The doctrine of equivalents: Patent construction and infringement following the UPC decision in Plant-e v Bioo

What is the doctrine of equivalents and why is it important?

The doctrine of equivalents impacts the extent of protection provided by a patent and determines whether actions undertaken by a third party constitute infringement. Consequently, this is an ongoing concern for both patentees and innovators who are wary of potential infringement claims.

The coverage of a patent is defined according to the wording of the granted claims. This has sometimes led to a narrow focus on the strict, often literal, wording of the claims. The doctrine of equivalents is a principle of patent law that provides that the proper scope of protection of a patent is in fact broader and covers product/process “variants” that are not within the literal wording of the claims but that nevertheless perform substantially the same function in substantially the same way to achieve the same result as those set out in the claims. The approach to equivalence in terms of patent construction and infringement has varied over time and is summarised below.

Equivalence in Europe

With one exception, all big jurisdictions in Europe developed a doctrine of equivalence and refined case law over time.

In the leading case “Cutting Blade I” (Schneidmesser I; case no. X ZR 168/00), the German Federal Supreme Court confirmed that the equivalence test according to established case law applied both to national German patents and German parts of European patents. The Protocol on the Interpretation of Article 69 EPC did not call for any changes in approach. The infringement analysis therefore required that three questions be addressed:

• Does the accused embodiment solve the problem underlying the invention with modified, but objectively equivalent means?
• Is the person skilled in the art able to identify the modified means as having the same effect?
• Are the considerations of the person skilled in the art focused on the essential meaning of the teaching according to the patent claim, such that the person skilled in the art regards the embodiment as equivalent?

Furthermore, in 1986 the German Federal Supreme Court recognised that there is no infringement by equivalence if the accused embodiment is not eligible for patent protection (Formstein, case no. X ZR 28/85). If, against the background of prior art, the embodiment is not novel or there is no inventive step, then the embodiment falls outside the scope of protection conferred by the patent in suit. In line with the name of the decision, this defence became internally known as the Formstein-Einwand.

In Italy, the doctrine of equivalents is expressly recognised in Art. 52,3-bis the Italian Industrial Property Code, which states that “when determining the scope of protection conferred by a patent [based on the patent claims interpreted in light of both description and drawings] due account must be taken of any element that is equivalent to the elements identified in the claims”.

Italian Courts have long applied different methods to assess equivalence. Earlier decisions focused on whether the alleged infringing product shared the same “inventive core” as the patented invention. Today, two main tests dominate. The Obviousness Test, according to which infringement is established if the modification used to avoid the literal claim wording would have been an obvious alternative to a skilled person addressing the same technical problem. However, the Italian Supreme Court (decision no. 120 of 4 January 2022) has recently noted that the originality of modifications does not necessarily prevent infringement, and that such an approach would eliminate so-called dependent inventions, which, although possessing originality, interfere with the patent.

The Function-Way-Result (FWR) test, according to which equivalence is found if the differing element in the accused product performs the same function, in substantially the same way and achieves the same result as the claimed feature. There are some decisions which, while referring to the triple test and to the concept of inventive step (or lack thereof) of the substitute solution, have highlighted the importance of the literal wording of the claims as an expression of the patent owner, who, if they had considered a particular element of the claimed invention non-essential, could have chosen not to claim it specifically.

Unlike some jurisdictions, Italy does not adopt prosecution history estoppel. Although arguments made during examination before the EPO are sometimes raised in litigation, Italian courts generally do not treat them as decisive. The Italian Supreme Court (decision no. 2977 of 07.02.2020) has confirmed that patent interpretation should not rest solely on such statements, as this would improperly make the scope dependent on the patentee’s subjective intent. Some case law allows limited consideration of amendments, but only when these were essential to distinguish the invention from prior art and to overcome objections of novelty or inventive step; amendments made to address purely formal objections (i.e. added matter) are not regarded as relevant to assess equivalence.

In the UK, by contrast, historically there was no general doctrine of equivalents. The courts preferred to rely on construing claims purposively and in context to achieve a just balance when faced with immaterial variations. However, the 2017 Supreme Court case of Actavis v Eli Lilly [2017] introduced the concept, meaning that infringement now covered both literal infringement and infringement under the doctrine of equivalents.

Equivalence according to the UPC

In Plant-e v Bioo, the Local Division in The Hague noted that the Agreement on a Unified Patent Court (UPCA) is silent on equivalence. However, according to Article 2 of the Protocol on Article 69 EPC equivalence must be considered, because “[f]or 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.” In the absence of guidance regarding the equivalence test in the UPC context, the Local Division set out to develop its own test based on case-law from different jurisdictions and legal discussions with the parties. That test involves four questions (para. 88 of the decision):

• Technical equivalence: does the variation solve (essentially) the same problem that the patented invention solves and performs (essentially) the same function in this context?
• Is extending the protection of the claim to the equivalent proportionate to a fair protection for the patentee: in view of his contribution to the art and is it obvious to the skilled person from the patent publication how to apply the equivalent element (at the time of infringement)?
• 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?
• Is the allegedly infringing product novel and inventive over the prior art? (i.e. no successful Gillette/Formstein defence).

Questions 1 and 3, for the German reader, are modelled on the questions according to “Cutting Blade I”, whereas question 4 introduces the Formstein defence into UPC case-law.

From the Italian perspective, the decision shows a focus on the substance of the patented invention rather than a narrow interpretation of the patent claims, a principle that will now be applied in Italian patent litigation through the UPC system. In order to assess equivalence, the Local Division in The Hague has adopted a new test, which disrupts established Italian case law and the prevailing stance in the Italian legal scholarship (Obviousness and FWR tests). The decision under review marks a turning point with the adoption of the test aimed at determining infringement under the doctrine of equivalents which undoubtedly constitutes an interesting precedent even within the national legal landscape.

Conclusion

For users of the new patent litigation system, Plant-e v Bioo is a helpful decision. It shows how contentious issues such as the doctrine of equivalence may be approached by the Unified Patent Court. In an exemplary manner, the Local Division in the Hague sought guidance on how national courts address equivalence, then it created its own “best of version” of an equivalence test. While that “best of version” is quite different from the Italian national approach, it will remind German practitioners of Schneidmesser. Of course, we are yet to see what Local Divisions based in other UPC Member States will make of Plant-e v Bioo. It may well take some years until different approaches converge. There is more to come!