Nippon Shinyaku unit NS Pharma today announced the accelerated FDA for Viltepso (viltolarsen). This targeted treatment is created for people with Duchenne muscular dystrophy amenable to exon 53 skipping. This group represents ~8% of total DMD cases.
Viltolarsen works by masking exon 53 causing cells to “skip” the exon when synthesizing mRNA thereby restoring the reading frame of mRNA and allowing the cell to synthesize a shorter but working dystrophin protein.
About the study
Viltepso was evaluated in two clinical studies with a total of 32 patients, all of whom were male and had genetically confirmed DMD. The increase in dystrophin production was established in one of those two studies, a study that included 16 DMD patients, with 8 patients receiving Viltepso at the recommended dose. In the study, dystrophin levels increased, on average, from 0.6% of normal at baseline to 5.9% of normal at week 25.
The most common side effects observed in DMD patients (pooled from the two studies) treated with 80 mg/kg once a week were: Upper respiratory tract infection, injection site reaction, cough and fever.
Although kidney toxicity was not observed in the Viltepso clinical studies, the clinical experience with Viltepso is limited, and kidney toxicity, including potentially fatal glomerulonephritis, has been observed after administration of some antisense oligonucleotides. Kidney function should be monitored in patients taking Viltepso.