Drug Repurposing Patent Disputes.
Drug Repurposing Patent Disputes
1. Introduction to Drug Repurposing
Drug repurposing (also called drug repositioning) refers to the discovery of new therapeutic uses for already known or approved drugs. For example, a drug originally developed for hypertension may later be found effective for cancer or viral infections.
From a patent perspective, drug repurposing raises critical questions:
Can a new use of a known substance be patented?
Does discovering a new mechanism of action amount to an invention?
How should courts balance innovation incentives and generic competition?
These questions frequently result in patent disputes, especially in developing countries where laws restrict “evergreening.”
2. Legal Framework Governing Drug Repurposing Patents
International Position
TRIPS Agreement allows patents for inventions that are new, involve an inventive step, and are capable of industrial application.
However, TRIPS does not mandate patent protection for new uses of known substances.
National Approaches
India: Section 3(d) and 3(e) of the Patents Act restrict patentability of new uses of known substances.
Europe: Allows “second medical use” claims under strict conditions.
United States: Permits method-of-treatment patents but requires novelty and non-obviousness.
3. Key Patent Issues in Drug Repurposing
Novelty – Is the new use previously known?
Inventive Step – Is the new use obvious to a skilled person?
Therapeutic Efficacy – Especially relevant in India.
Claim Drafting – Use claims vs method-of-treatment claims.
Evergreening Concerns – Extending monopoly without real innovation.
4. Major Case Laws on Drug Repurposing Patent Disputes
Case 1: Novartis AG v. Union of India (2013)
Relevance to Drug Repurposing
Though primarily an evergreening case, it set foundational principles for new use patents.
Facts
Novartis sought patent protection for a modified form of Imatinib, claiming improved properties.
Imatinib’s anti-cancer properties were already known.
Legal Issue
Whether a new form or use of a known substance qualifies as a patentable invention under Indian law.
Court’s Reasoning
Discovery of a new property or use of a known substance is not patentable.
Patentability requires enhanced therapeutic efficacy, not merely improved physical properties.
Significance
Established strict standards for repurposing claims in India.
Prevented strategic patenting of incremental therapeutic discoveries.
Case 2: Bayer Intellectual Property GmbH v. Union of India (2014)
Facts
Bayer attempted to protect extended therapeutic use of its cancer drug.
Generic manufacturers challenged the validity of repurposing-based claims.
Legal Issue
Whether secondary therapeutic uses of a known compound satisfy inventive step.
Decision
Court rejected the repurposing claim.
Held that mere identification of another disease target does not amount to invention unless it involves technical advancement.
Significance
Reinforced the principle that clinical insight alone is insufficient.
Set limits on lifecycle management strategies of pharmaceutical companies.
Case 3: Bristol-Myers Squibb v. Union of India (Dasatinib Case)
Facts
Drug: Dasatinib, originally developed for leukemia.
Company sought patent for extended therapeutic indications.
Issues
Whether broader medical indications constitute novelty.
Whether repurposing constitutes inventive step.
Ruling
Patent rejected.
New therapeutic indication was considered inherent in the known compound.
Significance
Clarified that latent properties discovered later do not automatically qualify for patent protection.
Prevented monopolization of follow-on medical research.
Case 4: AstraZeneca v. Intas Pharmaceuticals Ltd.
Facts
Drug: Gefitinib, initially approved for lung cancer.
AstraZeneca sought to protect modified therapeutic usage and dosage regimes.
Legal Issues
Patentability of new dosage and treatment protocols.
Whether altered therapeutic use amounts to invention.
Decision
Court rejected injunction against generics.
Held that treatment protocols and dosage adjustments are non-patentable discoveries.
Significance
Important for distinguishing medical practice from patentable inventions.
Limited enforcement of repurposing-based patents.
Case 5: Warner-Lambert v. Actavis (Pregabalin Case – UK)
Facts
Pregabalin was originally approved for epilepsy.
Warner-Lambert obtained a patent for treating neuropathic pain.
Legal Issues
Validity of second medical use patents.
Sufficiency of disclosure.
Judgment
Supreme Court invalidated the patent.
Held that the patent did not sufficiently disclose the claimed therapeutic efficacy.
Significance
Tightened standards for second medical use patents.
Influenced global jurisprudence on repurposing patents.
Case 6: Allergan v. Sandoz (United States)
Facts
Drug: Bimatoprost, initially for glaucoma.
Later repurposed for eyelash growth.
Legal Issue
Whether the new cosmetic use was obvious.
Court’s Holding
Patent invalidated due to obviousness.
Discovery was considered a predictable outcome of known side effects.
Significance
Reinforced the doctrine that new uses discovered through routine observation may lack inventiveness.
Prevented strategic monopolization of known compounds.
5. Comparative Judicial Approach
| Jurisdiction | Approach to Repurposing |
|---|---|
| India | Highly restrictive |
| UK | Conditional acceptance |
| USA | Allowed but strictly scrutinized |
| Developing Countries | Public health oriented |
6. Impact of Drug Repurposing Litigation
Positive Outcomes
Prevents evergreening
Promotes generic competition
Encourages genuine innovation
Challenges
Reduced incentives for repurposing research
Ambiguity in patent drafting
Conflicts between science and law
7. Conclusion
Drug repurposing patent disputes reveal a deep tension between pharmaceutical innovation and access to medicines. Courts—particularly in developing countries—have adopted a cautious and public-health–centered approach, refusing to grant patents for mere discoveries of new uses unless they involve significant technical advancement and therapeutic efficacy.
The jurisprudence makes it clear that:
New uses alone are insufficient
Inventive contribution must be demonstrable
Public interest remains paramount
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