(RTTNews) -  In a regulatory filing Monday, Merck & Co. Inc. (MRK: News ) announced that the Food and Drug Administration recently refused to file the application for MK-0653C, a combination of ezetimibe, the active ingredient in cholesterol drug, Zetia, with atorvastatin, the active ingredient in Pfizer Inc.'s (PFE: News ) Lipitor.

Merck submitted for filing a New Drug Application with the FDA for MK-0653C in September of this year. The regulatory agency has identified additional manufacturing and stability data that are needed to support the NDA and the company is assessing the FDA's response in order to determine a new timetable for filing.

In March 2007, Merck along with its partner Schering-Plough Corp. (SGP) decided to develop a new cholesterol drug, combining their Zetia with Pfizer's blockbuster Lipitor after its patent expiry in 2010. Zetia is developed by Schering-Plough and co-marketed by Merck.

Merck and Schering-Plough already market a combination cholesterol pill Vytorin -- a combination of Zetia and Zocor, which lost patent protection in 2006. The combined sales of Merck's cholesterol drugs, Vytorin and Zetia have taken a hit ever since the results of a study dubbed ENHANCE revealed in January 2008 that though Vytorin lowers bad LDL cholesterol, it did not provide any significant benefit over generic Zocor in reducing the risk of heart disease or stroke. For the nine months ended September 30, 2009 combined sales of Vytorin and Zetia dropped to $3 billion from $3.49 billion in the year-ago period.
Late last month, Merck and Schering-Plough received clearance from the U.S. Federal Trade Commission, the European Commission, the Swiss Competition Commission and the Canadian Competition Bureau for their proposed merger. The estimated $41 billion cash-and-stock deal between Merck and Schering-Plough has been structured as a reverse merger. Under the reverse merger, Merck would technically become a wholly owned subsidiary of Schering even though it is Merck, which is acquiring Schering. The combined company will be headed by Merck Chief Executive Officer Richard Clark. The transaction is expected to close this quarter.

MRK closed Monday's trading at $31.26, up 1.07%, on a volume of 21.39 million shares. In after-hours trading, the stock lost 0.03% and was at $31.25.

To receive FREE breaking news email alerts for Merck & Co Inc. and others in your portfolio

by RTT Staff Writer

For comments and feedback: contact editorial@rttnews.com