The patent authorities will now re-examine the case involving the renal cancer drug Sunitinib (sold as Sutent by Pfizer) after the Supreme Court returned the case back to Patent Office, it is learnt.

The apex court also lifted an injunction granted by the Delhi High Court against restraining Cipla from launching the generic version of the drug. Pfizer was granted a patent for kidney cancer drug Sutent in India in 2007.

Cipla filed a post-grant application and won the case in September this year, with the Patent Office rejecting the argument by Pfizer over the drug, on grounds that the invention claimed in patent (Sutent) did not involve an inventive step. However, Pfizer appealed in the Delhi HC which passed an injunction order to restrain Cipla from launching the generic drug. This prompted Cipla to go to the Supreme Court against the HC order.

Now the assistant controller of patents will hear the arguments of both the parties to take final decision on allowing the generic version. Sutent costs about Rs. 1.96 lakh for a 45-day treatment, while Cipla has priced its generic version Sunitib, substantially lower.

"Once the patent has been revoked, it is non-existent in the eyes of the law, and hence there can be no question of infringing it," Cipla had argued in the SC. "Thus, till the time such patent stands revoked, no restraint order could have been passed against the petitioner or any other party thereby restraining it from manufacturing its drug," Cipla said. Cipla claimed that the drug was a "life-saving drug" and any restraining order on its marketing was against public interest.

Sunitinib (previously known as SU11248) is an oral, small-molecule, multi-targeted receptor tyrosine kinase (RTK) inhibitor that was approved by the FDA for the treatment of renal cell carcinoma (RCC) and imatinib-resistant gastrointestinal stromal tumour (GIST) on January 26, 2006. Sunitinib was the first cancer drug simultaneously approved for two different indications.