Düsseldorf, August 4, 2025 – On July 29, 2025, EPO Board of Appeal 3.3.02 made a long-awaited referral (case G 1/25, "Hydroponics") to the Enlarged Board of Appeal (EBA) to resolve a divisive issue in European Patent Office (EPO) practice: whether patent descriptions must be amended to align with narrowed claims. Originating from case T697/22, this referral addresses conflicting EPO practices that have long frustrated applicants and representatives alike.
The current EPO Guidelines for Examination require deleting unclaimed subject matter from the description pre-grant or marking it as not encompassed by the claims, a practice not mandated by other patent offices. Critics, citing decisions like T1989/18 and T56/21, argue that Article 84 of the European Patent Convention (EPC), which requires claims to be clear and supported by the description, provides no legal basis for such mandatory description amendments. Conversely, other EPO Boards of Appeals (e.g. in cases like T1024/18 and T438/22) upheld the EPO’s mandatory description adaptation practice, emphasizing the importance of clarity and support. However, as practice often shows, amending descriptions risks affecting claim interpretation in national courts and opposition proceedings, where the granted patent’s description is considered as important source for interpreting the claims. It also increases the risk of added-matter violations, burdens applicants post-examination, and raises costs. In case of lengthy specifications or complex claim amendments performed during prosecution, adapting the description can be quite an undertaking.
G1/25 arises from an appeal involving European Patent No. EP 2124521, which claims a method for growing plants in a hydroponic medium. The dispute centers on an amendment to claim 1, narrowing its scope to specify an organic binder, creating a potential inconsistency with the description, which describes the binder more broadly. The Opponent argues that this discrepancy — where optional features in the description now are mandatory in the granted claims — violates the support requirement of Article 84 EPC.
In T697/22, the referring Board of Appeal acknowledges the inconsistency but notes conflicting case law. After reviewing a total of 115 Board of Appeal decisions, the referring Board identifies two divergent approaches in the case law: one mandating description adaptation (e.g., T1452/21, T1024/18, T438/22) and the other rejecting it absent any legal basis for it in the EPC (e.g., T1444/20, T56/21).
To resolve this, the Board of Appeal in G 1/25 refers three questions to the EBA:
- If the claims of a European patent are amended during opposition proceedings or opposition-appeal proceedings, and the amendment introduces an inconsistency between the amended claims and the description of the patent, is it necessary, to comply with the requirements of the EPC, to adapt the description to the amended claims so as to remove the inconsistency?
- If the first question is answered in the affirmative, which requirement(s) of the EPC necessitate(s) such an adaptation?
- Would the answer to questions 1 and 2 be different if the claims of a European patent application are amended during examination proceedings or examination-appeal proceedings, and the amendment introduces an inconsistency between the amended claims and the description of the patent application?
Just in one of its most recent cases, G1/24, the EPO’s Enlarged Board of Appeal had decided that the description should always be consulted when interpreting claims. This underscores the importance of G1/25 and the description amendments at issue there. The outcome of G1/25 which can be expected in 2026 will be pivotal for patent applicants and practitioners. The EBA’s ruling could either entrench the EPO’s unique practice or align EPO practice more closely with global standards. Stay tuned as we await a decision that could reshape European patent prosecution and claim interpretation practice.
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