Andrx

(ADRX)

got tentative approval from the Food and Drug Administration to sell a generic version of

Pfizer's

(PFE) - Get Report

diabetes treatment Glucotrol, although patent litigation over the drug continues.

Traders pushed the shares up 81 cents, or 5%, to $17.85 on the Instinet premarket session following the news.

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Andrx's version of the treatment, which is known generically as glipizide, will be a 10-milligram extended-release tablet. The company said Glucotrol XL did $217 million of sales in 2002. The company is seeking regulatory approval for 2.5-milligram and 5-milligram tablets as well.

Andrx was sued by Pfizer and Alza, which is now owned by

Johnson & Johnson

(JNJ) - Get Report

, in 2001. The companies alleged the generic version infringed several patents they owned.

"The 30-month stay of FDA regulatory approval applicable to this

abbreviated new drug application will not expire until November 2003," Andrx noted. "The patent infringement litigation pending between Andrx, Pfizer and Alza Corp., with respect to the three Glucotrol XL strengths for which Andrx has pending ANDAs, is continuing."