Pfizer continued its run of successful defences of its $12 billion-plus Lipitor drug in the courts yesterday, winning a preliminary injunction against the launch of a copycat version in Finland by Ranbaxy Laboratories.

The patent protection on the cholesterol-lowerer Lipitor (atorvastatin) has been under assault by India’s Ranbaxy in a number of markets. Ranbaxy won a challenge in Austria last March, but was subsequently defeated in the courts in countries including the UK, Spain and Norway, as well as the key US market. All the cases have subsequently gone to appeal.

Yesterday, the Helsinki Court of Appeal in Finland granted a preliminary injunction prohibiting Ranbaxy from marketing its generic.

Pfizer said the decision reverses an earlier lower court ruling and, subject to a possible appeal to the Finnish Supreme Court, will remain in place during further judicial proceedings - including a full patent infringement trial that has not yet been scheduled. The world’s biggest drugmaker maintains that its Finnish Lipitor patent does not expire until February 2009.

The ruling involves a patent that covers processes and intermediate compounds used to make atorvastatin.

Ranbaxy, which is India's largest drugmaker, is challenging patents on Lipitor in 18 countries overall.