On June 18, 2025, the Enlarged Board of Appeal of the European Patent Office (EPO), the highest judicial authority under the European Patent Convention (EPC), issued decision G1/24 relating to claim interpretation for the purpose of assessing the patentability of an invention. The Enlarged Board of Appeal, considering the role to be attributed to the description in the patentability assessment, has established that the claims alone do not suffice for the purpose, that they are only the starting point, and that the description (and any drawings, when present) must always be consulted. In view of authority of the Enlarged Board, decision G1/24 will have an impact on the assessment of patentability of any European patent application prosecuted before EPO Examining Divisions as well as on the assessment of validity of any European patent before the EPO Opposition Divisions and Boards of Appeal.
In the specific case under the scrutiny of the Enlarged Board of Appeal, the claim terms at issue were "gathered sheet" of an aerosol-forming material of an aerosol-forming substrate defined in a claim directed to an article for a vaping device comprising such a substrate. These terms were interpreted differently (as is virtually always the case) by the proprietor and the opponent in the opposition and subsequent appeal proceedings instituted before the EPO. On the one hand, the proprietor considered that based on their normal meaning, no prior art negated novelty of the article. On the other hand, the opponent considered that based on the broader, yet still technically meaningful interpretation of "gathered sheet" derivable from the description, the cited prior art did negate novelty of the article. The Board of Appeal charged with the appeal proceedings, confronted with these two interpretations by the parties, identified diverging lines of case law when interpreting the claims both in terms of relevant legal basis and in terms of the role played by the description and drawings and the circumstances under which these should be consulted. From a legal point of view, a first line essentially relies on Art. 69 EPC, which, together with its Protocol of interpretation, define the extent of protection of a European patent, while a second, alternative line relies more on Art. 84 EPC, which sets forth the clarity requirements. As to the description, according to several decisions of the Boards of Appeal, the description and drawings may be considered only in the case of lack of clarity or ambiguity of the claims.
Therefore, to seek a uniform interpretation of the law and establish a common principle, the Board of Appeal referred corresponding questions of law to the Enlarged Board of Appeal, which eventually issued the recent decision G1/24.
The Enlarged Board of Appeal was not satisfied with any of the two alternative legal bases, Art. 69 EPC being relevant when assessing infringement rather than patentability, and Art. 84 EPC being more focused on the content of a patent rather than its scope and having the nature of a formal requirement. In the absence of an explicit legal basis to be relied on to interpret the claims for the purpose of assessing their patentability, the Enlarged Board stated that the applicable principles can be extracted from the case law. Based on the principles identified in the case law by the Enlarged Board, each patentability assessment has to start with the claims and (despite the acknowledged existence of diverging decisions) the description and drawings should always be referred to when interpreting the claims, not only when the claims are unclear or ambiguous. The Enlarged Board's rationale in its analysis of the principles of the case law, which led to the exclusion of the case law relying on the description and drawings only in case of lack of clarity or ambiguity, was multifold: respecting the principle of Art. 69 EPC, which states that claims determine the scope of protection, but that "the description and drawings shall be used to interpret the claims," taking duly into account the practice of the national court in Europe and the (just two-years old) practice of the Unified Patent Court (UPC), and avoiding an illogical approach which would ultimately use a different basis for interpreting clear claims with respect to unclear or ambiguous claims.
With reference to the UPC decisions rendered so far, NanoString Technologies v. 10xGenomics, explicitly cited by the Enlarged Board of Appeal in decision G1/24, was the first substantive decision of the UPC Court of Appeal. This UPC decision appears to have set the initial standard applicable by the UPC for interpreting the claims for the purposes of assessing validity and infringement. While the UPC Court of Appeal, more focused on Art. 69 EPC, has stated that the claims are even more than the starting point ("not only the starting point, but the decisive basis") for determining the scope of protection of a European patent, it has also pointed out that "the description and the drawings must always be used as explanatory aids for the interpretation of the patent claim and not only to resolve any ambiguities in the patent claim."
Thus, in the EPO practice, in line with the recent UPC practice, the description and drawings become systematically relevant to interpret the claims. This should be kept in mind both when drafting a European patent application and when interpreting the claims of a European patent for the purpose of assessing its novelty and inventive step in case of a dispute. Particular attention should be given not only to explicit definitions, but also to implicit definitions as well as to explicit and implicit disclaimers or exclusions of a certain interpretation of a term based on its usage in the specification and representation in the drawings.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
