Navigating the Nuances of Patenting Pharmaceutical Substances

When a researcher develops a new drug molecule after years of painstaking laboratory work, the first question that arises is: can it be patented? And in India, that question is far more nuanced than a simple yes or no. The country’s patent law draws a precise and carefully reasoned line between genuine pharmaceutical innovation and incremental tweaks dressed up as invention. Understanding how Indian law defines a pharmaceutical substance – and what it takes to get one patented – is essential for anyone navigating the intersection of intellectual property and public health.

What is a pharmaceutical substance under Indian law? 🔗

The definition is deceptively brief. Section 2(1)(ta) of the Patents Act, 1970 defines a pharmaceutical substance as “any new entity involving one or more inventive steps.” Two words in this definition carry all the weight: new and inventive. A substance that is merely rediscovered, reformulated in a trivial way, or presented under a different name does not qualify. The entity must be genuinely new – not previously known – and its creation must involve at least one identifiable inventive step, meaning it cannot be something that a person skilled in the relevant field would have arrived at obviously.

This definition sits at the heart of a broader framework. Under Section 2(1)(ja), an inventive step is defined as a feature that represents a technical advance over existing knowledge, or has economic significance, such that the invention is non-obvious to a person skilled in the art. For pharmaceutical substances, satisfying this requirement is necessary but not sufficient – there is an additional, sector-specific hurdle that makes Indian patent law distinctive on the global stage.

The special barrier: Section 3(d) of the Patents Act 🔗

Most countries require novelty, an inventive step, and industrial applicability to grant a patent. India demands all three of these – and then adds a fourth test specifically for pharmaceuticals. Section 3(d) of the Patents Act, 1970 states that the mere discovery of a new form of a known substance – including salts, esters, ethers, polymorphs, metabolites, isomers, and similar derivatives – is not patentable unless it results in a significant enhancement of the known efficacy of that substance. In other words, if a pharmaceutical company finds a new crystalline form of an already-known drug, it cannot patent that form simply by pointing to its novelty. It must demonstrate that the new form actually works better therapeutically.

The explanation appended to Section 3(d) is explicit: 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 – unless they differ significantly in their efficacy-related properties. This is a deliberately high bar, and it was inserted with a specific purpose: to prevent evergreening.

What is evergreening, and why does it matter? 🔗

Evergreening refers to the practice of extending a patent’s effective commercial life by obtaining new patents on minor modifications of an existing drug – a slightly different salt form, a new crystalline structure, a modified dosage – without any meaningful improvement in how the drug works. This practice, if left unchecked, can allow multinational pharmaceutical companies to maintain monopoly pricing on a drug well beyond the initial 20-year patent term, keeping cheaper generic versions off the market. For a country like India, where affordability of medicines is a direct public health concern for over a billion people, this is not a theoretical problem – it is a lived reality.

Section 3(d) was therefore designed as a structural safeguard. It keeps the door open for genuine pharmaceutical innovation while closing it firmly on specious patent extensions. As the Supreme Court of India has noted, the amended Section 3(d) sets up a second layer of qualifying conditions for pharmaceutical products – to preserve space for authentic inventions while preventing repetitive patenting on superficial grounds.

The Novartis case: where it all came into focus 🔗

No discussion of pharmaceutical substance patenting in India is complete without examining Novartis AG v. Union of India (2013), the landmark Supreme Court ruling that gave Section 3(d) its authoritative interpretation. The case involved Novartis’s patent application for the beta-crystalline form of imatinib mesylate – a specific form of a compound used to treat chronic myeloid leukaemia, marketed under the brand name Glivec (or Gleevec internationally).

Novartis argued that the beta-crystalline form exhibited approximately 30% greater bioavailability than the known alpha form, and was more thermodynamically stable and less hygroscopic. The company contended these improvements should qualify the substance for patent protection. The Supreme Court disagreed. It held that in the context of pharmaceutical substances, “efficacy” means therapeutic efficacy – that is, the drug’s actual curative effect on the human body – not its physical or chemical properties such as stability or solubility. The court concluded that improved physical characteristics, without demonstrated improvement in treatment outcomes, do not meet the enhanced efficacy standard under Section 3(d). Novartis’s application was rejected.

The ruling had sweeping implications. It drew sharp criticism from multinational pharmaceutical companies, who argued it discouraged incremental innovation and created an uncertain investment climate. On the other hand, it was widely celebrated by public health advocates, international organisations including the WHO, and generic drug manufacturers. Médecins Sans Frontières welcomed the decision as a protection of affordable access to life-saving medicines. The case did not shut the door on all secondary pharmaceutical patents – it clarified that genuine improvements in therapeutic outcomes remain patentable. What it shut down was the practice of gaining patent protection merely by rearranging a molecule’s physical form without any clinical benefit.

What qualifies as a patentable pharmaceutical substance in India 🔗

Given this legal framework, what actually qualifies for a patent? A pharmaceutical substance is patentable in India when it satisfies all standard patentability criteria – novelty, inventive step, and industrial applicability – and clears the efficacy threshold under Section 3(d). Concretely, this means:

New chemical entities (NCEs) – entirely new molecules not previously known or disclosed – are the clearest candidates. They represent genuinely original pharmaceutical innovation and face the most straightforward path through examination, though Indian Patent Office examiners have increasingly raised Section 3(d) objections even against NCE applications, treating it as a general quality-control mechanism beyond its original purpose.

Modified forms of known substances – such as new polymorphs, salts, or esters – may be patentable if the applicant can demonstrate, with concrete data, that the modification produces a measurably superior therapeutic effect. Improved stability or better solubility alone will not suffice; the improvement must translate into better clinical outcomes for patients.

