Aug. 16 (Bloomberg) -- Ranbaxy Laboratories Ltd., India's biggest drugmaker, asked a U.S. appeals court to reconsider a ruling that would keep a generic version of Pfizer Inc.'s cholesterol medicine Lipitor off the market until 2010.

The U.S. Court of Appeals for the Federal Circuit in Washington on Aug. 2 upheld a patent on the drug that expires March 24, 2010, and invalidated one that expires June 28, 2011. Ranbaxy, which was challenging both patents, filed papers today asking the appeals court to reconsider the ruling on the 2010 patent.

Lipitor had sales of $12.2 billion last year, making it the world's best-selling drug. Analysts had projected that the drug, which accounts for about 40 percent of Pfizer's profit, wouldn't have competition from cheaper generic versions until June 2011. Today was the deadline for the companies to ask the court to reconsider any aspect of the ruling that didn't go their way.

``We have not yet filed anything with the appeals court,'' Pfizer spokesman Bryant Haskins said. He declined to comment further on Pfizer's plans.

The 2010 patent originally was set to expire in May this year. U.S. government agencies extended the term to 2009 to reimburse Pfizer for the time it took to get Food and Drug Administration approval for Lipitor. It was further extended an additional six months to March 2010 because Pfizer planned to test the drug's effects on children.

Narrow Scope

Ranbaxy claims that Pfizer told the patent office that the application covered a narrow scope of the drug compound to obtain the patent, and then claimed it covered a broader area to get the term extended.

``Rather than foster disclosure, the panel's decision allows patentees to take contradictory positions before the PTO regarding the same patent with impunity,'' Ranbaxy wrote.

The Gurgaon, India-based drugmaker also wants the court to reconsider the ruling that Ranbaxy's generic version would infringe the patent.

On the 2011 patent, the Federal Circuit, applying a standard it set in an unrelated case in February, said it was invalid because wording was inconsistent in what it covered.

On Aug. 2, Pfizer called the invalidity ruling the result of a ``technical defect'' that might be fixed by asking the U.S. Patent and Trademark Office to reissue the patent with the necessary change. Should it obtain a new patent, Pfizer could file another lawsuit to block generic Lipitor until 2011.

Ranbaxy Filing

In its filing today, Ranbaxy asked the Federal Circuit to either make it clear that the defect is one that can't be fixed in the patent office, or address Ranbaxy's arguments that the patent is invalid for other reasons as well.

Such a ruling ``would bring finality or at least clarify and narrow any remaining dispute,'' Ranbaxy said.

Shares of New York-based Pfizer rose 35 cents to $26.75 today in New York Stock Exchange composite trading. They've risen 2.7 percent in the past year.

The case is Pfizer Inc. v. Ranbaxy Laboratories Ltd., 06- 1179, U.S. Court of Appeals for the Federal Circuit. The lower court case is Pfizer Inc. v. Ranbaxy Laboratories Ltd., 03cv209, U.S. District Court, District of Delaware (Wilmington).

To contact the reporter on this story: Susan Decker in Washington at sdecker1@bloomberg.net; Shannon Pettypiece in Washington at spettypiece@bloomberg.net.

Last Updated: August 16, 2006 16:12 EDT