May 2020, the publication of the results of the phase II clinical trial of Viltolarsen, in 16 boys with DMD aged 4 to 9 years, shows that it induces a significant increase in the global level of dystrophin in the muscle, accompanied by a functional improvement after six months of treatment. In this double-blind, placebo-controlled trial, both doses of viltolarsen tested (40 and 80 mg/kg) were also well tolerated.
Following these positive results, an open-label extension phase has been initiated to evaluate the long-term safety and efficacy of this oligonucleotide that targets the skipping of exon 53 of the DMD gene. This phase, which is expected to last 192 weeks, is already providing the first results at 109 weeks of treatment:
- a good tolerance of Viltolarsen at the 2 evaluated doses.
- a maintenance of the improvement of motor functions observed during the initial study, compared to the motor decline observed in the untreated patients of an external control cohort (natural history study of the CINRG DNHS).
Evaluation of Viltolarsen is also ongoing in another international Phase III trial (RACER53) that is currently being conducted in a larger population.
