NS Pharma, a wholly owned subsidiary of Nippon Shinyaku, announced that JAMA Neurology has published results from a clinical trial of viltolarsen. Viltolarsen is an exon skipping therapy being reviewed under the FDA Accelerated Approval pathway for the treatment of Duchenne muscular dystrophy in patients amenable to exon 53 skipping therapy.
This Phase 2, two-period, dose-finding study enrolled 16 DMD patients, from four to less than 10 years of age, who were amenable to exon 53 skipping therapy. Study participants were randomized to two doses of viltolarsen (40 mg/kg/wk and 80 mg/kg/wk) for 20 to 24 weeks. At the end of the study, treatment with viltolarsen was associated with statistically significant increases in mean dystrophin expression (40 mg/kg/wk: p<0.001; 80 mg/kg/wk p=0.012). Mean dystrophin levels of 5.7% and 5.9% were observed in comparison to mean baseline levels of 0.3% and 0.6% in the 40 mg/kg/wk and 80 mg/kg/wk groups, respectively. Fourteen out of 16 patients (88%) reached dystrophin levels greater than 3%.
The most common treatment emergent adverse events occurring in greater than one patient were: cold, cough, nasal congestion, bruising, joint pain, diarrhea and vomiting. No serious adverse events were observed in the study.
Viltolarsen has not yet been approved in the U.S. and its New Drug Application was recently granted Priority Review by the FDA with an anticipated action date in the third quarter of 2020. In March 2020, viltolarsen was approved in Japan for the treatment of DMD patients amenable to exon 53 skipping therapy.
NS Pharma continues to study the safety and efficacy of viltolarsen in the confirmatory Phase 3 RACER53 trial. This study was initiated in October 2019 and is currently enrolling. The purpose of this Phase 3 trial is to confirm the clinical findings that were submitted under the Accelerated Approval pathway.
Viltolarsen has been granted Rare Pediatric Disease, Orphan Drug and Fast Track Designations in the U.S. The viltolarsen New Drug Application was granted Priority Review by the FDA with an anticipated action date in the third quarter of 2020. In March 2020, viltolarsen was approved in Japan for the treatment of patients with DMD who are amenable to exon 53 skipping therapy. Prior to its approval in Japan, viltolarsen was granted with the SAKIGAKE designation, Orphan drug designation, and designation of Conditional Early Approval System.