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Delhi High Court holds that patent revocation proceedings would continue to survive even after the expiry of the patent sought to be revoked
A division bench of the Delhi High Court (“Delhi HC”) in Boehringer Ingelheim Pharma Gmbh and Co Kg vs. The Controller of Patents and Anr[1], inter alia held that (a) a patent Revocation Petition (“Revocation Petition”) would be maintainable and would continue to survive, even after the patent sought to be revoked, expires by efflux of time; and (b) a Revocation Petition can be instituted even after an invalidity defence under Section 107[2] of the Patents Act, 1970 (“Patents Act”) is taken in a patent infringement suit by a defendant.
Brief facts
On October 5, 2022, Indian Patent (IN) 243301 (“Patent”) was granted to Boehringer Ingelheim Pharma Gmbh and Co Kg (“Boehringer”) for a pharmaceutical product. On February 17, 2022, Macleods Pharmaceuticals Limited (“Macleods”) filed a Revocation Petition before the Delhi HC seeking revocation of the Patent. On February 19, 2022, Boehringer filed a suit before the Himachal Pradesh High Court seeking to restrain Macleods from infringing the Patent (“Infringement Suit”). In its written statement, Macleods pleaded invalidity of the Patent under Section 107(1) of the Patents Act. The Patent expired on August 18, 2023 by efflux of time.
Boehringer filed 2 (two) interim applications before the Delhi HC seeking dismissal of the Revocation Petition inter alia on the grounds that: (a) no revocation proceedings would lie once the Patent itself had expired; and (b) the Revocation Petition would not lie given Macleods’ defence of invalidity of the Patent in the Infringement Suit. Both these interim applications were dismissed by a Ld. Single Judge of the Delhi HC (“Impugned Orders”).
Being aggrieved by the Impugned Orders, Boehringer filed an appeal before a Division Bench of the Delhi HC.
In the Appeal, Boehringer inter alia contended that: (a) an expired patent could not be revoked; (b) revocation merely wipes out monopoly with the patent holder and would not date back to its grant; and (c) once an infringement suit is filed, a revocation petition under Section 64[3] of the Patents Act cannot continue, and the only options available with the defendant are to raise an invalidity defence under Section 107 of the Patents Act or prefer a counter claim for seeking revocation of the patent.
Macleods inter alia contended that: (a) expiry of a patent does not efface the right of the patentee to claim damages for infringement which took place during the life of the patent; (b) the effect of revocation is effacement of the patent ab initio; (c) an invalidity defence under Section 107 of Patents Act does not, by itself, result in revocation of a patent; and (d) revocation of a patent can only occur if a counter-claim is filed in the infringement suit or if a revocation petition is filed under Section 64 of Patents Act.
Issue
Whether a revocation petition survives after: (a) the patent has expired; and (b) the defence of invalidity is pleaded under Section 107(1) of the Patents Act in an infringement suit filed by the patentee?
Findings and analysis
Delhi HC dismissed the appeal and inter alia held as follows:
- Section 64 of the Patents Act envisages revocation of a patent either by a counter claim in an infringement suit or by a revocation petition thereby rendering the same consequences. The counter claim in an infringement suit would invariably seek a declaration of invalidity of the patent ab initio. Consequently, revocation of the patent would, in either case, invalidate the grant of the patent from the date of such grant;
- if the grounds for seeking revocation under Section 64 of the Patents Act are justified, it would indicate that the very grant of the patent was invalid. Therefore, revocation of a granted patent under Section 64 of the Patents Act would relate back to the date when the patent was granted;
- the retrospective and in rem effect of revocation has also been recognised in the judgment of the UK Supreme Court in Virgin Atlantic Airways Limited vs. Zodiac Seats UK Limited [4] and the law declared therein is applicable to Indian jurisdiction. The statutory position in the United Kingdom regarding the revocation of patents is akin to that of the Patents Act;
- the expiry of a patent merely renders it unenforceable and does not deprive the patent of its status as a granted patent under the Patents Act. In an infringement suit, the expiry of a patent merely changes the goal post. The plaintiff still retains the right to claim damages for infringement which took place during the life of the patent, and the defendant, too, therefore has the right to, by way of a counter-claim or revocation petition as he may choose, seek revocation of the patent ab initio. Therefore, a revocation petition would be maintainable and would continue to survive even after the patent sought to be revoked expires by efflux of time; and
- a revocation action under Section 64 of the Patents Act and an invalidity defence under Section 107 of the Patents Act are fundamentally different. The right to file a revocation petition can never be impacted by the right to plead invalidity of the patent under Section 107 of the Patents Act as a defence to the infringement action. Therefore, a revocation petition can be instituted or continue even after an invalidity defence under Section 107 of the Patents Act is taken in the infringement suit.
Conclusion
By this decision, the Delhi HC has clarified that a revocation petition under Section 64 of the Patents Act and the defence of invalidity of a patent under Section 107 of the Patents Act operate in different spheres. The Delhi HC further clarified that an action for revocation of a patent can be sought by way of a counterclaim or by filing a revocation petition. The right to file a revocation petition under Section 64 of the Patents Act can never be impacted by the right to plead invalidity of a patent under Section 107 of the Patents Act as a defence in an infringement suit.
The Delhi HC emphasised that revocation operates retrospectively and renders the patent invalid from the date of grant. Consequently, the expiry of a patent does not render revocation proceedings infructuous, especially when claims of damages survive. This decision sheds light on the fact that the expiry of a patent does not foreclose the right of an interested party from seeking revocation of the patent through revocation proceedings, particularly where claims relating to past infringement and damages remain in issue.
This Prism is prepared by:
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Farhad Sorabjee |
Pratik Pawar |
Shanaya Cyrus Irani |
Sanjana Pandey |
For more details, please contact [email protected].
[1] LPA 129/2025, CM APPL. 10551/2025 (decided on 24 February 2026)
[2] Section 107 pertains to defences. in suits for infringement. Sub section (1) stipulates that in any suit for infringement of a patent, every ground on which it may revoked under Section 64 of the Patents Act shall be available as a ground for defence.
[3] Section 64 provides for revocation of patents. Sub section 1 reads as follows: “(1) Subject to the provisions contained in this Act, a patent, whether granted before or after the commencement of the 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 – …”
[4] [2009] EWCA Civ 1062
