In India, patent engineering is no longer limited to testing novelty, inventive step and industrial application. If your claim is even remotely “persistent,” Section 3(d) and its validity test may invalidate it sooner. For drug companies, and even now for some non-drug substances, the real question is whether they can build and prove a therapeutic (or product-specific) efficacy story that stands up to Novartis’ standards and evolving high court scrutiny.
Why Section 3(d) Became the Real Gatekeeper
Section 3(d) was strengthened in 2005 with a clear policy message. India allows patents on products but does not encourage trivial changes that extend monopolies without real benefit. It targets ‘new forms’ of known substances (salts, polymorphs, esters, combinations) and ask whether there is a clear increase in potency compared to the known substance.
In the case of Novartis AG vs. Union of India, the Supreme Court described Section 3(d) as not a parallel patent code but a filter for continuous improvement imposed on top of traditional tests. The warning was clear. Don’t confuse true incremental innovation with superficial change. Only the former is protected, and only if it is supported by reliable data.
Efficacy After Novartis: What Must You Prove?
Novartis’s main doctrinal move was that, with respect to drugs, “efficacy” in Section 3(d) means therapeutic effect, rather than simply an improvement in properties. Better solubility, flowability, or even 30% higher bioavailability are not enough if they are not combined with superior therapeutic outcomes in humans.
The court recognized that in some cases, increased bioavailability may indicate increased therapeutic efficacy, but only if it is specifically demonstrated and supported by reliable research data. Novartis failed because its beta-crystalline imatinib mesylate showed improved physicochemical properties, but there was no convincing clinical or pharmacodynamic evidence that the new formulation produced better patient outcomes.
For non-pharmaceutical substances, subsequent High Court decisions have treated effectiveness as contextual: for enzymes, agrochemicals or technical products, the relevant effectiveness may be catalytic performance, yield or functional efficiency, but the jump must always be real and measurable. The Madras High Court interpreted Section 3(d) to be applicable beyond conventional pharmaceutical chemicals, with product-specific benchmarks governing what counts as improved efficacy.
When 3(d) Is Raised: Litigation‑Ready Efficacy Analysis
In India, significant pharmaceutical patents almost inevitably become subject to Section 3(d) if they are examined, challenged or challenged after the patent is granted. At this point, one needs to stop treating efficacy as a slogan and start presenting it as a structured scientific argument.
First, it establishes a clear and narrow definition of “known substance”, distinguishing between what has already been disclosed in the prior art and what is truly new. Second, provide the examiner or court with measures of efficacy related to the product class, comparative data with known substances, and a reasonable explanation of why the observed benefits result in therapeutic or functional enhancements rather than cosmetic improvements.
Courts are becoming increasingly open to nuanced arguments in favor of non-pharmaceutical drugs, whose effectiveness may be matched by industry performance rather than human treatment results. But the basic lessons for litigators and patent engineers are the same. Without a solid data set, Section 3(d) becomes the easiest basis for invalidating a patent.
Why Section 3(d)‑Savvy Patenting Is a Competitive Edge
Studies on patent protection and innovation in India repeatedly emphasize that most pharmaceutical innovations are incremental rather than radical. Section 3(d) does not deny this reality. It just claims that only increases in efficiency are worth 20 years of exclusivity.
For companies and young patent professionals who understand this, Section 3(d) becomes a strategic filter: it pushes you toward projects where R&D can provide clear benefit to patients or the product, and forces you to think in terms of outcomes rather than decorative chemistry. Teams that build their claims, data and litigation strategy based on performance analysis are the ones whose patents actually survive and shape markets, not just fill out annual reports.
