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* IN THE HIGH COURT OF DELHI AT NEW DELHI Reserved on: 26.11.2025 Pronounced on: 24.02.2026 + LPA 129/2025, CM APPL. 10551/2025 BOEHRINGER INGELHEIM PHARMA GMBH AND CO KG .....Appellant Through: Dr. Abhishek Manu Singhvi and Mr. Prashanto Chandra Sen, Sr. Advs. with Dr Sanjay Kumar, Ms. Arpita Sawhney, Ms. Pallavi Kiran, Mr. Arun Kumar Jana, Ms. Pratiksha Varshney, Ms. Shivangi Mayaramka, Ms. Atiksha Girdhar, Mr. Siddhart Seem and Ms. Rashmi Goswami, Advs.

versus THE CONTROLLER OF PATENTS & ANR. .....Respondents Through: Ms. Nidhi Raman, CGSC with Mr. Arnav Mittal, GP with Mr. Mayank Sansanwal, Adv. for R-1 Mr. G. Nataraj, Mr. Rahul Bhujbal, Mr. Yash Raj and Mr. Jegadheesh R., Advs. for R-2 Ms. Swathi Sukumar, Sr. Adv. (Amicus Curiae)

CORAM:

HON'BLE MR. JUSTICE C. HARI SHANKAR HON'BLE MR. JUSTICE OM PRAKASH SHUKLA % JUDGMENT

24.02.2026 C. HARI SHANKAR, J.

[Statutory provisions have been reproduced to the extent relevant.]

A. The lis

1. This appeal raises the following two pure questions of law:

(i) Whether a revocation petition, under Section 64, 64. Revocation of patents. – of the Patents Act 1970, can be instituted or can survive after the petitioner has pleaded invalidity of the patent, of which revocation is being sought, as a defence under Section 107(1)2 of the Patents Act, in a suit instituted by the patentee against it? (ii) Whether a revocation petition can be instituted or can continue after the patent, of which revocation is being sought, has expired?

2. These questions were raised by Boehringer Ingelheim Pharma GMBH, “Boehringer” hereinafter, as Respondent 2 in CO (COMM IPD-PAT) 38/2022, instituted by Macleods Pharmaceuticals Limited, Signature Not Veri 4 f i“eMdacleods” hereinafter under Section 64 of the Patents Act.

3. Both questions have been answered in the negative by a learned (1) Subject to the provisions contained in this Act, a patent, whether granted before or after the commencement of this Act, may, be revoked on a petition of any person interested or of the Central Government or on a counter-claim in a suit for infringement of the patent by the High Court] on any of the following grounds, that is to say,—

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2 107. Defences, etc. in suits for infringement. –

(1) In any suit for infringement of a patent, every ground on which it may be revoked under Section 64 shall be available as a ground for defence.

Single Judge of this Court vide judgment dated 15 January 2025.

4. Aggrieved thereby, Boehringer is in appeal.

5. We have heard Dr. Abhishek Manu Singhvi and Mr Prashanto Chandra Sen, learned Senior Counsel for the appellant and Mr. Guruswamy Nataraj, learned Counsel for Macleods, at length.

Written submissions have also been filed.

B. Facts

6. Though the dispute is largely fact agnostic, we may briefly advert to the factual backdrop in which the above issues arose.

7. Indian Patent (IN) 243301, “IN’301” hereinafter was granted to Boehringer on 5 October 2022, with a priority date of 21 August 2002, for the pharmaceutical product Linagliptin. On 17 February 2022, CO (COMM. IPD-PAT) 38/2022, “the revocation petition” hereinafter was filed by Macleods under Section 64(1) of the Patents Act, seeking revocation of IN’301. Two days thereafter, Boehringer filed COMS 3/2022 in the High Court of Himachal Pradesh, Signature Not Veri 7 f i“etdhe Himachal suit” hereinafter alleging that Macleods had infringed IN’301 and, therefore, seeking injunctive and other reliefs against Macleods. Macleods, in its written statement in the said suit, pleaded invalidity of IN’301, thereby invoking Section 107(1) of the Patents Act.

8. Boehringer, in these circumstances, filed IA 7635/2024 and

46685/2024, seeking dismissal of the revocation petition on different grounds. Both these applications stand dismissed by the impugned judgment.

9. IA 7635/2024 pleaded that, as IN’301 had expired on 18 August 2023 by efflux of time, the revocation petition did not survive for further consideration, as no revocation proceedings could either be instituted or