Results from a phase 2 clinical trial testing the safety and efficacy of the investigational gene transfer therapy delandistrogene moxeparvovec, also known as SRP-9001, for Duchenne muscular dystrophy (DMD) suggest the treatment has a biological effect that may be clinically relevant.

These results were presented at this year’s Muscular Dystrophy Association Clinical & Scientific Conference held in Nashville, Tennessee, and virtually. 

The multicenter, randomized, double-blind, placebo-controlled trial funded by Sarepta Therapeutics is made up of 3 parts. The first part consists of a randomized, double-blind, placebo-controlled period lasting 48 weeks. In Part 2, also lasting 48 weeks, patients who received placebo in Part 1 are switched to delandistrogene moxeparvovec. Finally, Part 3 is an open-label, follow-up period estimated to last approximately 212 weeks.

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Read more about experimental therapies for DMD.

The primary outcome measures are a change from baseline in micro-dystrophin expression from baseline to Week 12, assessed by Western blotting and the North Star Ambulatory Assessment, from baseline to Week 48. Safety endpoints are serious and treatment-emergent adverse events. 

“Results suggest that delandistrogene moxeparvovec has a biological effect that may be clinically relevant in people with DMD,” the researchers wrote. “Results reinforce a potentially favorable benefit-risk profile.”

The trial enrolled 41 boys with DMD, aged 4 to 7 years, who were still able to walk and had a mutation between exons 18 and 58 in the DMD gene.

Delandistrogene moxeparvovec is gene therapy that contains a micro-dystrophin gene encoding for a shortened but still functional dystrophin protein that will be specifically expressed in skeletal and cardiac muscles.


Mendell J, Shieh P, Geffen D, et al. A phase 2 clinical trial evaluating the safety and efficacy of delandistrogene moxeparvovec (SRP-9001) in patients with Duchenne muscular dystrophy. Poster presented at: 2022 Muscular Dystrophy Association Clinical & Scientific Conference; March 13-16, 2022; Nashville, TN. Poster 50.

A randomized, double-blind, placebo-controlled study of SRP-9001 for Duchenne muscular dystrophy (DMD). US National Library of Medicine. Last updated December 7, 2021. Accessed March 4, 2022.