U.S. court upholds patent on Forest's Lexapro

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WASHINGTON, Sept 5 (Reuters) - A federal appeals court on Wednesday upheld the validity of a key patent on Forest Laboratories' (FRX.N: Quote, Profile, Research, Stock Buzz) blockbuster depression drug Lexapro and confirmed a lower court's decision to block sales of generic forms of the drug made by Teva Pharmaceutical Industries Ltd (TEVA.O: Quote, Profile, Research, Stock Buzz) and Cipla Ltd (CIPL.BO: Quote, Profile, Research, Stock Buzz).

The U.S. Court of Appeals for the Federal Circuit rejected an appeal by Teva aimed at overturning a 2006 decision by a federal court in Delaware, sending Forest shares up as much as 14.5 percent.

Forest filed suit in September 2003 alleging that the generic version of Lexapro infringed its patent covering the active ingredient in the drug.

Last year the lower court agreed, upholding the patent's validity and barring Teva and Cipla from selling any products that infringed on the patent.

In Wednesday's ruling, the appeals court modified the lower court's injunction so that it only applies to escitalopram oxalate, the active ingredient in Lexapro.

A representative of Teva was not immediately available for comment.

Shares of Forest pared their gains slightly to be 11 percent higher at $42.04 in afternoon trading on the New York Stock Exchange. Teva stock was 13 cents higher at $43.76 on Nasdaq.