Pfizer [Get Quote] has won a patent challenge in Denmark by India's largest drug-maker Ranbaxy Laboratories [Get Quote] on atorvastatin, the active ingredient of the world's largest selling cholesterol drug, Lipitor, which has global sales of over $13 billion.

A Pfizer statement said that the Eastern Division of the High Court in Copenhagen (Denmark) upheld the basic and salt patents on Lipitor. The basic patent on Lipitor expires in November 2011 in Denmark and the salt patent in July 2010. The decision, which is subject to an appeal, prevents launch of Ranbaxy's generic version before November 2011.

"Our settlements cover more than 90-95 per cent of the Lipitor market and the existing litigations are insignificant," commented a Ranbaxy spokesperson.

It may be noted that Ranbaxy, which has been taken over by Japanese drug maker Daiichi-Sankyo for $4.6 billion, had settled the Lipitor litigation out-of-court with Pfizer for most of the geographies, except for Finland, Spain, Portugal, Denmark and Romania.

Ranbaxy had challenged the Lipitor patent in about 18 geographies in the largest ever patent litigation.

Interestingly, a few weeks ago Pfizer had also settled the Lipitor patent challenge by the US generics major Apotex.