U.S. Patent Office rejects Lipitor patent extension, again
The U.S. Patent and Trademark Office has issued another preliminary rejection of Pfizer’s request for the reissue of a patent for cholesterol drug Lipitor.

The decision represents another setback in Pfizer’s attempt to extend Lipitor's U.S. market exclusivity by an additional 15 months to June 2011. The original Lipitor patent remains in effect until March 2010, after which the drug would become subject to generic competition.

The company said it will review the preliminary rejection, and continue to pursue the reissue. “We are confident that we will be able to address the issues raised by the examiner,” said Pfizer spokeswoman Vanessa Aristide.

The Lipitor patent rejected last week by the patent office was originally set to expire in June 2011; however, it was invalidated in 2006 by a federal appeals court after being challenged by Ranbaxy Laboratories, an Indian drug company that wants to sell a generic version of Lipitor.

The New York City-based Pfizer applied to the patent office in 2007 to have the 2011 patent reissued, saying it merely had to correct a “technical defect” in the patent.

However, in August 2007, the patent office issued its first “non-final rejection” of Pfizer’s request for a reissue.

Lipitor had nearly $13 billion in sales in 2007, making it the best-selling drug in the world. Pfizer relies heavily on the product for its sales and profitability, and the company is not currently well-positioned to offset the revenue lost to generic competition for Lipitor, according to Dow Jones News.