Updated from 11:12 a.m. EDTA British court on Wednesday declared a split decision for Pfizer's ( PFE) cholesterol fighter Lipitor, upholding the drug's main patent but declaring another patent invalid. Pfizer was challenged by India's Ranbaxy Laboratories, a generic drugmaker that has filed patent challenges against Lipitor in several countries, including the U.S. Shares of Pfizer were up 51 cents, or 2.1%, to $24.81 in heavy trading, thanks to a decision that will have more of a psychological impact on investors than a financial impact on the New York-based drug company. Analysts said Pfizer would have had to lose both patent challenges in order for Ranbaxy to have begun selling a copy of Lipitor, the world's best-selling prescription drug. Lipitor produced $10.9 billion in sales for Pfizer last year and accounted for 24% of corporate revenue. Because British patent law is different from U.S. law, the split decision is unlikely to have any effect on the U.S. case. A U.S. federal court judge is expected to issue a ruling in late 2005 or early 2006. The decision by the U.K.'s High Court of Justice upholding the key patent covering Lipitor until November 2011 "is an important victory not only for Pfizer but for all innovators pursuing high-risk medical discoveries," said Hank McKinnell, Pfizer's chairman and CEO, in a prepared statement. Pfizer said it would appeal the adverse decision affecting another patent, due to expire in July 2010, covering an ingredient in Lipitor. Ranbaxy was joined by another generic company, Arrow Generics, in challenging the 2010 patent. Ranbaxy plans to appeal the decision on the main patent. Writing before the decision was announced, Banc of America Securities analyst Chris Schott estimated that Lipitor produced sales of $500 million to $700 million in the U.K. Last year, Pfizer sold $4.2 billion worth of Lipitor in foreign markets and $6.6 billion in the U.S.