Mastering Post-Grant Patent Opposition: A Strategic Approach

A patent grant is not the final word on an invention’s validity. Under Indian patent law, any interested party has a window of opportunity – specifically one year from the date of publication of the patent grant – to formally challenge that grant through a process known as post-grant opposition. This mechanism, introduced through the Patents (Amendment) Act, 2005, reflects India’s commitment under the TRIPS Agreement to building a patent system that is rigorous, transparent, and accountable. Far from being a legal afterthought, post-grant opposition is a powerful tool that keeps patent holders honest and protects the public from monopolies built on questionable grants.

What is post-grant opposition? 🔗

Post-grant opposition is governed by Section 25(2) of the Patents Act, 1970, read with Rules 55A to 70 of the Patents Rules, 2003. Unlike pre-grant opposition – which can be filed by any person before a patent is granted – post-grant opposition is restricted to an “interested person.” Under Section 2(1)(t) of the Act, this includes individuals involved in or promoting research in the relevant field, as well as entities with a manufacturing, trading, or financial interest in the patented goods. This distinction matters: the post-grant route is designed for parties with a genuine stake in the outcome, not for abstract public interest challenges.

Before 2005, India had no formal mechanism to challenge a patent once it had been granted. The amendment introduced post-grant opposition specifically to align with international standards, filling a significant gap in the legal framework. Today, both pre-grant and post-grant oppositions share the same grounds for challenge, but they differ substantially in procedure, parties, fees, and the institutional machinery involved.

Who can file and when 🔗

The timing requirement is strict. Post-grant opposition must be filed after the grant of the patent but before the expiry of 12 months from the date of publication of that grant in the Indian Patents Journal. Missing this window forecloses the opposition route entirely, though the aggrieved party may still pursue revocation under Section 64 of the Act – a separate and more protracted process.

The notice of opposition is filed using Form 7 in duplicate, addressed to the Controller of Patents at the patent office where the original application was filed. Unlike pre-grant opposition, filing a post-grant opposition carries a mandatory fee. As of the current fee schedule under the First Schedule of the Patent Rules, 2003, natural persons and small entities pay ₹2,400 for e-filing and ₹2,600 for physical filing. Other entities, including companies and start-ups, pay ₹12,000 for e-filing and ₹13,200 for physical filing.

Grounds for opposition 🔗

The grounds for post-grant opposition under Section 25(2) of the Patents Act are identical to those available for pre-grant opposition. An opponent may challenge the patent on any of the following bases:

• Wrongful obtainment – the invention was improperly derived from the opponent.
• Prior publication – the invention was published before the priority date of the patent claim.
• Prior claiming – the subject matter was already claimed in a valid earlier patent.
• Publicly known or used in India before the priority date.
• Obviousness – the invention lacks an inventive step.
• Non-patentable subject matter – the invention falls outside the scope of patentability under the Act.
• Insufficient disclosure – the complete specification does not disclose the invention sufficiently.
• Failure to disclose foreign applications under Section 8 of the Act.
• Convention application not filed within 12 months of the first filing in the convention country.
• Non-disclosure or wrongful disclosure of the geographical origin of biological material used in the invention.
• Traditional knowledge – the invention is anticipated by knowledge available within any local or indigenous community in India or elsewhere.

This is an exhaustive list. An opponent cannot raise grounds outside this statutory framework, making it essential to identify and articulate the relevant grounds precisely at the outset.

Step-by-step procedure for post-grant opposition 🔗

Step 1: Filing the notice of opposition 🔗

The process begins when the interested person files a notice of opposition along with a written statement setting out the grounds of challenge and supporting evidence in duplicate. A copy of the notice and evidence must also be served directly on the patentee. The burden of initiating the process – including serving the other side – rests with the opponent. Incomplete filings or failure to serve the patentee can derail the proceeding at the threshold itself.

Step 2: Constitution of the Opposition Board 🔗

Once the Controller receives the notice of opposition, they are required under Rule 56 of the Patents Rules to constitute an Opposition Board consisting of three members. One member is nominated as chairperson by the Controller; the other members are generally patent examiners, but the examiner who originally dealt with the patent application is excluded from the Board. This exclusion is a safeguard against institutional bias – the examiner who recommended grant is not placed in the position of adjudicating a challenge to that very grant.

Step 3: Patentee’s response 🔗

The Controller informs the patentee of the opposition and gives them an opportunity to respond. The patentee must file a reply statement, setting out the grounds on which the opposition is contested along with supporting evidence, within two months of receiving the copy of the notice from the opponent. If the patentee chooses not to contest the opposition at all, the patent is liable to be revoked outright, without any further hearing.

Step 4: Reply by the opponent 🔗

If the patentee files a reply, the opponent has one month from the date of the patentee’s reply to file their own reply evidence. After this exchange, neither party may submit further evidence or submissions except on the specific direction of the Controller. This prevents the proceedings from becoming an open-ended exercise in evidence accumulation.

Step 5: Examination by the Opposition Board 🔗

Within three months of receiving all documents – written statements, replies, and evidence – the Opposition Board examines the submissions and issues a joint recommendation report to the Controller addressing each ground of opposition. This report is not a final order; it is a recommendation. However, following the Supreme Court’s ruling in Cipla Ltd. v. Union of India (2012), the Board’s recommendation must be shared with both parties so they can effectively respond to it during the hearing. Earlier, this report was treated as an internal document not accessible to the parties – the Supreme Court’s intervention changed that practice significantly.

