FDA approves Amondys 45 injection for rare form of Duchenne muscular dystrophy

The FDA announced that it has granted accelerated approval for Amondys 45 injections as a treatment for a rare form of Duchenne muscular dystrophy, according to a press release.

“Developing drugs designed for patients with specific mutations is a critical part of personalized medicine,” Eric Bastings, MD, deputy director of the Office of Neuroscience in the FDA’s Center for Drug Evaluation and Research, said in the press release.

Amondys 45 (casimersen; Sarepta Therapeutics) is the first FDA-approved targeted treatment for individuals with a confirmed mutation on the Duchenne muscular dystrophy (DMD) gene amenable to exon 45 skipping, which occurs in about 8% of patients with DMD, according to the agency.

The treatment was assessed in a double-blind, placebo-controlled study with 43 patients who were randomly assigned 2:1 to receive intravenous casimersen at 30 mg/kg or placebo.

All patients involved in the study had the mutation, were male and aged 7 to 20 years.

From baseline to week 48, patients who received casimersen experienced significantly greater increases in dystrophin protein compared with patients who were given placebo.

The FDA determined that the observed increase in dystrophin protein associated with casimersen shows that the treatment is “reasonably likely” to clinically benefit patients with the DMD gene mutation amenable to exon 45 skipping.

The agency noted that the clinical benefits of the drug, such as motor function improvements, have yet to be established.

Common adverse events associated with casimersen included upper respiratory tract infections, fever, headache, cough, throat pain and joint pain.

Kidney toxicity was not identified in clinical studies of casimersen, but it was observed in nonclinical studies and in some antisense oligonucleotides. Therefore, the FDA recommend that patients taking the drug are monitored for kidney function.

According to the FDA, the decision was made in consideration of the potential risks of the drug, the debilitation nature of DMD and the lack of available treatments.

“Today’s approval of Amondys 45 provides a targeted treatment option for Duchenne muscular dystrophy patients with this confirmed mutation,” Bastings said.