This article is written by Sakshi Bargaje, Government Law College, Mumbai, BA LLB, 2026, during her internship at LeDroit India.
SCOPE OF ARTICLE
- 1. Introduction: Why Patent Opposition Matters
- 2. The Patents Act, 1970 and the 2005 Amendment
- 3. Pre-Grant Opposition under Section 25(1)
- 4. Grounds Available for Pre-Grant Opposition
- 5. Post-Grant Opposition under Section 25(2)
- 6. Grounds Available for Post-Grant Opposition
- 7. Comparing the Two Mechanisms
- 8. Landmark and Recent Case Laws
- 9. Section 3(d) and the Evergreening Problem
- 10. Critical Analysis and Conclusion
ABSTRACT
India’s patent opposition framework is one of the more contested areas of its intellectual property law, and that’s actually a good thing. The Patents Act, 1970, as amended in 2005 to comply with TRIPS obligations, gives any person the right to oppose a patent application before it is granted, and any interested person the right to challenge a granted patent within a year of its publication. These are the pre-grant mechanism under Section 25(1) and the post-grant mechanism under Section 25(2).
Both exist because India made a deliberate choice: that keeping bad patents out of the system matters, especially in sectors like pharmaceuticals, where a wrongly granted monopoly can put medicines out of reach for millions of people. This article walks through both mechanisms, looks at how courts and the IPAB applied them, and pays particular attention to the Novartis litigation and Section 3(d), which together represent India’s most significant contribution to global patent law debates.
Keywords: Patent Opposition, Pre-Grant Opposition, Post-Grant Opposition, Patents Act 1970, Section 25, Section 3(d), TRIPS Agreement, Novartis, IPAB
1. INTRODUCTION
A patent gives its holder a monopoly. Twenty years, in most cases, of exclusive rights to make, sell, and use the patented invention. Nobody else gets to do any of that without permission, and permission usually comes at a price. That’s the deal: you disclose your invention to the public, and the state gives you a temporary exclusive right in return.
But what happens when the patent shouldn’t have been granted in the first place? What if the invention wasn’t actually new? What if someone had already figured it out, published it, or been using it for years? And What if the applicant just tweaked an existing drug compound slightly and called it a new invention? These aren’t hypothetical concerns. They describe situations that come up all the time, particularly in the pharmaceutical industry, and they’re exactly what patent opposition procedures are designed to catch.
India is unusual in offering two distinct opposition windows. The first is pre-grant, under Section 25(1) of the Patents Act, 1970. It lets anyone file a representation against an application while it’s still pending. The second is post-grant, under Section 25(2), which allows interested persons to formally challenge a patent within one year of its grant. Together, these provisions make the Indian patent system more open to challenge than most comparable jurisdictions. That’s deliberate, and understanding why requires a bit of context.
2. THE PATENTS ACT, 1970 AND THE 2005 AMENDMENT
India’s original Patents Act of 1970 was written with a specific purpose in mind. The country was poor. Medicines were expensive and largely controlled by multinational companies holding product patents. The legislature’s response was to strip out product patent protection in pharmaceuticals and food entirely. Only process patents were allowed. This meant Indian companies could legally manufacture patented drugs using different processes, which is exactly what gave rise to India’s now-massive generic pharmaceutical industry.
This arrangement came under pressure when India joined the WTO and signed onto TRIPS in 1995. TRIPS requires product patent protection in all fields of technology, including pharmaceuticals. India had a ten-year transition period, which ran out in 2005. The Patents (Amendment) Act, 2005, brought Indian law into compliance. Product patents in pharma came back. But Parliament wasn’t just rolling over. Several safeguards were built in. Section 3(d) was introduced to block evergreening. The opposition provisions were strengthened. And the two-track system we have today was put in place.
It’s worth being clear about what ‘evergreening’ actually means in this context. It refers to the practice of extending patent protection on a drug not by genuinely improving it but by making minor changes and filing new patents on each variation. Change the salt form. Change the crystal structure. Make it a prodrug. Each modification gets a fresh patent, each patent pushes the monopoly further into the future, and the generic competition that would bring prices down keeps getting delayed. Section 3(d) was specifically designed to stop this.
3. PRE-GRANT OPPOSITION UNDER SECTION 25(1)
Section 25(1) says that any person can file a representation opposing a patent application after it has been published under Section 11A but before it is granted. The phrase ‘any person’ is doing a lot of work here. It really does mean anyone. A competitor, a public interest organisation, a patient group, an individual researcher, even a private citizen with no commercial interest at all. No standing requirement beyond being a person.
The process works like this. Once an application is published in the Patent Office Journal, a public notice period begins. During this time, pre-grant representations can be filed with the Controller of Patents. The Controller reviews the representation. If it appears to raise a prima facie valid ground, the applicant is notified and allowed to respond. After considering both sides, the Controller decides whether to proceed with the grant, refuse it, or require amendments to the claims.