Step 6: The hearing 🔗

Under Rule 62, any party wishing to be heard must send a request to the Controller. The Controller fixes a hearing date and notifies both parties at least 10 days in advance. Members of the Opposition Board are also present at the hearing. Both parties present their oral arguments, and the Controller considers these submissions alongside the Board’s recommendation before passing an order.

Step 7: The Controller’s order 🔗

After the hearing – or without one if neither party requests it – the Controller passes a reasoned order. The Controller can either maintain the patent as granted, amend the patent, or revoke it entirely. This three-fold outcome reflects the nuanced nature of the review: it is not always all-or-nothing. A patent may be saved through amendment of claims that are found to be overly broad, even if the invention itself is valid.

Appeals against the Controller’s order 🔗

A party aggrieved by the Controller’s decision in a post-grant opposition can appeal under Section 117A of the Patents Act. Following the abolition of the Intellectual Property Appellate Board (IPAB) through the Tribunals Reforms (Rationalisation and Conditions of Service) Ordinance, 2021, such appeals now lie before the High Court. This is a significant procedural shift: the High Court now exercises jurisdiction that was previously vested in a specialized tribunal. It is worth noting that this appellate remedy is available only in post-grant opposition proceedings – there is no equivalent right of appeal against the Controller’s decision in pre-grant opposition proceedings.

Post-grant opposition vs. revocation: understanding the distinction 🔗

Students and practitioners often conflate post-grant opposition with revocation under Section 64 of the Patents Act. The two are distinct. Post-grant opposition must be filed within one year of the publication of the patent grant and is conducted before the Controller. Revocation, on the other hand, can be filed at any time during the 20-year life of the patent, either before the High Court by way of a petition or as a counterclaim in an infringement suit. Courts have held that one person cannot simultaneously pursue both a revocation application and a post-grant opposition against the same patent. The choice of forum, therefore, carries strategic consequences that must be thought through carefully.

Landmark case: the significance of scrutiny 🔗

The post-grant opposition framework has been tested in several high-profile disputes. The litigation around Roche’s Indian patent on Erlotinib Hydrochloride – the anti-cancer drug Tarceva – offers a useful lens into how these proceedings interact with infringement suits. Roche had been granted Indian Patent No. 196774 for Erlotinib Hydrochloride in 2007, after which Cipla launched a generic version at roughly one-third the price. Roche filed for infringement; Cipla challenged the patent’s validity on multiple grounds including obviousness and non-disclosure. The Delhi High Court’s handling of the case – spanning interim injunctions, revocation counterclaims, and appellate proceedings over several years – illustrated that a patent grant, even after examination, remains subject to sustained legal scrutiny. The case also reinforced the significance of Section 3(d) of the Patents Act as a check against evergreening in pharmaceutical patents.

Why the post-grant stage matters 🔗

The post-grant opposition mechanism is more than a procedural formality. It reflects a structural assumption built into Indian patent law: that the grant of a patent by the office, however thorough, does not make that patent immune from error. Examination is conducted under significant workload and time constraints; the patent office cannot always anticipate every piece of prior art or foresee every patentability issue. Post-grant opposition gives a structured, time-bound opportunity for the public and competitors to surface those issues through a formal, evidence-based process.

India’s opposition system – providing two separate windows of challenge at two different stages of patent prosecution – is considered distinctive in the global patent landscape. When a patent successfully withstands post-grant opposition, it emerges with considerably enhanced credibility: it has not merely passed office examination but survived adversarial scrutiny as well. Conversely, when a patent is revoked or amended through this process, the system has functioned exactly as intended – correcting an error before monopoly rights are exercised to their full detriment.

For any interested party – whether a competitor, a researcher, or a generic manufacturer – understanding the timelines, standing requirements, evidentiary standards, and procedural steps of post-grant opposition is not just academic knowledge. It is a practical necessity in navigating India’s patent landscape intelligently.

What do you think? Given that post-grant opposition must be filed within just one year of the patent’s publication, do you think this window is sufficient for interested parties to build a credible challenge – especially in technically complex fields like pharmaceuticals or biotechnology? And with the IPAB abolished and appeals now going directly to the High Court, how do you see this change affecting the accessibility and pace of patent disputes in India?

References

1. https://ipindia.gov.in/writereaddata/portal/ev/sections/ps25.html
2. https://blog.ipleaders.in/patent-pre-grant-post-grant-opposition-procedure-india-vs-re-examination-us/
3. https://maklaw.in/knowledge/patent-opposition-and-amendment/post-grant-opposition/
4. https://excelonip.com/post-grant-opposition-in-india/
5. https://thelegalschool.in/blog/section-25-of-patent-act
6. https://www.lexology.com/library/detail.aspx?g=a401f6dc-da48-4244-90c2-bada4a81b533
7. https://natlawreview.com/article/pre-and-post-grant-oppositions-india-part-3-8-part-series
8. https://www.obhanandassociates.com/blog/appeals-against-pre-grant-patent-oppositions-and-exhaustion-of-remedies/
9. https://www.lexology.com/library/detail.aspx?g=bc7dd620-6e3a-4888-a18a-21ada73cd544
10. https://www.wipo.int/documents/d/scp/docs-en-revocation-mechanisms-opposition-pdf-opposition_india.pdf