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.