A Gene Transfer Therapy to Evaluate the Safety and Efficacy of Delandistrogene Moxeparvovec (SRP-9001) Following Therapeutic Plasma Exchange (Plasmapheresis) in Participants With Duchenne Muscular Dystrophy (DMD) and Pre-existing Antibodies to AAVrh74 (HORIZON)

August 27, 2025 updated by: Sarepta Therapeutics, Inc.

An Open-Label, Systemic Gene Delivery Study to Evaluate the Safety, Tolerability and Expression of Delandistrogene Moxeparvovec Following Plasmapheresis in Subjects With Duchenne Muscular Dystrophy and Pre-existing Antibodies to AAVrh74

This is a gene transfer therapy study evaluating the safety of and delandistrogene moxeparvovec dystrophin protein expression from delandistrogene moxeparvovec following therapeutic plasma exchange (plasmapheresis) in ambulatory male participants with DMD and pre-existing antibodies to AAVrh74 over a period of 59 weeks.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

3

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Florida
      • Gainesville, Florida, United States, 32610
        • University of Florida, College of Medicine
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine in St. Louis
    • Ohio
      • Columbus, Ohio, United States, 43205
        • Nationwide Children's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Ambulatory per protocol specified criteria.
  • Has a definitive diagnosis of DMD prior to Screening based on documentation of clinical findings and prior confirmatory genetic testing.
  • Ability to cooperate with motor assessment testing.
  • Has elevated AAVrh74 antibody titers per protocol-specified requirements.
  • A pathogenic frameshift mutation, nonsense mutation or premature stop codon or pathogenic variant in the DMD gene that is expected to lead to absence of dystrophin protein with exception of a mutation in exon 8 and/or 9.
  • Stable daily dose of oral corticosteroids for at least 12 weeks prior to Screening, and the dose is expected to remain constant throughout the study (except for modifications to accommodate changes in weight).

Exclusion Criteria:

  • Has reduced left ventricular ejection fraction on the screening ECHO or clinical signs and/or symptoms of cardiomyopathy.
  • Presence of any other clinically significant illness, including cardiac, pulmonary, hepatic, renal, hematologic, immunologic, or behavioral disease, or infection or malignancy or concomitant illness or requirement for chronic drug treatment that in the opinion of the Investigator creates unnecessary risks for gene transfer or a medical condition or extenuating circumstance that, in the opinion of the Investigator, might compromise the participant's ability to comply with the protocol required testing or procedures or compromise the participant's wellbeing, safety, or clinical interpretability.
  • Exposure to gene therapy, investigational medication, or other protocol-specified treatment within the protocol specified time limits.
  • Abnormality in protocol-specified diagnostic evaluations or laboratory tests. .

Note: Other inclusion or exclusion criteria could apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Delandistrogene Moxeparvovec After Plasmapheresis Procedure
Participants will receive a single intravenous (IV) infusion of delandistrogene moxeparvovec on Day 1 after plasmapheresis procedure if AAVrh74 antibodies are sufficiently low.
Genetic: delandistrogene moxeparvovec
Single IV infusion of delandistrogene moxeparvovec
Other Names:
  • SRP-9001
  • delandistrogene moxeparvovec-rokl
  • ELEVIDYS
Procedure: Plasmapheresis
Therapeutic plasma exchange procedure

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change From Baseline in Quantity of Delandistrogene Moxeparvovec Dystrophin Expression in Biopsied Muscle as Measured by Immunofluorescence (IF) Fiber Intensity
Time Frame: Baseline, Week 12
Baseline, Week 12
Change From Baseline in Quantity of Delandistrogene Moxeparvovec Dystrophin Expression in Biopsied Muscle as Measured by IF Percent Dystrophin-positive Fibers (PDPF)
Time Frame: Baseline, Week 12
Baseline, Week 12
Mean Concentration of Vector Genome Copies Using Polymerase Chain Reaction in Muscle Tissue Biopsy, After Delandistrogene Moxeparvovec Administration
Time Frame: Week 12
Week 12
Change From Baseline in Quantity of Delandistrogene Moxeparvovec Dystrophin Expression Adjusted by Muscle Content Biopsied Muscle as Measured by Western Blot
Time Frame: Baseline, Week 12
Baseline, Week 12

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in rAAVrh74 Antibody Titers
Time Frame: Baseline, Week 1
Baseline, Week 1
Number of Participants with a Treatment Emergent Adverse Event (TEAE), Adverse Event of Special Interest (AESI), and Serious Adverse Event (SAE)
Time Frame: Baseline up to End of Study (Up to Week 59)
Baseline up to End of Study (Up to Week 59)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sarepta Therapeutics, Inc.

Investigators

  • Study Director: Medical Director, Sarepta Therapeutics, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 18, 2024

Primary Completion (Actual)

August 5, 2025

Study Completion (Actual)

August 5, 2025

Study Registration Dates

First Submitted

September 12, 2024

First Submitted That Met QC Criteria

September 12, 2024

First Posted (Actual)

September 19, 2024

Study Record Updates

Last Update Posted (Estimated)

September 4, 2025

Last Update Submitted That Met QC Criteria

August 27, 2025

Last Verified

August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • SRP-9001-105

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Duchenne Muscular Dystrophy

Clinical Trials on delandistrogene moxeparvovec

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Uganda

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe