In 'Perplexing' Move, FDA Approves First Muscular Dystrophy Drug Drug is controversial, not clear how effective it is By Newser Editors and Wire Services Posted Sep 19, 2016 6:54 PM CDT 18 comments Comments This Oct. 14, 2015, file photo shows the Food and Drug Administration campus in Silver Spring, Md. (AP Photo/Andrew Harnik, File)This Oct. 14, 2015, file photo shows the Food and Drug Administration campus in Silver Spring, Md. (AP Photo/Andrew Harnik, File) (Newser) – 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 AP reports. The approval came despite an internal dispute among Food and Drug Administration officials that ultimately had to be resolved by the agency's chief. Some staffers said there was little evidence the drug worked. Adding to the high-stakes decision, officials faced direct pleas 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 about 1 of every 3,600 boys worldwide and usually causes death by age 25. It's the first FDA approval for the degenerative condition, which causes muscle weakness and loss of movement before 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. The new drug targets a genetic mutation that affects about 13% of Duchenne's patients. Previously there were no US-approved drugs to fight the disease, though steroid drugs have been used to slow the loss of muscle strength. At a public meeting in April, an outside panel of experts did not support the drug's approval, voting 7-3 that it 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. The final ruling was made by FDA Commissioner Dr. Robert Califf. Wall Street analysts called the approval decision surprising and perplexing.