A Phase 3 Study to Evaluate the Safety and Efficacy of PF-06939926 for the Treatment of Duchenne Muscular Dystrophy

  • End date
    Jan 6, 2028
  • participants needed
  • sponsor
Updated on 19 August 2021
gene therapy
duchenne muscular dystrophy


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


The study will assess the efficacy of PF-06939926 gene therapy on ambulatory function while also monitoring its safety. Approximately 99 boys with DMD will be enrolled and randomly assigned to one of two groups: approximately two thirds will be in Cohort 1 and receive gene therapy at the start of the study; approximately one third will be in Cohort 2 and receive placebo at the start of the study and receive gene therapy after one year, as long as it remains safe to do so. The treatment (PF-06939926 gene therapy or placebo) will be given as an intravenous infusion lasting up to 2 hours.

The study includes boys who are at least 4 years old and less than 8 years old (including 7 year olds up until their 8th birthday). All boys will need to be on a daily dose of glucocorticoids (prednisone, prednisolone, or deflazacort) for at least 3 months prior to enrolling and to stay on daily glucocorticoids for the first 2 years of the study. All boys will need to be negative for neutralizing antibodies against AAV9, as measured by the test done for the study as part of screening.

The primary outcome of the study will be assessed at 52 weeks. All participants will be followed in the study for 5 years after treatment with gene therapy.

The study medication, all medical tests associated with the study, and the visits to the study sites are free of charge. Participants will also be supported for travel costs associated with study visits.

Condition Muscular Dystrophy, DUCHENNE MUSCULAR DYSTROPHY
Treatment Placebo, PF-06939926
Clinical Study IdentifierNCT04281485
Last Modified on19 August 2021


Yes No Not Sure

Inclusion Criteria

Confirmed diagnosis of Duchenne muscular dystrophy by prior genetic testing
Receiving a stable daily dose (at least 0.5 mg/kg/day prednisone or prednisolone, or at least 0.75 mg/kg/day deflazacort) for at least 3 months prior to Screening
Ambulatory, as assessed by protocol-specified criteria

Exclusion Criteria

Positive test performed by Pfizer for neutralizing antibodies to AAV9
Any treatment designed to increase dystrophin expression within 6 months prior to screening (e.g., Translarna, EXONDYS 51, VYONDYS 53)
Any prior treatment with gene therapy
Any non-healed injury that may impact functional testing (eg NSAA)
Abnormality in specified laboratory tests, including blood counts, liver and kidney function
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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