UPDATE 2-Swiss order withdrawal of Novartis's Zelnorm

(Adds company comment, background)

ZURICH, May 31 (Reuters) - Swiss health authorities ordered on Thursday the withdrawal of Novartis's (NOVN.VX) Zelmac, known as Zelnorm in the United States, for the treatment of irritable bowel syndrome. "After analysing new scientific data, Swissmedic has refused to extend the licence as the risks are greater than the benefit," Switzerland's regulatory agency said in a statement.

Swissmedic said the new analysis showed a higher cardiovascular risk in use of Zelnorm when compared to placebo.

Novartis shares were 0.2 percent lower at 68.75 Swiss francs by 1242 GMT, slightly lagging an index of European healthcare rivals .SXDP.

"I can confirm that Novartis is complying with the Swissmedic request," a company spokeswoman said. "Right now we are evaluating."

Novartis pulled Zelnorm from U.S. shelves earlier this year at the request of regulators because clinical trial data indicated a possible link to heart attacks and strokes.

That move was a blow to prospects for the drug, which previously had run into safety issues and was never approved for use in the European Union, prompting the Swiss drugmaker to cut its 2007 sales forecast.

Zelnorm had total sales of $561 million in 2006, of which $488 million was generated in the United States.

U.S. Food and Drug Administration officials have said Zelnorm might be able to return on a limited basis but only if a group of patients could be identified for whom the benefits outweighed the risks.

Switzerland had approved use of Zelnorm in women with irritable bowel syndrome in 2001. Swissmedic had already issued new administration recommendations in March 2007.

((Reporting by Sam Cage, editing by Sue Thomas;

Email: zurich.newsroom@reuters.com

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