When looking to block a competitor product, or assessing infringement risk, a hot topic in Europe is how the UPC is applying the Doctrine of Equivalents. Here we run through the latest developments and ask: are all tests equivalent?
It’s no secret that the Doctrine of Equivalents is baked into European patent law, not least via the authority of the Protocol on the Interpretation of Article 69 EPC.
Specifically, Article 2 of the Protocol tells us that, when determining the extent of protection conferred by a patent, “due account shall be taken of any element which is equivalent to an element specified in the claims”.
For proprietors wondering whether a competitor product infringes their patent, or for companies assessing third party risk, this leaves the question: what does equivalent to an element specified in the claims really mean?
In mainland Europe, the various national courts have established their own respective tests for applying the Protocol on Article 69. Now, with the UPC fast becoming the go-to forum for European patent litigation (even having the authority to decide on infringement on European patents in the UK), the various UPC divisions have the unenviable task of reconciling these national tests, all while bringing their approach to equivalents into harmony with the EPC.
In this article, we look at the approach to equivalents taken by various local divisions of the UPC, and look ahead to how the Court of Appeal might establish a “unified” approach to determining infringement by equivalence.
Plant-e v Arkyne
The Doctrine of Equivalents was first put to the test in November 2024 in Plant-e v Arkyne. In this case, the Hague Local Division (LD) found Plant-e’s patent to be infringed by equivalence, after applying the very first equivalents test seen in the UPC. In the decision, the court attempted to reconcile the different approaches by applying a test “based on the case law in the various national jurisdictions”. That test is as follows:
1) Technical equivalence: does the variation solve (essentially) the same problem that the patented invention solves and perform (essentially) the same function in this context?
2) Fair protection for patentee: Is extending the protection of the claim to the equivalent proportionate to a fair protection for the patentee?
3) 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?
4) Is the allegedly infringing product novel and inventive over the prior art?
Answering yes to each question would lead to a finding that the variation is an equivalent.
To those familiar with the various national tests, it quickly became apparent that the Hague LD’s test was very close to the approach taken by the Dutch National courts. It was perhaps expected, then, that later decisions might deviate from the Dutch approach as the various divisions would attempt to harmonize their approaches across all 18 UPC member states.
Harmonization across Europe
In the year since the Plant-e decision, there has been an uptick in the number of decisions that decide on, or at least comment on, infringement by equivalents.
At the beginning of this year, the Brussels LD held that functional equivalence is the bare minimum necessary to demonstrate infringement by equivalence. That is, regardless of the exact legal test applied, if the variant does not achieve the same function as the claimed element, then the variant is not an equivalent ([redacted] v OrthoApnea, 17 January 2025).
A few months later, the Mannheim LD followed the Brussels decision in Dish v Aylo, justifying the requirement for functional equivalence as a common theme among all the equivalence tests of the different UPC member states. Specifically, the court held that equivalent infringement in the different member states requires the variant to fulfil essentially the same function in order to achieve essentially the same effect.
In August 2025, the Paris LD went a step further and called for the most harmonized approach to infringement by equivalents to be adopted across the UPC. Whilst acknowledging that there are currently different tests applied within the UPC member states, the court identified the functional equivalence criterion as the lowest common denominator. This means that all tests should be harmonized insofar as the first question being asked is: Do the modified (or substitute) means essentially fulfil the same function to obtain essentially the same effect? (NJ Diffusion v Gisela Mayer).
More recently, the Hague LD had no hesitation in re-applying the four-step Plant-e test in Washtower v BEGA-Gruppe. The decision of 11 September 2025 states that both parties referred to this test, leaving the court no reason to deviate from its earlier approach (perhaps the reliance on the court re-applying this test was the reason for selecting this forum in the first place?).
Despite adopting the Dutch-specific approach, the court reiterated the desire for a harmonized approach across the UPC that relies firstly on functional equivalence. Specifically, the court noted that “the bottom line is that a finding of equivalent patent infringement is excluded where there is no technical-functional equivalence… that the variant performs essentially the same function as the element recited in the claim, with essentially the same result”.
Looking ahead
The calls for harmonization from the various UPC divisions have so far established that, regardless of the specific legal test applied, any approach must start by determining whether the variant performs essentially the same function to fulfil essentially the same effect. Whilst perhaps not strictly intentional, this starting point conveniently aligns with the first step of the UK’s well-established Actavis questions (...does the variant achieve substantially the same result in substantially the same way as the invention...?), providing at least some level of legal certainty across the UK and European litigation forums.
Of course, we are yet to see the UPC Court of Appeal weigh in on how equivalent infringement should be tackled. If and when they do, it wouldn’t be unreasonable to expect 1) a very careful weighing up of the diverging national approaches with the desire for harmonization, and 2) any test set by the Court of Appeal to start with functional equivalence, given the existing findings of the first instance Courts.
In the meantime, whilst we wait for a division other than the Hague to apply their own legal test (or for the Court of Appeal to step in), it’s essential to consistently take “due account” of equivalents when carrying out any commercial exercise involving patents.
We have a large team of experts that can advise on claim interpretation in the context of a large range of commercial activities, from identifying and managing third-party IP risk to assessing whether a competitor infringes your patent. If you would like to know more, please speak to Matthew Woodhill, Jessica Duncombe, Laura Ramsay, Caelia Bryn-Jacobsen or your usual K&S advisor.