A mixed bag for Indian generics firm Ranbaxy after a Spanish court upheld Pfizer's patent covering its blockbuster cholesterol-lowerer Lipitor (atorvastatin), but on the plus side the firm settled US litigation with GlaxoSmithKline over its herpes drug Valtrex (valaciclovir) that will see Ranbaxy enjoy 180 days' market exclusivity in the USA from late 2009 for its copycat offering. The positive news sent the latter's shares up 10%.

Furthermore, Ranbaxy has also obtained a license to two additional patents covering GSK’s drug, which pulls in around $1.3 billion a year. Ranbaxy received a final approval from the US Food and Drug Administration in February this year to market and manufacture valacyclovir hydrochloride tablets in the world's largest pharmaceutical market, and says it believes it has first-to-file status (permitting 180 days' market exclusivity) on a further 20 generic drug approval applications worth $26 billion at branded prices.

Positive decision from Spain for Lipitor

Meanwhile, in Spain, a court upheld Pfizer's enantiomer patent covering the calcium salt of atorvastatin, the active ingredient in Lipitor. However, it also ruled that a second patent covering a stabilized formulation that includes atorvastatin is invalid.

This case is the fourth in a series of challenges to the calcium salt patent by generic companies in Spain. The patent was upheld in one of three previous cases and found invalid in two others. All of the previous decisions are currently on appeal. The calcium salt patent expires in July 2010 and the stabilized formulation patent expires in December 2013. Ranbaxy can appeal the decision.