The study will assess the safety and tolerability of fordadistrogene movaparvovec gene therapy. Approximately 10 participants will be enrolled in the study and receive a single IV infusion of PF-06939926; there is no placebo arm. The study includes boys who are at least 2 years old and less than 4 years old (including 3 year olds up until their 4th birthday). 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as part of screening.~The primary analysis will occur when all participants have completed visits through Week 52 (or withdrawn from the study prior to Week 52). All participants will be followed in the study for 5 years after treatment with gene therapy.
The study will evaluate the safety and dystrophin expression following gene therapy in boys with Duchenne Muscular Dystrophy (DMD). It is a single-arm, non-randomized, open-label study