Summary
The Delhi High Court Division Bench held that patent revocation petitions under Section 64 of the Patents Act remain maintainable even after patent expiry, and that filing a Section 107 invalidity defence in an infringement suit does not preclude a separate revocation petition. The Court emphasized that revocation operates retrospectively and in rem (affecting all parties), while Section 107 defence operates only in personam (between specific parties), making them fundamentally distinct remedies serving different purposes.
Factual Background
In February 2022, Macleods Pharmaceuticals filed a revocation petition under Section 64 of the Patents Act, 1970 seeking to invalidate Boehringer Ingelheim's Indian Patent IN'243301 covering the pharmaceutical compound Linagliptin (a diabetes medication). Two days after the revocation petition was filed, Boehringer Ingelheim initiated infringement proceedings against Macleods before the Himachal Pradesh High Court.
In response to the infringement suit, Macleods raised an invalidity defence under Section 107 of the Patents Act in its written statement filed before the Himachal Pradesh High Court. Subsequently, on August 18, 2023, Patent IN'243301 expired by efflux of time (expiry of the statutory 20-year patent term).
Following the patent's expiry, Boehringer filed two applications before the Delhi High Court seeking dismissal of Macleods' revocation petition on two grounds: (i) the patent had expired and therefore revocation was no longer legally possible or necessary, and (ii) Macleods had already raised patent invalidity as a defence under Section 107 in the Himachal Pradesh infringement suit, and therefore could not pursue a separate revocation petition. A learned Single Judge of the Delhi High Court dismissed both applications, prompting Boehringer to file the present Letters Patent Appeal before the Division Bench.
Legal Issues Before the Court
The appeal raised two pure questions of law of significant importance to patent litigation in India:
- Can a patent revocation petition under Section 64 be instituted or survive after the patent in question has expired by efflux of time?
- Can a revocation petition under Section 64 be instituted or continue after the petitioner has already pleaded patent invalidity as a Section 107 defence in an infringement suit filed by the patentee?
Arguments Advanced by Boehringer Ingelheim (Appellant)
Boehringer Ingelheim contended that:
1. Revocation Presupposes a Subsisting Patent: The concept of "revocation" inherently presupposes the existence of a living, enforceable patent right. Once a patent expires by operation of law, there is nothing left to revoke. The term "patent" under Section 2(m) of the Patents Act refers to a patent in force, not an expired patent right.
2. Loss of "Person Interested" Status: After patent expiry, Macleods ceased to be a "person interested" within the meaning of Section 2(1)(t) of the Patents Act, as there was no longer any live patent right that could affect their interests. The revocation petition therefore became non-maintainable.
3. Risk of Conflicting Decisions: Allowing parallel proceedings—a Section 107 invalidity defence in the Himachal Pradesh infringement suit and a standalone Section 64 revocation petition in Delhi—created a serious risk of conflicting judicial findings on the validity of the same patent, which would undermine legal certainty and judicial discipline.
4. Reliance on Aloys Wobben Precedent: Boehringer relied heavily on the Supreme Court's decision in Aloys Wobben v. Yogesh Mehra [(2014) 15 SCC 360], arguing that once an infringement suit is filed by a patentee, the defendant's only permissible avenue for challenging patent validity is by way of a counter-claim under Section 64(1) in the infringement suit itself—not through a separate standalone revocation petition. Boehringer argued that allowing Macleods to pursue both a Section 107 defence and a separate revocation petition violated this principle.
Arguments Advanced by Macleods Pharmaceuticals (Respondent)
Macleods Pharmaceuticals countered that:
1. No Textual Limitation to Subsisting Patents: Section 64 of the Patents Act uses the expression "a patent may...be revoked" without any qualification that the patent must be "in force" or "subsisting." The legislature consciously chose not to restrict revocation to live patents. If Parliament intended such a restriction, it would have expressly stated so in the statutory language.
2. Fundamentally Different Remedies: A revocation petition under Section 64 and an invalidity defence under Section 107 are fundamentally different legal remedies with entirely different consequences:
- Revocation (Section 64): Operates in rem (against all persons), removes the patent from the Register of Patents with retrospective effect from the date of grant, and benefits the entire public.
- Section 107 Defence: Operates in personam (only between the parties to the suit), results merely in dismissal of the infringement suit without removing the patent from the Register, and has no effect beyond the specific litigation.
3. Continued Legal Interest Despite Patent Expiry: Although the patent had expired, Boehringer's infringement suit (including claims for damages for past infringement allegedly committed during the patent term) remained pending before the Himachal Pradesh High Court. As long as Macleods faced potential liability for past infringement, it retained a real, tangible, and continuing legal interest in establishing that the patent was invalid ab initio (from the beginning). A successful revocation would eliminate any liability for past infringement.
