A Gene Delivery Study to Evaluate the Safety and Expression of Delandistrogene Moxeparvovec in Participants Under the Age of Four With Duchenne Muscular Dystrophy (DMD)

Study Overview
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Brief Summary
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This open-label, single-arm study will evaluate the safety and expression of delandistrogene moxeparvovec in participants with DMD. Participants will be in the study for approximately 264 weeks.

Official Title
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A Two-Part, Open-Label Systemic Gene Delivery Study to Evaluate the Safety and Expression of RO7494222 (SRP-9001) in Subjects Under the Age of Four With Duchenne Muscular Dystrophy

Conditions
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Duchenne Muscular Dystrophy

Intervention / Treatment
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* Genetic: delandistrogene moxeparvovec


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Cohort A: >=3 years of age to <4 years of age Cohort B: >=2 years of age to <3 years of age Cohort C: >6 months to <2 years of age Cohort D: <=6 months of age Has a definitive diagnosis of DMD prior to screening based on documentation of clinical findings and prior confirmatory genetic testing using a clinical diagnostic genetic test Able to cooperate with age-appropriate motor assessment testing A pathogenic frameshift mutation or premature stop codon contained between exons 18 and 79 (inclusive) Exclusion Criteria: Exposure to gene therapy, investigational medication, or any treatment designed to increase dystrophin expression, within protocol-specified time limits Recombinant Adeno-Associated Virus Serotype rh74 (rAArh74) antibody titers are elevated, as per protocol-specified criteria Receiving regular oral corticosteroids as a treatment for DMD or planning to receive oral corticosteroids as a treatment for DMD within 1 year of baseline Presence of any other clinically significant illness, medical condition, or requirement for chronic drug treatment that in the opinion of the Investigator creates unnecessary risk for gene transfer 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 well-being or safety, or clinical interpretability Other inclusion or exclusion criteria could apply

Ages Eligible for Study
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Maximum Age: 3 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Delandistrogene Moxeparvovec<br>Participants will receive a single intravenous (IV) infusion of delandistrogene moxeparvovec on Day 1. | Genetic: delandistrogene moxeparvovec<br>* Single IV infusion of delandistrogene moxeparvovec<br>* Other names: delandistrogene moxeparvovec-rokl;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants with a Treatment-emergent Adverse Event (TEAE), Serious Adverse Event (SAE), and Adverse Event of Special Interest (AESI) |  | Baseline up to Week 260 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Quantity of Delandistrogene Moxeparvovec Dystrophin as Measured by Western Blot |  | Baseline, Week 12 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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DMD, Duchenne, Dystrophin, Gene-Delivery, Pediatric