Combination inventions face yet another hurdle under Section 3(e), which bars patents on substances obtained by merely mixing known components, unless the combination produces synergistic effects – results that go beyond the sum of the individual components’ properties. The Indian Patent Office routinely raises Section 3(e) objections against pharmaceutical composition claims that lack demonstrated synergy.

The innovation-access tension at the core of pharmaceutical patenting 🔗

The challenge of defining and patenting pharmaceutical substances in India cannot be fully understood without acknowledging the fundamental tension it embodies. Pharmaceutical companies invest billions of dollars in drug research, and of every thousand potential compounds screened, only one is typically approved for marketing. Patent protection for 20 years is the primary mechanism through which these companies recover research and development costs. Without it, the incentive to invest in discovering new treatments diminishes significantly.

At the same time, India has an extraordinary role in global medicine supply. Its generic pharmaceutical industry – built in large part on the pre-2005 patent regime that did not recognise product patents for drugs – supplies affordable medicines to developing countries across the world. The concept of a pharmaceutical substance under Indian law – “any new entity involving one or more inventive steps” – read together with Section 3(d)’s efficacy requirement – is the legal expression of this balancing act. It is India’s way of saying: genuine innovation will be rewarded, but patent protection will not be used as a lever to keep essential medicines out of reach.

This balance is not static. The Patents Act itself has evolved through three sets of amendments – in 1999, 2002, and 2005 – each responding to India’s TRIPS obligations under the WTO, while preserving domestic policy space. The 2005 amendment was the most significant, reintroducing product patents for pharmaceuticals after a 35-year absence, but doing so on India’s own terms – with Section 3(d) as the gatekeeper.

Practical challenges in defining pharmaceutical substance patentability 🔗

Despite the legal clarity that the Novartis ruling provides in principle, significant ambiguities persist in practice. The Patents Act does not define how unique a new molecule must be, introducing subjectivity into the examination process. What one examiner treats as a genuinely new pharmaceutical substance, another may challenge under Section 3(d) as a derivative of something already known.

The question of what constitutes “known efficacy” of a prior substance is also frequently contested. Indian patent law requires that the prior art must not only disclose a structurally similar compound, but also establish its known efficacy – the applicant is not required to demonstrate enhanced efficacy over a compound whose therapeutic effect has never been established. This is an important nuance that applicants and their legal counsel must navigate carefully.

Additionally, the lack of clear guidance on how much efficacy data is sufficient – what type of studies, what magnitude of improvement – leaves pharmaceutical patent prosecution in India more uncertain than in comparable jurisdictions. Section 3(d) has evolved from a targeted anti-evergreening measure into a broader examination tool, sometimes applied in ways that strain its original legislative intent.

For biotechnology companies working with biomolecules such as nucleic acids and polypeptides, the uncertainty is compounded further. Many biotech firms find that the law does not clearly address the patentability of such entities, making patent eligibility determinations feel more unpredictable than in the US or European patent systems.

Why this framework matters beyond India 🔗

India’s approach to defining and patenting pharmaceutical substances carries weight well beyond its borders. As one of the world’s largest producers of generic medicines, India’s patent decisions directly influence drug access in Africa, Southeast Asia, and Latin America. The Novartis ruling is cited in international policy discussions at the WHO and WTO as a model for how developing countries can lawfully use TRIPS flexibilities to protect public health. It established that physicochemical changes without demonstrated therapeutic benefits are inadequate for pharmaceutical patent protection – a principle that has since influenced legal debates in multiple jurisdictions.

For law students and IP practitioners in India, understanding the statutory definition of pharmaceutical substance under Section 2(1)(ta), the specific patentability bar under Section 3(d), and the interpretive framework established by the Supreme Court is not merely an academic exercise. It is the foundation for advising pharmaceutical clients, challenging or defending patent applications, and engaging with one of the most consequential intersections of law, science, and public welfare in contemporary legal practice.

What do you think? Should India consider providing more precise legislative guidance on what data or evidence is sufficient to demonstrate “enhanced therapeutic efficacy” under Section 3(d) – or does judicial case-by-case development serve the public interest better? And given that Section 3(d) was designed to prevent evergreening while preserving genuine innovation, do you think the current legal framework strikes the right balance between rewarding pharmaceutical research and ensuring affordable access to medicines?

References

1. https://indiankanoon.org/doc/65643/
2. https://ipindia.gov.in/writereaddata/Portal/IPOAct/1_31_1_patent-act-1970-11march2015.pdf
3. https://www.lexology.com/library/detail.aspx?g=6a117884-0840-4cfc-b698-12131a965722
4. https://www.aipla.org/list/innovate-articles/the-global-significance-of-india-s-pharmaceutical-patent-laws
5. https://www.lexology.com/library/detail.aspx?g=1b13bcbb-27b9-4e51-a152-6abc53eb6f18
6. https://www.drishtijudiciary.com/landmark-judgement/intellectual-property-rights/novartis-ag-v-union-of-india-2013-6-sc-1
7. https://recordoflaw.in/novartis-ag-v-union-of-india-2013-6-scc-1/
8. https://en.wikipedia.org/wiki/Novartis_v._Union_of_India_%26_Others
9. https://www.drugpatentwatch.com/blog/indian-pharmaceutical-patent-prosecution-the-changing-role-of-section-3d/
10. https://www.anandandanand.com/news-insights/chemical-patents-peculiarities-indian-patent-laws/
11. https://pmc.ncbi.nlm.nih.gov/articles/PMC2900001/
12. https://www.bananaip.com/ip-news-center/the-origin-of-the-definition-of-section-3d-indian-patent-act-1970/
13. https://www.intellectbastion.com/comprehensive-analysis-of-the-patent-act-1970-legal-framework-strategic-evolution-in-india/