Ranbaxy Laboratories received another blow and lost Lipitor patent case against Pfizer in Court of Appeals for the Federal Circuit. A panel of the Court of Appeals for the Federal Circuit has upheld the exclusivity of the main patent covering atorvastatin, the active ingredient in Lipitor, maintaining patent protection for Lipitor in the US until March 2010.

The Appeals Court also ruled that a second patent (US 5,273,995) at issue in the lawsuit covering the calcium salt of atorvastatin is invalid on technical grounds. That patent would have expired in June 2011.

The Appeals Court ruled in a lawsuit brought by Pfizer against the generic manufacturer Ranbaxy Ltd. The court held that Ranbaxy's generic atorvastatin product would infringe the company's basic patent (US 4,681,893) broadly covering atorvastatin.

In December 2005 the US District Court of Delaware ruled against Ranbaxy Laboratories in its case for non-infringement and invalidation of two Pfizer patents on atorvastatin.

"While we are pleased that the court has affirmed that our basic patent is valid and infringed, we are disappointed in the decision on the '995 patent," said Peter Richardson, Pfizer's senior vice president, associate general counsel and chief of intellectual property. "The decision turned on a technical defect in the patent. There is a process for correcting such defects in the US Patent and Trademark Office, and Pfizer plans to pursue that option."

In addition, either party may seek review of the decision by the full US Court of Appeals for the Federal Circuit.

Commenting on the decision, Jay R. Deshmukh, senior vice president, Global Intellectual Property for Ranbaxy said, "We are pleased by the Courts decision on the '995 patent and are evaluating our options with respect to the '893 patent."