US court overturns prior ruling on lipitor patent

Pfizer's patent battle with Ranbaxy over the blockbuster anti-choloesterol drug lipitor rumbles on as the US Court of Appeals for the Federal Circuit (CAFC) judged one of Pfizer's atorvastatin patents, invalid but upheld another.

The cholesterol-lowering drug atorvastatin, marketed by Pfizer as Lipitor, is the largest-selling drug in the world with estimated annual sales in the US of US$8.5bn. Ranbaxy has challenged two key atorvastatin patents held by Pfizer

The CAFC sided with Ranbaxy by invalidating one of Pfizer's atorvastatin patents, US Patent No. 5,273,995. The decision overturns a Delaware District Court judgement. However, it affirmed the judgement that Ranbaxy's product infringes Pfizer's US Patent No. 4,681,893.

Commenting on the decision, Jay Deshmukh, senior vice-president, Global IP 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."

Subject to the appellate process and market authorisation by the US Food & Drug Administration, Ranbaxy now has the opportunity to bring the launch date forward to March, 2010 from June, 2011 with 180-day exclusivity in the US market.

Peter Richardson, Pfizer's senior vice-president, associate general counsel and chief of intellectual property said: "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.

"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."

Either party may seek review of the decision by the full US Court of Appeals for the Federal Circuit.