4. Misinterpretation of Aloys Wobben: Macleods argued that Boehringer had fundamentally misread the Aloys Wobben decision. That judgment only prohibits a party from simultaneously pursuing both a standalone Section 64 revocation petition and a Section 64 counter-claim in an infringement suit—i.e., using two routes under Section 64 at the same time. It does not address or restrict the filing of a Section 64 revocation petition when the party has taken a Section 107 defence (which is an entirely different statutory provision and legal mechanism).
Court's Detailed Legal Analysis
1. Retrospective Operation of Patent Revocation
The Division Bench held that revocation under Section 64 operates retrospectively (ab initio)—it invalidates the patent from the very date of its grant, not merely prospectively from the date of revocation. This conclusion was based on:
(a) Nature of Section 64 Grounds: All grounds for revocation listed in Section 64(1) (such as lack of novelty, obviousness, non-patentable subject matter, insufficiency of disclosure, etc.) relate to defects that existed at the time of grant. If any ground is established, it proves that the patent should never have been granted in the first place. The logical and legal consequence is that the patent is deemed never to have existed.
(b) Statutory Equivalence of Revocation Petition and Counter-Claim: Section 64(1) draws no distinction between the effect of revocation achieved through a standalone petition versus revocation achieved through a counter-claim in an infringement suit. Since both routes fall under Section 64, they must produce identical legal consequences—namely, retrospective invalidation.
(c) Persuasive UK Precedent: The Court found strong persuasive support in the UK Supreme Court's decision in Virgin Atlantic Airways Ltd v. Zodiac Seats UK Ltd [2013] UKSC 46, which confirmed that revocation of a patent under UK law (which is closely analogous to Indian patent law, both deriving from similar legislative traditions) operates retrospectively and in rem. The UK Supreme Court held that revocation invalidates the patent from grant, meaning the patentee is treated as never having had any enforceable rights under the patent.
2. Maintainability of Revocation After Patent Expiry
The Court held that a revocation petition remains maintainable even after the patent has expired by efflux of time, reasoning as follows:
(a) Legal Existence vs. Enforceability: Patent expiry renders the patent unenforceable going forward—meaning no one can any longer be sued for infringement committed after the expiry date. However, expiry does not erase the patent's legal existence or its historical legal effects. The patent continues to appear on the Register of Patents and continues to have legal significance for past acts.
(b) Definition of "Patent" in Section 2(m): Section 2(m) defines "patent" broadly as "a patent for any invention granted under this Act." This definition is not limited to patents that are currently in force. The term encompasses all patents granted under the Act, whether subsisting or expired.
(c) Continuing Interest Where Infringement Suit Pending: Where, as in the present case, the patentee is actively pursuing an infringement suit claiming damages for past infringement (even after the patent has expired), the alleged infringer retains a clear, direct, and continuing legal interest in establishing that the patent was invalid from the outset. If the patent is revoked with retrospective effect, the basis for the infringement claim (including any damages claim) disappears entirely. Therefore, Macleods remained a "person interested" under Section 2(1)(t).
(d) Public Interest in Accurate Patent Register: The Court noted that the Patent Register serves as an important public record. Allowing expired but invalid patents to remain unchallenged on the Register would be contrary to public interest, as it could mislead the public, suppress follow-on innovation, and perpetuate unjustified barriers to competition.
3. Distinction Between Section 64 Revocation and Section 107 Defence
The Court emphatically held that Section 64 revocation petitions and Section 107 invalidity defences are fundamentally distinct remedies operating in entirely different legal spheres:
(a) In Rem vs. In Personam:
- Section 64 Revocation: Operates in rem, meaning it affects the patent's validity as against the entire world. A successful revocation removes the patent from the Register of Patents and benefits not only the petitioner but the entire public.
- Section 107 Defence: Operates in personam, meaning it affects only the parties to the specific infringement suit. Even if a Section 107 defence succeeds and the suit is dismissed, the patent remains on the Register and the patentee remains free to sue other alleged infringers.
(b) Different Legal Consequences:
- Revocation under Section 64: Results in the patent being struck off the Register with retrospective effect. The patentee loses all rights under the patent, and no one can be sued for infringement—past, present, or future.
- Section 107 Defence: Results merely in dismissal of the particular infringement suit. The patent remains intact on the Register, and the patentee can enforce it against others.
(c) Statutory Recognition of the Distinction—Section 151: The Court noted that Section 151 of the Patents Act itself explicitly recognizes the distinction between these two remedies:
- Revocation orders under Section 64 must be entered in the Register of Patents maintained under Section 67.
