Previewing the 2026 EPO Guidelines for Examination

Products on the Market: G 1/23 

One of the most significant amendments concerns the treatment of commercially available products as prior art. This story has been subject of some of our earlier articles here and here. Part G, Chapter IV, Section 2, has been revised to reflect the Enlarged Board's ruling in G 1/23. According to the updated guidelines, a product placed on the market before the filing date of a European patent application cannot be excluded from the state of the art under Article 54(2) of the European Patent Convention (EPC) solely because the skilled person could not analyse and reproduce its composition or internal structure prior to that date. 

The requirement of reproducibility — a cornerstone of enabling disclosure — is deemed to be inherently satisfied by the ability of the skilled person to obtain and possess the marketed product (G 1/23, Reason 73). Consequently, all analysable properties of such a product are part of the state of the art (G 1/23, Reasons 74 and 91). The term "product put on the market" encompasses man-made products and naturally occurring materials (G 1/23, Reason 30). Technical information relating to such products, including technical brochures, non-patent literature, and patent literature made publicly available before the filing date, constitutes prior art under Article 54(2), regardless of whether the skilled person could reproduce the product. 

This has significant practical implications: Applicants must file patent applications before any public disclosure, product launch, or publication of technical materials because such acts constitute citable prior art, regardless of the reproducibility of the disclosed subject matter. 

Further Medical Use Claims: G 2/21 

Part F, Chapter III, Section 10 introduces a new section dedicated to sufficiency of disclosure for further medical use claims. These are claims directed to a known substance or composition for use in a new therapeutic application where the claimed therapeutic effect is a functional technical feature. 

Consistent with G 2/21, the Guidelines confirm that proof of the claimed therapeutic effect must be provided in the application as filed. Post-published evidence cannot remedy an insufficiency in this respect. The application must provide either experimental data demonstrating the therapeutic effect or scientific reasoning based on the known effects of the claimed substance or composition. Mere verbal assertions are insufficient. 

“A claim directed to a further medical use wherein the active pharmaceutical agent is defined only in terms of functional features meets the requirements of Article 83 EPC if the following conditions are met: 

(a) specific compounds that achieve the claimed function must be part of common general knowledge or are known from the prior art or must be disclosed in the application as filed in a manner that makes it credible that the compounds achieve the claimed function; 

(b) The claimed function must be verifiable by tests or procedures which are adequately specified in the description or are known to the skilled person and which to not require undue experimentation. 

(c) The application as filed shows that the claimed function is causal for the solution of the problem underlying the invention, such that it is credible that any compound achieving the claimed function is suitable for the claimed therapeutic application.” 

This three-part test provides a structured framework for assessing sufficiency in the pharmaceutical and biotechnology sectors, where functional claiming is prevalent. 

Artificial Intelligence: Insufficiency Example 

Part F, Chapter III, Section 3 has been updated to include a revised example of insufficiency in the field of artificial intelligence. The updated text clarifies that an AI-related disclosure may be insufficient if the mathematical methods and training datasets are not disclosed with enough detail for a skilled person to reproduce the invention across the entire scope of the claim, particularly if the application does not credibly demonstrate that the stated purpose or technical effect can be achieved. 

Claim Interpretation: G 1/24 

The question of whether and to what extent the description and drawings can be consulted to interpret claims for purpose of patentability was addressed by the Enlarged Board of Appeal in G1/24. We reported previously on the referral, preliminary opinion and decision. 

With the 2026 EPO Guidelines,  significant changes have been introduced to claim interpretation practices in response to G 1/24. Part F, Chapter IV, Section 4.2, now expressly states that the description and drawings are always consulted when interpreting the claims, not just in cases of ambiguity or lack of clarity. This marks a departure from the previous "claims-only" approach, aligning EPO examination practice more closely with the interpretive methodology of the Unified Patent Court (UPC) and national courts. 

However, the guidelines impose an important limitation: The description and drawings cannot import a restrictive feature into a claim if that feature is not suggested by the claim's wording. Conversely, if the description provides a broad definition of a term used in a claim, that definition governs the claim's interpretation for patentability purposes if the definition is technically meaningful. 

