The Food and Drug Administration (FDA) has granted accelerated approval for the first drug to treat Duchenne muscular dystrophy (DMD), the most common type of muscular dystrophy. DMD is a rare gentic disorder characterized by progressive muscle deterioration and weakness.
Exondys 51, also known generically as eteplirsen, is specifically indicated for patients who have a confirmed mutation of the dystrophin gene amenable to exon 51 skipping, which affects about 13% of the DMD population. Under the accelerated approval procisions, the FDA is requiring the manufacturer to conduct a cliical trial to confirm the drug’s clinical benefit in improving motor function.
Exondys 51 doesn’t cure Duchenne muscular dystrophy and will only help a minority of patients. It is designed for the 13% of patients with a particular genetic mutation that prevents them from making dystrophin, a key protein that keeps muscles intact. Without that protein, muscles weaken so that children are unable to walk and must use wheelchairs by the time they’re teens. Eventually, the disease can fatally weaken the heart and muscles needed to breathe. Patients often die in their 20s or 30s.
The FDA’s decision speeds up the approval process for Exondys 51, allowing it onto the market based on preliminary data that suggests the drug will strengthen children’s muscles, even though the company has not yet produced clear proof that the medication will delay paralysis or improve symptoms.
In clinical trials, some patients treated with Exondys 51 had more dystrophin in their skeletal muscles, which people use to move their arms and legs. The FDA will require Sarepta to launch another clinical trial to show whether it actually improves patients’ symptoms. If the drug doesn’t help, the FDA could withdraw approval.
Source: US Pharmacist