In Neurocentria Inc. vs Deputy Controller of Patents and Designs [C.A.(COMM.IPD-PAT) 5/2025, decision dated 18 May 2026], the Delhi High Court refused to permit the Appellant to retrospectively disclaim the earliest priority date in their Patent Cooperation Treaty (PCT) national phase application in order to overcome the statutory timeline governing national phase entry and filing of Request for Examination (RFE). The judgment is significant for its emphatic reaffirmation that the timelines under Rules 20(4)(i), 22 and Rule 24B(1)(i) of the Patents Rules, 2003 are mandatory and non-extendable, and that post-facto amendments under Section 57 cannot be used to revive applications already deemed withdrawn by operation of law.

The subject patent application bearing number 1015/DELNP/2010, entitled “Magnesium Compositions and Uses Thereof” was treated as withdrawn by the Controller, under Section 11B(4) owing to the Appellant’s failure to file the application within 31 months from the first/earliest priority date as required under Rule 20(4)(i) and failure to file the RFE within 48 months from the first/earliest priority date under Rule 24B(1)(i) read with Section 11B(1). The application originated from PCT application number PCT/US2008/058073 filed on March 24, 2008, claiming three US priorities: US 60/896,458 dated March 22, 2007, US 60/994,902 dated September 20, 2007, and US 61/066,592 dated February 20, 2008. However, while entering the Indian national phase on February 15, 2010, the Appellant disclosed only the second and third priority dates in Form-1 and omitted the earliest priority date of March 22, 2007. The RFE was subsequently filed on September 16, 2011.

In the First Examination Report (FER), the Patent Office objected that the Appellant had not disclosed the earliest priority date in Form-1 and that both the national phase application and the RFE had not been timely filed. In response, the Appellant contended that the earliest priority date had been disclaimed at the time of national phase entry and the RFE was filed calculating the timeline from the second priority date of September 20, 2007. Eventually, in 2024, the Appellant formally filed Form-13 under Section 57(5) seeking amendment of the date of priority claimed by disclaiming the earliest priority date. By way of the instant appeal, the Appellant sought direction to the Controller to allow their Form-13.

The principal issue before the Court was whether the Appellant could be permitted to disclaim and/or amend the earliest priority date to claim priority from the second priority date under Section 57(5) in order to extend the deadline for national phase entry and filing of RFE.

The Appellant argued that the omission of the earliest priority date in Form-1 reflected the Appellant’s intention from the outset to disclaim that priority. According to the Appellant, the failure to formally file Form-13 at the relevant stage was attributable solely to negligence of the erstwhile patent agent, and the applicant should not suffer irreversible loss of substantive patent rights due to an error committed by their agent. Reliance was placed on several recent Delhi High Court decisions including European Union vs Union of India, Bry-Air, and Synertec Pty Ltd., where relief had been granted in situations involving negligence of patent agents and absence of intention to abandon applications.

The Controller, on the other hand, argued that the statutory timelines were absolute and incapable of extension. It was contended that the earliest priority date had been deliberately suppressed in Form-1 to circumvent the mandatory timelines under Rule 20(4)(i) and Rule 24B. It was further argued that once the application had been deemed withdrawn under Rule 22 read with Section 11B(4), no subsequent amendment under Section 57 could revive it. Reliance was placed primarily on Nippon Steel Corporation vs Union of India and the Division Bench ruling in Diebold Self Service Systems vs Union of India.

The Court upheld the Controller’s decision and dismissed the appeal. The Delhi High Court took note of the fact that the earliest priority date had admittedly not been disclosed in Form-1 at the time of filing the national phase application and the Appellant had not informed the Patent Office of their intention to disclaim/disregard the first date. While the Appellant attempted to attribute this omission to erroneous legal advice by its patent agent, the Court found that the omission had clearly operated to the applicant’s strategic advantage by extending both the 31-month national phase deadline and the 48-month RFE deadline. The Court observed that the omission remained undisclosed until objections were raised in the FER, and Form-13 was filed only in 2024, nearly fourteen years after the filing of the application.

The Court held that the statutory framework governing PCT national phase applications leaves no scope for extension beyond the prescribed timelines which are mandatory and non-extendable. The Court examined Rule 20(4)(i), Rule 22, Section 11B and Rule 24B together with Article 2(xi) of the PCT, and reiterated that where multiple priorities are claimed in a PCT application, the “priority date” for computing timelines is the filing date of the earliest priority application.

The Court held that the Appellant could not belatedly rewrite the statutory consequences of non-compliance through a later amendment application under Section 57(5). The Court observed that the amendment sought by the applicant was not a mere procedural correction but an attempt to fundamentally alter the basis on which the statutory deadlines were calculated. Permitting such amendment would effectively allow applicants to circumvent mandatory timelines prescribed under the Act and Rules.

Significantly, the Court distinguished the line of cases where relief had been granted against consequences arising from patent agent negligence. The Court held that those cases largely concerned procedural defaults where the statutory framework permitted some degree of curative intervention and where applicants had otherwise complied substantially with statutory requirements. In contrast, the present case involved mandatory and non-extendable timelines expressly coupled with deeming provisions under Rule 22 and Section 11B(4). Once the application stood deemed withdrawn by operation of law, there remained no surviving application capable of amendment or revival.

The Court also relied on the Division Bench ruling in Diebold Self Service Systems, which had upheld the validity and mandatory nature of Rule 22. Reaffirming Diebold, the Court held that the patent regime requires strict adherence to filing timelines and does not permit indefinite flexibility in matters affecting certainty and public notice within the patent system.

The judgment is significant for drawing a clear distinction between curable procedural irregularities and statutory lapses that extinguish substantive rights. While recent Delhi High Court jurisprudence has increasingly shown willingness to protect applicants from consequences of patent agent negligence in appropriate cases, Neurocentria clarifies that such equitable considerations cannot override mandatory statutory timelines governing PCT national phase entry and RFE filing. The decision also reinforces the importance of complete and accurate disclosure of all priority claims at the time of national phase entry.