R&D In Brief

Zetia/Lipitor combo NDA becomes Merck's latest cardiovascular casualty: FDA refused to file Merck's NDA for a fixed-dose combination pill of ezetimibe (Merck's Zetia) and atorvastatin (Pfizer's Lipitor) known as MK-0653C, the drug maker revealed in a filing with the SEC on Nov. 2. "FDA has identified additional manufacturing and stability data that are needed, and the company is assessing the FDA's response in order to determine a new timetable for filing," Merck said. Ezetimibe, a cholesterol absorption inhibitor, is approved in the fixed-dose combination Vytorin with a different statin, simvastatin (Merck's Zocor and generics), that has faced its share of controversy. The ENHANCE study found that Vytorin was no better than simvastatin alone in preventing the formation of arterial plaque, despite lowering cholesterol (1"The Pink Sheet," April 21, 2008). Other Merck attempts at expanding its cardiovascular franchise have also hit roadblocks, including the heart failure candidate rolofylline, which flunked a Phase III trial in April, and the combination of niacin with the novel anti-flushing agent laropitant, which was deemed "not approvable" in 2008 and is not expected to be refiled until at least 2013 (2"The Pink Sheet" DAILY, June 20, 2008)