India's Intellectual Property Apelate Board (IPAB) has revoked a patent granted to GlaxoSmithKline (GSK) in a reinforcement of the country's hard line on "incremental" inventions in the pharmaceutical field.

Tykerb (lapatinib ditosylate) is a dual tyrosine kinase inhibitor sold by GSK for combination therapy against HER2-positive breast cancer and is the subject of a patent to the compound which is due to expire in India in 2019.  GSK had additionally secured protection for the specific salt based upon a 2001 application that would have extended Indian protection to 2021.  It is this latter patent that the IPAB has now revoked while upholding the earlier patent to the compound.

The use of the patent system for so-called "evergreening" of pharmaceutical protection by filing applications to ever smaller refinements has been the subject of debate in many countries.  In 2009, for example, a report by the European Commission looked into the question of whether the strategies adopted by innovative pharmaceutical companies to keep generic products off the market were in breach of European competition law.  India is, however, one of the few countries to explicitly limit the patenting of new forms of a drug substance.

Section 3(d) of the Indian Patents Act requires that new forms of a known chemical substance have "improved efficacy" in order to be patentable.  The first high-profile case to test this requirement came with Novartis AG's appeal to the Indian Supreme Court which was decided in April of this year.  In that decision the Court concluded that improved efficacy should be interpreted strictly on a therapeutic basis with no account being taken of benefits in properties such as improved flow, greater stability or lower hygroscopicity.  The GSK decision now reinforces this ruling by holding the patent to the original compound valid but the "Incremental" patent to the salt as disallowed under section 3(d).

India has been criticised in the past, particularly by multinational companies, for not adequately fulfilling its obligations under TRIPS to provide patents for pharmaceutical products.  However, generic pharmaceutical manufacturing is an important industry in India and the government there will be under increasing pressure to supply low-cost drugs to an expanding population.  With modern pharmaceuticals increasingly taking advantage of secondary effects, such as specific salts or specialised delivery systems, to improve their overall viability, further conflicts between pharmaceutical companies and the Indian patent system can be expected in the near future.