A Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of a Single Dose of SRP-5051 (Vesleteplirsen) in Patients With Duchenne Muscular Dystrophy (DMD)

A Phase 1 Trial to Evaluate the Safety, Tolerability, and Pharmacokinetics of a Single Dose of SRP-5051 in Patients With Duchenne Muscular Dystrophy Amenable to Exon 51 Skipping Treatment

The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of 5 escalating doses of SRP-5051 (vesleteplirsen) administered as a single dose to patients with DMD amenable to exon 51 skipping treatment.

Inclusion Criteria:

• Has a genetic diagnosis of DMD and an out-of-frame deletion mutation of the DMD gene amenable to exon 51 skipping treatment
• Has been on a stable dose of oral corticosteroids for at least 12 weeks prior to study drug administration with continued dosing of oral corticosteroids while participating in the study*, or has not received corticosteroids for at least 12 weeks prior to study drug administration and will not initiate dosing of oral corticosteroids while participating in the study

Exclusion Criteria:

• Has a left ventricular ejection fraction (LVEF) less than (<) 40 percent (%) based on an echocardiogram (ECHO) performed within 3 months prior to Screening or at the Screening visit
• Has a QT interval corrected with Fridericia's method (QTcF) >= 450 millisecond (msec) on the Screening electrocardiogram (ECG)
• Initiation or change of dosing (except for modifications to accommodate changes in weight) within 12 weeks prior to Screening and while participating in the study for any of the following: angiotensin-converting enzyme (ACE) inhibitors, angiotensin-receptor blocking agents (ARBs), beta-blockers, or potassium
• Requires antiarrhythmic and/or diuretic therapy for heart failure
• Forced vital capacity (FVC) <40% of predicted value within 3 months of Screening or at the Screening visit
• Known kidney disease or had an acute kidney injury within 6 months prior to Screening
• Treatment with eteplirsen or drisapersen within 6 months prior to Screening, or any experimental gene therapy for the treatment of DMD at any time
• Use of any herbal medication/supplement containing aristolochic acid

Other inclusion/exclusion criteria apply.

*The dose of steroids must remain constant except for modifications to accommodate changes in weight.