Navigating Post-Grant Opposition in the Patent Lifecycle

A patent grant is not necessarily the end of the road for scrutiny. Under Indian patent law, even after the Patent Office has examined an application and issued a grant, third parties retain the right to challenge whether that patent should have been granted at all. This is the mechanism of post-grant opposition – a formal, structured process that keeps the patent system accountable and ensures that exclusive rights are not handed out in error. For anyone involved in innovation, pharmaceuticals, technology licensing, or competitive industries, understanding how post-grant opposition works is essential knowledge.

What is post-grant opposition? 🔗

Post-grant opposition is the process by which an interested party challenges the validity of a patent after it has been granted. It is governed by Section 25(2) of the Patents Act, 1970, read with Rules 55 to 62 of the Patents Rules, 2003. The opposition must be filed within 12 months from the date of publication of the patent grant in the Indian Patents Journal. Once this window closes, this specific route is no longer available – though other remedies like revocation under Section 64 may still be pursued.

India’s patent opposition framework is considered one of the more open systems globally. It offers two distinct stages of challenge: pre-grant opposition under Section 25(1), which can be filed by any person before a patent is granted, and post-grant opposition under Section 25(2), which is restricted to interested persons and operates after the grant. Both mechanisms serve the same underlying goal – preventing patents that are legally or technically flawed from surviving unchallenged.

Who can file? Understanding “interested person” 🔗

Unlike pre-grant opposition, which is open to anyone, post-grant opposition can only be initiated by a “person interested” as defined under Section 2(1)(t) of the Patents Act. This includes:

• Any person actively engaged in research in the same field as the patented invention.
• Any company or entity with a manufacturing, trade, or financial stake in goods associated with the patented product.
• Competitors who may be directly affected by the exclusivity conferred by the patent.

This standing requirement is intentional. Since the patent has already been granted and confers exclusive rights on the patentee, the legislature restricted this stage to those who have a genuine stake in the outcome – reducing the risk of frivolous or harassing oppositions that might have little to do with patent validity.

Grounds for post-grant opposition under Section 25(2) 🔗

The grounds on which a post-grant opposition can be filed are identical to those for pre-grant opposition. This consistency allows a challenge that was initiated before grant to continue seamlessly into the post-grant stage if needed. The recognized grounds include:

• Wrongful obtainment: The patentee obtained the invention from someone else.
• Prior publication: The invention was published before its priority date.
• Prior public use or knowledge in India: The invention was publicly known or used in India before the priority date of the claim.
• Obviousness and lack of inventive step: The invention is obvious to a person skilled in the relevant field.
• Non-patentable subject matter: The claimed invention falls outside what the Act permits to be patented.
• Insufficient disclosure: The complete specification does not sufficiently describe the invention.
• Failure to disclose information under Section 8: The applicant failed to disclose or provided false information about corresponding foreign applications.
• Convention application not filed in time: In a convention application, the Indian filing was not made within 12 months of the first filing abroad.
• Non-disclosure or wrongful disclosure of biological material: The source or geographical origin of biological material used in the invention was not properly disclosed.
• Anticipation by traditional knowledge: The invention was already known through the traditional knowledge of any community, anywhere in the world.

The step-by-step procedure 🔗

Step 1: Filing the notice of opposition 🔗

The process begins when an interested person files a notice of opposition in Form 7, addressed to the Controller of Patents at the patent office where the original application was filed. The notice must be filed in duplicate and accompanied by a written statement setting out the grounds of opposition along with all supporting evidence. A mandatory filing fee is also required – unlike pre-grant opposition, which carries no official fee. As of current rules, the fee is ₹2,400 for natural persons and small entities (e-filing) and ₹12,000 for others, with slightly higher amounts for physical filing.

Step 2: Serving the patentee 🔗

Once the notice is filed, a copy of the statement and evidence must be delivered to the patentee. The Controller of Patents is required to inform the patentee of the opposition. The patentee then gets an opportunity to file a counter-statement and supporting evidence in response, typically within two months of receiving the notice. This adversarial structure – where both sides present their case – is a key feature of the post-grant opposition process.

Step 3: Constitution of the Opposition Board 🔗

One of the distinctive elements of post-grant opposition in India is the role of the Opposition Board. After receiving the opposition, the Controller constitutes a board consisting of three members, one of whom is nominated as chairperson. Members are generally patent examiners, though the examiner who handled the original patent application is excluded from the board to prevent bias.

