An experimental drug to treat Duchenne muscular dystrophy, a devastating degenerative disease that mostly affects young boys, was not supported by enough evidence to prove it is effective, a U.S. advisory panel concluded, decreasing the drug's chances of approval.

The vote followed an emotional meeting at a hotel in Hyattsville, Maryland, in which hundreds of patients and their advocates gathered to urge the Food and Drug Administration to approve the drug, Sarepta Therapeutics Inc's eteplirsen, saying their children had benefited from it.