FDAnews Drug Daily Bulletin

The U.S. Patent & Trademark Office (USPTO) has notified Pfizer that it will confirm the viability of the company’s ’893 basic patent for cholesterol drug Lipitor.

The office had conducted a patent re-examination in response to a request by a law firm representing Ranbaxy. The patent, which expires in March 2010, has been the subject of past litigation.

The USPTO’s decision is the latest chapter in Pfizer’s worldwide fight to prevent Ranbaxy from launching a generic version of Lipitor (atorvastatin calcium) before the patent expires. In March, a Canadian appeals court overturned a lower court decision and found that Pfizer’s ’546 patent on Lipitor is valid. The ruling prevents Ranbaxy Laboratories from launching its generic version of the drug in that country until 2010.

The ruling overturned a Federal Court of Canada judge who found the ’546 patent invalid for not correctly describing the invention. The lower court had upheld Pfizer’s basic Lipitor patent, which expired in May 2007.

Pfizer has filed separate lawsuits against Ranbaxy to prevent the firm from marketing generic versions of Lipitor and Caduet, which combines Lipitor with Pfizer’s hypertension drug Norvasc (amlodipine besylate), until after two of its process patents expire.