Shares of Amarin Corp. dropped almost 60 percent in premarket trading Thursday, a day after a panel of federal health advisers dealt a major blow to the specialty drugmaker's plans to expand the use for its prescription fish-oil drug.
A Food and Drug Administration's panel of outside advisers voted 9-2 on Wednesday against recommending broader use of Vascepa, which is designed to lower triglycerides, a type of fat in the bloodstream.
Vascepa was approved in 2012 for a relatively narrow use in patients with unusually high triglyceride levels. Dublin-based Amarin has asked the FDA to allow marketing of the drug for patients with high triglyceride levels and heart disease who are already taking a statin drug to help control their cholesterol.
A majority of panelists said that while Vascepa significantly lowers fat levels, it is unclear whether that actually translates into fewer heart attacks. The panel members said the FDA should delay a decision on expanding the drug's use until Amarin completes a study of heart attack rates in patients. Results from that study are not expected until 2015 or 2016.
The FDA is scheduled to make a ruling on Vascepa by Dec. 20. It often follows the recommendation of its advisory panels.
The panel's decision surprised Jefferies analyst Thomas Wei, who had said he expected members to vote 7-3 in favor of the expanded use. He said in a Thursday morning research note that a delay for the study data could push back the debut of the drug's expanded label until 2019.
If the expanded use is never approved, Wei values the company at only $1 per share. But he said its acquisition value could be higher due in part to advantages like Amarin's Irish tax rate.
Amarin shares sank 59 percent, or $3.04, to $2.13 in premarket trading about 75 minutes ahead of the market opening. That put the shares down more than 75 percent since closing 2012 at $8.09.