G 1/25 (description amendments) amicus curiae: The battle lines are drawn
Rose Hughes
G 1/25 (description amendments) amicus curiae: The battle lines are drawn
If you want to start an argument amongst European patent attorneys, just mention description amendments. As the comments on this and other blogs attest, adaptation of the description is a highly divisive issue and the debate can get decidedly heated (with our US colleagues looking on with bemusement). On one side of the debate are those who believe that aligning the description with the claims is crucial for legal certainty. On the other side, are those with the view that mandatory description amendments are unnecessary, costly, and risky for patentees. The issue is now to be considered by the Enlarged Board of Appeal in G1/25 (IPKat). With the deadline approaching for submitting observations to the referral, it is worth taking a look at the submissions so far.
Description amendments: Background
The requirement for the description to be amended in line with the claims is provided in the EPO Guidelines for Examination, and is followed by examiners and Boards of Appeal with varying degrees of strictness. However, a line of case law has emerged from certain Boards of Appeal, according to which there is no legal basis in the EPC for mandatory adaptation of the description (T 1989/18, IPKat). Indeed, one Board of Appeal found the lack of legal basis for the adaptation of the description so unequivocal as to render a referral to the EBA on the issue unnecessary (T 56/21, IPKat). The divergence between the Boards of Appeal on the issue finally led to a referral last year (G1/25, IPKat).
G1/25: Case background
The referral in G1/25 is derived from T 0697/22, involving a patent owned by Knauf Insulation relating to a hydroponics growing medium. The Board of Appeal referred three questions to the EBA asking for clarification on the necessity (or otherwise) of description adaptation in both opposition and examination proceedings:
"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 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?
Question 2: If the first question is answered in the affirmative, which requirement(s) of the EPC necessitate(s) such an adaptation?
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 of the patent application?" (emphasis added)
So far, there have been 4 amicus curiae briefs submitted;
- Michael Schmid, Richardt Patentanwälte (6 October 2025)
- Marcel Kortekaas, EP&C Patent Attorneys (9 October 2025)
- International federation of intellectual property attorneys (FICPI) (6 November 2025)
- Olaf S. Roelands, Patentwerk B.V. (13 November 2025)
Analysis of the amicus curiae
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| Description amendments |
Article 84 EPC: One direction?
A theme in the arguments against mandatory adaptation (notably by FICPI and Schmid) is the directionality of Article 84 EPC. FICPI argues that Article 84 EPC requires claims to be supported by the description, but there is no reciprocal requirement for the description to be supported or constrained by the claims. FICPI thus argues that as long as the claimed subject matter is present in the description, the presence of additional, unclaimed features (e.g., "A comprising B or C" when only B is claimed) does not logically negate that support.
Schmid's submissions align with this view, arguing that "Article 84 EPC operates in one direction only—from the claims toward the specification. It cannot be applied in reverse to exclude unclaimed subject matter from the description. Consequently, the claims take precedence in determining the extent of protection".
Article 69 EPC as legal basis for description adaptation
The debate over Article 69 EPC in the amicus curiae submissions centres on whether the description's role as an interpretive tool necessitates amendment or its preservation. Schmid argues "description adaptation has limited relevance in national infringement proceedings governed by Article 69 EPC and its Protocol. For example, the doctrine of equivalence, as applied in many EPC member states, considers whether elements not explicitly claimed may nonetheless fall within the scope of protection".
By contrast, Kortekaas views Article 69 EPC as a mandate for consistency between the claims and description, arguing that leaving inconsistencies in the text creates legal uncertainty, risks divergent judicial interpretations across different jurisdictions and would "jeopardize the philosophy of harmonization." Meanwhile, Roelands maintains that Article 69 EPC is primarily a guide for infringement courts and does not provide an explicit legal basis for the EPO to require description amendments during the grant or opposition process.
The relationship between G1/24 and G1/25
The recent G 1/24 decision is used by both sides of the argument. In G 1/24, the EBA ordered that the description should always be consulted for claim interpretation. However, the consequences of this for claim interpretation are not as clear-cut as they might have first appeared. The Boards of Appeal have so far interpreted G1/24 as not permitting patentees to use narrowing information in the description to restrict the meaning of otherwise clear claim language (IPKat). On the other hand, one Board of Appeal found that a broad definition in the description could be used to broaden otherwise clear claim language (IPKat). The approach the UPC will take remains unclear, other than that they agree with the EPO that the description should be "consulted" to interpret the claims (IPKat).
Kortekaas uses G 1/24 as a primary reason for supporting the legal basis for mandatory adaptation of the description. According to Kortekaas, "G 1/24 is a new standard which aims to harmonize the proceedings before the EPO with that of the national courts and UPC. Since the description must be consulted to interpret the claims, it is essential that the description has been subjected to a high quality examination. G 1/25 should not undermine the new standard of G 1/24".
Conversely, Schmid argues that G 1/24 proves adaptation is unnecessary. For Schmid, given that courts are now required to use the description for context, they are perfectly capable of seeing that a narrowed claim excludes broader embodiments mentioned in the text, just as they handle prosecution history estoppel.
