Viltolarsen (NS-065 / NCNP-01) is an antisense oligonucleotide developed by the Japanese laboratory Shinyaku Co. Ltd. that targets the skipping of exon 53 in the dystrophin gene in Duchenne muscular dystrophy. Viltolarsen has been authorized in Japan since March 2020, an authorization which was based on two clinical trials, an American phase II trial whose results were published in May 2020 and a Japanese phase I / II trial whose results have just been published in the journal Annals of clinical and translational neurology.
Results that confirm those of the American study
In this open-label phase I / II trial, 16 ambulant and non-ambulant boys with DMD aged 5 to 12 years were treated with 40 and 80 mg / kg / week of viltolarsen for 12 to 24 weeks. The results of this trial show:
- good tolerance of viltolarsen;
- a significant increase at 12 and 24 weeks of dystrophin in muscle by 2.78% over baseline for the 80 mg / kg / week dose and less marked motor decline in treated patients with increased dystrophin levels in muscle;
- an average increase in the exon 53 skipping rate of 42.4% and 21.8% for the high and low dose of viltolarsen, respectively.
Two international phase II and phase III trials are underway to confirm these results.
