After consecutive litigation losses against Pfizer in its bid to grab a market share of the world's largest selling drug, Lipitor, Ranbaxy can now breathe easy. Last week, the Indian company got a shot in the arm, with the US Patent and Trademark Office (USPTO) issuing a a preliminary rejection of Pfizer's request for reissue of a patent for Lipitor. The verdict gives Ranbaxy hope to launch the cholesterol lowering drug Lipitor as early as March 2010. In 2007, the patent office had issued its first non-final rejection of Pfizer's request for a reissue of patent to extend Lipitor's US-market exclusivity by about 15 months, to June 2011. A Pfizer spokeswoman is reported to have said that the company would review the preliminary rejection. "Such rejections of patent reissue requests are relatively common and the company will continue to pursue the re-issue. We are confident that we will be able to address the issues raised by the examiner," she said. The global market for Lipitor is estimated to be around $13 billion, of which the US alone constitutes $8.5 billion. The USPTO's verdict has come following Ranbaxy's request for a re-examination of the '893 basic patent for Lipitor. Ranbaxy and Pfizer are engaged in patent infringement battles in various countries, including the UK and other European countries. Atorvastatin is a member of the drug class known as statins which are used to lower cholesterol. In March, Ranbaxy suffered a major setback in its ongoing Lipitor battle, following a federal court in Canada reversing a lower court order which held that Pfizer's Enantiomer (calcium salt) patent could not block Ranbaxy from obtaining approval for a generic counterpart to Lipitor. The ruling prevented Ranbaxy from launching the generic version in the Canadian market until 2010, when Pfizer's Canadian patent for Enantiomer expires. A Ranbaxy spokesperson said, "The USPTO's decision of rejecting the reissue of Pfizer's application is self- explanatory." In December 2007, a US federal judge ruled in favour of Pfizer by deciding to grant Pfizer's motion to dismiss Ranbaxy's counterclaims, following Ranbaxy's suit against Pfizer for the marketing rights of Caduet, a combination of the active ingredients in Lipitor (atorvastatin calcium) and its hypertension drug Norvasc (amlodipine besylate). However, Ranbaxy has received favourable verdicts from the courts in Austria, the Netherlands and Spain in the suits filed against Pfizer.