G 1/25 Decided: Enlarged Board Clarifies When the Description Must Be Adapted

The Enlarged Board of Appeal has now issued its long-awaited decision in G 1/25, providing welcome clarity on one of the most contentious issues in European patent practice: when must a description be adapted to align with amended claims? 

The answer is neither the strict approach adopted by many Examining Divisions in recent years, nor the complete absence of any adaptation requirement. Instead, the Enlarged Board has prescribed a more nuanced position.

On 3 September 2026, the Enlarged Board of Appeal (EBA) issued its decision in G 1/25 (Hydroponics), answering questions referred by Technical Board of Appeal T 697/22 concerning inconsistencies between amended claims and the description.

As discussed in our previous article on the referral, the case arose from diverging lines of EPO case law. One line of decisions held that the description must be adapted to conform to amended claims, whereas another questioned whether the EPC provided any legal basis for refusing an application or patent merely because the description contained subject matter falling outside the scope of the claims.

The Decision

The Enlarged Board answered the referred questions by setting out the following principle:

"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."

The Enlarged Board therefore rejected both extremes of the debate. It confirmed that there is no universal requirement to amend the description whenever the claims are amended. Equally, it confirmed that adaptation may be required where inconsistencies create a substantive EPC problem.

The decision establishes a two-step test:

1. Is there an inconsistency between the amended claims and the description (including the drawings)?
2. Does that inconsistency result in non-compliance with a provision of the EPC, such as Articles 54, 56, 83, 84, 123(2) or 123(3)?

If both questions are answered in the affirmative, adaptation is required.

What Is Meant by an "Inconsistency"?

A key aspect of the decision is the Enlarged Board's explanation of what constitutes an inconsistency between the claims and the description.

The Enlarged Board held that:

"An inconsistency between the claims and the description, and any drawings, exists where one or more statements in the description, including the drawings, suggest an understanding of a claim which is incompatible with the apparent meaning of the claim, and that incompatibility cannot readily be resolved by applying the principles set out in G 1/24."

Importantly, the Enlarged Board acknowledged that many apparent inconsistencies can be resolved through normal claim interpretation. Referring to G 1/24, it reiterated that "the description and drawings shall always be consulted to interpret the claims when assessing the patentability of an invention". As a result, a “true” inconsistency arises only where the skilled person, reading the claims in light of the description and drawings, would be left in “real doubt” as to the meaning of the claim.

The decision also provides welcome clarification that an inconsistency is not established merely because the description contains material that falls outside the scope of the claims. The Enlarged Board expressly stated 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."

This is likely to be one of the most significant aspects of the decision for applicants, given the EPO's recent practice of requiring extensive amendment of embodiments that are no longer covered by amended claims.

Answers to the Referred Questions

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, including any drawings, of the patent, is it necessary, to comply with the requirements of the EPC, to adapt the description, including any drawings, to the amended claims so as to remove the inconsistency?”

If the inconsistency is such as to cause a non-compliance with the EPC, Question 1 is to be answered “Yes”.

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

The answer to Question 2 does not lie in a single provision of the EPC which, in all circumstances, mandates an adaptation of the description, including any drawings, whenever the claims are amended. Whether such an adaptation is required depends on whether, in the circumstances of the case, the inconsistency is such as to result in non-compliance with a requirement of the EPC. Question 2 is therefore to be answered to the effect that the legal basis for any necessary adaptation is the provision of the EPC with which compliance is lacking by reason of the inconsistency in question. 

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, including any drawings, of the patent application?”

EBA held that the role of the description and any drawings in assessing the requirements of the EPC is not dependent on the procedural stage. The Enlarged Board can thus see no reason, in the context of this referral, to treat the proceedings before the examining and opposition divisions differently, and none have been suggested in the submissions. Therefore, the answer to Question 3 is “No”.

Practical implications

The key practical takeaway from G 1/25 is that the EPC does not require the description to be adapted solely for the sake of strict conformity with the claims. As the Enlarged Board stated, "the EPC does not require an adaptation of the description, including any drawings, merely for the sake of formal concordance."

That said, applicants should not assume that description adaptation will no longer be required. Instead of a largely administrative exercise of deleting or labelling embodiments that fall outside the claims, the focus may well shift to a more substantive assessment of whether statements in the description give rise to objections under EPC Articles such as Articles 54, 56, 83, 84 or 123 EPC. As a result, examiners may raise more detailed objections directed to the content of the description itself, and applicants may need to provide more extensive arguments explaining why particular passages can remain or why amendments are appropriate.

The decision provides an example illustrating this point. It explains that where a claim has been amended to establish inventive step under Article 56 EPC, but the description still contains a technical teaching reflecting the broader claim, that particular passage represents an inconsistency and must be amended/removed because it conflicts with the requirement of non-obviousness.

The decision may also have implications beyond examination. Under previous practice, description adaptation was largely associated with Article 84 EPC, which is not a ground of opposition. Following G 1/25, however, the justification for amending the description may increasingly be linked to provisions such as Articles 54, 56 and 123 EPC. This raises the possibility that statements made during examination regarding description amendments could become relevant in post-grant proceedings, providing opponents with additional lines of attack.

In short, G 1/25 rejects the idea that the description must always be amended simply to mirror the claims. Instead, adaptation is only required where an inconsistency results in non-compliance with a substantive provision of the EPC. Although the decision provides a clearer legal basis for description adaptation, it remains to be seen whether it will reduce the amount of amendment required in practice or merely shift the debate from formal consistency to substantive EPC compliance.

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