The Opposition Board examines the evidence submitted by both parties and prepares a written recommendation for the Controller. This recommendation must now be disclosed to both parties – a requirement that came out of the Supreme Court’s ruling in Cipla Ltd. v. Union of India (2012), which held that parties must receive the board’s recommendation so they can effectively argue their positions before the Controller.

Step 4: The hearing 🔗

After receiving the Opposition Board’s recommendation, the Controller schedules a hearing. Both parties receive advance notice – at least 10 days before the hearing date. The members of the Opposition Board are also present at the hearing. If neither party wishes to be heard, the Controller can proceed on the basis of the written submissions alone.

Step 5: The Controller’s decision 🔗

After hearing both sides and considering the Opposition Board’s recommendation, the Controller passes an order. The possible outcomes are:

• Maintain the patent – if the opposition is found to be without merit.
• Amend the patent – if parts of the specification or claims need correction.
• Revoke the patent – if the grounds of opposition are established and the patent should not have been granted.

Post-grant opposition vs. pre-grant opposition: key differences 🔗

While both mechanisms share the same grounds, the procedure differs significantly. Pre-grant opposition can be filed by any person, carries no official fee, and is procedurally quicker. Post-grant opposition is limited to interested persons, requires a fee, and involves a more elaborate adjudication process including an Opposition Board and a formal hearing. The post-grant route is also generally considered more rigorous, and a patent that survives a post-grant challenge carries considerably higher legal credibility.

Landmark cases that shaped the post-grant opposition landscape 🔗

Cipla v. Sugen (Sunitinib patent) 🔗

A patent for Sunitinib – a drug used in treating gastrointestinal tumors – was granted on August 23, 2007. Cipla filed a post-grant opposition primarily arguing obviousness and lack of inventive step. The Controller agreed and revoked the patent, finding that the invention did not involve an inventive step and was obvious to a skilled person in the relevant field.

Cipla Ltd. v. Union of India (2012) 🔗

This Supreme Court decision was a procedural milestone. The Court held that the Opposition Board’s recommendation in a post-grant proceeding must be shared with the parties before the final hearing before the Controller. This ruling significantly strengthened the due process rights of both opponents and patentees, ensuring that neither side is surprised by the board’s conclusions at the hearing stage.

Why post-grant opposition matters 🔗

Patent grants are not infallible. Examiners work under significant workload pressures, and errors – whether in assessing novelty, inventive step, or patentable subject matter – do occur. Post-grant opposition acts as a critical quality-check mechanism that the market and public can use to correct these errors before they cause widespread harm. This is particularly significant in sectors like pharmaceuticals, where a wrongly granted patent can block access to affordable generic medicines, or in technology sectors where broad patent claims can stifle competition and follow-on innovation.

India’s opposition framework has been cited by scholars and international bodies as a model for balancing patentee rights with broader public interest considerations. The two-stage opposition system – pre and post grant – provides layered protection against invalid patents, making India’s patent regime both competitive and rights-conscious.

Limitations and practical considerations 🔗

Despite its importance, the post-grant opposition mechanism comes with practical challenges. The 12-month window is strict – once it lapses, opponents must pursue the more costly and time-consuming route of revocation under Section 64 or seek relief through litigation. The pendency of opposition proceedings before the Patent Office has also been a concern, with disposal timelines sometimes stretching well beyond what the statute contemplates. Additionally, constituting an Opposition Board and coordinating hearings adds procedural layers that can slow down resolution, which can be frustrating when commercial interests are at stake.

That said, for any stakeholder who becomes aware of a potentially invalid patent, the 12-month post-grant window remains the most structured, cost-effective, and legally recognized forum for challenging it directly before the Patent Office itself – before the matter escalates into full-blown litigation.

What do you think? Given that post-grant opposition is restricted to “interested persons” while pre-grant opposition is open to anyone – does this distinction strike the right balance between preventing frivolous challenges and ensuring patent quality? And with the 12-month deadline being as strict as it is, should Indian law consider extending this window to give more time for thorough technical review of complex patents in fast-moving fields like biotechnology or artificial intelligence?

References

1. https://maklaw.in/knowledge/patent-opposition-and-amendment/post-grant-opposition/
2. https://www.wipo.int/patent-judicial-guide/en/full-guide/india/6.2.2
3. https://excelonip.com/post-grant-opposition-in-india/
4. https://www.iam-media.com/regionindustry-guide/india-managing-the-ip-lifecycle/2020/article/the-patent-opposition-process-in-india
5. https://thelegalschool.in/blog/section-25-of-patent-act
6. https://link.springer.com/chapter/10.1007/978-3-030-83114-1_6