Controller Of Patents Must Specify Known Substance Against Which Claimed Invention Is Being Assessed In Hearing Notice: Delhi High Court

Section 3(d) of the Patents Act, 1970 bars the patentability of a 'new form' of a 'known substance' unless it demonstrates enhanced therapeutic efficacy.

Justice Amit Bansal said that in order to sustain an objection under Section 3(d), the following factors have to be clearly identified by the Controller:

i) the 'known substance' with 'known efficacy';

ii) clear explanation as to how and why the claimed substance is a derivative or otherwise a new form of a 'known substance';

iii) an objective comparison between the therapeutic efficacy of the claimed invention and that of the known substance.

The bench further explained that the 'known substance' must be clearly specified in the hearing notice issued to the patent applicant, in order to enable him to make his defence. It observed,

“The focus of Section 3(d) is on the 'new form of known substance'...The aforesaid aspects have to be identified by the Controller in the hearing notice, so as to afford a reasonable opportunity to the applicant to respond to it.”

In the case at hand the Court noted that the patent application of the Appellant, a pharmaceutical entity based in Japan, was rejected on the ground that the claim lacks inventive step as required under Section 2(1)(ja) and is non patentable under the Section 3(d).

However, on perusal of the records it noted that the hearing notice failed to properly identify the 'known substance'. The hearing notice only referred to D1 as the closest prior art and made a general observation regarding structural similarity between the compounds of the subject patent application and those disclosed in D1.

It further noted that the Controller in the hearing notice failed to identify a specific 'known substance' from D1 against which the claimed invention was being assessed.

Taking exception to such an approach it held,

“The appellant cannot be expected to infer a 'known substance' and furnish efficacy data based on such inference. By not identifying any particular 'known substance' in the hearing notice, the appellant was not afforded a fair opportunity to respond to the same, by demonstrating, through comparative research data, that the claimed compound possesses enhanced therapeutic efficacy over the particular 'known substance'. In the absence of such identification, the rejection on the ground of Section 3(d) is not sustainable and warrants a remand for fresh consideration.”

Further coming to the objection of the patent application lacking inventive step in terms of Section 2(1)(ja), the Court said,

“Since the reasoning under Section 2(1)(ja) is closely intertwined with the assessment under Section 3(d) of the Act, the objection under Section 2(1)(ja) also warrants reconsideration upon proper identification of the 'known substance' from the closest prior art and comparison of the enhanced efficacy data thereof by the appellant.”

Accordingly, the matter was disposed of.

Appearance: Mr. Ankush Verma, Mr. Debashish Banerjee, Ms. Vaishali Joshi, Mr.Vineet Rohilla, Mr. Pankaj Soni, Mr.Rohit Rangi, Mr. Tanveer Malhotra & Ms. Gurmeet Kaur, Advocates for Appellant; Mr. Premtosh K. Mishra, CGSC with Mr. Manish Vashisht, Ms. Sanya Kalsi and Mr. Prakhar Singh, Advocates for Respondent

Case title: Taiho Pharmaceutical Co. Ltd v. The Controller Of Patents

Citation: 2025 LiveLaw (Del) 558

Case no.: C.A. (COMM.IPD-PAT) 6/2022

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