The EPO’s Enlarged Board of Appeal issued its long-awaited decision on the adaptation of the description on September 3, 2026.

The question addressed therein is of great practical importance because it concerns all European patent applications and patents where a claim has been narrowed in scope: Does such a restriction necessitate an amendment to the description to remove an inconsistency between the narrower claim and the original language of the description?

For decades, the EPO required the description strictly to be brought in line with such a narrower claim, especially if a claim limitation was originally described as “preferred” or “optional” but was then made a mandatory feature of the main claim. Also, concrete examples which no longer fall within the scope of the narrower amended claim needed to be expressly marked as not being according to the invention or deleted altogether.

More recently, however, some Boards of Appeal decided that no such adaptation was necessary (mainly because there was no express legal basis for such a requirement).


In July 2025, a Board of Appeal sought to resolve this divergence in the case law by referring the following questions to the Enlarged Board of Appeal:

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?
(Questions as referred by the Board of Appeal in interlocutory decision T 697/22.)

Those who hoped that the Enlarged Board of Appeal would provide an answer that leaves no questions unanswered may be disappointed. The Enlarged Board of Appeal decided as follows:

If the claims of a European patent, or patent application, are amended during proceedings before the departments of the EPO, or in appeal proceedings, and the amendment introduces an inconsistency between the amended claims and the description, including any drawings, of the patent, or application, and because of that inconsistency Articles 52 to 57, 76(1), 83, 84, 123(2) or 123(3) EPC are not complied with, it is necessary to adapt the description, including any drawings, to the amended claims so as to remove that inconsistency.

Thus, in essence, the Enlarged Board of Appeal answered the above questions as follows:

Question 1:
An inconsistency between the amended claims and the description need only be removed where, and to the extent that, it leads to non-compliance with a requirement of the EPC. In the Board’s words: “It follows that the necessity to adapt the description or any drawings is not a consequence of the existence of an inconsistency as such, but arises only where, and to the extent that, the inconsistency has legal significance because it leads to non-compliance with a requirement of the EPC.” (Reasons, point 43)

Question 2:
The legal basis for any necessary adaptation is the particular provision of the EPC with which compliance is lacking by reason of the inconsistency; the Order names Articles 52 to 57, 76(1), 83, 84, 123(2) and 123(3) EPC as the provisions that may be engaged.

Question 3:
No, the position is the same in examination and in opposition proceedings.
So the Enlarged Board of Appeal neither approved the long-established practice of requiring strict adaptation, nor the more recent line of decisions that held that no adaptation was needed at all.

 

Rather, a first review of the decision suggests that the Board takes a middle line, according to which the description must be adapted to the amended claims only insofar as an inconsistency remaining in the description would prevent the patent – or the application – from complying with a specific requirement of the EPC. That is the case, in particular, where the skilled person would be left in “real  doubt” as to the meaning of the claim, or where the remaining passage bears on novelty, inventive step, sufficiency of disclosure or added subject-matter. Amendment for the sake of formal concordance alone is no longer required.

The Board built its answer squarely on its earlier decision G 1/24 on claim interpretation. An “inconsistency” now exists only where a statement in the description suggests an understanding of a claim that is incompatible with the claim’s apparent meaning “and that incompatibility cannot readily be resolved by applying the principles set out in G 1/24” (G 1/25, point 18); what still requires adaptation of the description is an inconsistency where the skilled person “would be left in real doubt as to the meaning of the claim” (point 19). Crucially, the Board confirmed that “An inconsistency is not established merely because the description, including any drawings, contains a technical teaching, examples, or embodiments that do not fall within the claimed subject-matter.” (point 20), and that “The EPC does not require an adaptation of the description, including any drawings, merely for the sake of formal concordance.” (point 22). Any amendment that is required must therefore be tied to the specific EPC provision that is not complied with, rather than to a general “tidiness” requirement.

However, it remains unclear what exactly “real doubt” and “not readily resolved” will mean in a given case.

While some adaptations that the old practice would have considered necessary may no longer be needed (because the remaining inconsistency does not lead to “real doubt” as to what the claims mean), the adaptation of the description may actually become a more complex task and may result in more controversy between applicants and examiners (and especially between patent proprietors and opponents!).

In practice, applicants and proprietors can now rely on the Enlarged Board of Appeal decision to resist generic requests to bring the description “into conformity” with amended claims and may ask which provision of the EPC is actually infringed. The trade-off is that every amendment to the description could now be seen to depend on a substantive requirement such as inventive step. That implied reasoning (and the amendments themselves) may later be relied upon when the claims are interpreted after grant, whether before the EPO, national courts or the Unified Patent Court. Especially a deletion might even be argued to be an acknowledgement that the deleted passage affected the scope of the claim.

So the conclusion from the decision may be twofold: there is more room to resist purely formal amendment requests, but each amendment that is actually made deserves careful thought, because fewer amendments may now carry greater consequences.

In any case, it will be interesting to see how the examining and opposition divisions apply the present decision in practice.