Why does G 1/25 matter?
Practitioners welcome G 1/25 as it lies at the heart of a very practical debate between applicants working together with their patent attorneys, and EPO examiners: after narrowing the claims, how much of the description must be rewritten? For years, applicants invested significant time, effort, and money adapting sometimes lengthy descriptions, despite the EPC containing no explicit requirement for perfect concordance.
We observe that in about 80 % of EP patent applications, claims evolve during examination, potentially several times. An applicant may narrow them to distinguish the invention from prior art, while the description still contains broader definitions or embodiments from the original application.
This had led to diverging approaches in EPO case law. Some Boards considered Article 84 EPC to provide a basis for requiring the description to be brought into line with amended claims. Others considered that the mere presence of unclaimed subject matter in the description did not necessarily prevent grant.
The Enlarged Board provides the following answer in G 1/25: what matters is not the existence of a difference between the claims and the description, but if this difference leads to non-compliance with the EPC.
A simple example
Consider the following hypothetical example:
A patent application originally claims a product comprising feature A or feature B. During examination, the claim is narrowed to a product comprising feature A.
The description still contains an embodiment directed to a product comprising feature B.
Does that example have to be deleted?
Not necessarily. If it is clear to the skilled person that the feature B embodiment simply falls outside the amended claim, its presence alone does not require adaptation.
The situation is different if the description states that, for the purposes of the invention, the term “feature A” also includes feature B or that feature A is an alternative to feature B. This could create genuine uncertainty as to how the amended claim should be understood.
In that case, the inconsistency may affect compliance with the EPC and would need to be addressed.
Interestingly, according to G 1/25, the embodiment comprising feature B might not be relevant only for determining whether the description should be adapted. According to point 38 of the decision, the technical teaching contained in the description may, in some circumstances, be relevant to the assessment of inventive step. Thus, even if the embodiment comprising feature B clearly falls outside the amended claims and does not create any inconsistency for the purposes of Article 84 EPC, it could still become relevant if its technical content affects the evaluation of the inventive contribution of the claimed invention. This observation reinforces the idea that the description is not merely a background document for claim interpretation but may itself play an active role in the assessment of compliance with EPC requirements.
This key aspect of G 1/25 provides an important missing piece of the legal certainty required for assessing description adaptation, while also highlighting that the relevance of the description may extend beyond issues of formal consistency.
G 1/25 and claim interpretation
The decision should also be read alongside G 1/24, in which the Enlarged Board held that the description and drawings must always be consulted when interpreting claims for the assessment of patentability under Articles 52 to 57 EPC, reinforcing the central importance of the description and drawings.
G 1/25 nevertheless rejects the idea that the description must simply mirror the claims. Examples or embodiments outside the amended scope of the claims do not automatically have to be removed.
A statement left in the description can potentially affect how an amended claim is interpreted under the EPC. As a reminder, iterative claim amendments may confer upon the independent claim a meaning that becomes more complex to ascertain.
This also means that description amendments themselves acquire greater significance. Removing or modifying explanatory passages may affect the way claims are construed in later opposition or potentially, in national revocation or infringement proceedings, where the principles of G 1/24 and G 1/25 may prove influential. This is particularly relevant in light of T 439/22, where amendments to the description ultimately became central to the assessment of compliance with Article 123 EPC. Description adaptation can therefore no longer be regarded as a purely administrative exercise, but should be assessed carefully in view of its potential impact on both claim interpretation and future post-grant challenges.
What does this mean in practice?
Following a significant claim amendment, applicants and patent owners should review the description and drawings with three questions in mind:
How has the meaning of the amended claims evolved?
Does the interpretation of the description or the drawings trigger an inconsistency with the amended claims?
Could that inconsistency affect compliance with the EPC?
If so, adaptation will be required. If a passage merely describes subject matter that is no longer claimed, without creating a legally relevant inconsistency, G 1/25 does not impose a general obligation to remove it. As is apparent from the above, the concept of “inconsistency” endorses a central role. Interestingly, the decision extensively discusses this concept to provide some useful guidance.
Particular attention should be paid to situations where the skilled person could be left in “real doubt” as to the meaning of a claim or as to whether a specific embodiment falls within its scope. The Enlarged Board identifies these situations as examples of inconsistency. However, the precise boundary between a mere clarity issue and a legally relevant inconsistency remains uncertain and will likely require further clarification through future case law. In this respect, G 1/25 does not resolve all questions concerning the relationship between claims and description. It will be interesting to see whether the forthcoming G 1/26 decision provides any further guidance on related aspects of claim interpretation and on the circumstances in which the description may influence the understanding of claim language.
Key takeaways
G 1/25 confirms that description adaptation is a substantive, not merely formal, exercise.
Applicants and patent owners should therefore avoid both extremes: leaving potentially problematic inconsistencies untouched, but also mechanically deleting every embodiment or statement that falls outside amended claims. Superfluous excision from the description may affect claim interpretation, enforcement, or validity assessments at a later stage. Determining the appropriate extent of description adaptation therefore requires careful review by a patent attorney.
For companies managing European patent portfolios, the decision is a good reason to review prosecution practices. Significant claim amendments should trigger a focused review of the description and drawings to identify inconsistencies that could have real consequences under the EPC. The objective is not to achieve a perfectly “clean” description, but to ensure that the description does not undermine the legal position established by the amended claims.
View EPO decision
