In decision G 1/24 of June 18 2025, the Enlarged Board of Appeal of the EPO addressed a significant issue with regard to principles of claim interpretation. The ruling arose from a referral by a technical board of appeal of the EPO, T 439/22 of June 24 2024, in which the referring board noted that diverging lines of EPO case law with respect to claim interpretation had developed over the years.
A fundamental principle of patent law, as reflected in Article 69 of the European Patent Convention (EPC), is that the scope of protection conferred by a patent shall be determined by the claims. Article 69 of the EPC, however, additionally provides that the description and drawings shall be used to interpret the claims.
In application of Article 69 of the EPC, courts in Europe, including the Unified Patent Court (UPC), generally refer to the description when interpreting claims for both infringement and invalidity assessments.
As noted by the referring board in T 439/22, a line of EPO case law has, however, developed, following which claims should be interpreted on their own merits without regard to the description in the context of the assessment of novelty, inventive step, sufficiency of disclosure, and added subject matter. In contrast to that line of decisions, an alternative line of case law has held that the terms of claims should be given their normal meaning in the relevant art unless the description gives the terms a special meaning, thus implying that the description can be relied upon in the context of claim construction.
Primarily following the latter line of case law, the Enlarged Board of Appeal has now decided in G 1/24 that, while the claims are the starting point and the basis for assessing the patentability of an invention, the description and drawings shall always be consulted to interpret the claims when assessing the patentability. The decision is seen by many as an important step towards harmonisation between UPC and EPO case law.
