Safety and Tolerability of WVE-210201 in Patients With Duchenne Muscular Dystrophy

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.