On 18 June 2025, the Enlarged Board of Appeal of the European Patent Office (EPO) issued the long-awaited decision G 1/24, which is expected to have significant implications for claim interpretation under the European patent system.

According to Article 69(1) EPC, the extent of protection conferred by a European patent is determined by the claims, but the description and drawings are to be used to interpret the claims. The Unified Patent Court (UPC) has also adopted this principle[1]. Consequently, the description and drawings are always to be considered when interpreting the claims in the context of assessing potential patent infringement and invalidation.

In contrast, the EPO’s Boards of Appeal have so far been divided in their case law concerning whether the description and drawings must be taken into account when assessing the patentability of an application or the validity of a patent in opposition proceedings. Some decisions held that the claims alone should be interpreted if they appear clear on their face –even if the interpretation contradicts the description.

This divergence had serious consequences in certain cases. Notably, in decisions T 1473/19 (30 September 2022) and T 1127/16 (18 February 2021), European patents were revoked due to a missing comma in the claim wording. The deciding boards took the view that claims must be interpreted in isolation if they are deemed clear, and that it was not permissible to modify their meaning by reference to the description – even when the result conflicted with it. In these and other decisions, the Boards of Appeal refused to consult the description and drawings to interpret otherwise unambiguous claims. In contrast, other decisions allowed such reference to the description and drawings to aid in construing the subject-matter.

This inconsistency also became evident in appeal case T 0439/22. In an interlocutory decision dated 24 June 2024, the board was confronted with the issue of whether a term in the main claim should be interpreted according to its narrower, customary technical meaning (without reference to the description) or according to a broader definition given in the description. In the former case, the claimed subject-matter was considered novel; in the latter, it was not. The question of patentability therefore hinged on whether the claim term could be interpreted in isolation or only in light of the description.

Unable to resolve the legal question itself, the board referred the matter to the Enlarged Board under Article 112 EPC, which has the task of ensuring uniform application of the law and settling important points of legal principle.

With its decision G 1/24 of 18 June 2025, the Enlarged Board has now settled the issue: the description and drawings must always be taken into account when interpreting patent claims when assessing the novelty and inventive step, also in examination and opposition proceedings.

This decision sets a paradigm for the examination of the novelty and inventive step before the EPO as well as for the opposition proceedings. Future decisions on novelty and inventive step must consult the description and drawings – an interpretation based solely on a claim wording  should no longer occur.

Ultimately, this decision harmonises the EPO’s claim interpretation practice with that of national courts across Europe and the Unified Patent Court.

On the practical side, the decision by the Enlarged Board of Appeal seems to pave the way for an even harsher check of the need to adapt the description to the claims during examination before the EPO.

For the daily practice, this decision means in particular:

• When drafting a new application, the utmost care is required. Terms, expressions, and parameters used in the claims should be specifically supported by definitions, explanatory clarifications, and fallback positions in the description (and, where appropriate, in the drawings).
• The description should be drafted in a way that allows for the broadest possible interpretation of the claimed subject-matter, without compromising consistency with the claims.
• Special attention must be paid to ensuring that the embodiment intended by the inventor or applicant – or the preferred technical implementation – clearly falls within the scope of interpretation of the claimed subject-matter.

BOEHMERT & BOEHMERT has already implemented the new decision in practice and will be happy to consult you further on this topic.

 

[1] UPC decisions CoA_335/2023 / App_576355/2023 of 26 February 2024 and CoA_1/2024 / ApL_8/2024 of 13 May 2024