Madras High Court at odds with Indian Patent Office over prosecution process following Signal Pharmaceuticals application refusal

In a continuing trend of Indian courts coming down heavily on the Indian Patent Office (IPO) for failing to conduct proper examination and assessment of patent applicants’ arguments during prosecution, the Madras High Court recently adjudicated on issues involving a non-speaking refusal decision passed by the Controller of Patents and Designs in Signal Pharmaceuticals v Deputy Controller of Patents and Designs ((T)CMA(PT) 145 of 2023). The ruling highlights the importance of proper analysis of an applicant’s responses and written submission during prosecution.

Signal Pharmaceuticals filed a patent application in India titled “mTOR kinase inhibitors for oncology indications and disease associated with the mTOR/P13K/AKT Pathway”. The claims are directed to heteroaryl compounds of “Formula (II)” – as outlined in claim 1 – and composition comprising these compounds. Signal contended that the claimed compounds are structurally distinct from those disclosed in the closest prior art document (D1) as cited by the IPO. It also submitted a technical affidavit demonstrating enhanced therapeutic efficacy of the claimed compounds compared to a compound disclosed in D1.

In the impugned refusal decision, the IPO opined that the claimed compounds and the compounds of D1 were the same, and that the claimed compounds did not exhibit enhanced efficacy. It therefore rejected the application for lacking inventive step and for failing to meet the requirements of Section 3(d) of the Indian Patents Act. The order was completely silent on the plaintiff’s technical affidavit and written submission demonstrating the enhanced therapeutic efficacy.

In the appeal, Signal contended that the IPO’s order was erroneous, non-speaking and lacked proper reasoning as to how and why the claimed compounds were not inventive in view of D1. The plaintiff specifically argued that the IPO had not considered its response or technical affidavit and ignored the clear gap between the structures of the claimed compounds and the compound disclosed in the cited prior art. Signal also mentioned that the IPO had failed to take note of the grant status of the corresponding US and European patent applications, which would support the inventive step aspect of the invention for the purpose of prosecution in India. 

The Madras High Court carefully analysed all the evidence on record and ruled that the IPO had given no sufficient reasoning for concluding that the appellant’s claimed invention lacked inventive step. The court held that the IPO had failed to properly analyse the structures of the claimed compounds and those disclosed in D1, and that it provided no proper reasoning for deciding that these were the same. The court further relied on the Supreme Court’s decision in Novartis v Union of India and held that in patent applications relating to pharmaceutical compounds, the efficacy test can only be related to therapeutic efficacy (6 SCC 1, 2013) – however, the IPO did not give any reason as to why Signal’s claimed invention does not satisfy this test.