Every patent professional who has prosecuted a patent application for a pharmaceutical invention in India knows the routine: the examiner issues a Section 3(d) objection, cites the landmark Novartis judgment, and demands comparative data showing enhanced therapeutic efficacy. But what happens when the invention isn’t a pharmaceutical drug at all; but an agrochemical or a materials-science invention?
The Delhi High Court’s recent decision in Syngenta Participations AG v. Controller of Patents and Designs, May 2026 [C.A.(COMM.IPD-PAT) 49/2023] provides a crucial corrective to this reflexive.
The Case Background
Syngenta sought a patent for a monohydrate crystalline polymorph of a known fungicidal compound. The prior known form of the compound was unstable in suspension concentrate formulations, routinely undergoing polymorphic conversion and crystal growth. In the industry, this meant thickening, solidification, and clogged spray equipment. Syngenta’s data demonstrated that its new monohydrate form stayed thermodynamically stable at 50–60°C and resisted crystal growth.
The Controller of Patents refused the application on two principal grounds: lack of inventive step under Section 2(1)(ja), and that the claim fell within Section 3(d), relying heavily on Novartis, because the alleged improvement (thermal stability) was treated as not amounting to “enhanced efficacy” of a known substance. The Controller’s reasoning treated “efficacy” in the strictly pharmaceutical, therapeutic sense. Syngenta filed an appeal before the Delhi High Court under Section 117A of the Patents Act, 1970 against the order passed by the Controller of Patents.
Where the Controller’s Reliance on Novartis Broke Down
The Delhi High Court went back to the text of the Novartis judgment itself to dismantle the reasoning of the Controller in the order of refusal:
- Context Matters: Paragraph 157 of Novartis explicitly states that the test of efficacy depends on “the function, utility or the purpose of the product under consideration.” The Supreme Court narrowed the test to therapeutic efficacy specifically because it was evaluating a medicine.
- The Wrong Yardstick: Paragraph 164 of Novartis, the passage routinely quoted to rule out thermodynamic stability as efficacy, was strictly confined to a medicine’s therapeutic effect. Novartis never said thermodynamic stability is irrelevant to efficacy generally; it said it is irrelevant to therapeutic efficacy. For a fungicide, asking for therapeutic data is simply the wrong question.
- Judicial Precedent: The Court drew on the Madras High Court’s reasoning in the Novozymes phytase case, where thermostability that enabled pelletisation without losing enzymatic activity was held to enhance efficacy, proving Section 3(d) was never textually confined to pharma.
What the Court Held & Practical Takeaways for Prosecution
- For non-medicinal inventions, efficacy must be assessed against the product’s actual function or utility. For agrochemicals, field performance (e.g., better formulation stability, enhanced shelf-life, reduced phytotoxicity and improved suspension properties under Indian field conditions of 35–50°C) directly qualifies as enhanced efficacy.
- Enhanced thermodynamic/physical stability of a polymorph can qualify as enhanced efficacy where that property is what determines whether the product performs in practice.
- The Court noted that the Patent Office disregarded Syngenta’s technical data without sufficient reasoning and leaned on assumptions of “inherency” without disclosing a source. If the Office claims a property is “well-known,” it must identify the source or give reasons for rejecting the applicant’s data; silent assumptions will not stand.
- The Patent Office cannot collapse a substantive inventive step analysis into a Section 3(d) objection. Section 2(1)(ja) must still be evaluated cleanly under the five-step framework laid down in Roche v. Cipla.
The refusal was accordingly set aside by the Court, and the matter remanded to the Patent Office for a fresh hearing, with directions to decide within six months.
For anyone handling agrochemical, chemical, or materials-science applications facing 3(d) objections, this is a useful precedent to have in your back pocket; it pushes back against the reflexive application of a pharma-shaped test to inventions that were never meant to be measured that way. It is also a reminder that examiners cannot lean on “this property is inherent” as a substitute for reasoning; if that is the basis for refusal, the source of that “known” fact needs to be on the record. They must also assess efficacy in relation to the invention’s field of use. For patent practitioners the take away is clear: efficacy must be demonstrated, and the claimed property improvement should link to the invention’s practical utility in its field. In the case of agro-chemical inventions, where new forms of known substances are claimed, improvements must be shown to be intrinsic to the invention’s utility in agriculture and therefore constitute enhanced efficacy under Section 3(d), even though they are not therapeutic in nature.
