a stable dose of corticosteroids for at least 6 months.

Exclusion Criteria:

• Previous treatment with the experimental agents BMN-195 (SMT C1100) or PRO053.
• Current or previous treatment with any other experimental treatments within 12 weeks prior to study entry.
• Major surgery within the last 3 months.
• Presence of other clinically significant illness.
• Major change in physical therapy regime within the last 3 months.

Other inclusion and exclusion criteria may apply.