Jerry Mendell from Ohio State University and colleagues from seven countries reported the failure of the third phase of clinical trials of gene therapy for Duchenne muscular dystrophy. The multicenter randomized EMBARK trials involved 124 children with this diagnosis aged 4–7 years. About half of them were given a single placebo, the other half were given the delanistrogene moxeparvovec at a dose of 1.33 × 1014 vector genomes per kilogram of body weight. This drug is a working copy of the dystrophin gene, which is associated with the development of the disease, on the adeno-associated viral vector rh74. The results of the study were published in the journal Nature Medicine.
After 52 weeks, the average change in symptoms on the NSAA scale in the main and control groups (primary endpoint) was 2.57 versus 1.92 points; a difference of 0.65 points (95% confidence interval from -0.45 to 1.74; p = 0.2441) — the difference is statistically insignificant. The results for individual motor skills (secondary endpoints) were also insignificant. The authors of the study do not rule out that this is due to the relatively short trial period. Monitoring of patients continues, as do other ongoing trials of the drug.