Viltolarsen Available to U.S. DMD Patients Under Expanded Access Program

Marta Figueiredo, PhD avatar

by Marta Figueiredo, PhD |


NS Pharma launched an expanded access program (EAP) in the U.S. to allow certain Duchenne muscular dystrophy (DMD) patients to gain access to its investigational exon-skipping therapy viltolarsen.

The program will allow physicians to prescribe viltolarsen to U.S. DMD patients amenable to exon 53 skipping who meet other eligibility criteria, at no cost.

EAPs are intended to make pre-approval, investigational therapies available outside the clinical trial setting to people with serious or life-threatening conditions, who have few or no adequate treatments, and when the therapy’s potential benefit outweighs its potential risks.

NS Pharma, a subsidiary of Nippon Shinyaku, said in a press release that it is committed to studying the efficacy and safety of viltolarsen.

To apply for the program, a patient’s healthcare provider must make a request to NS Pharma, and each case will be reviewed for eligibility. Physicians may request more information by emailing [email protected].

People with DMD have impaired production of dystrophin, an essential protein for muscle integrity, due to mutations in the DMD gene.

Viltolarsen (NS-065/NCNP-01), an exon-skipping therapy injected directly into the bloodstream, is designed to treat DMD patients whose disease-causing mutations are in exon 53, which accounts for about 8% of all DMD cases.

Exons are like pieces of a puzzle that contain information to produce proteins. The therapy works by “masking” the mutated exon 53 and allowing the other pieces of the puzzle in the DMD gene to attach in a way that enables production of a shorter but functional version of dystrophin.

NS Pharma’s application seeking the approval of viltolarsen is under priority review by the U.S. Food and Drug Administration (FDA), with a decision expected between July and September. The agency previously granted viltolarsen fast trackorphan drug, and rare pediatric disease designations, all meant to expedite the therapy’s development and review.

In Japan, viltolarsen received Sakigake (intended for early introduction of innovative medicines or medical devices) and orphan drug designations, and a similar application is also being reviewed by the Japanese Ministry of Health, Labour and Welfare.

The applications were based on promising results from a Phase 2 clinical trial (NCT02740972) in North America and a Phase 1/2 trial in Japan, which evaluated the safety and effectiveness of two doses of viltolarsen, given weekly, in eligible DMD patients.

Data from the trial in the U.S. and Canada showed that six-month treatment with viltolarsen was safe and restored dystrophin levels in the muscles of DMD boys ages 4 to 10.

Nippon Shinyaku and NS Pharma are now enrolling up to 74 boys (ages 4-7) with DMD amenable to exon 53 skipping for a Phase 3 trial, called RACER53 (NCT04060199), to further test 80 mg/kg of viltolarsen for up to 48 weeks.

Currently, participants are being recruited only in Japan and in the U.S., but sites in other countries are expected to open in the future. More information on contacts and clinical sites can be found here.

If approved by the FDA, viltolarsen would become the second therapy for DMD patients with mutations amenable for exon 53 skipping, following the recent conditional approval of Sarepta Therapeutics’ Vyondys 53 (golodirsen) in the U.S.