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.

The purpose of this study is to evaluate the safety and efficacy of exogenous gene transfer in DMD patients by measuring biological and clinical endpoints in two parts: a 48-week randomized, double-blinded, placebo-controlled period (Part 1), and a 96-week, double-blinded extension period (Part 2).

This study will follow patients who are screened and confirmed with a genetic diagnosis of Limb-girdle muscular dystrophy type 2E (LGMD2E/R4), Limb-girdle muscular dystrophy type 2D (LGMD2D/R3), or Limb-girdle muscular dystrophy type 2C (LGMD2C/R5). These enrolled patients will be followed to evaluate mobility and pulmonary function for up to 3 years after enrollment. Additional patient data will be collected from the time the individual began experiencing LGMD symptoms to the present.

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 purpose of this extension study is to evaluate the ongoing safety and tolerability of additional treatment with eteplirsen administered once weekly by intravenous (IV) infusion in male DMD patients who have successfully completed the 96-week eteplirsen study: Study 4658-102 (NCT03218995)

The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics (PK) of 5 escalating doses of SRP-5051 administered as a single dose to patients with DMD amenable to exon 51 skipping treatment.

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 purpose of this extension study is to evaluate the safety, tolerability, and pharmacokinetics of repeat administrations of SRP-5051 in patients with Duchenne muscular dystrophy (DMD) who participated in studies of SRP-5051.

The specific aim of this Phase I/II study is to assess the safety of intravenous administered Morpholino oligomer directed against exon 51 (AVI-4658 PMO).

This is a first-in-human dose-titration and open-label extension study to assess safety, tolerability, and pharmacokinetics of SRP-4045 in advanced-stage Duchenne muscular dystrophy (DMD) patients with deletions amenable to exon 45 skipping.

This study is designed to assess the efficacy, safety, tolerability, and pharmacokinetics (PK) of AVI-4658 (eteplirsen) in both 50.0 mg/kg and 30.0 mg/kg doses administered over 24 weeks in subjects diagnosed with Duchenne muscular dystrophy (DMD).

The primary objective of this study is to assess the ongoing efficacy, safety, and tolerability of an additional 212 weeks of treatment with eteplirsen injection in Duchenne muscular dystrophy (DMD) subjects who have successfully completed the 28 week eteplirsen study: Study 4658-us-201. This study will also evaluate the correlation between biomarkers for DMD and the clinical status of participating DMD subjects.

The proposed clinical trial is the first-in-human, single-center, open label, gene delivery study of SRP-9003 LGMD2E patients. Six total subjects will be enrolled.

This is a first-in-human, multiple-dose 2-part study to assess the safety, tolerability, efficacy, and pharmacokinetics of SRP-4053 in Duchenne muscular dystrophy (DMD) patients with deletions amenable to exon 53 skipping.

The primary objective of this study is to explore safety and tolerability of eteplirsen in participants with advanced stage Duchenne muscular dystrophy (DMD) who are amenable to exon 51 skipping.

This is an open-label study to assess the safety, tolerability, efficacy and pharmacokinetics of eteplirsen in patients with early stage Duchenne muscular dystrophy (DMD) who are amenable to exon 51 skipping.

The main objective of this study is to provide evidence of efficacy of eteplirsen (AVI-4658) in Duchenne muscular dystrophy (DMD) patients that are amenable to skipping exon 51. Additional objectives include evaluation of safety, biomarkers and the long-term effects of eteplirsen up to 96 weeks, followed by a safety extension (not to exceed 48 weeks).

This is a multicenter, open-label, dose-escalation study to evaluate the safety, tolerability, PK, and efficacy of once-weekly IV infusions of eteplirsen in approximately 12 male patients, ages 6 months to 48 months (inclusive), who have genotypically confirmed DMD with a deletion mutation amenable to exon 51 skipping.

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

The proposed clinical trial is a single-dose controlled trial using rAAVrh74.MHCK7.micro-dystrophin for DMD subjects. Cohort A will include six subjects ages 3 months to 3 years, and Cohort B will include six subjects ages 4 to 7 years old. All subjects will receive intravenous micro-dystrophin vector (2X10e14 vg/kg in 10mL/kg)

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 SRP-5051 (vesleteplirsen) at MAD levels to determine doses to be administered in Part B, and 2) Part B will be conducted to further evaluate the SRP-5051 doses selected in Part A. Participants enrolling in Part B will be those who completed Part A or Study 5051-102 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.