NS Pharma, a subsidiary of Nippon Shinyaku, has secured the US Food & Drug Administration (FDA) approval for Viltepso (viltolarsen) injection to treat Duchenne muscular dystrophy (DMD) in patients who are eligible for exon 53 skipping therapy.

The US regulatory agency has granted accelerated approval for the drug, based on its activity to boost dystrophin, a protein that supports muscle health, as deficiency of dystrophin due to genetic mutations is the root cause of DMD.

Prior to the US regulatory approval, Viltepso was granted Priority Review, Rare Pediatric Disease, Orphan Drug and Fast Track designations, along with Japanese regulatory approval in March 2020.

NS Pharma president Tsugio Tanaka said: “On behalf of NS Pharma and Nippon Shinyaku, I would like to express our deepest gratitude to the families and physicians who participated in our clinical trials and made today’s approval possible.

“We are proud to now offer an important new treatment option to help address the significant unmet needs caused by this devastating disease.”

The FDA approved Viltepso based on results from clinical trials conducted in North America and Japan

The company’s New Drug Application (NDA) for Viltepso was supported by results from a North American Phase 2 clinical trial in paediatric patients aged between four and 10 years, and a Japanese open-label study in boys aged between five and 18 years.

In the clinical trials, patients received 80mg/kg/wk dose of Viltepso, and all the patients in the Phase 2 study showed an increase in levels of dystrophin and 88% of patients showed greater levels of dystrophin than normal.

The Viltepso treatment for 20-24 weeks resulted in an increase in dystrophin expression to approximately 6% of normal compared to the baseline, said the company.

Also, no patients in the clinical studies experienced kidney toxicity during treatment, where drugs like Viltepso may cause potential kidney toxicity. The most common side effects due to Viltepso treatment include upper respiratory tract infection, injection site reaction, cough and fever.

Study investigator Vamshi Rao said” “For decades, neurologists who treat DMD have hoped for the discovery of therapies capable of significantly improving dystrophin production, and the magnitude of dystrophin increases observed with Viltepso are impressive.

“The approval of Viltepso is an exciting development for DMD patients amenable to exon 53 skipping therapy and may rapidly become a foundational treatment for these patients.”