Aligning Claims and Description –
Why G 1/25 Matters for Legal Certainty

A practitioner’s view on description amendments and their impact on legal certainty under the EPC

Christoph D. Schober, Professional Representative before the EPO; part-time Technically Qualified Judge at the Unified Patent CourtThis article reflects the personal opinion of the author in his capacity as a legal practitioner. It does not express any view in his judicial capacity as a technically qualified judge at the Unified Patent Court, nor does it represent the position of any professional body or organisation in which he is involved.

This article discusses the pending referral G 1/25 concerning the adaptation of the description under the EPC. It analyses the legal basis, practical implications, and the broader impact on legal certainty within the European patent system.

Procedural Background

On 29 July 2025, Technical Board of Appeal 3.3.02 issued its interlocutory decision in case T 0697/22See https://www.epo.org/en/boards-of-appeal/decisions/t220697ex1, referring the following legal questions to the Enlarged Board of Appeal under Article 112(1)(a) EPC. The referral was registered as G 1/25:

1. Is the description of a European patent required to be adapted in opposition or opposition appeal proceedings to remove inconsistencies with amended claims?
2. If so, what is the legal basis in the European Patent Convention for this obligation?
3. Does the answer to question 1 differ if the inconsistency arises during examination or examination appeal proceedings?

The referral was officially announced in the Official Journal of the European Patent OfficeNotice from the EPO President concerning referral G 1/25, OJ EPO 2025, A59. and seeks to resolve diverging lines of case law within the EPO - specifically, decisions that require alignment between amended claims and the description versus those that tolerate discrepancies - to promote legal uniformity and procedural predictability.

The Question at Stake

The referral in G 1/25 crystallises a long-standing divergence in EPO case law. Some Boards, such as T 1024/18, require strict consistency between claims and description, whereas others accept certain inconsistencies, for example, when broader embodiments remain in the description but are evidently no longer covered by the amended claims, and the examining division considers that no legal uncertainty arises.

This divergence reaches beyond internal EPO practice. It affects legal certainty for third parties, the integrity of the granted patent, and ultimately the credibility of the European patent system.

The Broader Debate Reflected in the Amicus Curiae SubmissionsThe author acted as first drafter of the amicus curiae submission of the Patentanwaltskammer and participated in the working group preparing the epi submission. The views expressed in this article are strictly personal.

The extraordinary interest in G 1/25 is reflected in the number and scope of the amicus curiae submissions. In total, thirty-nine submissions were filed, amounting to approximately seven hundred pages of argumentationbased on compilation of amicus filings as of 26 February 2026, see https://www.epo.org/en/case-law-appeals/organisation/eba/referrals-pending-enlarged-board-appeal#G125Hydroponics..

A clear majority advocates answering Question 1 in the negative. While the number of submissions is not determinative, it illustrates the practical sensitivity of the issue within the profession. Many of these contributions focus on the absence of an explicit legal basis in the EPC, the one-directional wording of Article 84 EPC, and concerns regarding procedural economy, litigation risk, and the proliferation of auxiliary requests. In this view, potential inconsistencies should be addressed, if at all, through substantive validity analysis and claim interpretation rather than through a structural requirement of adaptation.

A smaller but institutionally weighty group supports an affirmative or qualified affirmative answer. The President of the European Patent Office argues that the internal coherence of the patent text follows from the combined effect of Articles 84 and 69 EPC, and that G 1/24 reinforces this systemic requirement. The Patentanwaltskammer likewise stresses structural consistency, limiting the obligation to cases of genuine technical contradiction. The Institute of Professional Representatives before the European Patent Office adopts a differentiated position, recognising that adaptation may be necessary where genuine lack of clarity arises, while cautioning against formalistic excess.

The divergence of views illustrates that the referral concerns more than a question of drafting practice. It ultimately raises a constitutional question within the EPC framework, namely whether interpretation alone can remedy internal inconsistency, or whether the European patent must meet a structural standard of coherence at the moment it is granted or maintained.

Legal Certainty as the Guiding Principle

In daily practice, clients and third parties rely on the published patent specification to assess risks and plan commercial activities. When the granted claims define one subject-matter, yet the description continues to discuss broader, unqualified embodiments, ambiguity results.

It becomes unclear whether such unclaimed embodiments are definitively excluded, possibly protected under the doctrine of equivalents, or merely editorial remnants. This uncertainty undermines the reliability of the patent as a legal title and increases the risk of costly litigation.

This concern is not theoretical. In proceedings before national courts and the Unified Patent Court (UPC), the description plays a vital role in claim interpretation. The Enlarged Board in G 1/24Decision of the Enlarged Board of Appeal G 1/24, OJ EPO 2025, A60 (“Interpretation of patent claims”). reaffirmed that the description and drawings must always be consulted when construing claims.

