No Second Chances: Delhi HC Enforces India’s Strict Patent Entry Timelines

Summary: The Delhi High Court has clarified that post facto amendments of priority date cannot be used to revive lapsed applications and bypass missed deadlines for filing national phase applications and examination requests.

Introduction                                             

A priority claim in a patent application is crucial in determining novelty and the applicant’s legal rights, and also, critically, helps in ascertaining statutory timelines for filing applications and related documents.

The statutory requirements around priority claiming in India can be summarised as follows:

• Under Rule 20(4)(i) of the Patents Rules, 2003 (“Rules”), a national phase (NP) application under the Patent Co-operation Treaty (PCT) must be filed within 31 months from the earliest priority date.
• Missing this 31-month deadline will deem the application automatically withdrawn (Rule 22).
• Under Section 11B of the Patents Act, 1970 (“Act”) and Rule 24B, a Request for Examination (RFE) must also be filed within 31 months from the earliest priority or filing date. Note that this period was 48 months earlier, modified by a 2024 amendment to the Rules.
• Missing this 31-month deadline will also deem the application automatically withdrawn. However, the 2024 amendment to the rules somewhat relaxes this position and allows applicants to seek extensions for up to six months under Rule 138.
• While Section 57(5) of the Act allows applicants to amend a claim’s priority date, courts in India have strictly enforced these statutory timelines. Extensions for filing the national phase entry or the RFE are rarely granted unless sufficient cause is shown.

The judicial stance on strict deadlines for entering the national phase and filing requests for examination was upheld recently by the Delhi High Court in Neurocentria vs Deputy Controller of Patents & Designs (C.A.(COMM.IPD-PAT) 5/2025, decision dated 18.5.2026). Although the decision analyses the Rules before the 2024 amendments, as that was the applicable statutory position, it is possible to extrapolate general principles on adherence to mandatory deadlines and related matters.

Background facts

The assignee-predecessor to Neurocentria Inc. (the appellant here) entered the national phase in India for its PCT application dated 24 March 2008, with its Indian patent application filed on 15 February 2010.

The PCT application claimed three US priorities, whereas the NP application was entered with details of only the second and third priorities in its application Form-1, omitting the earliest priority date of 22 March 2007 (see table).

On examination, the Indian Patent Office (IPO) issued a First Examination Report (FER), finding that the application was not maintainable because:

• The earliest priority date of 22 March 2007 (as per the PCT application) had not been disclosed in Form 1; and
• The RFE was not filed within 48 months from the earliest known priority date.

In response, the applicant contended that the earliest priority date of 22 March 2007 had been disclaimed at the filing stage, and that the NP entry and RFE timelines were therefore computed from the priority date of 20 September 2007.

The IPO issued a hearing notice (which was allegedly not received by the applicant’s agents) and owing to non-attendance and non-compliance of timelines, the application was rejected as ‘withdrawn under Section 11B(4)’.

Citing agent negligence and non-representation, the applicant asked for, and was granted, another hearing in 2024. On this occasion, the applicant, through its new agent, sought to amend the priority date under Section 57(5)  nearly 14 years after NP entry. The IPO rejected the amendment request, holding that the application stood withdrawn for non-compliance with the timelines under Rules 20(4)(i) and 24B(1)(i).  This refusal was challenged by Neurocentria before the Delhi High Court by way of the present appeal.

Key question

The Court had to assess whether the appellant could be permitted to disclaim and/or amend the earliest priority date under Section 57(5) after a patent application has already been deemed withdrawn.

The appellant’s case

The appellant’s case rested on a few clarifications and arguments:

• The March 2007 priority claim was always intended to be disclaimed, which is why the NP was entered into with only the second and third priority details, and statutory filing dates calculated accordingly.
• Form 13 was filed specifically to disclaim the priority date, and not to amend the patent application itself, as contained in Form 1 (which already had the correct details). There was no delay in filing Form 13, for, as soon as the appellant realized the matter, it filed Form 13 with a petition to condone the delay (under Rule 137).
• Relying on IPO practice and judicial precedent, the appellant argued that petitions under Rule 138 seeking extensions for NP entries and RFE could be allowed if sufficient cause was shown. However, a Rule 138 petition was neither applicable nor was it availed by the appellant in the present case.
• The request to amend the priority claim (Section 57(5)) did not come with a strict limit, and in any case, it was not filed originally due to a mistake by the old agent.
• Relying on precedent, the appellant argued that an applicant should not suffer irreversible loss because of an agent’s error.

The IPO’s case

The IPO argued that the earliest priority date had been deliberately concealed to circumvent the missed deadlines for filing the NP application and RFE, and to mislead the IPO to accept a time-barred application. The intention to disclaim the priority was only brought on record by filing a belated Form 13, 14 years after filing the application.

The IPO also said that the stipulated 31-month and 48-month time periods (for NP and RFE, as the Rules stood then) had to be computed from the earliest priority date, which was 22 March 2007, and not 20 September 2007 (which was four months later).

Pointing out that these timelines were mandatory and non-extendable, IPO contended that an extension under Rule 138 was not available, as it allows an extension of only one month, and in any case, such an extension was never sought by the appellant.

The decision

The Court ruled on the major questions as follows:

1. Non-disclosure: The Court found that the appellant had not disclosed the earliest priority, nor did it inform the IPO of its intention to disclaim the same while filing. The plea of negligence by former agents was rejected. The Court inferred that the first priority was disclaimed by the applicant only to strategically extend the missed deadlines, which cannot be rectified by a belated request.
2. Statutory and non-extendable timelines: Relying on multiple judicial precedents on this account, the Court held that the timeframes prescribed for NP entry and RFE are mandatory and cannot be extended beyond the statutory period.
3. Limits of Section 57: The IPO rightly rejected the request for amendment under Section 57(5), for it was filed (a) after the application was deemed withdrawn, and (b) with a view to circumvent missed deadlines, a practice strictly condemned by this Court previously in other cases.
4. Agent negligence: Even if the agent was negligent, missed mandatory timelines cannot be extended. The Court differentiated certain condonable delays in meeting deadlines (e.g., filing responses to first examination reports) from mandatory, non-extendable deadlines (i.e., NP entry and RFE).

Could this application have been saved? One could speculate that, perhaps, if the IPO had been informed of the applicant’s intention to disclaim the earliest priority at the time of entering the national phase, a different case could have been made out. However, there was no opportunity to test this position in the present case.

Key takeaways

The ruling is significant for applicants entering India through the PCT route and for practitioners managing international patent portfolios. The decision highlights that amendments sought with a sole purpose of overcoming a missed statutory deadline will not be allowed. Reliance on agent negligence may also not always overcome non-compliance with statutory deadlines.