On 1 April 2013, The Supreme Court in India dismissed Novartis AG's appeal for patent protection for its cancer drug Glivec. 

The application sought to protect the beta crystalline form of Imatinib Mesylate.  However, the court ruled that Imatinib Mesylate was disclosed in a patent application filed previously by Zimmermann (Imatinib is a derivative of N-phenyl-2-pyrimidine-amine and Imatinib Mesylate is a methanesulfonic acid addition salt of this).  The court then sought to determine whether the beta crystalline form of Imatinib Mesylate could be considered to be a new product and patentable under Indian law.

The main consideration of this point took into account section 3(d) of the Indian Patents Act, which sets out some exclusions to patentable subject matter in India.  In particular relevance to this case, Section 3 (d) indicates that

"the mere discovery of a new form of a known substance which does not

result in the enhancement of the known efficacy of that substance" may not constitute an invention.  In the explanatory notes to this section, it is stated that "For the purposes of this clause, salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substance shall be considered to be the same substance, unless they differ significantly in properties with regard to efficacy.” 

In this case, although the beta crystalline form of Imatinib Mesylate had been shown to possess some advantageous properties over the known compounds, the court indicated that therapeutic efficacy needs to be enhanced in order for an adapted compound to be considered to fall outside of the Section 3(d) exclusion.  Since this was not demonstrated in the court's opinion, the beta crystalline form of Imatinib Mesylate was found to be unpatentable. 

The section 3(d) requirement discussed above is a feature of Indian law that is present to prevent "evergreening", i.e. to prevent a monopoly being created for drugs simply by making minor changes to compounds in order to achieve further patent protection.  However, this novelty-type exclusion to patentability seems to be a peculiarity to Indian law, as is evidenced by the fact that Novartis have achieved patent protection for their product in nearly 40 other countries worldwide.  In this case, Novartis had not previously enjoyed patent protection for Glivec in India and it seems that this decision may effect investment in R&D and innovation in India made by pharmaceutical companies.