Merck blood clot drug in limbo after mixed results
March 24, 2012 at 09:25 AM EDT
CHICAGO, March 24 (Reuters) - Impressive efficacy but worrisome bleeding was seen for a new type of blood clot preventer tested by Merck & Co in one of the largest heart-drug studies ever conducted, raising questions whether the company will seek approval of the drug and whether it can pass muster with regulators, researchers said on Saturday.