Viltolarsen (NS-065/NCNP-01) for the treatment of Duchenne muscular dystrophy. Preliminary results of the analysis of the phase III trial (RACER53) study.-Nipppon Shinyaku.

This study is a randomized, double-blind, placebo-controlled, multi-center, comparative study of 77 boys with ambulatory Duchenne muscular dystrophy (DMD) with dystrophin gene mutations that are amenable to exon 53 skipping. The study evaluated the efficacy and safety of viltlarsen against placebo by administering viltolarsen 80 mg/kg or placebo once weekly for 48 weeks.

The primary endpoint of the study was Time to Stand from Supine evaluated as velocity (rise/sec). The viltolarsen group showed a trend of increased velocity from baseline after treatment for 48 weeks. However, the placebo group also showed a trend of increased velocity, and there was no statistically significant difference between the viltolarsen group and the placebo group.

Regarding safety, there was no difference in the incidence of adverse events between the viltolarsen group and the placebo group. All adverse events occurred in the viltolarsen group were mild or moderate, and there were no cases that led to discontinuation of treatment.

We have a confidence that viltolarsen is a beneficial medicine in response to the need of DMD patients, considering the results of prior clinical studies. We are currently conducting further detailed data analyses and identifying factors that may have influenced the results (e.g. age, treatment period, and effect of concomitant drugs including glucocorticoid therapy).

We will work closely with regulatory authorities to determine how to proceed based on the results of the analysis and in the best interest of patients. We will report on additional analyses and discussions with the regulatory authorities at a later date.