The Division Bench (DB) of the Delhi High Court (DHC) has issued an order, observing prima facie, that a revocation petition against a patent whose statutory term has expired is not maintainable. DB has also appointed Senior Advocate Swathi Sukumar as amicus to assist the Court on this issue. This prima facie observation contradicts the position of the Single Bench of DHC in Macleods Pharmaceuticals Ltd v. The Controller of Patents (previously covered here), which had concluded that a revocation petition against an expired patent is maintainable when the patentee has sued the infringer for past acts of infringement. Upon reading the contra views expressed by both the SB and DB, one wonders, what’s happening here? How do we ensure that we do not get distracted from the purpose of the provision? This post will attempt to clarify that.
First, A Quick Recap:
The suit patent against which the revocation petition was filed is the species part of a genus-species pair covering the molecular compound Linagliptin (an anti-diabetic drug).
Macleods Pharmaceuticals (Respondent) launched the generic version on February 22, 2022, after the genus patent expired on February 21, 2022. Macleods also filed a revocation petition before the Delhi High Court (DHC) against the species patent, which was set to expire on August 18, 2023.
As I had noted in a previous post, the revocation petition was followed by an infringement suit in the Himachal Pradesh High Court, resulting in an interim injunction. After the expiry of the species patent, an interim application was filed before the Single Judge Bench (SB) of the DHC stating that the revocation petition be dismissed in light of the fact that the suit/species patent has expired. In deciding this interim application, the SB concluded that a right to file a revocation petition against an expired patent exists when the patentee has filed an infringement suit seeking damages for past alleged acts of infringement based on the expired patent.
An appeal was filed against the judgment of the SB, which led to the Division Bench expressing prima facie views on the unsustainability of a revocation petition against a patent whose term has expired.
To Revoke or not to Revoke:
How does one make sense of the disagreement between the SB and DB? It begins with examining paragraph 10 of the DB order, which states that the concept of revocation in itself implies the existence of a live patent that needs to be revoked. Then the DB observes in a slightly dramatic fashion, “Can one kill a dead body?”
The DB’s analogy may not quite hold up here, as the so called ‘dead body’ is continuing to provide the holder the right to file an infringement suit. The analogy does not capture the fact that ‘dead’ patents can come back to haunt you. Such analogies are not helpful, as they cloud judgment and divert focus from concepts relevant to the matter at hand.
It seems that the DB’s prima facie view has tied the right to file a revocation to the patent term. Thus, it follows that once the patent term expires, the right to file a revocation also expires or is unsustainable. Once a patent is dead (expired), it cannot be killed (revocation).
In contrast, the SB has tied the right to file a revocation petition against an expired patent to the specific fact situation in the case, where, during the pendency of the suit, the patent had expired. SB focused on the question of whether residual claims of past infringement arising from an expired patent are being asserted. If yes, then the right to file a revocation is also available, irrespective of whether the patent’s statutory term has expired.
The text of Section 64 does not put any such limitation, allowing for a revocation to be filed against any patent that has been “granted before or after the commencement of” the Patents Act, 1970. DB notes that there is no explicit bar in Section 64 against filing a revocation petition towards patents whose term has expired. But holds on to the prima facie view that a revocation itself somehow inherently means it can be filed only against a ‘live’ patent.
The DB further observed that the Calcutta High Court in Star Textile Engineering Works Ltd v James Mackie Holdings Ltd, made a passing reference to North Eastern Marine Engineering Co. Ltd v Leeds Forge Company Ltd in support of the proposition that expired patents can be revoked, but the Calcutta High Court as DB notes merely reproduced an observation made by the arguing counsel, and did not seem to provide a positive finding on the matter hence reducing its persuasive value.
North Eastern Marine Engineering Co. Ltd v Leeds Forge Company Ltd (North Eastern Marine Engineering) a UK case, is an interesting case in itself, wherein North Eastern Marine Engineering moved the Chancery Division seeking a declaration that the patent was invalid, even though it had expired, as they feared that a holder of the patent might sue them for infringement with respect to past actions. When the Court asked a pointed question on why they did not file a revocation petition provided for in Section 26 of the Patents, Designs, and Trade Marks Act, 1883, they replied that they were worried that such a petition would be rejected on a technical reason that the patent has expired, hence no petition was filed. The Chancery Division ruled that North Eastern Marine Engineering should file a revocation petition and denied to grant the declaration.
Under the 1883 Act, to file a revocation petition, one must submit it to the Attorney General for approval, unless specific conditions are met. When North Eastern Marine Engineering did so, the Attorney General rejected the petition on the same technical ground they feared it would be rejected.
The matter was appealed to the Court of Appeal, which, in an effort to provide some relief to North Eastern Marine Engineering, Court of Appeal ruled that the mere fact that a patent has expired is not, in itself, sufficient to reject a revocation petition by the Attorney General.
Note that the trigger in North Eastern Marine Engineering was the threat of an infringement suit; in contrast, in Macleods’ case, an infringement suit was already filed and active before the Himachal Pradesh High Court.
Revocation as Ex Tunc?
The Patents Act 1970 provides multiple avenues for the general public and interested parties to prevent a patent from being granted, and to further challenge the validity of the patent.
This can be done in multiple ways, including by filing a pre-grant opposition, post-grant opposition, revocation petition, or a claim of invalidity during an infringement proceeding. Hence, it is possible that a patent is liable to be revoked at any time during its statutory term.
As Swaraj had pointed out in a personal conversation, these legal mechanisms serve as correctives to address the fact that the Patent Office has, shall, and will inadvertently grant some patents that, in hindsight, should not have been granted in the first place. Thus, these legal mechanisms correct for errors that inevitably creep into the examination process due to various reasons.
This understanding of Section 64 (the subject of this post) as a corrective measure to prevent the enforcement of legally invalid patents gains relevance in light of recent developments. There has been an increase in the number of patents being filed and granted. Along with this is the constant stream of instances where the controller’s orders are remanded back for being unreasoned, with the latest instance of such remand coming from the Delhi High Court’s Division Bench. Other institutional factors, such as performance metrics incentivising grants over rejections, perverse incentives to file patents, and intra-institutional conflicts, raise questions about the ability of the IPO to grant legally robust patents through the process of examination.
Hence, given this context, the understanding of Section 64 as a legal corrective to address lacunas in patent examination gains significance. This allows us to shift focus to the purpose, i.e., the core problem Section 64 attempts to remedy. The purpose is to prevent the enforcement of legally invalid patents against the broader public. If an expired patent (which may or may not be legally valid) is being enforced and is likely to be enforced against past acts, then it automatically follows that a Section 64 petition can be filed against such an expired patent.
The above principle is further supported by the observation made by another Division Bench of the Delhi High Court in Ajay Industrial Corporation v. Shiro Kanao of Ibaraki City that the right to file a revocation under Section 64 is an independent right and which in turn cannot be linked to whether a suit of infringement has been filed, and instead linked it to the petitioner’s commercial interest.
Focusing on the statutory term of the patent only distracts us from the core issue at hand and the purpose of Section 64. DB has clarified that these are preliminary views and are subject to change.
I wish to thank Swaraj for his inputs