In a confrontation between the hopes of desperate patients and clinical trial data, advisers to the Food and Drug Administration voted on Monday not to recommend approval of what would become the first drug for Duchenne muscular dystrophy.
The negative votes came despite impassioned pleas from patients, parents and doctors who insisted that the drug, called eteplirsen, was prolonging the ability of boys with the disease to walk well beyond when they would normally be in wheelchairs.
The problem was that the drug's manufacturer, Sarepta Therapeutics, was trying to win approval based on a study involving only 12 patients without an adequate placebo control.
The advisory panel voted 7 to 3, with three abstentions, that the clinical data did not meet the F.D.A. requirements for well controlled studies necessary for approval. However, some of the panel members had trouble reconciling the often compelling patient testimony with the F.D.A. legal requirements.
"I was just basically torn between my mind and my heart," said Richard P. Hoffmann, a pharmacist who was the consumer representative on the committee and who abstained.
Dr. Bruce I. Ovbiagele, chairman of neurology at the Medical University of South Carolina, voted against approval but said, "Based on all I heard, the drug definitely works, but the question was framed differently."
On another question of whether the drug could qualify for so-called accelerated approval, a lower hurdle, the panel voted 7 to 6 against the drug.
The F.D.A., which does not have to follow the advice of its advisory panels, is scheduled to decide whether to approve eteplirsen by May 26.