Here’s the honest limitation of this procedure, though. It’s administrative, not adjudicative. The opponent doesn’t necessarily get an oral hearing. There’s no guaranteed right to appear and argue. The Controller has discretion over how much procedural latitude to give the opponent, and Controllers under workload pressure don’t always give pre-grant representations the careful attention they deserve. Civil society organisations that have used this route extensively will tell you the quality of engagement varies significantly from office to office.
4. GROUNDS FOR PRE-GRANT OPPOSITION
Section 25(1) lists specific grounds on which opposition can be filed. These include:
- That the invention was publicly known or used in India before the priority date of the application.
- That the invention was published, in India or abroad, before the priority date.
- That the claimed invention was already the subject of an earlier Indian application filed by someone else.
- That the invention is obvious and lacks any inventive step, judged against published prior art.
- That the subject matter is not patentable under the Act, which includes the exclusions in Sections 3 and 4.
- That the specification fails to sufficiently describe the invention or the method of performing it.
- That the applicant has not disclosed required information under Section 8, or has provided false information.
- That the invention involves biological material or traditional knowledge obtained from India in violation of applicable law.
That last ground deserves a moment. India has significant biodiversity and a rich tradition of indigenous medicinal knowledge. There have been documented cases of foreign entities filing patents on traditional remedies, claiming novelty for things that Indian communities had known and used for generations. The Traditional Knowledge Digital Library was created partly in response to this, cataloguing traditional knowledge specifically so it can be cited as prior art in patent proceedings. The opposition system is one of the mechanisms through which these claims get challenged.
5. POST-GRANT OPPOSITION UNDER SECTION 25(2)
The post-grant procedure is a different animal altogether. It’s more formal, more adversarial, and more procedurally complete. Under Section 25(2), any ‘interested person’ can file a notice of opposition within one year from the date on which the grant of the patent is published in the Official Journal. The one-year window is fixed and non-extendable, so timing matters.
The term ‘interested person’ is defined in Section 2(t) of the Act to include any person engaged in or promoting research in the same field as the invention. This is broad enough to cover most competitors and research organisations, though it does exclude the wider public standing available at the pre-grant stage.
Once a notice of opposition is filed, an Opposition Board is constituted by the Controller. The Board examines the opposition, the patentee files a reply, both sides can file evidence, and oral hearings are held. The Board gives a recommendation, and the Controller then passes a final order based on that recommendation. It’s a proper hearing, with real procedural rights on both sides.
Until 2021, decisions in post-grant proceedings were appealable to the Intellectual Property Appellate Board. The IPAB was abolished by the Tribunals Reforms Act, 2021, and patent appeals now go to the High Courts. This is controversial. The IPAB had its problems, certainly, but it had also built up a body of specialised jurisprudence over the years. Whether High Courts, which deal with an enormous range of subject matter, will develop equivalent depth in patent law is a legitimate concern.
6. GROUNDS FOR POST-GRANT OPPOSITION
The grounds available in post-grant proceedings largely mirror that available pre-grant, but with some additions. Everything in Section 25(1) is available under Section 25(2). On top of that, post-grant opponents can also raise the ground that the patent was obtained by wrongful obtaining from the true and first inventor, and that the complete specification doesn’t disclose or wrongly mentions the source of biological material used.
Post-grant proceedings also interact with the revocation provisions under Section 64 of the Act, which sets out an even longer list of grounds on which a patent can be revoked entirely. In practice, parties sometimes pursue both opposition and revocation proceedings, or move from one to the other depending on how the litigation develops.
7. COMPARING THE TWO MECHANISMS
The most obvious difference is standing. Pre-grant is open to everyone. Post-grant requires the opponent to be an interested person. In most commercial disputes, this barely matters, since a competitor will always qualify. But for public interest litigants like NGOs and patient advocacy groups, this distinction can be significant. Their main opportunity to formally intervene is at the pre-grant stage.
Timing works differently, too. Pre-grant has a variable window, depending on when the application is published and how quickly the Controller moves toward a grant. It can be short. Post-grant is fixed at one year from publication of the grant. More predictable, but by then the patent is already in force and potentially being enforced.
The procedural quality differs sharply. Post-grant gives opponents a proper hearing with evidence filing and oral arguments as a matter of right. Pre-grant is more at the Controller’s discretion. And the stakes are different too. A successful pre-grant opposition prevents the patent from ever coming into existence. A successful post-grant opposition revokes a patent that may already have shaped commercial arrangements and licensing deals.
8. LANDMARK AND RECENT CASE LAWS
Novartis AG v. Union of India (2013) 6 SCC 1
There’s really no other place to start. Novartis AG v. Union of India (2013) 6 SCC 1 is the most consequential patent judgment in Indian legal history, and its significance extends well beyond India’s borders. The case involved Novartis’s application for a patent on the beta-crystalline form of imatinib mesylate, sold under the brand name Gleevec, a drug used in the treatment of chronic myeloid leukaemia. The application was opposed at the pre-grant stage by several generic manufacturers and patient groups. The Controller rejected it. The IPAB upheld the rejection. Novartis challenged the constitutional validity of Section 3(d) before the Madras High Court, arguing it violated TRIPS. The High Court rejected that challenge too.
