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# FDA OKs Viltepso for Duchenne MD Mutation
- URL: https://www.fdaweb.com/fda-oks-viltepso-for-duchenne-md-mutation/
- Published: 2020-08-12T12:00:00.000Z
- Updated: 2026-09-14T16:24:49.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5147417

FDA has granted accelerated approval to NS Pharma’s Viltepso (viltolarsen) to treat Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping. An agency [announcement](https://www.fda.gov/news-events/press-announcements/fda-approves-targeted-treatment-rare-duchenne-muscular-dystrophy-mutation?ref=fdaweb.com) says this is the second approved targeted treatment for patients with this type of mutation.

Viltepso was evaluated in two clinical studies with a total of 32 patients, all of whom were male and had genetically confirmed DMD. FDA says it concluded that the company’s data demonstrated an increase in dystrophin production that is reasonably likely to predict clinical benefit in patients with DMD who have a confirmed mutation of the dystrophin gene amenable to exon 53 skipping. A clinical benefit of the drug has not been established, the agency says.

As part of the accelerated approval process, FDA is requiring the company to conduct a clinical trial to confirm the drug’s clinical benefit. The study is designed to assess whether Viltepso improves the time to stand for DMD patients with the confirmed mutation. “If the trial fails to verify clinical benefit,” the notice says, “FDA may initiate proceedings to withdraw approval of the drug.”

The most common side effects observed in DMD patients were upper respiratory tract infection, injection site reaction, cough, and fever.

The NS Pharma application was given priority review as well as accelerated approval.