US drugmakers Merck & Co and Schering-Plough are planning to capture a bigger slice of the cholesterol-lowering market by developing a combination of Zetia and Pfizer’s Lipitor.

Lipitor (atorvastatin), the world’s top-selling drug, pulled in sales of $12.9 billion for Pfizer in 2006, but is likely to lose its patent armour in 2011, opening the floodgates to a potential rush of copycat versions all vying for a piece of this highly-lucrative market.

Merck & Co and Schering-Plough say they are trying to get their new combination ready for launch as soon Lipitor’s patent expires. The groups already market the cholesterol-buster Vytorin - a combination of Zetia (ezetimibe) and Merck's statin Zocor (simvastatin) - and industry observers suggest that, if successful, the new combo may well eat into Vytorin’s market share.

Dual inhibition

Zetia works in the digestive tract to inhibit the absorption of cholesterol and the statin Zocor reduces the production of cholesterol in the liver, and together they offer a powerful tool in the management of blood lipids. “The dual inhibition approach to the treatment of elevated cholesterol has clearly been established,” said Peter Loescher, President of Global Human Health at Merck & Co. “The development of ezetimibe and atorvastatin is an extension of this approach,” he explained.

And Schering-Plough’s Chairman and Chief Executive Fred Hassan is certainly optimistic about the product’s potential. "Given the size of the worldwide market in which this product would compete, we believe the combination of ezetimibe with atorvastatin could be an important contributor to Schering-Plough’s future," he said.

The cholesterol-management market is one of the largest worldwide, with 2006 total global sales of $32 billion (according to IMS Health).