Bangalore: India's generics giant Cipla has won a landmark patent case against Swiss drug maker Roche in the Delhi High Court. Roche had filed a patent infringement case against Cipla in 2008 for its generic copy of lung cancer drug Tarceva.

The judgment in favor of the Indian company came after four years court battle. The court observed in its judgment that it has been scientifically proven that Cipla's generic version was a polymorph B variant of Roche's patented drug and that it did not infringe any patent in India. The court also said Roche's patent on the drug is valid.

Roche had applied for a patent for the polymorph B version of erlotinib, which is the generic name of the drug, at the Indian patent office. But the application was rejected on the grounds that it doesn't qualify for a patent in India. Indian patent law doesn't qualify variants of a basic drug molecule (erlotinib in this case) unless such versions demonstrate an enhanced therapeutic efficacy.

The judgment comes at a time when all eyes are on India's patent system. The ruling comes ahead of the Supreme Court hearing of the Glivec case. Pharma giant Novartis has filed a case against the Indian patent office for the latter's refusal to grant it a patent for Glivec. In another case earlier this year, German company Bayer lost a trial when the Indian Patent Office granted compulsory licence to local generic manufacturer Natco Pharma for Nexavar in India.