“These questions are not only decisive for the current case, they are also fundamental questions of law that affect the practice of the boards and all other departments of the EPO.” (T 0697/22, R21.4).

The need for description amendment

Patents granted by the European Patent Office (EPO) can be opposed by a third party. This may result in the patentee needing to amend the claims to be more limited, in order to overcome an objection and have the patent maintained.

However, there is a chance that such maintained amended claims may then be inconsistent with the description of the patent as originally granted. For example, the description might state that the invention includes embodiments which are no longer within the scope of the maintained amended claims.

Common practice before the EPO is that the description is therefore "adapted", usually at the end of the opposition proceedings, to be in line with the maintained amended claims.

For much the same reasons, later stages of examination proceedings where the claims have been amended also commonly tend to involve the amendment of the description, to be in line with the allowed claims.

However, some recent Board of Appeal decisions have questioned the legal basis for this practice.

This has led to the following questions being referred to the Enlarged Board of Appeal in G 1/25:

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

In short:

1. Does one need to amend the description to be consistent with amended claims maintained following opposition proceedings?
2. What would be the legal basis for this requirement?
3. Would this be any different during examination proceedings?

Why these questions have arisen now

The questions referred in G 1/25 stem from the Board of Appeal decision T 0697/22, in which amended claims were maintained following opposition proceedings, with a more limited definition of an “organic binder” than the claims as granted.

However, the description in this case included passages indicating that the binder used in the invention was not as limited as the binder recited in the claims maintained by the Opposition Division. As such, there were considered to be inconsistencies between the maintained claims and the description as granted.

The Board of Appeal then discussed in some detail the case law regarding the need to adapt the description, and considered that there are two clearly diverging lines of case law.

First line: most commonly followed, finding that there is a need to adapt the description. This derives from various sources of legal basis, including Article 84 EPC (clarity, support) or Rule 42 EPC (content of the description), alone or in combination with other legal provisions.

Second line: recent decisions in examination-appeal proceedings, finding that there is no need to adapt the description, because there is no legal basis for such a requirement. Article 84 EPC and other provisions are rejected for not providing the requisite legal basis.

In addition, the Board of Appeal referred to the UPC Hamburg local division decision AGFA NV v Gucci Sweden AB et al. This decision upheld a patent with a broader description than the maintained claims, but decided that this inconsistent description could not be used to interpret more limited claims.

This appears to be a clear instance of diverging case law, leading to the need to refer these questions to the Enlarged Board of Appeal.

It will be interesting to see whether the Enlarged Board of Appeal in G 1/25 will reinforce the traditional approach that has long determined the general practice before the EPO, or will be sympathetic to the more recent "radical" decisions that question the legal foundations of description amendment.

If you would like to be notified of updates on the referral in G 1/25, and what it means for European patent practice, you can sign up for our IP news and communications at www.dyoung.com/subscriptions.

Referral to the Enlarged Board of Appeal

View the communication dated 29 July 2025 from the EPO Boards of Appeal.