Authorities in India have revoked a patent on GlaxoSmithKline's breast cancer drug Tykerb,in the latest blow to big pharma in terms of intellectual property.

The country's Intellectual Property Appellate Board upheld a GSK patent granted on the active pharmaceutical ingredient in Tykerb, lapatinib, citing innovative merit. However Tykerb is the salt form of lapatinib and the board decided it represents an incremental innovation.

A GSK spokesman told Pharma Times that given the board has upheld the basic patent, the situation now is that for the lapatinib compound, the drug remains subject to protection until the expiry of that patent in 2019. The patent covering lapatinib ditosylate salt would have gone out to June 2021.

The move follows the end of the long-running landmark case settled in April  when the Supreme Court of India rejected Novartis' application to patent an updated version of its cancer drug Glivec (imatinib). The Tykerb case was brought by Fresenius which had challenged patents granted to GSK for both the original molecule and Tykerb, saying both lacked innovation.

GSK issued a statement saying that Tykerb has provided significant benefit to women with HER-2 positive breast cancer in India over the four years it has been available. The firm added that "we already offer significantly discounted prices for Tykerb in India [and] will continue to take steps to ensure that Tykerb is available to women with breast cancer in India who need it".

The company had already cut the price of the drug by a third in India as part of its access programme for certain emerging markets. Reuters reported that a strip of 10 Tykerb tablets costs about 4,160 rupees (some £45) and a patient should take five tablets a day for 21 days if the cancer is in an advanced stage.

The drugs giant concluded by saying "we are studying the IPAB’s decision but maintain our belief in the inventiveness of the lapatinib ditosylate salt and will consider the possibility of taking further steps before the appropriate authorities to validate this". GSK noted that "intellectual property protection is an important aspect in ensuring that innovation is encouraged and appropriately rewarded. It underpins the continued commitment from research-based pharmaceutical companies to invest in developing new medicines".