Pfizer sues Ranbaxy to halt generic Lipitor

NEW YORK Pfizer has filed a lawsuit against Ranbaxy Laboratories in an attempt to block it from marketing a generic version of its best-selling drug Lipitor, according to published reports.

The suit filed by Pfizer in the U.S. District Court in Delaware claims Ranbaxy's generic would infringe two patents covering the process for making Lipitor that don't expire until July 2016.

Lipitor had sales of $12.7 billion in 2007.

Separately, Pfizer filed another suit against Ranbaxy citing the same patents in order to extend the exclusivity of Caduet, a combination of Lipitor and hypertension drug Norvasc. Caduet had 2007 sales of $568 million.