Federal regulators on Monday granted tentative approval to the first drug for muscular dystrophy, following an intense public campaign from patients and doctors who pushed for the largely unproven medication.
The approval comes nearly five months after the Food and Drug Administration and a panel of outside advisers panned the drug, saying there was little evidence that it helped. But regulators faced a public backlash from patients' families, politicians and physicians.
The FDA cleared Sarepta Therapeutics' Exondys 51 for a rare form of Duchenne muscular dystrophy, a deadly inherited disease that affects boys. It's the first FDA approval for the degenerative condition, which causes muscle weakness, loss of movement and eventually death.
The approval was based on a company study of just 12 boys. The agency is requiring Sarepta to conduct a larger study examining whether Exondys 51 results in improved movement and function for patients. If the study fails to shows it helps, the FDA said it could withdraw the drug.
Duchenne's muscular dystrophy is a rare disease, affecting about 1 of every 3,600 boys worldwide and usually causing death by age 25, according to the National Institutes of Health.
The new drug targets a genetic mutation that affects about 13 percent of Duchenne's patients. Previously there were no U.S.-approved drugs to fight the disease, though steroid drugs have been used to slow the loss of muscle strength.
The FDA cleared Sarepta's drug under its accelerated approval program, reserved for drugs that show promising early results that have not been confirmed. The drug acts on a protein called dystrophin, which plays a role in the growth of muscle fibers. The 12-patient study showed an increase in dystrophin "that is reasonably likely to predict" benefit in some patients, the FDA said in its announcement
"Accelerated approval makes this drug available to patients based on initial data, but we eagerly await learning more about the efficacy of this drug through a confirmatory clinical trial," said Dr. Janet Woodcock, director of the FDA's drug center.
FDA staff said at a public meeting in April that they "strongly encouraged" Sarepta to conduct a larger, more comprehensive study of its drug with a randomly selected control group of patients receiving a placebo — considered the gold standard of study design.
An outside panel of experts voted 7-3 at the meeting that the drug did not show effectiveness in treating the disease. The FDA is not required to follow the advice of its advisory panels, though it often does.
Shares of Sarepta Therapeutics jumped more than 75 percent to $21.37 in morning trading. The company is based in Cambridge, Massachusetts.