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The case that defined what "efficacy" means
Supreme Court of India · 2013 · (2013) 6 SCC 1
What happened
Novartis applied for a patent on the beta-crystalline form of imatinib mesylate, a form of a known cancer compound. The application was refused, and the refusal was upheld all the way to the Supreme Court.
What the fight was about
Whether a new physical form of a known substance clears section 3(d), which bars a new form unless it differs significantly in properties with regard to efficacy.
What the court decided
For a medicine, efficacy in section 3(d) means therapeutic efficacy, judged strictly and narrowly. Physicochemical advantages - better flow, greater stability, lower hygroscopicity - do not count. The Court accepted an increase in bioavailability of roughly thirty per cent but held that increased bioavailability does not by itself establish enhanced therapeutic efficacy. Section 3(d) operates as a second tier of qualification for pharmaceutical and chemical substances, over and above novelty and inventive step, so a substance can satisfy both and still fail. The Court was explicit that section 3(d) is not a bar on all incremental innovation - it is a bar on evergreening where no enhanced therapeutic efficacy is shown. The appeals were dismissed.
Why an inventor should care
If your invention is a salt, polymorph, isomer, particle size, complex or combination of something already known, the patent question is not whether it is new. It is whether you can prove it works better therapeutically - and that proof has to be designed into your experiments before you file.
What a patent professional should take from it
Section 3(d) evidence is a drafting decision, not a prosecution one. The efficacy comparison has to be asserted in the specification as filed and supported by data. Later-generated data is more vulnerable and cannot rescue an effect the specification never claimed.
In India, a better form of a known medicine is not enough. It has to be a therapeutically better one, and you have to prove it.
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This is an editorial case note prepared by Ragulika IP - a summary of a decision, not the text of the judgment, and not authority. Read the judgment itself before relying on any point.
Sources & further reading
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Educational guidance, not legal advice. This material is published by Ragulika IP for general education and information. It is not legal advice, it does not create a professional-client relationship, and it is not a substitute for advice on your own facts. Patentability, infringement, prosecution strategy and every other IP outcome turn on the specific facts and on the law and Patent Office practice as they stand at the time you act. Please take professional advice before making a decision, and read the underlying provision or judgment before relying on any point stated here.
Last reviewed by Ragulika IP on 2026-08-23. Indian patent law and Patent Office practice change; check the position before you rely on it.