This contribution reviews the developing case law on infringement by equivalence at the Unified Patent Court (UPC).
The doctrine of equivalence addresses situations in which an alleged infringer adopts the technical teaching of a patent while introducing one or more variations often designed to avoid a finding of literal infringement. The underlying concern is that the patent proprietor’s rights would be undermined if such insubstantial modifications were allowed to fall outside the scope of protection.
The European Patent Convention (EPC) expressly recognises that concern in Article 69 EPC and the Protocol on the interpretation of Article 69 EPC (Protocol). Article 2 of the Protocol provides that, “for the purpose of determining the extent of protection conferred by a European patent, due account shall be taken of any element which is equivalent to an element specified in the claims”. Pursuant to Article 24(1)(c) of the Agreement on a Unified Patent Court (UPCA), the UPC is required to apply the EPC and the Protocol when determining the extent of protection of European and unitary patents.
Neither the UPCA nor the Rules of Procedure, however, defines what constitutes an “equivalent element” or sets out a test for determining equivalence. The UPC is therefore required to develop its own doctrine of equivalence, drawing on general principles and on the national doctrines of equivalence applied in the Contracting Member States.
Based on the UPC decisions published to date, an emerging structure can be identified. The case law points towards atwo-layered approach. First, all divisions treat technical-functional equivalence as aminimum threshold: if the alleged variant does not essentially perform the same function to achieve essentially the same effect, infringement by equivalence is excluded. Second, it remains open whetheradditional normative criteria—such as fair protection for the patentee, legal certainty for third parties, or a prior-art screen—apply once that threshold is met.
1. Legal background: equivalence without a statutory test
Neither the EPC nor the Protocol defines “equivalent elements”. Earlier codification efforts suggested that a variant element should generally be regarded as equivalent if, at the time of the alleged infringement:
- Either the variant element performs substantially the same function in substantially the same way and produces substantially the same result as the element specified in the claim;
- Or it is obvious to the skilled person that the same result can be achieved by means of the variant element.
The first formulation reflects the classic function-way-result test; the second aligns with what many systems know as an “obviousness of substitution” or Formstein/Gillette defence, under which a variant that is itself obvious over the prior art cannot be treated as infringing by equivalence.
Across Europe, national courts have developed different doctrinal structures. Belgian courts typically apply a function-way-result analysis. German courts apply a structured three-step test focusing on whether the skilled person, based on the patent, recognises the variant as solving the problem with modified means, combined with a Formstein defence to prevent an extension of protection beyond the prior art. Dutch courts apply a four-step test that, in addition to technical equivalence, explicitly weighs fair protection for the patentee, legal certainty for third parties, and a Formstein/Gillette defence.
Against this background, the UPC has been required to navigate between divergent national traditions while ensuring uniform application of Article 69 EPC and the Protocol.
2. UPC equivalence case law
2.1 Hamburg Local Division: early indication that technical means matter
The first UPC decision to address equivalence was the order of the Hamburg Local Division’s of 3 June 2024 (UPC_CFI_151/2024) on provisional measures in Ballinno v UEFA, concerning VAR technology for detecting offside situations in football games. The Court held that the accused “Connected Ball Technology” did not use equivalent means because it did not achieve the claimed effect of sound signals in the same technical manner. The Court emphasized that equivalence cannot be assessed solely by the effect achieved, and that the decisive question is how that effect is achieved. Although the Court did not articulate a formal test, in substance, its reasoning closely resembles a function-way-result analysis, and underscores the importance of the technical means employed.
2.2 The Hague Local Division (1): a structured four-step test
The first UPC decision on the merits to articulate an explicit doctrine of equivalence is the judgment of theHague LocalDivision of 22 November 2024 (UPC_CFI_239/2023) in Plant-ev Bioo. Having found no literal infringement, the court assessed infringement by equivalence and applied a four-step test essentially derived from Dutch national case law, which the parties had agreed should govern the analysis.
