Summary
The Delhi High Court recently set aside the Controller's order rejecting an anti-cancer patent by Taiho Pharmaceutical. The decision reiterated the need for clear identification of a “known substance” under Section 3(d) of the Patents Act. The Court also directed re-evaluation of inventive step, considering the applicant's efficacy data and prior patent grants globally.
The Delhi High Court, in a recent decision, set aside an order passed by the Assistant Controller of Patents (“Controller”) rejecting a patent application filed by Taiho Pharmaceutical Co. Ltd. (“Taiho”), and remanded the matter to the Patent Office for fresh consideration. The Court stated that when raising an objection under Section 3(d) of the Patents Act, 1970, the Controller must explicitly identify the “known substance” against which the claimed invention is being assessed, and such identification must be clearly stated in the hearing notice.
Background
The case pertained to a PCT national phase application (Application No. 7283/DELNP/2014) titled “Novel Piperidine Compound or Salt Thereof”, relating to a new class of compounds exhibiting Aurora A kinase inhibitory activity, intended for use in anti-cancer therapy.
The Controller refused the application on two grounds: lack of inventive step under Section 2(1)(ja) and non-patentability under Section 3(d).
It was observed that the claimed compound constituted a new form of known substances disclosed in prior art D1, without any demonstrated enhancement in therapeutic efficacy, thereby attracting the bar under Section 3(d). Additionally, the invention was held to be obvious to a person skilled in the art in view of D1 and thus found to lack inventive step under Section 2(1)(ja). Efficacy data submitted by the applicant, based on a comparison with Paclitaxel, was disregarded on the ground that Paclitaxel was not structurally similar to the claimed compounds.
Taiho challenged the refusal, arguing that the Controller had failed to identify the “known substance” from the closest prior art (D1) in the hearing notice and in the impugned order. They also submitted that the Controller had overlooked research data provided in the complete specification, which demonstrated increased oral absorbability. Taiho also pointed out that the invention had been granted patent protection in several major jurisdictions, reinforcing the patentability of the claimed invention.
Court’s Analysis and Findings
Relying on the precedent set in S Biopharma Ltd. v. Controller of Patents & Designs, the Court reiterated that for an objection under Section 3(d) to be valid, the Controller must clearly identify:
i) the “known substance” with “known efficacy”;
ii) an explanation as to how and why the claimed substance is a derivative or otherwise a new form of a “known substance”; and
iii) an objective comparison between the therapeutic efficacy of the claimed invention and that of the “known substance”.
The Court found that, in the present case, the hearing notice merely referred to prior art D1, which disclosed a broad Markush structure encompassing numerous possible compounds, without specifically identifying any one compound as the “known substance”. It observed that an applicant cannot reasonably be expected to infer the “known substance” from a generic disclosure and furnish comparative efficacy data based on such inference. The failure to pinpoint a specific “known substance” in the hearing notice, according to the Court, deprived the applicant of a fair opportunity to respond and substantiate enhanced efficacy. Consequently, the rejection under Section 3(d) was found to be procedurally flawed and unsustainable.
Given the overlap in the analysis of inventive step and Section 3(d), the Court observed that the objection under Section 2(1)(ja) also warranted re-evaluation. It directed that, while reconsidering the objection under Section 3(d), any research data demonstrating enhanced therapeutic efficacy, must also be duly considered in the context of the inventive step under Section 2(1)(ja) of the Act.
Conclusion
The Delhi High Court set aside the impugned order and remanded the matter for fresh consideration. The Controller has been directed to issue a fresh hearing notice, clearly identifying the known substance, and to afford the applicant an opportunity to respond before arriving at a decision.
Citation: Taiho Pharmaceutical Co Ltd vs The Controller Of Patents, (H.C. Delhi May 15, 2025), C.A. (COMM.IPD-PAT) 6/2022.
Available at https://indiankanoon.org/doc/154120720/
Article Review: Vinita Radhakrishnan
Accessibility Review: Rakesh Krishnan
