FDA puts off its decision on BioMarin's DMD drug with Sarepta on the docket

The FDA is postponing its final decision on BioMarin's ($BMRN) treatment for Duchenne muscular dystrophy after taking a dim view of the drug in a staff-prepared review.

The drug, drisapersen, is designed to slow the effects of DMD, a rare and fatal disease that leads to progressive muscle deterioration. The FDA had promised to make up its mind on BioMarin's treatment by Dec. 27 but has now pushed that date to "early January," the company said.

The FDA delay follows last month's roundly negative reception for drisapersen at a meeting of independent agency advisers. The FDA's outside experts took BioMarin to task for what they saw as a flimsy case for the drug's efficacy that didn't make up for some alarming safety risks observed in drisapersen's supporting trials. The panelists echoed a harshly critical review from FDA staff released ahead of the discussion. Following the meeting, a few analysts completely ruled out the possibility of BioMarin's drug winning approval, while even the most optimistic voices on Wall Street give it a 50-50 chance.

Meanwhile, Sarepta Therapeutics ($SRPT) and its rival DMD treatment are slated to go before the same panel on Jan. 22, seeking approval for a therapy that has had a similarly rocky path through clinical development. After BioMarin's tough time at the FDA panel, many expected the agency might delay its decision on drisapersen until Sarepta's drug, eteplirsen, went before the same committee. BioMarin's assertion that the agency plans to hand down final word in the early days of January suggests that won't happen, but the agency could well delay the process further.

Both drugs target the roughly 13% of DMD patients whose disease stems from a flaw in the gene responsible for producing the protein dystrophin. Each works by getting the body to skip over that genetic defect, restoring the flow of dystrophin and alleviating symptoms of DMD.

- read the statement