Section 3(d) in Indian Courts: What the Case Law Says

Explainer · Patent Law · Last verified October 2026

Updated for 2026 · Claw Editorial

A patent lawyer, an in-house counsel at a drug company, or a generic manufacturer all face the same question sooner or later: is this small change to a known medicine patentable in India? Section 3(d) of the Patents Act, 1970 is the provision that decides it, and the answer lives in case law that has grown for nearly twenty years. This explainer sets out what Section 3(d) says, the Novartis v Union of India lineage, what later courts did with it, and how to trace the cases yourself. Last verified October 2026.

01The problem: what is evergreening

“Evergreening” is the common name for a pattern where a patent owner files for a new form of a known medicine, such as a new salt, a new crystal form or a new combination, to extend the life of protection. The original patent lasts 20 years. A string of follow-on patents can keep competitors out for much longer.

India chose to deal with this directly in the statute. Section 3(d) sits in the list of things that are not inventions. It does not ban follow-on innovation. It sets a higher bar for it. That is why the section has produced so much litigation, and why a simple keyword search for it returns a very large and messy pile of results.

For a pharma company the stakes are a patent term. For a generic maker they are market entry. For a patient group they are access to a medicine. Each side needs to know how the courts have actually applied the section, not just what the text says.

02What Section 3(d) says

Section 3(d) was brought in by the Patents (Amendment) Act, 2005. In plain words, it says the following are not inventions:

• The mere discovery of a new form of a known substance that does not result in increased efficacy of that substance.
• The mere discovery of any new property or new use of a known substance.
• The mere use of a known process, machine or apparatus, unless the process results in a new product or uses at least one new reactant.

An Explanation then says that salts, esters, ethers, polymorphs, metabolites, pure forms, particle sizes, isomers, mixtures of isomers, complexes, combinations and other derivatives of a known substance are treated as the same substance. The exception is where they differ significantly in properties with regard to efficacy.

So the test has two steps. First, is the claim a new form of a known substance? Second, if yes, does it show significantly better efficacy? If the second answer is no, the claim fails at the threshold, before the usual tests of novelty and inventive step are even applied. Always read the exact wording from the Act on the IP India website before you quote it in a filing.

03The Novartis lineage

The claim

Novartis applied for a patent on the beta crystalline form of imatinib mesylate, the cancer drug sold as Glivec. Imatinib itself was already known from an earlier patent. The Patent Office and the IPAB refused the application, and Novartis went up through the courts.

The Madras High Court, 2007

Novartis also challenged Section 3(d) itself, arguing it was vague and breached Article 14 and India’s TRIPS obligations. The Madras High Court dismissed that challenge in 2007. The court held that the section is not arbitrary and that the TRIPS question was not one for it to decide in that way.

The Supreme Court, 1 April 2013

The leading authority is Novartis AG v Union of India, (2013) 6 SCC 1, decided on 1 April 2013. The Supreme Court held that:

• The word “efficacy” in Section 3(d) means therapeutic efficacy, at least for medicines.
• Better physical properties, such as improved flow or stability, do not by themselves show enhanced therapeutic efficacy.
• The claimed 30 percent rise in bioavailability was measured against the free base, not against the known imatinib mesylate salt, so it did not meet the test.
• Section 3(d) is not a bar on all incremental innovation. It filters out new forms that do not show a real improvement in therapeutic effect.

Read the full judgment on Indian Kanoon and on the Supreme Court website. Lawyers quote it for the “therapeutic efficacy” reading and for the point that the comparison must be with the known substance.

04What later courts did with it

After 2013, most Section 3(d) arguments were run in the High Courts, mainly the Delhi High Court, in infringement and revocation matters. Three themes come up again and again.

Section 3(d) is not a defence to infringement

In F. Hoffmann-La Roche v Cipla (erlotinib, sold as Tarceva), a Division Bench of the Delhi High Court in 2015 set aside the Single Judge and held that Section 3(d) should not be used as a defence to an infringement claim. It also treated the section as a provision that recognises incremental innovation while guarding against trivial changes.

Layered patents on the same drug

In disputes such as the dapagliflozin litigation involving AstraZeneca, courts have looked hard at whether a later patent is really a separate invention or an attempt to extend protection of a drug already covered by an earlier patent. We do not state an outcome here, because later orders and appeals may have changed the position. Check the latest order before you rely on it.

Evidence of efficacy

Courts and the Patent Office now expect comparative data against the known substance. Statements in the specification that a form is “better” are not enough without data.

05Practical tests that come out of the cases

Putting the lineage together, a careful reader can run a simple checklist on any claim.

This table is a reading aid, not legal advice. Facts decide each case, and a single later ruling can narrow or widen a point.

06How to trace the case law without missing a later ruling

The hardest part of this topic is not the first case. It is finding every later case that applied, followed, distinguished or limited it. A good workflow looks like this.

1. Start with the primary sources: the Act on IP India, then Novartis on Indian Kanoon or the Supreme Court site.
2. Search for judgments that cite Novartis and Section 3(d) together, then sort by court and date.
3. Open each hit and read the paragraph where Section 3(d) is discussed, not just the headnote.
4. Check whether the decision was appealed, set aside or followed in a later order.
5. Record the count and the date of the search, so your note says how many judgments you reviewed and when.

That last step matters. A statement like “the courts have consistently held” means little without the number of judgments behind it and the date of the search.

07Where Claw fits

Claw is an all-in-one legaltech platform for Indian advocates, law firms, and corporate legal teams, combining AI-based case search, an AI legal assistant (Legal GPT), case management, and compliance automation across all Indian courts and tribunals.

The hard part of Section 3(d) is not Novartis itself. It is finding every later judgment that applied, followed or distinguished it. Claw searches 30 crore+ judgments, covering the Supreme Court from 1950 and the High Courts from 1990, with results in under 5 seconds, so you can pull the cases that cite Novartis and Section 3(d) together and sort them by court and date. It also tracks cases, orders and hearings across 9,102 courts, benches and forums, so a live matter can be followed by party or advocate name.

Claw does not use customer documents to train AI models. Create a FREE Claw account to trace the Section 3(d) case law and track a pending matter by party or advocate name. To search the wider body of law, see case search across Indian courts.

08Sources and further reading

• Patents Act, 1970 and patent rules: ipindia.gov.in
• Novartis AG v Union of India, 1 April 2013: Indian Kanoon
• Supreme Court of India: sci.gov.in
• F. Hoffmann-La Roche v Cipla: Indian Kanoon (2008 interim order; check the 2015 Division Bench decision separately)
• Claw: clawlaw.in

Last verified October 2026. This page is general information, not legal advice. Case outcomes can change on appeal, so confirm the current position before relying on any ruling.

09Frequently asked questions