AFFINITY DUCHENNE: RGX-202 Gene Therapy in Participants With Duchenne Muscular Dystrophy (DMD)

RGX-202 is a gene therapy designed to deliver a transgene for a novel microdystrophin that includes functional elements of naturally-occurring dystrophin including the C-Terminal (CT) domain.This is a multicenter, open-label dose evaluation clinical study to assess the safety, tolerability and clinical efficacy of a one-time intravenous (IV) dose of RGX-202 in participants with Duchenne.

Inclusion Criteria:DMD gene mutation in exons 18 and above, and a clinical picture consistent with typical DMD.Participant is able to walk 100 meters independently without assistive devices, as assessed at screening.Participant is able to complete the TTSTAND per protocol-specific criteria.Participant has been on a stable dose of systemic glucocorticoids according to the standard of care for at least 12 weeks prior to screening.Clinical laboratory test results, including hepatic and renal function, are within the normal range during screening, or if abnormal, are not clinically significant, in the opinion of the investigator.Exclusion Criteria:Participant has any condition that would contraindicate treatment with immunosuppression.Participant has received ataluren (a protein restoration therapy) or an exon-skipping therapy for the treatment of DMD within 6 months of study entry or is unable to refrain from taking ataluren or exon-skipping therapy for a duration of 5 years from the time of RGX-202 administration.Participant has received any investigational or commercial gene therapy product over his lifetime.Participant is currently taking any other investigational intervention or has taken any other investigational intervention within 3 months prior to the scheduled Day 1 intervention.Participant has detectable AAV8 total binding antibodies in serum.Participant has impaired cardiac function defined as a left ventricular ejection fraction on screening cardiac MRI <55%.Participant is not a good candidate for the study, in the opinion of the investigator.