NS-050/NCNP-03 in Boys With DMD (Meteor50)

Inclusion Criteria: * Male ≥ 4 years and \<16 years of age; * Confirmed DMD exon deletion in the dystrophin gene that is amenable to skipping of exon 50 to restore the dystrophin mRNA reading frame; * Able to walk independently without assistive devices; * Able to complete the TTSTAND without assistance in \<20 seconds; * Stable dose of glucocorticoid for at least 3 months and the dose is expected to remain on a stable dose for the duration of the study. Other inclusion criteria may apply. Exclusion Criteria: * Evidence of symptomatic cardiomyopathy; * Current or previous treatment with anabolic steroids (e.g., oxendolone, oxandrolone) or products containing resveratrol or adenosine triphosphate within 3 months prior to first dose of study drug; * Currently taking another investigational drug or has taken another investigational drug within 3 months prior to the first dose of study drug; * Surgery within the 3 months prior to the first dose of study drug or planned during the study duration; * Having taken any gene therapy. Other exclusion criteria may apply.