The Supreme Court, in a judgment by Justices Aftab Alam and Ranjana Prakash Desai, dismissed Novartis’s final appeal in 2013. The Court upheld Section 3(d), found that the beta-crystalline form did not demonstrate significantly enhanced therapeutic efficacy over the known compound, and offered a detailed defence of India’s right to set its own patentability standards within the space TRIPS allows. The judgment is careful, well-reasoned, and genuinely important. It’s worth reading in full, not just in extract.
Bayer Corporation v. Natco Pharma Ltd (2012)
The Bayer v. Natco case produced India’s first compulsory licence, for the cancer drug Sorafenib (Nexavar). While technically a compulsory licence case rather than a straight opposition, it sits within the same policy space: the question of whether patent holders are genuinely working their patents in India and making patented medicines available at reasonable prices. The IPAB upheld the Controller’s decision to grant the licence. It remains a landmark in how India balances patent rights against public access obligations.
F. Hoffmann-La Roche Ltd v. Cipla Ltd (2009)
In F. Hoffmann-La Roche Ltd v. Cipla Ltd 2009 (40) PTC 125 (Del), the Delhi High Court dealt with an infringement action over the lung cancer drug Erlotinib. Cipla had launched a generic version, and Roche sought an injunction. The Court declined to grant the injunction, in part because of concerns about public health impact. The case illustrates how opposition and infringement proceedings can run in parallel, and how public interest considerations can influence the outcome at interim stages.
Recent Trends
Pre-grant oppositions in the pharmaceutical space have continued to be used actively. Organisations like I-MAK (Initiative for Medicines, Access and Knowledge) and MSF (Medecins Sans Frontieres) have filed oppositions against patent applications for HIV medications, hepatitis C drugs, and cancer treatments, with a reasonable success rate. The volume of pharmaceutical patent oppositions in India remains far higher than in comparable jurisdictions, which tells you something about both the accessibility of the procedure and the stakes involved.
9. SECTION 3(d) AND THE EVERGREENING PROBLEM
Section 3(d) says that the mere discovery of a new form of a known substance doesn’t count as an invention unless it results in significantly enhanced efficacy. Salts, esters, ethers, polymorphs, metabolites, and similar derivatives of known substances are treated as the same substance unless they show a meaningful improvement in how the drug actually works.
What this does in practice is put a hard barrier in front of the evergreening strategy. A company can’t just file a patent on the sodium salt of a known drug and claim a new monopoly. It can’t file a patent on a different crystalline form unless it can show that the new form is therapeutically better. This forces genuine innovation as a condition of extended protection, rather than allowing incremental tweaking to substitute for it.
The pharmaceutical industry’s criticism of Section 3(d) is that it goes beyond what TRIPS requires and discriminates against a field of technology. The Supreme Court in Novartis rejected this firmly. TRIPS sets a floor, not a ceiling. Countries have discretion in how they define patentability requirements, provided they apply those requirements consistently across technologies. India’s approach is a legitimate exercise of that discretion. This interpretation has since been referenced in academic commentary and policy debates in other developing countries looking to build similar safeguards into their own patent laws.
10. CRITICAL ANALYSIS AND CONCLUSION
India’s two-track opposition system genuinely works better than most countries’ single-track alternatives. The pre-grant mechanism catches bad applications early, before a monopoly ever comes into existence. The post-grant mechanism provides a proper adversarial forum for more complex challenges. And the combination of both, together with Section 3(d), makes India’s patent quality filter one of the most robust in the developing world.
But it’s not a perfect system. The pre-grant procedure still needs strengthening on the procedural side. Opponents should have clearer rights to participate and to be heard. Controllers need resources and time to give representations proper consideration rather than treating them as administrative boxes to tick. And the abolition of the IPAB, while it may make structural sense in terms of tribunal reform, has removed a body of specialised expertise that took years to build. High Courts will need to develop that expertise again, and that takes time.
There’s also the tension that’s unlikely to ever fully go away. The pharmaceutical industry needs patent protection to fund research and development. That’s a real concern, not just a lobbying point. But in a country where most people pay for medicines out of pocket, and where a month’s supply of a patented cancer drug can cost more than a year’s earnings, the social costs of weak patent quality control are just as real. The opposition system, imperfect as it is, is one of the most important tools India has for keeping that balance.
For practitioners, the practical lesson is to take both procedures seriously. Pre-grant oppositions are underused in non-pharmaceutical fields despite the broad standing they offer. Post-grant proceedings, now before the High Courts rather than the IPAB, will likely evolve in their procedural character. Staying across both is not optional for anyone doing serious IP work in India.
