UPDATE 1-AstraZeneca trial to compare Crestor and Lipitor

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LONDON, Jan 15 (Reuters) - AstraZeneca Plc (AZN.L) announced on Tuesday the first head-to-head clinical trial comparing its cholesterol-fighting drug Crestor with Pfizer Inc's (PFE.N) Lipitor, the world's top-selling medicine.

The Anglo-Swedish drugmaker said the new trial, called SATURN, would compare the drugs' ability to reduce the progression, or induce regression, of atherosclerosis, the main cause of cardiovascular disease, following two years of treatment in patients with coronary artery disease.

Lipitor and Crestor are the two most potent drugs within a class of medicines called statins. Lipitor made $12.9 billion of sales in 2006, compared with Crestor's $2 billion.

News of the trial comes a day after U.S drugmakers Merck & Co (MRK.N) and Schering-Plough Corp SGP.N said their shared Vytorin cholesterol treatment failed to significantly halt clogging of arteries better than an older generic drug.

AstraZeneca said the first of around 1,300 patients in the SATURN trial would be enrolled later this month and the study was expected to complete in 2011.

At 1340 GMT, AstraZeneca shares were down 2.8 percent at 2,243 pence, underperforming a 1.6 percent fall on the the DJStoxx European healthcare index SXDP.

(Reporting by Mark Potter, Editing by Dan Lalor/Rory Channing)

((mark.potter@reuters.com; +44 20 7542 7717; Reuters Messaging: mark.potter.reuters.com@reuters.net)) Keywords: ASTRAZENECA/

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