Under that test, equivalence is established only if four questions are answered in the affirmative:
- Technical equivalence: does the variant solve (essentially) the same problem as the patented invention and does it perform (essentially) the same function in this context;
- Is extending the protection to the variant proportionate in light of fair protection for the patentee andthe patentee’s contribution to the art;
- Reasonable legal certainty for third parties: does the skilled person understand from the patent that the scope of the invention is broader than what is claimed literally; and
- Is the allegedly infringing product novel and inventive over the prior art?
Applying all four steps, the Court found infringement by equivalence and granted a multi-country injunction. To date, this remains the only UPC judgment on the merits that has upheld infringement by equivalence.
2.3 Brussels Local Division: technical-functional equivalence as a threshold
Next, in its decision of 17 January 2025 (UPC_CFI_376/2023) in Mr. N. v OrthoApnea, the Brussels Local Division referred to Plant-e for its theoretical framework but then adopted a more restrained approach. The Court held that, regardless of the test used, the analysis must begin with technical-functional equivalence: whether the variant performs essentially the same function to achieve essentially the same effect (the first step of the Dutch test). If that requirement is not satisfied, a claim of infringement by equivalence necessarily fails, without any need to assess additional criteria. On the facts, the Court found that this threshold was not met and rejected the equivalence claim without engaging with further steps of the Dutch test.
The OrthoApnea proceedings also resulted in a significant procedural order of the Court of Appeal of 21 November 2024 (UPC_CoA_456/2024). The Court of Appeal held that not every new argument constitutes an amendment of the case that requires leave under R.263 RoP, and that such amendment arises only if the nature or scope of the dispute changes, for example by invoking a different patent or targeting a different product. In the Court’s view, the equivalence argument, directed at the same patent and the same product as the literal infringement case, did not change the nature or scope of the dispute. The Court further considered that the reliance on equivalence was a response to new non-infringement arguments raised by OrthoApnea in its Statement of Defence and did therefore not infringe Rule 13 RoP.
2.4 Mannheim Local Division: identifying a common denominator
In its judgment of 6 June 2025 (UPC_CFI_471/2023) in DISH v AYLO, the Mannheim Local Division explicitly addressed the need for a UPC-specific doctrine of equivalence. The Court distinguished between acts governed by national substantive law (for example, pre-1 June 2023 acts) and acts governed by the UPCA. For the former, it considered that the UPC should apply the relevant national doctrine of equivalence in the same way as the competent national court. For the latter, it considered that the UPC should develop its own doctrine of equivalence, informed by, but not limited to, national traditions.
The court observed that all national doctrines of equivalence share at least one common element: there can be no infringement by equivalence if there is no technical-functional equivalence of the variant, i.e. if it does not fulfil essentially the same function in order to achieve essentially the same effect. Technical-functional equivalence was thus identified as the lowest common denominator. Where it is absent, infringement by equivalence must be rejected. Just like the Brussels Local Division, the Court found that this minimum requirement was not satisfied and did not articulate any additional criteria.
2.5 Paris Local Division: rejecting national tests absent agreement
In its judgment of 1 August 2025 (UPC_CFI_363/2024) in NJ Diffusion v Gisela Mayer, the Paris Local Division adopted a similar approach. In what it considers to be “in line with the spirit of the UPCA”, it held that the assessment must begin with the lowest common denominator of equivalence: whether the modified means essentially fulfil the same function to achieve essentially the same effect.
The Court expressly declined to apply the four-step Dutch test from Plant-e v Arkyne, noting that it reflected Dutch national case law and had been applied because the parties had agreed on it. In the absence of such agreement, the Paris Local Division confined its analysis to the minimum threshold. Finding that technical-functional equivalence was lacking, the Court rejected infringement by equivalence, without proceeding further.
2.6 The Hague Local Division: consistency in outcome
The Hague Local Division has revisited equivalence in later decisions. In a provisional measures order of 11 September 2025 (UPC_CFI_479/2025) in Washtower v Wasombouw, it again applied the Dutch four-step test, emphasising that both parties accepted that framework and that, in the absence of guidance from the Court of Appeal, there was no reason to depart from it.
