Nov. 17 (Bloomberg) -- Eli Lilly & Co. sued four generic- drug makers, including Novartis AG's Sandoz Inc., that have been seeking to produce and market their own version of the antidepressant Cymbalta drug.

Wockhardt Ltd., Impax Laboratories Inc. and Cobalt Laboratories Inc. were also accused in separate lawsuits of trying to manufacture a drug that infringes on Lilly's patent, which doesn't expire until June 2013. In the lawsuits filed in federal court in Indianapolis on Nov. 14, Lilly is seeking an order that the companies are infringing its patent and halt them from seeking approval for their products.

Cymbalta has been Lilly's second-biggest product, with sales increasing 40 percent in the company's third-quarter to $716.4 million, the company said on Oct. 23.

Sandoz, Impax, Cobalt and Wockhardt have filed papers with the U.S. Food and Drug Administration seeking approval for its Duloxetine HCL capsules, which violate Lilly's patent, the Indianapolis-based company claims.

Representatives for Hayward, California-based Impax, Bonita Springs, Florida-based Cobalt and the U.S. representatives from Maharashtra, India-based Wockhardt, and Basil, Switzerland-based Sandoz didn't immediately return calls seeking comment on the lawsuits.

Lilly, which agreed to buy ImClone Systems Inc. on Oct. 6 for $6.5 billion, rose 7 cents to $32.13 today in New York Stock Exchange composite trading.

The cases are Eli Lilly v. Sandoz Inc., 08cv1548; Eli Lilly v. Wockhardt Ltd., 08cv1547; Eli Lilly v. Impax Laboratories Inc., 08cv1549; and Eli Lilly v. Cobalt Laboratories Inc., 08cv1550, U.S. District Court for the Southern District of Indiana (Indianapolis).

To contact the reporters on this story: William McQuillen in Washington at bmcquillen@bloomberg.net.

Last Updated: November 17, 2008 17:54 EST