Revoking Expired Patents and the Strict Bounds of Auxiliary Review at the UPC
The Paris Central Division confirms that expired patents can be revoked at the UPC if a threat of damages remains, while highlighting strict pleading requirements when attacking auxiliary requests.
Advising a client who has just been subjected to an ex parte order for the preservation of evidence in a national court is stressful enough. When the underlying patent expired nearly a year ago, the immediate strategic reflex is to clear the lingering damages threat by filing a revocation action. But does the Unified Patent Court (UPC) entertain actions against patents that have already lapsed? In UPC-CFI-461/2025, the Paris Central Division confirmed that it does, while simultaneously demonstrating a strict approach to claim construction and the assessment of auxiliary requests.
Adjudicating expired rights
The dispute concerned EP 1 516 720, a patent held by BASF SE relating to a composite element containing a polyurethane adhesion promoter. The patent reached its maximum 20-year term on 7 August 2024. Ten months later, Huntsman lodged a Statement for revocation (Rule 44 RoP) at the UPC, prompted by BASF's initiation of ex parte evidence preservation proceedings before a Belgian national court regarding alleged past infringement.
The panel examined the claimants' legal interest ex officio. It held that a revocation action is not necessarily inadmissible in the event of the patent expiring due to the lapse of time (reasons 2). Because damages can still be claimed for the period the patent was in force, and the claimants were directly affected by the Belgian proceedings, the legal interest in revocation was firmly established (reasons 13–14).
Re-framing the objective problem
Moving to the substance, the panel exercised its authority to re-evaluate the invention's purpose. While the patent itself stated the problem was to provide a composite element that meets flame retardancy requirements with reduced flame retardants, the panel disagreed. It noted that the court is not bound by the objective problem stated in the patent, but can determine it itself based on the description and drawings in their entirety (reasons 37).
The panel concluded the actual objective problem was to provide a composite element and manufacturing method wherein the adhesion between a cover layer and a foam layer containing polyisocyanurate is improved using an adhesion promoter (reasons 39).
Internal reactivity and customary densities
The core of the validity debate hinged on the term "noch reaktionsfähig" (still reactive). The claimants argued this merely meant reactive towards the foam layer. The panel sided with the defendant, finding that the term requires the adhesion promoter to be applied as a liquid reaction mixture of at least two components where the polyaddition reaction is still ongoing internally (reasons 53–54).
Despite this narrow construction, the main request fell to lack of inventive step over prior art document D19. The only distinguishing features were the specific densities of the adhesion promoter (400 to 1200 g/l) and the foam layer (30 to 100 g/l). The panel found these ranges to be customary for the skilled person, rendering the main request obvious (reasons 113).
The strict bounds of auxiliary review
BASF defended the patent with an Application to amend the patent (Rule 30 RoP), submitting Auxiliary Request 1. This request further specified that the adhesion promoter is obtained by reacting polyisocyanates with polyetherols and/or polyesterols at a specific ratio of 0.8 to 1.8:1.
Crucially, the panel noted that when examining auxiliary requests, it is bound by the arguments submitted by the claimant regarding their patentability and considers only these (reasons 124). Because the claimants' specific attacks on clarity, added matter, and inventive step against this request failed, the patent was maintained in amended form.
Practical implications
This decision establishes two vital procedural baselines. First, the UPC is a viable forum for clearing the path against expired patents, provided a credible threat of damages for past infringement exists. The expiration of the 20-year term does not shield a patent from central revocation if it is still being weaponised in national courts.
Second, the panel's handling of Auxiliary Request 1 highlights a strict pleading standard: grounds for invalidity raised against the granted patent are not automatically considered when examining auxiliary requests unless the claimant explicitly relies on them (reasons 124). Practitioners must ensure that their invalidity attacks are comprehensively mapped to every pending auxiliary request, rather than assuming the panel will carry over arguments ex officio.
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Further Reading
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