At the two-year follow-up, two out of the three patients treated at the effective dose maintained stabilization of motor functions, while untreated patients showed a significant decline in NSAA scores.

The pivotal phase of the trial is set to commence in mid-2025 in Europe and the United States, following the successful dose escalation phase.

Duchenne Muscular Dystrophy is a rare genetic disorder primarily affecting boys, characterized by progressive muscle degeneration due to the absence of dystrophin.

Genethon is a nonprofit organization dedicated to developing gene therapies for rare diseases, with a strong commitment to innovative treatments for genetic disorders.

Genethon CEO Frederic Revah emphasized the positive outcomes of GNT0004, noting both microdystrophin expression and clinical efficacy, with the effective dose being lower than that used in other DMD trials.

GNT0004 employs an AAV8 vector to deliver a shortened version of the dystrophin gene, requiring only a single intravenous injection for administration.

Significantly, the trial showed a sustained reduction in creatine phosphokinase (CPK) levels, with reductions ranging from 50% to 87% maintained at 24 months post-treatment.

The safety profile of GNT0004 remained reassuring, with no serious adverse effects reported two years after treatment at the effective dose, which is lower than doses used in other DMD gene therapies.

Genethon recently showcased two-year results from its GNT0004 gene therapy trial for Duchenne Muscular Dystrophy (DMD) at the ASGCT 2025 conference, demonstrating clinical efficacy in stabilizing motor functions.

The trial involved five patients aged 6 to 10 years, with three receiving the effective dose of 3x10³ vg/kg, which was identified as optimal for further study.

Patients treated with GNT0004 exhibited prolonged stabilization of motor functions, as indicated by a +4.7 point improvement on the North Star Ambulatory Assessment (NSAA) scale compared to a control group of 34 untreated patients.