AstraZeneca PLC (AZN) has asked a U.S. court for an early ruling on a patent dispute over the U.K. company's blockbuster statin Crestor which is being challenged by a number of generic firms planning to sell their own versions of the cholestrol-lowering drug.

The U.K.'s second-biggest drug maker by sales after GlaxoSmithKline PLC (GSK) filed for summary judgment in the U.S. District Court for the District of Delaware on Friday, an AstraZeneca spokesman said. If the court refuses to deal with the dispute on this basis, the case will have to go to a full trial which isn't scheduled to take place until February next year, he added.

The seven generic companies include Mylan Inc. (MY) of the U.S., Sandoz, the generic arm of Swiss Novartis AG (NVS) , Canada's Apotex Inc. and Cobalt Pharmaceuticals Inc., India's Aurobindo Pharma Ltd. (524804.BY) and Sun Pharmaceutical Industries (524715.BY) and Par Pharmaceutical Cos. (PRX).

All seven companies announced in 2007 that they intended to sell generic versions of Crestor. Israel's Teva Pharmaceutical Industries Ltd. (TEVA) made a later announcement in June last year and isn't included in the consolidated action.

Giant pharma companies are coming under increasing pressure as their blockbuster drugs face patent expiry, exposing them to cheaper generic versions. In addition to an increase in patent litigation to counter this, the traditional drugmakers are increasing investment in young biotech companies either buying them outright or entering into joint ventures to boost their pipelines which is more cost-effective than building up their own R&D units.

Crestor, which lowers cholesterol and has also been shown to lower the risk of heart attacks in patients who wouldn't normally take a cholesterol-lowering pill, sold $3.6 billion worldwide in 2008.

-By Marietta Cauchi, Dow Jones Newswires; +44 207 842 9241; marietta.cauchi@dowjones.com