G 1/25: Enlarged Board Of Appeal Issues Preliminary Opinion On Amendment Of The Description

The Enlarged Board of Appeal (EBA) has issued its preliminary opinion in case G 1/25. The case concerns whether the description of a European patent application should be amended to address any inconsistencies with the claims. The EPO is unique among major patent offices in its longstanding requirement for the description to be adapted in pre- and post-grant proceedings in such a way. The preliminary opinion is short and does not contain much detail on reasoning, but does provide an indication of how the EBA is currently minded to answer the referred questions.

The three questions referred to the EBA by the referring board of appeal in T 697/22 are set out below, together with comments on the EBA's preliminary opinion in relation to each question. Further information on the background to the present referral can be found in our briefing note on the referring board's decision.

Question 1. 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?

Question 1 essentially asks whether it is necessary to amend the description of a patent such that it is consistent with any amendments made to the claims during post-grant opposition proceedings. The preliminary view of the EBA is that logically, there are only two types of "inconsistencies", namely (i) those that cause a non-compliance with the EPC and (ii) those that do not. If an inconsistency is of type (ii), then no amendment of the description should be necessary. If, however, an inconsistency is of type (i), the EBA preliminarily considers that adaptation of the description is necessary.

The EBA therefore preliminarily considers that it would be appropriate to reformulate question 1 as follows (with amendments shown in underlining):

If the claims of a European patent are amended during opposition proceedings or opposition-appeal proceedings, and the amendment introduces an inconsistency that causes a non-compliance with the EPC 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 that causes a non-compliance with the EPC?

The preliminary answer to the amended question would then be "yes".

Question 2. If the first question is answered in the affirmative, which requirement(s) of the EPC necessitate(s) such an adaptation?

The EBA notes that the referring decision T 697/22 identifies two conflicting lines of EPO case law. A first line of case law considers that Article 84 EPC (which states inter alia that "[The claims] shall be clear and concise and be supported by the description") provides legal basis for requiring the description to be amended for consistency with the claims. A second, divergent, line of case law (notably exemplified by the decision in T 56/21) however sets out that Article 84 EPC only requires that the subject-matter of a claim must be taken from the description of the application, but this does not constitute legal basis for requiring the description to be brought into line with an amended set of claims.

In the preliminary view of the EBA, the "first" line of case law is correct and the "second" line of case law (specifically the conclusions of T 56/21) is incorrect. Thus, the preliminary view of the EBA is that Article 84 EPC requires a patentee to bring the description of a patent into line with an amended set of claims.

The EBA does not provide detailed reasoning for its conclusion in the preliminary opinion. However, the EBA notes that it is of the opinion that the "second" line of case law would be inconsistent with the EBA's recent decision in G 1/24. That decision explained that the description shall always be consulted to interpret the claims when assessing the patentability of an invention. Thus, it would appear that the view of the EBA is that if one must turn to the description to interpret the meaning of the claims, the proprietor should also ensure that the content of the description is consistent with any amendments or limitations made to the claims.

Question 3. 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?

Finally, the referring board noted that although the specific issue before it concerned amendments to a patent in post-grant opposition proceedings, the requirement to amend the description arises routinely during pre-grant examination proceedings. The referring board thus also asked the EBA to rule on whether description amendments are also required during pre-grant examination proceedings.

The preliminary answer of the EBA to this question is simply "no" – the board sees no reason to distinguish between proceedings in examination and proceedings in opposition with regard to description amendments. This is not a surprising conclusion.

The present opinion is only preliminary and is still subject to change: the parties to the case have an opportunity to expand further on their written arguments at oral proceedings before the EBA. As previously reported, these oral proceedings have been scheduled for 8 May 2026. We will await the outcome of those oral proceedings and the final, reasoned written decision of the EBA with interest.