On 3 September 2026, the Enlarged Board of Appeal of the European Patent Office issued its decision G 1/25 concerning the circumstances in which the description of a European patent application or patent must be adapted following amendments to the claims. The full decision is available on the EPO website.
Description adaptation remains required – but not for formal reasons alone
The Enlarged Board confirmed that an adaptation of the description may be required where amended claims create an inconsistency with the description or drawings. However, such adaptation is not required merely to achieve formal concordance between the claims and the description.
An adaptation is necessary only where the inconsistency has legal significance because it results in non-compliance with Articles 52 to 57, 76(1), 83, 84, 123(2) or 123(3) EPC. The decision therefore confirms the established practice of adapting the description to amended claims, while at the same time making clear that there is no general requirement to remove passages merely because they are no longer reflected in the claims.
When does an inconsistency require amendment of the description?
The decisive distinction under G 1/25 is between a merely formal mismatch and a legally relevant inconsistency.
An inconsistency exists where statements in the description suggest an understanding of the claim that is incompatible with its apparent meaning and this incompatibility cannot readily be resolved by applying the principles of claim interpretation established in G 1/24. In particular, an inconsistency arises where the skilled person, reading the claims together with the description and drawings, would be left in real doubt as to the meaning of the claim.
By contrast, the mere presence of technical teachings, examples or embodiments that do not fall within the claimed subject-matter is not sufficient to require an adaptation of the description.
G 1/25 will not eliminate disputes over description amendments
For applicants, patent proprietors, opponents and their representatives, G 1/25 is unlikely to put an end to discussions concerning adaptation of the description. The decisive question will often be whether, when the patent is read as a whole, a particular passage actually creates real doubt as to the meaning of a claim.
That assessment necessarily involves claim interpretation and may therefore remain contentious in individual cases. This is likely to become particularly relevant in EPO opposition proceedings, where the parties may take different views as to whether amended claims and the remaining description can still be read consistently.
Such disputes are not entirely new. Similar issues have already been argued under the previous, divergent lines of case law. G 1/25 now provides a clearer legal framework for those discussions, but the precise boundaries of what constitutes a legally relevant inconsistency will have to be developed further by the Boards of Appeal in future decisions.
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Author: Dr. Michael Schmid