The FDA has issued Merck a not approvable letter regarding its developmental cholesterol-lowerer dubbed Cordaptive.
Regulators have also rejected the brand name of Cordaptive for the drug, which is also known as Mk-0524a. The drug is a combination of good-cholesterol raising vitamin niacin and laropiprant, a drug designed to lessen the facial flushing caused by niacin.
Merck said it plans to meet with the agency to provide additional data and further examine the drug’s benefit-risk profile. 
Merck planned to package Cordaptive with its treatment Zocor, a $5 billion-a-year blockbuster before losing patent protection in 2006.
The failure of Cordaptive “comes as a surprise, given the publicly disclosed data,” said Deutsche Bank analyst Barbara Ryan in a note to investors today. “Without more information, it is difficult to gauge what the FDA took issue with, or what additional data Merck could provide to gain approval.”