In a later decision of 18 November 2025 (UPC_CFI_507/2024) in Advanced Cell Diagnostics v Molecular Instruments, the same division rejected a claim of infringement by equivalence on the basis that functional identity was lacking. Although the Court also referred to legal certainty for third parties, the outcome is fully consistent with the approach taken by other divisions: where technical-functional equivalence is absent, the claim fails.
2.7 Düsseldorf Local Division: broad literal scope excludes equivalence
In a very recent decision of 28 January 2026 (UPC_CFI_315/2024) in Labrador Diagnostics v bioMériueux, the Düsseldorf Local Division addressed infringement by equivalence in the context of a bifurcated case concerning an amended patent relating to instruments for detecting biological analytes. Having found no literal infringement, the Court turned to the alternative equivalence claim.
The Court held that infringement by equivalence was excluded on two distinct grounds. First, because even a broad interpretation of the claim did not lead to infringement, there was no room for infringement by equivalence: the alleged equivalent addressed the modular construction of components which was already covered by the literal wording of the claim. Second, the Court found that the alleged equivalent did not perform essentially the same function as the claimed device, since no means distinct from the sample unit was identified by the claimant as performing the function of the device “to comprise the reagent units and a sample unit“.
The decision is noteworthy in that it forecloses recourse to equivalence where the variant in question falls within the scope of what is already covered by a broad construction of the literal claim language. Although the Düsseldorf Local Division indicated that the question of admissibility of the equivalence claim could be left open, it proceeded to reject the claim on its merits, thereby confirming that technical-functional equivalence remains a necessary threshold even where admissibility is contested.
3. Emerging structure and open questions
Although the Court of Appeal has not yet ruled on the substance of the doctrine of equivalence, the UPC first instance case law to date supports the identification of a two-layered structure.
- The first layer is a minimum threshold: technical-functional equivalence is a necessary condition for infringement by equivalence before the UPC. If the alleged variant does not essentially perform the same function to achieve essentially the same effect, infringement by equivalence is excluded.
- The second layer concerns the question of whether additional criteria apply once that threshold is met. To date, only the Hague Local Division has proceeded beyond the minimum requirement, applying the Dutch four-step test where the parties agreed to do so. Other divisions have not yet been required to decide whether considerations such as fair protection for the patentee, legal certainty for third parties, or a prior-art screen form part of the UPC’s own doctrine, because in all cases before them the minimum threshold of technical-functional equivalence was not satisfied.
Two further features of the emerging practice merit emphasis. First, party agreement currently plays a significant role in shaping the equivalence analysis, allowing national doctrinal frameworks to be applied on a consensual basis. The reliance on party agreement may be a transitional phenomenon, but it has clear strategic implications for UPC litigation. Second, the UPC’s formulation of technical-functional equivalence appears closer to a function–effect analysis than to a full function–way–result test, with the “way” in which the result is achieved being relevant but not consistently articulated as an autonomous requirement.
4. Conclusion
In the absence of substantive guidance from the Court of Appeal, the UPC’s doctrine of equivalence remains in a formative stage. The existing case law nevertheless reveals a clear convergence on technical-functional equivalence as a minimum threshold common to all divisions. Beyond that threshold, the contours of the doctrine remain open. The UPC may ultimately adopt a structured multi-factor test akin to the Dutch model, or it may settle on a narrower approach closer to a function–effect or function–way–result analysis.
Each option involves a policy trade-off. A purely technical-functional approach, if treated as sufficient in itself, risks producing misaligned outcomes: it may either extend protection to variants that should remain free in light of the prior art or legal certainty for third parties, or conversely fail to capture variants that appropriate the patentee’s contribution in a less straightforward technical form. A multi-factor test on the other hand risks reintroducing fragmentation and uncertainty if national models are applied selectively.
These questions will only be definitively resolved once the Court of Appeal addresses the substance of equivalence under the UPCA.
