Sean Hutchinson

June 2025

Headnote Summary

In case G 1/24, the Enlarged Board of Appeal of the European Patent Office (“EPO”) had been asked to answer the following questions:

“Question 1

Is Article 69(1), second sentence, EPC and Article 1 of the Protocol on the Interpretation of Article 69 EPC to be applied to the interpretation of patent claims when assessing the patentability of an invention under Articles 52 to 57 EPC?

Question 2

May the description and figures be consulted when interpreting the claims to assess patentability and, if so, may this be done generally or only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation?

Question 3

May a definition or similar information on a term used in the claims which is explicitly given in the description be disregarded when interpreting the claims to assess patentability and, if so, under what conditions?”

The Enlarged Board’s decision in G 1/24 was issued earlier today (18 June 2025), holding that Question 1 should be answered “no” but that the claims of a European patent / patent application should nonetheless be interpreted using the description and drawings, i.e. taking into account the principles enshrined in Article 69(1) EPC, because there is a large body of case law which supports this practice and because this is the practice of the national courts of the European Patent Convention (“EPC”) contracting states and of the European Union’s new Unified Patent Court (“UPC”).

The decision also holds that the answer to Question 2 is that the description and drawings must always be used to interpret the claims, without exception.

Question 3 has been held inadmissible on the grounds that the answer to Question 2 has rendered an answer to Question 3 unnecessary.

Additional detail is provided below.

In Detail

It has long been the practice of the EPO to require patent applicants to amend their claims so that their meaning is clear when the claims are read in isolation, with EPO examiners generally being reluctant to interpret claims based on disclosures in the description and drawings. Additionally, certain Boards of Appeal of the EPO have held that the description and drawings should only be used to interpret the claim wording if the claims are unclear or ambiguous on their own.

In 2024, EPO Board of Appeal 3.2.01 referred the above three questions regarding claim interpretation to the Enlarged Board of Appeal for clarification in its decision T 439/22, given that the question of how a certain term in claim 1 was to be interpreted was considered decisive to the outcome of that case. Specifically, if the term were to be interpreted according to its usual meaning in the art, i.e. if the claim were interpreted in isolation, then the subject matter of claim 1 would be considered novel. However, if the term were to instead be interpreted according to the broader meaning assigned to it in the description, then the subject matter of claim 1 would be considered to lack novelty.

The question of how the claims should be interpreted is also vitally important for many other European patent applications and EPO oppositions, as evidenced by the fact that more than 30 amicus curiae briefs (i.e., written opinions from third parties) were submitted to the Enlarged Board to consider in reaching its decision. After all, claim interpretation is an essential first step in analysing whether the claimed subject matter is novel and inventive.

In its decision in G 1/24, the EPO’s Enlarged Board of Appeal has come down firmly in favour of the description and drawings being used to interpret the claims, explicitly rejecting the approach of only referring to the description and drawings in cases where the claims are considered unclear or ambiguous. In fact, in the order at the end of its decision, the Enlarged Board stated that the description and drawings must be referred to in all cases, with no exceptions:

“The claims are the starting point and the basis for assessing the patentability of an invention under Articles 52 to 57 EPC. The description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention under Articles 52 to 57 EPC, and not only if the person skilled in the art finds a claim to be unclear or ambiguous when read in isolation.”

It is of note that the Enlarged Board held “there is no clear legal basis, in terms of an article of the EPC, for claim interpretation when assessing patentability” (see G 1/24, sheet 6, Reasons 9). However, the Enlarged Board considered that the core principles at the heart of its order, namely (i) that patentability should be assessed based on the invention as defined in the claims, and (ii) that the description and drawings must be used to interpret the claims can be derived from a large body of case law of the EPO’s Boards of Appeal, and acknowledged that its conclusion is consistent with the practice of the national courts of the EPC contracting states and of the UPC. The Enlarged Board additionally highlighted the importance of establishing a consistent approach to claim interpretation between the patent-granting forum (the EPO) and the patent-enforcing fora (the courts).

Summary

The issuance of this decision is an incredibly significant moment in the development of European patent law. In fact, one might argue G 1/24 will now force a monumental change in practice at the EPO, whose examiners are very unlikely to now be able to raise objections against the claims of a European patent application based on an interpretation inconsistent with the description and drawings.

To those of us practising in the UK, G 1/24 is a welcome development which should bring EPO practice more closely into line with that of the UK courts, which have long interpreted patent claims as having the meaning the proprietor most likely intended them to mean, taking into account factors such as the disclosure of the description and drawings (a practice known as “purposive construction”).

It will be interesting to see how this seismic development affects prosecution of European patent applications in the future!