The Legal Basis for Adaptation

The obligation to adapt the description is embedded in the internal logic of the EPC. Several provisions, read together, make clear that the claims and description must form a consistent whole.

1. Article 84 EPC provides that “_the claims shall define the matter for which protection is sought_” and “_shall be clear and concise and be supported by the description_.” The requirement of support establishes a substantive link between the claims and the technical teaching presented in the description. Where the description continues to present, as part of “_the invention_,” subject-matter that no longer falls within the amended claims, this link is disrupted. In such circumstances, the specification no longer presents a coherent account of the invention as claimed, and adaptation becomes necessary to restore conformity with Article 84 EPC.
2. Article 69 EPC, together with the Protocol on Interpretation, confirms that the description is integral to determining the extent of protection. The claims cannot be interpreted in isolation; they must be read in the light of the description and drawings. Internal inconsistency between these parts risks distorting the scope of protection, contrary to the intent of Article 69 EPC.
3. Rule 42(1)(c) EPC adds a procedural dimension: the description must disclose the invention as claimed in such terms that the technical problem and its solution can be understood. When claims are amended, the invention “as claimed” changes; leaving outdated embodiments in the description would therefore contravene this rule.
4. Rule 48(1)(c) EPC reinforces this structural requirement by prohibiting statements that are obviously irrelevant or unnecessary under the circumstances. While not every non-claimed embodiment is irrelevant, passages that continue to present excluded subject-matter as forming part of the invention may, in certain cases, fall within this prohibition and require correction.

Taken together, these provisions provide a coherent and sufficient legal basis for requiring adaptation. No new doctrine or interpretation is needed: the EPC itself, through the combined effect of Articles 84 and 69 and Rules 42 and 48, already demands that the patent specification form a single, self-consistent instrument.

Examination vs. Opposition: No Difference in Outcome

Some argue that the adaptation requirement may apply differently depending on whether the inconsistency arises during examination or opposition. The procedural framework indeed differs in the two stages, in particular with regard to the scope of Article 84 EPC in opposition proceedings.

However, from the perspective of legal certainty and third-party reliance, the decisive factor is the final text in which the patent is maintained. Regardless of the procedural route by which amendments are introduced, the patent must ultimately present a coherent and self-consistent specification. The stage of the proceedings may affect the procedural mechanism, but it should not alter the substantive requirement that the maintained text accurately reflects the invention as claimed.

Cost Considerations Are Not a Valid Objection

It has been suggested that adapting the description imposes an unreasonable cost burden on applicants. In my view, this concern is overstated.

Such adaptation is usually a minor editorial task that arises only when the applicant chooses to amend the claims. It is a natural and expected consequence of claim limitation - one that clarifies and strengthens the intended scope of protection. Moreover, the modest effort required is far outweighed by the systemic benefit of ensuring that the granted patent is legally coherent. The cost of not adapting, i.e., the risk of interpretative ambiguity, inconsistent enforcement, and increased litigation, is much higher for both applicants and third parties.

Patent rights confer exclusive legal power. With this privilege comes the responsibility to define the protected subject-matter clearly and consistently. Editorial alignment is therefore part of good practice and an established element of the dialogue between applicants and the EPO.

National Decisions vs. the European Context

While national case law may offer useful reference points, it can only serve as a limited guide for interpreting the EPC framework. National court decisions may have precedent-setting effects, whereas the prosecution history before the EPO typically plays little or no interpretative role.See, e.g., BGH, judgments of 12 March 2002 – X ZR 43/01 (“Kunststoffrohrteil”), GRUR 2002, 511 (headnote 1), and 14 June 2016 – X ZR 29/15 (“Pemetrexed”), GRUR 2016, 921 [35 ff.]: events during prosecution are generally not relevant for claim interpretation; statements made in examination may indicate the skilled person’s understanding but do not form part of the public disclosure.

As a result, the structure and coherence of the granted text, including the alignment between claims and description, carry particular weight in the European context. This underscores the importance of the Enlarged Board’s role in providing a harmonised and authoritative interpretation, particularly where national and institutional practices diverge and where applicants, courts, and third parties alike require legal certainty.

Conclusion

The Enlarged Board in G 1/25 now has the opportunity to bring long-awaited clarity to this issue. It should confirm that adaptation of the description is required where amended claims give rise to a technical inconsistency between the claimed subject-matter and the description as maintained.

Such confirmation would enhance legal certainty, reduce interpretative ambiguity, and preserve the integrity of the European patent system - both during examination and in post-grant proceedings. It would also assist national courts and third parties, who rely on a coherent and unambiguous patent specification to assess infringement risks and determine the boundaries of protection.

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