viltolarsen

Viltolarsen, marketed as Viltepso, is an antisense oligonucleotide therapy for Duchenne muscular dystrophy (DMD) in patients whose mutations are amenable to skipping exon 53 of the dystrophin gene. It is a phosphorodiamidate morpholino oligomer that binds dystrophin pre-mRNA to exclude exon 53 during splicing, thereby restoring the reading frame and enabling production of a truncated but functional dystrophin protein.

Developed by Nippon Shinyaku’s NS Pharma, viltolarsen received regulatory approval in the United States in 2020 for DMD patients amenable to exon 53 skipping and has also been approved in Japan. Regulatory status varies by region.

Clinical evidence from phase 2 trials demonstrated increased dystrophin expression in muscle biopsies and stabilization or modest improvements in selected motor-function endpoints in treated patients, with a safety profile generally consistent with other antisense therapies for DMD. The sponsor emphasizes monitoring for infusion-related reactions and common infection-related symptoms.

Administration is by intravenous infusion, typically on a weekly schedule, as part of standard DMD care. Common adverse events reported include injection-site reactions and upper respiratory tract infections; serious adverse events were infrequent in trials.

See also Duchenne muscular dystrophy; exon skipping therapy; antisense oligonucleotide.