FDA OKs treatment for rare mutation of Duchenne muscular dystrophy
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The FDA announced that it has granted accelerated approval for viltolarsen, an injection to treat Duchenne muscular dystrophy in those with a confirmed mutation.
“The FDA is committed to fostering drug development for serious neurological disorders like Duchenne muscular dystrophy,” Billy Dunn, MD, director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, said in a press release.
Viltolarsen (Viltepso; NS Pharma) is the second FDA-approved targeted treatment for patients with Duchenne muscular dystrophy (DMD) and a confirmed mutation on the DMD gene amenable to exon 53 skipping, which is present in approximately 8% of patients with the disease.
DMD is the most common type of muscular dystrophy, according to the FDA. It is caused by DMD gene mutations that result in an absence of dystrophin, a protein that helps muscle cells remain intact. Typically, the first signs of the disease are seen in children aged 3 years to 5 years; the symptoms worsen with age.
According to the FDA, DMD is present in one in 3,600 male infants and rarely occurs in females.
Viltolarsen was assessed in two clinical studies involving 32 male patients with genetically confirmed DMD, the FDA said. Dystrophin levels increased in one of the studies from an average of 0.6% at baseline to 5.9% at week 25.
Based on these findings, the FDA concluded that viltolarsen demonstrated an increase in dystrophin production that is likely to be clinically beneficial for patients with DMD who have this confirmed gene mutation.
The agency noted that the decision was made in consideration of potential risks associated with the treatment, the lack of available therapies, and the life-threatening and debilitating nature of the disease.
According to the FDA, common adverse events associated with viltolarsen include upper respiratory tract infection, cough, fever and reaction at injection site. Kidney toxicity was not observed in clinical studies of the drug, but the FDA noted that kidney function should be monitored in patients taking the drugs, as kidney toxicity has been observed in similar antisense oligonucleotides.
The FDA will require the manufacturer to conduct a clinical trial to confirm the benefits of the treatment, and an ongoing study is evaluating whether the drug improves time to stand in these patients. If the trial does not demonstrate clinical benefits, then the approval may be withdrawn.
Dunn said in the press release that the approval “provides an important treatment option for Duchenne muscular dystrophy patients with this confirmed mutation.”