NS Pharma’s Viltepso Fails Confirmatory Phase III Trial for Duchenne Muscular Dystrophy Treatment

1. Viltepso Failure: NS Pharma's Duchenne muscular dystrophy drug Viltepso (viltolarsen) failed to meet its primary endpoint in the confirmatory Phase III RACER53 study, which evaluated its efficacy and safety in 77 ambulatory boys with DMD.
2. Study Details: The RACER53 study was a randomized, double-blind, placebo-controlled trial that compared the efficacy of Viltepso (80 mg/kg once weekly) versus placebo over 48 weeks. The primary endpoint was time to stand from supine, measured as velocity (rise/sec).
3. Results: Although the viltolarsen group showed a trend of increased velocity, the placebo group also showed improvements, resulting in no statistically significant difference between the two groups.
4. Safety Profile: Preliminary safety results indicated that adverse events associated with Viltepso were mild or moderate, with no treatment emergent adverse events leading to discontinuation.
5. Regulatory Implications: The failure of the confirmatory trial may put Viltepso's 2020 accelerated FDA approval in jeopardy. NS Pharma will work with regulatory authorities to determine how to proceed based on the results of further detailed data analyses.
6. Prior Studies: Previous studies, including a phase 2, open-label, long-term extension study, showed statistically significant improvements in time to stand and increased dystrophin production, which formed the basis of the FDA approval.
7. Competitor Landscape: The failure of Viltepso follows a similar setback for Pfizer's gene therapy fordadistrogene movaparvovec, while Sarepta's Elevidys (delandistrogene moxeparvovec-rokl) has faced criticism for weak efficacy data and a high price tag.