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) - Non-Ambulatory CohortCohort 8 (non-ambulatory participants) is currently enrolling new participants. Enrollment for Cohorts 1 through 7 has been completed. This is an open-label gene transfer therapy study evaluating the safety of and expression from delandistrogene moxeparvovec in participants with Duchenne Muscular Dystrophy (DMD). The maximum participant duration for this study is 156 weeks.