This is a Phase 1, double-blind, placebo-controlled, single ascending dose cohort study to evaluate the safety, tolerability, and plasma concentrations of WVE-210201 in ambulatory and non-ambulatory male pediatric patients with DMD amenable to exon 51 skipping intervention.

Inclusion Criteria:

• Diagnosis of Duchenne muscular dystrophy (DMD) based on clinical phenotype with increased serum creatine kinase

• Documented mutation in the Dystrophin gene associated with DMD that is amenable to exon 51 skipping

• Ambulatory or non-ambulatory male patients aged ≥5 - ≤18 years

• Stable pulmonary and cardiac function as measured by:

  1. Reproducible percent predicted forced vital capacity (FVC) ≥50%
  2. Left ventricular ejection fraction (LVEF) >55% in patients <10 years of age and >45% in patients ≥10 years of age, as measured (and documented) by echocardiogram within one year prior to enrollment into the study.

Exclusion Criteria:

• Severe cardiomyopathy; cardiomyopathy that is managed by angiotensin-converting enzyme (ACE) inhibitors or beta blockers is acceptable provided the patient meets the LVEF inclusion criteria.
• Need for mechanical or non-invasive ventilation OR anticipated need for mechanical or non-invasive ventilation within the next year, in the opinion of the Investigator.
• Changes in nutritional or herbal supplements or concomitant medications within 1 month prior to Screening visit or plans to modify dose or regimen during the study.
• Currently on anticoagulants or antithrombotics.
• Received treatment with eteplirsen or ataluren within the past 14 weeks.
• Received prior treatment with drisapersen.
• Received any investigational drug within the past 3 months or 5 half-lives, whichever is longer.