When foreign counsel hear about Section 3(d) of the Indian Patents Act 1970, they usually have one of two reactions.
The first reaction is vague familiarity. They know it came from the Novartis case. They know it is about pharmaceuticals. They treat it as a background risk to note in a memo and move on.
The second reaction is overcorrection. They assume Section 3(d) makes pharmaceutical patents in India essentially unattainable and advise clients accordingly.
Both reactions miss the mark. And both can cost a client real value.
What Section 3(d) Actually Says
Section 3(d) says that the following are not inventions under the Patents Act.
The mere discovery of a new form of a known substance which does not result in the enhancement of the known efficacy of that substance or the mere discovery of any new property or new use for a known substance or of the mere use of a known process, machine or apparatus unless such known process results in a new product or employs at least one new reactant.
The explanation added to Section 3(d) says that salts, esters, ethers, polymorphs, metabolites, pure form, particle size, isomers, mixtures of isomers, complexes, combinations and other derivatives of known substances shall be considered to be the same substance, unless they differ significantly in properties with regard to efficacy.
The Supreme Court interpreted this provision in Novartis AG v Union of India in 2013. That decision is a masterclass in statutory construction and should be read carefully by anyone advising pharmaceutical clients on India strategy.
The key holding is that efficacy for the purpose of Section 3(d) means therapeutic efficacy in the context of a pharmaceutical substance. Improved bioavailability, better physical stability, or easier manufacture does not satisfy the efficacy requirement unless it translates to enhanced therapeutic efficacy.
Where the Real Traps Are
The first trap is in how compounds are characterised in the claims.
If your claim is for a polymorph of a known active pharmaceutical ingredient, you need evidence of enhanced therapeutic efficacy before you file. Not better solubility. Not improved dissolution rate. Not reduced hygroscopicity. Enhanced therapeutic efficacy.
If that evidence does not exist at the time of filing, the Section 3(d) problem is baked in. You cannot fix it later. Amendments cannot add new matter and data generated after the filing date creates its own difficulties in Indian practice.
The second trap is in formulation claims.
A formulation claim that achieves a therapeutic result through a combination of known substances can face a Section 3(d) challenge if the examiner or an opponent characterises the combination as a derivative of known substances without enhanced efficacy.
The claim must be drafted to clearly identify what is new and what the technical contribution is, beyond the individual components. If the novelty rests entirely on the combination and not on any technical synergy with demonstrable efficacy data, the claim is vulnerable.
The third trap is in the way clinical data is used during prosecution.
In the US and Europe, post filing data can be submitted during prosecution to demonstrate inventive step or unexpected results. Indian practice is more restrictive about relying on data that was not available at the date of filing for the core Section 3(d) assessment. A prosecution strategy built around submitting Phase II or Phase III clinical trial data to overcome a Section 3(d) rejection may not work as cleanly as it would in a US continuation practice.
The Agricultural Chemistry Parallel
Section 3(d) is most often discussed in the pharmaceutical context. But it applies equally to agrochemical compounds.
If your invention is a new form of a known pesticide active ingredient, or a new formulation of a known herbicide, the same analysis applies. Enhanced efficacy in the relevant agrochemical application must be established and it must be connected to the new form or formulation being claimed.
I have seen agrochemical applications in India that sailed through US and European prosecution but failed Indian examination entirely because the Section 3(d) analysis was not built into the original filing strategy.
The failure is preventable. It requires only that an Indian patent attorney with pharmaceutical or agrochemical IP experience review the claim and data strategy before filing.
What Section 3(d) Does Not Block
This is the part that often surprises foreign counsel who have overcorrected.
Section 3(d) does not block new chemical entities with demonstrated therapeutic efficacy. A genuinely novel compound with clinical evidence of therapeutic effect is not excluded by Section 3(d).
Section 3(d) does not block process claims for pharmaceutical manufacturing. A new process for making a known compound, or a new process that uses at least one new reactant, is patentable in India.
Section 3(d) does not block combination products where there is genuine synergy supported by efficacy data.
Section 3(d) does not apply to non pharmaceutical technologies.
Many foreign counsel tell clients that India is not a viable patent jurisdiction for pharmaceutical inventions. That advice is often based on an incomplete reading of the law and the case law. India grants pharmaceutical patents regularly. The bar is higher than in the US or Europe. It is not insurmountable.
How Startups in Biotech and Medtech Get This Wrong
A startup working on a drug repurposing platform came to me after filing in India based on a US attorney’s advice.
The claims were drafted around a new use of a known compound. The US attorney had structured the claims as method of treatment claims, which is standard practice in the US.
Indian patent law excludes methods of treatment of human beings and animals under Section 3(i). The claims were entirely ineligible in India as drafted.
The correct approach would have been to claim the compound for use in the treatment of the new indication, structured as a Swiss type use claim or a purpose limited product claim. That formulation may survive Indian examination. A method of treatment claim will not.
The specification supported the Swiss type claim. The application could have been salvaged. But it required significant prosecution work that added cost and time.
The original filing would have been correct for India if an Indian attorney had reviewed the claim structure before filing.
If you advise pharmaceutical, agrochemical, or biotech clients who are considering India as a filing jurisdiction, I am available for a pre filing assessment of Section 3(d) risk and claim strategy.
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