A Missouri judge handed European drug giant AstraZeneca ( AZN) a defeat in a case involving two patents for the hypertension drug Toprol-XL, finding both invalid and unenforceable.

AstraZeneca said it will appeal the ruling. Both patents are due to expire in September 2007.

The patents had been challenged by Andrx ( ADRX), KV Pharmaceutical ( KV.A) and Eon Labs, a unit of Novartis ( NVS), who want to sell generic versions of Toprol-XL.

The drug, in addition to treating hypertension, is also used for the long-term treatment of angina pectoris and certain types of heart failure. Andrx believes it may be entitled to 180 days of market exclusivity on the 50 mg strength of generic Toprol-XL. The drug had total U.S. sales of $1.29 billion last year, AstraZeneca said.

Shares of Andrx were rising 4.9% to $17.40 in premarket trading. AstraZeneca's American depositary shares were losing 3.8% to $47.48.

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