In G 1/25, the EPO’s Enlarged Board of Appeal has ruled on the extent of description adaptation following claim amendments, establishing a “conditional middle position” – with legal and practical risks for the practitioner.

Applicants are required to “adapt” the description to the amended claims of a patent application once the claims are allowable. This requirement must be fulfilled in proceedings before the Examining Divisions, the Opposition Divisions, and the Technical Boards of Appeal (TBoA). However, there has been inconsistent case law among the TBoAs on whether and to what extent such description adaptation is necessary. The Enlarged Board of Appeal (EBoA) has now decided the matter in G 1/25, establishing a “conditional middle position” that nevertheless still carries legal and practical risks for the practitioner.

Background: The Adaptation Requirement in Practice

The description adaptation requirement was introduced by the European Patent Office (EPO) to avoid legal uncertainty. Often, patent applications start with a broad, generalized description of the invention, and the initial claims are drafted equally broadly. During prosecution before the Examining Division, claims are usually amended and narrowed, sometimes focusing on only one specific embodiment out of several originally claimed. In the EPO’s view, leaving a broad description alongside narrower granted claims could cause confusion regarding the true scope of protection.

In practice, however, this requirement puts a heavy burden on the applicant. Constant “rewriting” and fine-tuning of the description to match the amended claims consume attorney hours and client budget. Furthermore, some examiners demand excessive deletion of allegedly non-claimed subject-matter, which risks worsening the applicant’s fall-back positions in future proceedings.

Conflicting Case Law on Article 84 EPC

Before this decision, the case law of the Boards of Appeal had developed along two conflicting lines. One line of decisions considers the support requirement of Article 84 of the European Patent Convention (EPC) to demand strict “consistency” between the claims and the description. On that view, passages describing embodiments that are no longer covered by the claims cannot simply remain unchanged: they must either be removed or expressly stated as not forming part of the claimed invention.

A fundamentally different approach was adopted in decisions such as T 1989/18, T 2194/19, and T 1444/20, and was developed in greater detail in T 56/21. These decisions construe the second sentence of Article 84 EPC as imposing a requirement solely on the claims to find support in the description, rather than creating a separate requirement for the description to conform to the claims. According to this reasoning, neither Article 84 EPC nor Rules 42, 43, and 48 EPC provide a legal basis for requiring applicants to amend the description accordingly.

Nevertheless, the Examining Divisions traditionally followed the former approach, requiring extensive adaptation of the description prior to grant.

From T 697/22 to G 1/25: A Conditional Middle Position

This issue arose in concrete terms in T 697/22, the case underlying the referral. There, the referring Board considered the claims of auxiliary request 1E of the proprietor to comply with the EPC, but identified an issue in the description: claim 1 had been limited to a more specific binder definition, whereas paragraphs [0013] and [0016] of the description still referred to broader disclosures. Unable to reconcile the diverging case law on whether such an inconsistency had to be removed, the Board of Appeal referred the matter to the Enlarged Board.

In its resulting decision, G 1/25, the Enlarged Board did not adopt either of the two opposing approaches. Instead, it formulated a new framework establishing a conditional middle position: adaptation is neither universally mandatory for formal concordance nor purely optional, but required only when an unresolved inconsistency leads to a concrete violation of the EPC.

A Restricted Definition of an Inconsistency

As a first step in this new framework, the Enlarged Board set a standard noticeably more relaxed than current Examination practice, ruling that:

“The EPC does not require an adaptation of the description, including any drawings, merely for the sake of formal concordance” (Reason 22).

Indeed, the Enlarged Board acknowledged that in many cases, “what may appear at first to be such an incompatibility can be resolved without difficulty by applying the principles for claim interpretation set out in G 1/24” (Reason 19) and therefore does not need to be removed. Nor is an inconsistency established “merely because the description, including any drawings, contains a technical teaching, examples, or embodiments that do not fall within the claimed subject-matter” (Reason 20).

This principle builds on the “holistic approach” established in G 1/24, under which claim interpretation is the result of reading the claims, the description, and the drawings as a unitary process. For example, if the description contains a specific definition of a term used in the claims that deviates from ordinary usage, reading the claims and the description together may resolve the apparent mismatch without creating an inconsistency.

Correspondingly, G 1/25 defines an inconsistency narrowly:

“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” (Reason 18).

When Must an Inconsistency Be Removed?

Crucially, even when an inconsistency in the above sense is established, it is not always necessary to adapt the description. The Enlarged Board held that the description and drawings must be adapted to amended claims only where:

“[T]he 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” (Headnote of the decision).

The Enlarged Board highlighted the most prominent scenarios where such non-compliance arises. Under Article 84 EPC, if an unresolved inconsistency leaves it genuinely unclear whether particular information, examples, subject-matter, or embodiments are or are not within the scope of the claim, the claim is not supported by the description (Reason 35).

Furthermore, under Article 56 EPC, if a claim has been amended to establish inventive step over the prior art, but the description continues to express a broader technical teaching reflecting the unamended claim that conflicts with the rationale for non-obviousness, that contradictory statement in the description must be removed (Reason 38).

Evaluation: Form Over Function Persists

While G 1/25 provides welcome pushback against purely formalistic amendments, notable legal uncertainty remains. In practice, examiners and representatives will now have to assess two distinct hurdles before amending the description: first, whether a genuine inconsistency exists under G 1/24 principles, and second, whether that inconsistency causes a violation of the EPC.

The standard for establishing an inconsistency remains vague. The Enlarged Board noted that an inconsistency arises if the skilled person reading the claim in light of the description and drawings would be left in “real doubt” as to the meaning of the claim (Reason 19). However, because the term “real doubt” is undefined, it is open to subjective interpretation. A skilled person knows that patent specifications often contain broader disclosures extending beyond the scope of the claims, and understands that it is the claims that define the scope of protection. Against that background, it may be questioned whether statements in the description can create any genuine ambiguity as to what is actually claimed.

Furthermore, national courts have always capably handled the interpretation of patent claims in view of a broader description (as illustrated, for example, in the German Federal Court of Justice’s Occlusion Device decision, BGH X ZR 16/09). There was little need for the EPO to “help” national courts by maintaining such an exhaustive adaptation practice.

Applicants must now allocate resources either to adapt the description extensively or to argue extensively against an examiner’s request. This means more work for attorneys and more costs for applicants with little substantive gain—a classic case of form over function. Most concerningly, forced deletions of subject-matter during EPO prosecution risk being interpreted by courts in later proceedings as a voluntary waiver, with potentially severe consequences for patent enforcement.

Practical Implications

For daily practice, this decision means, in particular, that the description-adaptation practice widely criticized today is unlikely to disappear. If anything, the confirmation of the holistic approach to claim interpretation established in G 1/24 makes the need to adapt the description even more prevalent, not less.

When drafting an application, the future need for description adaptation should already be borne in mind, which makes terminological consistency particularly important. This is especially true for American-style drafting, where the terms used in the claims are often deliberately chosen to differ from those used in the description, and the description contains language that shifts the original meaning of those terms. Such applications will not only be harder to bring into line once description adaptation is called for, but will also carry a substantial risk under Article 123(2) EPC. Particular caution is warranted here.