Pfizer’s bid to protect the world’s best-selling drug has received a boost in Spain after a court there upheld a key patent on the firm’s cholesterol-lowerer Lipitor.

The New York-based drugs giant says that the Court of Appeal of Barcelona has upheld the company's enantiomer patent which covers the calcium salt of atorvastatin, the active ingredient in Lipitor, known in Spain as Zarator and Cardyl, reversing an earlier decision. The calcium salt patent was challenged by the Slovenia-headquartered generic manufacturer Lek Pharmaceuticals, a subsidiary of Novartis, and is one of four separate challenges to the aforementioned patent (which expires in July 2010). Lek can still appeal and take the case to the Supreme Court of Spain.

General counsel Allen Waxman said that "this is a victory not only for Pfizer, but for all innovators pursuing high-risk medical discoveries and for the patients who benefit from those discoveries". The company has been battling all over the world to defend its patents on Lipitor, sales of which declined 5% to $3.17 billion for the third quarter, as doctors switched patients to generic versions of Merck & Co’s similar drug Zocor (simvastatin).