Section 4.1, updated to cite G 1/24, further confirms that the correct response to any lack of clarity is amendment of the claim. Section 4.22 explicitly states that broad claims are not inherently unclear: the clarity of a claim is not affected by the breadth of a term if its meaning is clear to a skilled person. A broad claim lacks clarity only when the skilled person cannot determine its scope without undue burden. Discrepancies between the claims and the description may result in objections under Articles 84 (support) and 83 (sufficiency). However, the 2026 wording softens the previous suggestion that such discrepancies would lead to a finding of insufficiency in most cases. 

The practical consequence for applicants is that description language directly affects claim scope during examination. Applicants should ensure consistency between the language of the claims and the description. They may also be better positioned to challenge unduly narrow interpretations of the claims by referencing the description. 

Patentability of Antibodies 

Part G, Chapter II, Section 6.2 has been supplemented with the following addition regarding the inventive step of antibodies: “In addition, subject-matter relating to antibodies can be inventive if the application overcomes technical difficulties in generating or manufacturing those antibodies. A novel type of functional antibody format may also be considered inventive”. This addition provides useful guidance in a technically complex field where assessments of inventive step have historically been contentious. 

Opposition Proceedings 

Several procedural amendments affect opposition practice. Part D, Chapter VI, Section 7.1, has been expanded to clarify the conditions under which Opposition Divisions may issue decisions without oral proceedings. 

Part E, Chapter VI, Section 2.2.1, introduces guidance on exercising discretion to refuse further auxiliary requests under Rule 116 EPC. First, the Opposition Division must review the content of any such request to assess whether the amendments constitute a genuine attempt to overcome the objections and whether the request is prima facie allowable. Refusal may be appropriate when there are signs of procedural abuse, such as successive unsuccessful amendments indicating that the proprietor is not attempting to genuinely overcome the objections, but rather delaying proceedings. To prevent the sequential filing of multiple requests, the division may require the proprietor to present all requests addressing a specific issue at once. 

Part E, Chapter VIII, Section 5, addresses accelerating opposition proceedings when infringement or revocation actions are pending before the Unified Patent Court or a national court. A new paragraph clarifies that accelerated processing is maintained even after the EPO is informed of the termination of parallel court proceedings, unless that information is received by the EPO before it invites the proprietor, under Rule 79(1) EPC, to submit observations. In this case, acceleration will not be initiated. 

Artificial Intelligence at the EPO 

The 2026 Guidelines address AI use in three distinct contexts. The General Part, Section 5, reaffirms that parties and their European representatives bear full responsibility for the content of patent applications and submissions, regardless of whether AI tools were used in their preparation. This position is consistent with the generative AI guidelines issued by epi in 2024. 

Part E, Chapter III, Section 10.1 introduces new provisions on using AI to draft minutes of oral proceedings conducted via videoconference before Examining and Opposition Divisions. Sound recordings will be made to support AI-assisted minute-taking; however, these recordings will not be made available to the parties and will be deleted upon issuance of the minutes. Given the well-documented risk of AI-generated inaccuracies, practitioners are advised to maintain their own detailed notes from proceedings and carefully review EPO-issued minutes for accuracy. 

Selected Procedural Changes 

Additional noteworthy changes include the following: 

- The formal confirmation that electronic filing of color and grayscale drawings is permitted as of October 1, 2025, including for divisional applications (Part A). This change has been desired for a long time. 

- The deletion of the “Accelerated Search” option under the PACE program (Part E, Chapter VIII, Section 4.1), which the EPO considers unnecessary given the consistent timeliness of its searches. 

- Clarifications regarding the right to oral proceedings in examination (Part C, Chapter IV, Section 3), reminding Examiners to verify whether a request for oral proceedings is on file before issuing a refusal. 

This text is based exclusively on the EPO's published preview of the 2026 EPO Guidelines and commentary thereon. It does not constitute legal advice. If you have any questions regarding the EPO Guidelines, please do not hesitate to contact us at info@dcp-ip.com.