The primary purpose of this study is to evaluate the safety of SRP-9003 and to quantify expression of β-SG in the skeletal muscle of participants with limb-girdle muscular dystrophy, type 2E/R4 (LGMD2E/R4). The study will include both ambulatory (Cohort 1) and non-ambulatory (Cohort 2) participants.

The study will evaluate the safety and efficacy of delandistrogene moxeparvovec gene transfer therapy in non-ambulatory and ambulatory males with DMD. This is a randomized, double-blind, placebo-controlled 2-part study. Participants will be in the study for approximately 128 weeks. All participants will have the opportunity to receive intravenous (IV) delandistrogene moxeparvovec in either Part 1 or Part 2.

The study will evaluate the safety and efficacy of gene transfer therapy in boys with DMD. It is a randomized, double-blind, placebo-controlled study. The participants who are randomized to the placebo arm will have an opportunity for treatment with gene transfer therapy at the beginning of the second year.

This study was an open-label single-dose gene transfer therapy study evaluating the safety of delandistrogene moxeparvovec intravenous (IV) administration in boys with DMD. This study was originally designed to consist of 12 patients across 2 Cohorts. Cohort A would have included participants ages 3 months to 3 years, and Cohort B included participants ages 4 to 7 years old. No participants were enrolled in Cohort A.

The purpose of this study is to evaluate the safety and efficacy of exogenous gene transfer in DMD participants by measuring biological and clinical endpoints in three parts: two 48-week randomized, double-blinded, placebo-controlled periods (Part 1 and Part 2), and an open-label follow-up period (Part 3). Participants who are randomized to placebo in Part 1 will have the opportunity for treatment with delandistrogene moxeparvovec in Part 2. In order to provide a uniform approach to monitoring long-term safety and efficacy in participants who received SRP-9001 in a clinical trial, the Sponsor has amended Study Completion for this study to occur at Week 130. Therefore, participants have transitioned and will complete the remainder of the Part 3 follow up visits in a long-term extension study, SRP-9001-305 (NCT05967351).

This study will be comprised of 2 parts: Part 1 (dose escalation) will be conducted to evaluate the safety and tolerability of 2 doses (100 milligrams/kilogram [mg/kg] and 200 mg/kg) of eteplirsen in approximately 10 participants with DMD; Part 2 (dose finding and dose comparison) will be conducted for the selection of a high dose (100 mg/kg versus 200 mg/kg) and its comparison with the 30 mg/kg dose of eteplirsen, in approximately 144 participants with genetically confirmed deletion mutations amenable to treatment by skipping exon 51.

The main objective of this study is to evaluate the safety and tolerability of long-term treatment with casimersen or golodirsen in patients with Duchenne muscular dystrophy (DMD).

The proposed clinical trial is the first-in-human, single-center, open-label, gene delivery study of SRP-9003 (bidridistrogene xeboparvovec) in participants with LGMD2E.

The main objective of this study is to evaluate the efficacy of SRP-4045 (casimersen) and SRP-4053 (golodirsen) compared to placebo in participants with DMD with out-of-frame deletion mutations amenable to skipping exon 45 and exon 53, respectively.

This study will be comprised of 2 parts: 1) Part A (Multiple Ascending Dose [MAD]) will be conducted to evaluate the safety and tolerability of vesleteplirsen at MAD levels to determine the maximum tolerated dose (MTD), and 2) Part B will be conducted to further evaluate the vesleteplirsen doses selected in Part A. Participants enrolling in Part B will be those who completed Part A or Study 5051-102 (NCT03675126) and meet applicable eligibility criteria for Part B, as well as additional participants who meet applicable eligibility criteria for enrollment at the beginning of Part B.