Preliminary Opinion Of The Enlarged Board Of Appeal On Description Amendments (G 1/25)

A preliminary opinion of the Enlarged Board of Appeal has issued in G 1/25, the referral regarding amendment of the description when inconsistencies arise after amendment of the claims.

Three questions were referred in G 1/25 and the Enlarged Board of Appeal have indicated that their current thinking is to answer the questions as follows:

1. In opposition proceedings, amendment is required to remove any non-compliance with the European Patent Convention.
2. Article 84 EPC provides basis for requiring description amendments to remove inconsistencies following claim amendments.
3. There should be no difference between opposition and examination proceedings in the context of the referral.

First question

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?

The Enlarged Board of Appeal interpreted this question broadly and noted that different types of inconsistencies are possible. Some inconsistencies would fail to result in a non-compliance with the EPC, in which case amendment would not be required. Other inconsistencies would result in a non-compliance with the EPC, in which case amendment of the description and/or the claims would be required.

The Enlarged Board of Appeal were very thorough in providing reasoning for this obvious piece of logic, and illustrated that it followed by rewriting the first question as:

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?

So, the Enlarged Board of Appeal currently believe that if an inconsistency gives rise to non-compliance with the EPC, that inconsistency should be removed.

Second question

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

Fundamentally, this referral arises from a split in case law regarding the need for description amendments. A first line of case law suggests that Article 84 EPC provides basis to require amendment of the description to remove inconsistencies with the claims.

A second and more limited line of case law suggests the opposite, of which the decision in T 56/21 presents the most detailed arguments. The Board of Appeal in T 56/21 believed that the clarity requirement of Article 84 EPC applied to the claims but not to the description, and that the description was not relevant to determining the clarity of the claims.

In the preliminary opinion, the Enlarged Board of Appeal say that they are currently of the view that many of the conclusions of T 56/21 are inconsistent with the decision in G 1/24 and its underlying reasoning. G 1/24 says that the description should always be consulted when interpreting the claims. This implies a link between the claims and description, and suggests inconsistencies between the description and amended claims may give rise to a lack of clarity contrary to Article 84 EPC.

That said, some recent decisions coming out of the Boards of Appeal suggest this link may not be very strong. In some cases, it appears that the Board consulted the description but disregarded any inconsistencies in favour of adhering to the principle of the primacy of the claims.

In any event, the Enlarged Board of Appeal are currently of the view that the first line of case law should be followed. That is Article 84 EPC provides basis for requiring amendment of the description to remove inconsistencies with amended of the claims.

Third question

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?

As is to be expected, the Enlarged Board of Appeal see no reason to draw a distinction between opposition and examination proceedings in the context of the referral.

Takeaway

This preliminary opinion suggests that we can expect a decision endorsing:

1. a requirement to make description amendments to remove inconsistencies with amended claims to meet the requirements of Article 84 EPC, and
2. that this will apply both to examination and opposition proceedings (including appeals from examination and opposition decisions).

The oral proceedings will take place on 8 May 2026, at which time we may gain more insights into the direction of the eventual written decision.

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