For pharma companies filing in India, Section 3(d) of the Patents Act is the single provision that decides whether a patent on a new form of a known drug survives. It is why the imatinib (Glivec) patent was refused, and it is the first thing an Indian examiner reaches for when a claim looks like an incremental change to an existing molecule. If your portfolio touches India, tracking the Section 3(d) posture of every application is not optional, it is the difference between a granted patent and a rejection you could have seen coming.
What Section 3(d) Actually Says
Section 3(d) excludes from patentability the mere discovery of a new form of a known substance that does not result in the enhancement of the known efficacy of that substance. It also bars the mere discovery of a new property or new use for a known substance, and the mere use of a known process unless that process produces a new product or uses at least one new reactant. An explanation to the section treats salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations, and other derivatives of a known substance as the same substance, unless they differ significantly in properties with regard to efficacy.
The phrase that carries the weight is enhancement of known efficacy. In Novartis v. Union of India (2013), the Supreme Court read efficacy in the pharmaceutical context as therapeutic efficacy, not merely improved physical properties like better solubility or stability. So a new polymorph that dissolves faster but does not demonstrably treat the disease better can still fall foul of 3(d).
Why It Trips Up Pharma Portfolios Specifically
Lifecycle management in pharma leans heavily on exactly the kinds of claims 3(d) scrutinizes: new salts, polymorphs, formulations, combinations, and dosage regimens of an already-disclosed active. A claim set that sails through the USPTO or EPO on novelty and inventive step can still need a separate, evidence-backed efficacy story to clear 3(d) in India. Teams that treat the Indian national phase as a formality discover the gap only when the first examination report cites 3(d), often years after the priority filing, when generating fresh efficacy data is hard.
What to Track for Every India-Bound Application
The practical answer is to make 3(d) exposure a tracked attribute of each case, not a surprise in prosecution. For each application entering or planned for India, keep a clear record of:
- Known-substance status: is the claimed compound a new form, new use, or derivative of a substance already in the public domain?
- Efficacy evidence on file: what comparative therapeutic-efficacy data exists against the known form, and where does it live?
- Priority and disclosure dates: what was publicly disclosed before filing, since the known substance baseline drives the whole analysis.
- Family linkage: which parent and sibling filings share the same active, so a 3(d) position taken in one case stays consistent across the family.
- Examination deadlines: the response windows on any 3(d) objection, which are unforgiving in India.
Build the Efficacy Story Before You File, Not After
The strongest 3(d) defense is comparative data generated while it is still feasible: head-to-head therapeutic-efficacy results for the new form against the known substance, tied to the specific advantage the claims rely on. Capturing what prior art defines the known substance is half the battle, and it starts with a thorough prior art search that pins down exactly what was already disclosed about the molecule. Drafting then has to argue enhanced efficacy explicitly rather than assume it, which is why an AI-assisted draft aimed at the Indian jurisdiction is built around Section 3(d) and the related Section 3 exclusions from the start, not bolted on during prosecution.
Keep It Visible Across the Portfolio
A single application is easy to reason about. A portfolio of fifty India-bound cases, each with its own known-substance baseline and efficacy evidence, is not. Treating 3(d) posture as structured case data, alongside deadlines and family relationships in your patent docketing system, means a manager can answer which Indian cases carry 3(d) risk and which already have the efficacy data to meet it, without reopening every file. That visibility is what turns a notorious rejection ground into a position you have prepared for.