Viltepso Approved to Treat Duchenne Muscular Dystrophy

August 12, 2020 – The U.S. FDA has approved ViltepsoTM (viltolarsen), manufactured by NS Pharma, to treat Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping.

DMD is a genetic condition in which the body doesn’t produce enough dystrophin, a protein needed to strengthen and protect muscle fiber. Without sufficient dystrophin, muscles waste away and die. The disease is progressive and can manifest in children as young as two years of age. Patients can begin to experience life-threatening cardiac and respiratory problems due to muscle weakness by the time they are adolescents.

In a clinical study, 100% of patients who received Viltepso had an increase in dystrophin levels, and 88% of patients had dystrophin levels of 3% of normal or greater. Viltepso delivered a mean increase in dystrophin expression of 5.9% of normal after 20-24 weeks of treatment.

Recommended dosing is 80mg/kg of body weight administered once weekly via intravenous infusion over the course of one hour. Serum cystatin C, urine dipstick, and urine protein-to-creatinine ratio should be measured prior to starting patients on Viltepso, and measurement of glomerular filtration rate should also be considered. Monitoring for kidney toxicity during treatment is recommended. Viltepso must be administered by a healthcare professional but can be given either in a clinical setting or in the patient’s home.

Because Viltepso received accelerated approval, continued approval may be contingent on confirmation of a clinical benefit in a Phase 3 confirmatory trial. The drug is available at a wholesale acquisition cost (WAC) of $1,410 per vial.