Two exclusions that require different analysis
Section 3(d) and Section 3(e) of the Patents Act address different subject matter. Section 3(d) concerns, among other things, a new form of a known substance that does not enhance its known efficacy, a new property or use of a known substance, and the mere use of a known process unless the statutory exception applies. Its Explanation lists forms such as salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures, complexes, combinations and other derivatives as the same substance unless they differ significantly in properties with regard to efficacy.
For pharmaceutical products, the Supreme Court in Novartis AG v. Union of India, (2013) 6 SCC 1, explained the role of therapeutic efficacy in the Section 3(d) analysis. The evidence must address the relevant known substance and the claimed form; a useful property or improved formulation characteristic does not, by itself, answer the statutory efficacy question.
Section 3(e), by contrast, excludes a substance obtained by a mere admixture that results only in the aggregation of the properties of its components. For a claimed combination, the specification and evidence should explain what the combination does and whether the asserted interaction goes beyond simply placing known components together. The inquiry is fact-specific; describing a combination as synergistic is not a substitute for a supported technical explanation.
Recent decisions: read the procedural posture
In Natco Pharma Ltd. v. Novartis AG (Delhi High Court, 24 April 2024), the Court considered a Section 3(d) challenge to a patent for a salt form of a known pharmaceutical substance while reviewing an interim injunction. The decision is useful for understanding the evidence and arguments raised around known substances and therapeutic efficacy, but it was an interim-injunction appeal, not a final trial ruling on patent validity.
In Grains Research and Development Corporation v. Assistant Controller of Patents and Designs (Delhi High Court, 23 February 2026, C.A.(COMM.IPD-PAT) 66/2024), the Court set aside a refusal and remanded the application for a fresh, reasoned assessment of inventive step and Section 3(d). The Court noted the need to identify the relevant known process or known substance and conduct an independent Section 3(d) analysis before relying on the exclusion. The matter was remanded; the Court did not itself grant the patent or decide that the claims were patentable.
Drafting and prosecution implications
A robust record usually starts with a carefully identified closest known substance, process or combination; a clear statement of the claimed difference; and comparative data that addresses the statutory issue. The complete specification should explain the invention and support the claims from filing. Later submissions cannot safely replace missing disclosure or add new matter.
For Section 3(d), keep the comparison tied to the known substance and the relevant efficacy. For Section 3(e), explain the role of each component and the evidence for an effect beyond aggregation. In either case, address novelty, inventive step, sufficiency and claim scope independently; satisfying one test does not resolve the others.
As of 10 October 2026, IP India has listed draft pharmaceutical and biotechnology examination guidelines published in October 2026. Draft guidance is not an amendment to the Act or Rules; check the official guidelines and updates for their current status before relying on them. The statutory text and judicial decisions remain central.
This article is a general overview, not an assessment of any particular compound, formulation or patent claim.