Aug. 17 (Bloomberg) -- Eli Lilly & Co.’s method of use patent for its cancer drug Gemzar was invalidated by a federal court in Michigan, the drugmaker said today.

The court ruled in a lawsuit filed by generic drug maker Sun Pharmaceutical Industries Ltd., said Mark Taylor, a spokesman for Lilly. The patent at issue deals with methods of use for Gemzar, which was set to expire in 2013.

The decision has no bearing on Lilly’s compound patent for Gemzar, a medicine for lung, breast, pancreatic and ovarian cancer with 2008 worldwide sales of $1.7 billion, Lilly said in a statement. Mira Desai, a Sun Pharmaceutical spokeswoman in Mumbai, declined to comment.

“Today’s court decision does not allow for the immediate entry of generic gemcitabine in the U.S. market,” Robert Armitage, general counsel at Lilly, said in a statement. “Gemzar’s compound patent remains in force through 2010.”

Sun Pharmaceutical sued Lilly in 2007 claiming its method of use patent for Gemzar is invalid. Sun is seeking to market a generic version of the drug before Lilly’s patent expires, court documents say. Lilly claimed Sun’s generics infringe on its Gemzar patents.

Sun Pharmaceutical declined 0.9 percent to 1,170 rupees as of 9:56 a.m. in Mumbai trading, while India’s benchmark Sensitive Index gained 0.5 percent.

Lilly plans to appeal the ruling, according to the company’s statement.

The case is Sun Pharmaceutical v. Eli Lilly, 07-15087, U.S. District Court, Eastern District of Michigan (Detroit).

To contact the reporter on this story: Karen Gullo in San Francisco at kgullo@bloomberg.net.

Last Updated: August 18, 2009 00:33 EDT