Indian drugmaker Ranbaxy Laboratories has been granted leave to appeal a ruling last month that its generic atorvastatin product would infringe Pfizer's patents on the drug.

Atorvastatin, sold by Pfizer as Lipitor, is the world’s top-selling medicine and currently has sales running at $12 billion dollars a year. On October 12, a UK judge ruled that a European patent held by Pfizer – No 247633 – was still in force and was infringed by Ranbaxy’s generic atorvastatin. He said that another European patent, - 409 281 - was invalid in the UK but that Ranbaxy's proposed product would infringe patent 247633.

The judge has granted permission to both Ranbaxy and Pfizer to appeal the respective rulings in the UK Court of Appeal. The outcome of both appeals is expected by the end of 2006.