RecruitingPhase 1Genetic interventionA Gene Transfer Therapy Study to Evaluate the Safety of and Expression From Delandistrogene Moxeparvovec (SRP-9001) in Participants With Duchenne Muscular Dystrophy (DMD)This is an open-label gene transfer therapy study evaluating the safety of and expression from delandistrogene moxeparvovec in participants with DMD. The maximum participant duration for this study is 156 weeks.