- Invalidity findings in infringement suits (under Section 107) are merely recorded in a separate supplemental record—not in the main Patent Register.
This statutory differentiation confirms that the legislature itself treats these as distinct remedies with different legal effects.
(d) No Bar to Pursuing Both Remedies: Since Section 107 and Section 64 serve fundamentally different purposes and have different scopes, taking a Section 107 defence in an infringement suit does not—and cannot—bar a party from separately filing a Section 64 revocation petition. The two remedies are complementary, not mutually exclusive.
4. Correct Interpretation of Aloys Wobben v. Yogesh Mehra
The Court clarified that Boehringer had misread the scope of the Supreme Court's decision in Aloys Wobben:
(a) What Aloys Wobben Actually Decided: The Supreme Court in Aloys Wobben held that once an infringement suit is filed and the defendant wishes to challenge the patent's validity, the defendant must do so either by way of a counter-claim under Section 64(1) or by way of a separate standalone revocation petition under Section 64(1)—but not both simultaneously. The decision was aimed at preventing duplicative proceedings under the same statutory provision (Section 64).
(b) What Aloys Wobben Did Not Decide: The Supreme Court's judgment in Aloys Wobben did not address—and therefore does not restrict—the relationship between a Section 107 invalidity defence (which is a defensive plea in an infringement suit) and a Section 64 revocation petition (which is an independent statutory remedy). The prohibition in Aloys Wobben applies only to pursuing two Section 64 routes simultaneously, not to pursuing a Section 107 defence alongside a Section 64 petition.
(c) Policy Rationale: The purpose of the Aloys Wobben rule is to prevent duplicative validity challenges under Section 64, which could lead to conflicting determinations under the same statutory provision. That concern does not arise when a party pursues a Section 107 defence (which is limited to the specific suit) alongside a Section 64 revocation petition (which has broader public effect).
Final Decision and Directions
The Delhi High Court Division Bench dismissed Boehringer Ingelheim's appeal and affirmed the Single Judge's order, holding conclusively that:
- A revocation petition under Section 64 of the Patents Act remains maintainable and can survive even after the patent in question has expired by efflux of time.
- A revocation petition under Section 64 can be instituted and continued even where the petitioner has simultaneously taken a Section 107 invalidity defence in an infringement suit filed by the patentee.
The Court therefore allowed Macleods' revocation petition to proceed despite the patent's expiry and despite Macleods having raised invalidity as a defence in the parallel infringement suit.
Significance and Implications
1. Clarity on Post-Expiry Revocation Rights: This decision provides much-needed clarity that patent challengers retain the right to seek revocation even after a patent has expired, so long as they have a continuing legal interest (such as defending against a damages claim for past infringement). This prevents patentees from strategically delaying revocation proceedings until expiry and then arguing the proceedings are moot.
2. Affirmation of Retrospective Effect of Revocation: The judgment strongly affirms the principle that patent revocation operates ab initio (from the beginning), meaning a successfully revoked patent is treated as never having existed. This has critical implications for damages claims, licensing disputes, and competition law issues arising from patents later found to be invalid.
3. Preservation of Dual Remedies: By clearly distinguishing Section 64 revocation from Section 107 defences, the Court preserves accused infringers' ability to pursue both remedies strategically:
- The Section 107 defence provides immediate protection in the specific infringement suit.
- The Section 64 revocation petition provides broader, public-benefiting invalidation with retrospective effect.
4. Public Interest in Patent Validity: The decision underscores that patent validity is not merely a private matter between patentee and accused infringer—it is a matter of public interest. Invalid patents should be capable of challenge and removal from the Register even after expiry, to ensure the public record is accurate and to prevent perpetuation of unjustified monopolies.
5. Strategic Guidance for Patent Litigants:
- For Accused Infringers: The judgment confirms that defensive strategies can include both a Section 107 defence (for immediate protection in the infringement suit) and a Section 64 revocation petition (for broader public-benefit invalidation), and that neither remedy precludes the other.
- For Patentees: Patentees should be aware that expiry of a patent does not shield it from revocation challenges, particularly where infringement suits (including damages claims) remain pending. Patent expiry does not provide finality or immunity from validity challenges.
6. Alignment with International Best Practices: The Court's reasoning—particularly its reliance on UK precedents such as Virgin Atlantic v. Zodiac Seats—aligns Indian patent revocation jurisprudence with internationally accepted principles regarding the retrospective and in rem nature of patent revocation, promoting harmonization and predictability in cross-border patent disputes.
This landmark decision will serve as authoritative precedent for patent revocation proceedings and infringement litigation throughout India, providing critical guidance on the scope, effect, and interplay of different statutory mechanisms for challenging patent validity.
No comments:
Post a Comment