Macleods Pharma Wins Legal Battle Over Linagliptin Patent

The judgment, pronounced by Justice Amit Bansal on 15th January 2025, addressed crucial issues concerning the maintainability of a revocation petition when the petitioner has raised a defence of invalidity in a parallel infringement suit and the impact of patent expiration on such petitions.

The dispute centered around Indian Patent IN 243301, registered to Boehringer Ingelheim, for the anti-diabetic drug 'LINAGLIPTIN.' Granted on 5th October 2022 with a priority date of 21st August 2002, the patent expired on 18th August 2023. Macleods Pharmaceuticals, engaged in manufacturing generic pharmaceuticals, filed a revocation petition on 17th February 2022 under Section 64(1) of the Patents Act. This was shortly before its planned commercial launch of a generic version of 'LINAGLIPTIN,' which led to Boehringer Ingelheim filing an infringement suit against Macleods in the Himachal Pradesh High Court.

Boehringer Ingelheim, represented by Senior Counsel, argued that the revocation petition was unnecessary and should be dismissed. Their contention was twofold: first, the defence of invalidity raised by Macleods under Section 107 of the Patents Act in the infringement suit covered similar grounds as the revocation petition, potentially causing conflicting judgments. Second, they asserted that the petitioner ceased to qualify as a 'person interested' under Section 2(1)(t) of the Act post-expiry of the patent, thereby rendering the revocation petition unsustainable.

Macleods Pharma, represented by Counsel, countered that Section 64 provides an independent statutory right to seek revocation of a patent, distinct from the defence of invalidity in an infringement suit. They emphasized that a revocation petition operates in rem, impacting the validity of the patent itself, while a defence under Section 107 is limited to the parties involved. Furthermore, they argued that the expiry of the patent does not nullify the petitioner’s interest, as damages could still be pursued for alleged infringement during the patent’s term.

In its detailed analysis, the Court differentiated the scope and effect of Sections 64 and 107 of the Patents Act. While Section 107 allows invalidity as a defence in infringement suits, adjudicated at the District Court level unless a counter-claim is filed, Section 64 empowers the High Court or the Intellectual Property Appellate Board to revoke a patent entirely, removing it from the Register of Patents. The Court highlighted that these provisions operate independently, allowing parallel proceedings without statutory conflict. It observed;

"The scope and effect of a revocation petition filed under Section 64 of the Patents Act and the defence of invalidity taken under Section 107 of the Patents Act in an infringement suit is entirely different. Hence, the present revocation petition is maintainable."

On the issue of sustainment post-expiry, the Court held that the petitioner’s interest remains valid due to the ongoing infringement suit and the possibility of damages claims. Expiry of the patent does not extinguish the cause of action for revocation, as a finding of invalidity would have significant implications for pending or future claims related to the patent. The court clarified;

"The petitioner in the present case is a person who is interested in manufacture and sale of the patented products and he is also a defendant in the patent infringement suit filed by the respondent no.2. Therefore, the petitioner qualifies as a 'person interested' in terms of Section 2(1)(t) of the Patents Act and it would be entitled to file and maintain the present revocation petition."

"Just because the term of the patent has expired, it would not mean that the suit has become infructuous, as the cause of action, insofar as damages are concerned, still survives. Applying the same rationale, it cannot be argued that a revocation petition cannot be filed or will not survive (if filed earlier) after the term of the patent has expired."

Subsequently, Justice Bansal dismissed the applications filed by Boehringer Ingelheim seeking dismissal of the revocation petition. The Court affirmed the maintainability of the revocation petition and directed that it proceed to be adjudicated on its merits. It held;

"The Himachal Suit filed by the respondent no.2 (Boehringer) is still continuing despite the term of the patent having expired. If the petitioner succeeds in the present petition and the subject patent is revoked, the suit of the respondent no. 2 would be liable to be dismissed. Therefore, there is a valid cause of action in favour of the petitioner to pursue the present petition and simply because the life of the patent has expired, would not mean that the present petition becomes infructuous. Therefore, I am of the opinion that the present petition can be sustained even after the expiry of the subject patent."

"In light of the discussion above, I do not find merit in the objections taken by the respondent no. 2 with regard to the maintainability and sustainability of the present rectification petition. Consequently, both I.A. 7635/2024 and I.A. 46685/2024 are dismissed."

To view the original judgement, click on the link below:

https://indiankanoon.org/doc/83528155/