G1/24: Decision Of The Enlarged Board Of Appeal Of The European Patent Office On Claim Interpretation

On 18^th June 2025, the Enlarged Board of Appeal of the European Patent Office issued Decision G1/24. During Appeal Proceedings (T0439/22) in the Opposition to European Patent No. 3076804B1 (Philip Morris Products S.A.) filed by Yunnan Tobacco International Co., Ltd, the following questions had been referred by the Board of Appeal (Referring Board) to the Enlarged Board of Appeal and subsequently found admissible by that Enlarged Board:

1. Are Article 69(1) EPC¹, second sentence, 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?

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?

The Referring Decision was an appeal against a finding of the Opposition Division rejecting the opposition to the patent-in-suit. Said patent-in-suit concerned an article for a vaping device, which contained an aerosol forming material (tobacco). A central issue in the appeal was whether claim 1 of the patent-in-suit as granted was novel. Specifically claim 1 of the patent-in-suit as granted contained the feature that the material is a "gathered sheet". The patent proprietor (Respondent) on appeal had argued that if this term is assigned its usual meaning in the art, claim 1 is to be regarded as novel. The appellant (Opponent) argued that if "gathered sheet" is interpreted in the light of the description, then it would have a broader but still technically sensible meaning: this interpretation of "gathered sheet" would lead to a lack of novelty. The contrary arguments duly noted, it was not a matter of dispute that the departments of the EPO, in the course of their duties, are required to interpret patent claims when assessing the patentability of an invention under Articles 52 to 57 EPC.

The reference of the above questions to the Enlarged Board had been deemed admissible given the identification of diverging lines of case law by the Referring Board. As regards the Question 1: a first line of case law took Article 69 EPC and Article 1 of the Protocol as the legal basis for interpretation of patent claims when assessing the patentability of an invention under Articles 52 to 57 EPC; and, a second line of case law took Article 84 EPC² as the basis. As regards Question 2: one line of case law was that a board only consulted the description and drawings when interpreting the claims to assess patentability if the person skilled in the art found a claim to be unclear or ambiguous when read in isolation; and, a further line of case law was that a board always consulted the description and drawings when interpreting the claims to assess patentability.

In Decision G1/24, the Enlarged Board indicated that in a strictly formal sense, the answer to the first referred question is "No". The Enlarged Board considered that neither Article 69 EPC and Article 1 of the Protocol, nor Article 84 EPC are entirely satisfactory as a basis for claim interpretation when assessing patentability.

• Article 69 EPC and the Protocol are arguably only concerned with infringement actions before national courts and the Unitary Patent Court (UPC): "[s]uch a conclusion can be drawn from the wording of Article 69 EPC and the Protocol, the drafting history of these provisions, and from their position in the EPC".
• Using Article 84 EPC as an alternative basis for interpretation of the claims can also be criticized. Article 84 EPC "addresses the content of the patent application and is formal in nature, does not mention the invention and provides no guidance on how to interpret claims".

The Enlarged Board thus considered that "there is no clear legal basis, in terms of an Article of the EPC, for claim interpretation when assessing patentability".

In drawing the above conclusion, the Enlarged Board did not, however, indicate that it was necessary to invent from scratch new principles of claim interpretation. The Enlarged Board noted that certain prevalent principles of claim interpretation could be extracted from the divergent case law utilizing either Article 69 EPC or Article 84 EPC as the basis for claim interpretation. Specifically:

Prior case law in which a given Board had seen no need to refer to the descriptions and drawings when interpreting a claim - unless that claim was unclear or ambiguous – was thus rejected as being contrary to the wording of Article 69 EPC and interestingly "also contrary to the practice of the national courts of the EPC states and to the practice of the UPC". In spite of the long-standing EPO practice of confining itself to matters of patent grant - and not considering the subsequent enforcement of the patent - the Enlarged Board deemed it an unattractive proposition for the EPO to deliberately adopt a contrary practice to that of the tribunals that are downstream of its patents. A further reason for rejecting this line of Board of Appeal case law was a logical one: the finding that the language of a claim is clear and unambiguous is an act of interpretation, not a preliminary stage to such an interpretative act.

The Enlarged Board thus answered Question 2 above as follows: the description and any drawings are always referred to when interpreting the claims, and not just in the case of unclarity or ambiguity. The Enlarged Board noted that this conclusion was consistent with current case law of the Unitary Patent Court, specifically NanoString Technologies versus 10x Genomics (UPC_CoA_335/2023).

The above order doesleave open the question of what exactly is meant by "consulting" or "referring to" the description. Certainly, Decision G1/24 does not require the reader to strictly follow the description. However, under what circumstances may a statement or definition in the description be discounted when interpreting the claims? A practical guideline to answering this question – which would, in my view, follow the established EPO approach that "the patent must be construed by a mind willing to understand, not a mind desirous of misunderstanding" and which would not be determined by any intent of the patentee – may be that: it is first determined what the skilled artisan would understand a claimed term to mean; it is then assessed whether this is in line with any definitions given in the description; and, a determination is subsequently made as to whether these definitions may then be discounted if following the description would result in a nonsensical meaning.

Certainly Decision G1/24 will dictate that the use of boilerplate definitions within the description should be very carefully considered when drafting a patent application. Definitions within the description must be reviewed for consistency with how claimed terms are intended to be defined. While a claimed term may not lack clarity per se, the Examining Division is obliged by Decision G/24 to review the description and thereby not ignore inconsistent or alternative definitions given therein.

It, of course, remains to be seen how EPO examiners will apply this decision to novelty and inventive step. It may be expected that an Examiner's initial prior art objections will still be raised on the basis of the wording of the claims but that an attorney may then counter such objections with an alternative interpretation based on a reference to the description. However, the submission of such counter arguments and any further submissions engaging with the Examiner thereon, should be carefully considered both in view of Article 84 EPC² and in view of the potential risk of prosecution estoppel should this continue to develop at the UPC. UPC Decisions UPC_CoA_402/2024 (Alexion Pharmaceuticals, Inc. v. Samsung Bioepic NL B.V.) and UPC_CoA_405/2024 (Alexion Pharmaceuticals v. Amgen Technology Ireland et al.) may be noted in the latter context.

It is postulated that Decision G1/24 may permit the EPO Examiners to further enforce the requirement for an Applicant to align the claims and the description before grant through amendment. Such amendments are fraught with the risk. Where the meaning of a term in a claim must be determined in part by reference to the description, it is clear that any changes to the description may impact how the skilled artisan interprets the claims: this risks inadvertently adding subject matter which goes beyond the content of application as filed (Article 123(2) EPC violation) and, in opposition proceedings against a patent, extending by a remediative amendment the scope of protection afforded by the patent (Article 123(3) EPC violation).

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