Interaction with the UPC
A key question following G1/24 is whether the UPC and EPO are aligned on claim interpretation. The impact of G1/25 on the UPC will depend on where the UPC case law settles on this issue. Kortekaas argues that the EPO must mandate description adaptation to ensure legal certainty and avoid divergent interpretations of the claim in the courts. Kortekaas specifically points to the UPC Court of Appeal decision in NanoString v. 10x Genomics (UPC_CoA_335/2023, IPKat), noting its requirement that the description "must always be used" for claim interpretation as a primary reason for the EPO to ensure internal consistency between the claims and description.
However, Kortekaas also notes in a footnote that '[t]he expressions “are always referred to” in Reason 19 and “shall always be consulted” in the Order of G 1/24 are different from the expression “must always be used” that has been used in Headnote 2 of the order of the UPC Court of Appeal of 26 February 2024 in NanoString v. 10x Genomics (as rectified by the order of 11 March 2024). This difference in wording has led some to question the intended meaning of these expressions. It would help if the EBA reflects on this.' (Emphasis added. On past evidence of the EBA's willingness to provide clarity, PatKat won't be holding her breath).
Conversely, Schmid cites the Hamburg Local Division decision in Agfa v Gucci (UPC_CFI_278/2023) as evidence that mandatory adaptation is unnecessary. Schmid argues that Agfa v Gucci established a clear mechanism for handling discrepancies between the description and claims, whereby specifications in the description that are inconsistent with granted claims cannot be used to broaden the scope of protection (IPKat). Schmid quotes Headnote 3 of Agfa v Gucci, according to which: “specifications in the description that are not consistent with the granted claims cannot serve as a basis for a broad interpretation of a claim”.
Risks of adding matter
FICPI argues that forced adaptation can fundamentally alter the legal and technical interpretation of the patent, potentially leading to Article 123 EPC added matter issues. FICPI argues that if the presence of unclaimed subject matter affects claim interpretation, deleting it would change that interpretation, potentially invalidating the patent under Art. 123(2) or (3) EPC in view of Article 69 EPC and G 1/24. (IPKat).
Sufficiency of Disclosure (Article 83 EPC): The risk of under-enablement
FICPI and Roelands also express significant concerns that deleting "non-relevant" embodiments can leave the remaining claimed invention technically hollow, failing the requirement for a sufficient disclosure under Article 83 EPC. FICPI points out that an unclaimed embodiment often contains specific technical details or examples that provide the necessary support for a feature that remains claimed elsewhere. If these details are excised because they are no longer literally encompassed by narrowed claims, FICPI warns that the remaining description might no longer provide enough information for a person skilled in the art to carry out the invention. FICPI concludes that identifying and removing every passage that could never contribute to the interpretation of an amended claim is not only an undue burden but is practically impossible, but doing so risks creating a disclosure issue that could inadvertently invalidate an otherwise valid patent.
The relevance of "claim-like clauses"
The FICPI submission strongly contests the mandatory removal of these clauses, arguing that such a requirement is technically and legally unjustified (IPKat). According to FICPI, features or embodiments presented in the description cannot be confused with the actual claims provided there is no explicit reference to them as "claims". They warn that forced deletion can be detrimental, as these clauses often serve as a vital source of support for Article 123(2) EPC compliance, particularly in divisional applications where the initial set of claims is often appended to the description for precisely this purpose. FICPI submits that this "cleansing" process may unnecessarily harm applicants by removing the very basis they need for future amendments.
Roelands presents a more nuanced middle-ground on claim-like clauses. Roelands argues that regardless of the presence of clauses or not, the description must contain a verbatim definition of the invention or a reference to the claims to satisfy Article 84 EPC. As such, for Roelands, the adaptation of clauses should only be necessary if they render the verbal support of the amended claims ambiguous, such as when a clause presents a full alternative definition of the invention that contradicts the new claims. Otherwise, Roelands argues that if the clauses do not create such ambiguity, no additional adaptation or removal should be required.
Application-as-filed or granted?
In a recent thought-provoking addition to the debate, a recent article by KatFriend Greg Corcoran highlighted an interesting point of claim interpretation in two recent UPC Court of Appeal decisions. Greg points out that in Meril v Edwards and Amgen v Sanofi the UPC appeared to favour the application as filed over the granted specification as the basis for claim interpretation. Greg observes that, by identifying the "objective problem" and construing claims based on the original disclosure, the UPC effectively bypasses description amendments made during grant. By contrast, according to case law of the EPO Boards of Appeal, the description of the patent application is irrelevant for claim interpretation and the claims should be interpreted in view of the granted patent (T 450/20, r. 2.16, IPKat).
Final thoughts
From this Kat's point of view, mandatory adaptation of the description seems entirely unnecessary. As FICPI points out, no other major patent office requires it. Why then has the EPO chosen to dig its heels in on the issue? The official line appears to be that description adaptation is part of the EPO's "focus on quality". However, quite apart from the legal risks pointed out in the submissions, adaptation of the description also unnecessarily increases the costs for the applicant. Indeed, this Kat heard directly from a partner at a top-tier firm (which shall remain nameless) that the billable hours were one reason he remained in favour of the requirement. Although this Kat feels that AI may very quickly remove this perverse incentive, if it has not already done so.
Regardless of where you stand on the issue, G1/25 will be closely watched.
Further reading