India has granted product patents for medicines only since 2005, and it wrote the rules with its generic industry in view. A pharmaceutical patent that issued without difficulty in the United States or Europe can be refused, opposed or revoked here on grounds that exist nowhere else. This guide sets out those grounds, the exceptions that favour generic entry, and what a patentee can do about them.
Quick reference
| New forms of known drugs | Not patentable unless they show enhanced therapeutic efficacy, proven by data |
| Combinations | Not patentable if they are a mere mixture; synergy must be shown |
| Methods of treatment | Not patentable; new uses of known drugs are not either |
| Generic preparation before expiry | Allowed — the regulatory-use exception |
| Patent linkage | None; the drug regulator does not check patents |
| Data exclusivity | None |
| Term extension | None; twenty years, full stop |
The efficacy rule
The provision every pharmaceutical applicant meets is the one excluding a new form of a known substance that does not result in enhanced efficacy. Salts, esters, ethers, polymorphs, metabolites, pure forms, particle sizes, isomers and their mixtures, complexes, combinations and other derivatives of a known substance are treated as the same substance unless they differ significantly in properties with regard to efficacy. The same provision excludes a new use of a known substance.
The Supreme Court read it in Novartis (2013), refusing a patent for the beta-crystalline form of imatinib mesylate. Efficacy means therapeutic efficacy — the effect of the drug on the disease — and it is to be judged strictly. Improved bioavailability, better stability, easier processing or lower hygroscopicity are physical properties, not therapeutic ones, and do not count unless they are shown to translate into a therapeutic advantage. And the enhancement has to be proven: an assertion in the specification is not enough; comparative data is what the Office and the courts look for.
For applicants, the consequences are practical:
- A second-generation patent on a new form of a marketed drug needs comparative efficacy data against the known form, ideally in the specification, or at least available when the objection comes.
- Formulation patents that rely on stability or bioavailability alone are at risk.
- Where the new form genuinely works better in patients, say so with numbers.
Combinations
A mere admixture resulting only in the aggregation of the properties of its components is not an invention. A fixed-dose combination of two known drugs is patentable only if the combination does something the components do not do separately — a synergistic effect, again supported by data. “Convenient to take together” is not enough.
Methods of treatment and new uses
Any process for the medicinal, surgical, curative, prophylactic, diagnostic or therapeutic treatment of humans or animals is excluded. Products — the drug, the device, the kit — are patentable; the method of using them on a patient is not.
The exclusion is broader in practice than its counterparts elsewhere, because India also excludes a new use of a known substance outright. There is no second-medical-use claim, and the Swiss-type formulation used to get around treatment exclusions in Europe is rejected here. A known drug found to treat a new condition cannot be repatented for that condition.
What generics may do before expiry
Two exceptions in the Act are written for the generic industry.
Regulatory use. Making, using, selling or importing a patented drug solely for uses reasonably related to developing and submitting information required under any law — Indian or foreign — regulating the manufacture or sale of a product is not infringement. A generic manufacturer can develop its product, run bioequivalence studies and file for marketing approval, in India or abroad, while the patent is in force. It cannot launch.
Parallel import. Importing a patented product from a person duly authorised under the law to produce and sell it is not infringement. Drugs legitimately sold abroad can be brought in.
What India does not have
Patent linkage. The drug regulator approves generics on safety and efficacy without regard to patents. The Delhi High Court rejected an attempt to read linkage into the law in Bayer (2010), holding that the two statutes operate in separate fields, and the Supreme Court declined to interfere. A patentee that wants to stop a generic launch must sue for infringement; the regulator will not do it for them.
Data exclusivity. Clinical data submitted for approval of a new drug is not given a period of protection against reliance by generic applicants. Proposals to introduce it have not been enacted.
Term extension. The term is twenty years from filing. There is no supplementary protection or patent term adjustment for time lost in regulatory approval or examination.
The opposition and revocation landscape
Indian generic companies use the pre-grant opposition heavily. Anyone can file one, from publication until grant, on grounds that include the efficacy rule and the other exclusions, and a pharmaceutical application of any commercial interest should expect at least one. Since 2024 the opposition is screened for a prima facie case and carries a fee, which has reduced the purely tactical filings, but not the serious ones.
After grant, the same grounds are available in a post-grant opposition for a year, and by way of revocation — usually as a counter-claim when the patentee sues. A pharmaceutical patent in India is never entirely settled.
Compulsory licensing exists and has been used once, for a cancer drug in 2012, on grounds of price, availability and local working. The provisions remain, and the statement of working the patentee files every three years is the record they would be tested against.
Biologics
Biological drugs are patentable as products, subject to the same exclusions and to the requirement that biological material used in the invention be disclosed and, where it is of Indian origin, that access be approved. Biosimilars follow their own regulatory guidelines, and the regulatory-use exception covers their development.
For patentees
A pharmaceutical patent strategy for India starts from what the Act will not allow. File the compound patent early and prosecute it well; it is the one that holds. For second-generation filings, gather the efficacy data before filing rather than after the objection. Keep the working statements accurate. Watch the journal for oppositions, and answer them fully rather than treating them as a nuisance. And plan enforcement around the fact that the regulator will not act — the only route to stopping a generic is the court, and the interim injunction is where the case is decided.
Frequently asked questions
Why was the Novartis patent refused in India? The application claimed a new crystalline form of a known cancer drug. The Supreme Court held that a new form of a known substance is patentable only if it shows enhanced therapeutic efficacy, judged strictly and proven by data, and that improved bioavailability alone did not meet the test.
Can a new formulation or salt of a known drug be patented in India? Only where it shows significantly enhanced therapeutic efficacy over the known form, supported by comparative data. Improvements in stability, processing or bioavailability do not qualify unless they are shown to produce a therapeutic advantage.
Are second medical use claims allowed in India? No. A new use of a known substance is excluded, and methods of treatment are excluded, so neither a use claim nor a Swiss-type claim is accepted.
Can a generic company develop a patented drug before the patent expires? Yes. Making, using and importing the drug to generate the data required for regulatory approval, in India or abroad, is expressly not infringement. Commercial launch before expiry is.
Does India have patent linkage? No. The drug regulator grants marketing approval without reference to patents, and the courts have refused to read linkage into the law. A patentee must sue to stop a generic launch.
Can a pharmaceutical patent term be extended in India? No. The term is twenty years from filing, with no extension for regulatory or examination delay.
Useful official resources
- IP India — patents — the Act and the manual of practice
- Central Drugs Standard Control Organisation — the drug regulator
See our related notes on pre-grant opposition, compulsory licensing, patent infringement and the regulatory-use exception and the statement of working.
A pharmaceutical filing facing the efficacy objection, or an opposition from a generic manufacturer? Talk to us.