EPO publishes preview of the 2026 European Patent Office Guidelines

The EPO has published a preview of the 2026 versions of its various Guidelines, which will become the official versions on 1 April 2026.  The published previews include:

• Guidelines for Examination in the European Patent Office, under the European Patent Convention (EPC),
• Guidelines for Search and Examination at the EPO as PCT Authority (PCT-EPO),
• Unitary Patent Guidelines (UP).

The EPO also opened its annual public consultation on the Guidelines, welcoming feedback comments by 3 April 2026. Any comments received by 3 April will be taken into consideration when preparing updates for 2027, with involvement of senior EPO staff and external reviewers in a working group which will meet in May 2026 and again later in the year.

If you have recommendations for the EPO for changes to their Guidelines, whether commenting on recent changes or other required changes, you can participate directly via the online survey, or you can email mail@vennershipley.co.uk.

The comments below focus on the Guidelines for Examination in the EPO (i.e. under the EPC) and reference the change-tracked text which is available here. These comments are not intended to be a comprehensive list of all changes to the Guidelines (there are many clarifications) and should not be relied on without the full content of the Guidelines and case law of the EPO.

Substantive changes

Some of the main changes in 2026 are to reflect recent decisions of the EPO’s Boards of Appeal.

Sufficiency and Enabling disclosure

1. G1/23 and Enablement

Part G, Chapter IV section 2 includes this added text:

“A product put on the market before the date of filing of a European patent application cannot be excluded from the state of the art within the meaning of Art. 54(2) for the sole reason that its composition or internal structure could not be analysed and reproduced by the skilled person before that date (G 1/23, order 1). The requirement of reproducibility (enablement, see G1/23, summary V) is inherently fulfilled, as it is satisfied by the skilled person’s ability to obtain and possess the marketed product (G 1/23, reason 73). A product put on the market is thus part of the state of the art and all analysable properties of that product are also part of the state of the art (G1/23, Reasons 74 and 91). In this context, the term “product put on the market” includes man-made products as well as naturally occurring materials (G1/23, Reasons 30). Such products are usually relied upon as prior use, see G-IV, 7.2. Technical information about such a product (e.g. a technical brochure, non-patent or patent literature) which was made available to the public before the filing date forms part of the state of the art within the meaning of Art. 54(2), irrespective of whether the skilled person could analyse and reproduce the product and its composition or internal structure before that date (G 1/23, order 2).”

2. Further medical use example

Part F, Chapter III, section 10 is a new section relating to “Further medical use claims”, where the claimed therapeutic effect is a functional technical feature of the claim (such claims are commonly limited to a known substance or composition for use in a new therapeutic application). This section states:

“In order to meet the requirements of Art. 83, the proof of a claimed therapeutic effect has to be provided in the application as filed, in particular if, in the absence of experimental data in the application as filed, it would not be credible to the skilled person that the therapeutic effect is achieved. An insufficiency in this respect cannot be remedied by post-published evidence (G 2/21).

It is therefore necessary that, at the date of filing, the application render it credible that the known substance or composition is suitable for the claimed therapeutic application and that the therapeutic effect arises as a result of the therapeutic measures defined in the claims. Mere verbal statements are not sufficient to render the therapeutic effect credible. The application as filed must provide either suitable evidence in which the therapeutic effect is demonstrated or scientific reasoning based on known effects for the claimed substance or composition. While it is not necessary for every conceivable treatment falling within the scope of the claims to be therapeutically effective, an undue amount of research should not be needed for the skilled person to arrive at therapeutically effective treatments.”

This is followed by a helpful explanation of when a patent application with a functionally-defined claim directed to a further medical use meets the requirements of Article 83:

“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 Art. 83 if all of the following conditions are met:

(a) specific compounds achieving the claimed function are part of common general knowledge or are known from the prior art or are disclosed in the application as filed in such a way that it is credible that the compounds achieve the claimed function;

(b) the claimed function can be verified by tests or procedures which are adequately specified in the description or known to the skilled person and which do not require undue experimentation; and

(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.”

3. AI example

A relatively minor textual change relating to sufficiency deserves a mention here. In Part F, Chapter III, section 3 entitled “Insufficient disclosure” and starting with a comment that applications which have a fundamental insufficiency are occasionally filed, an example of insufficiency in the field of artificial intelligence was taken from a decision of a Board of Appeal of the EPO. This text has now been edited to the following: “Another example can be found in the field of artificial intelligence if the mathematical methods and training datasets are disclosed in insufficient detail for the skilled person to be able to reproduce the invention without undue burden using common general knowledge over the whole scope of the claim, e.g. if the application does not make it credible that a purpose or technical effect stated in the claim can be achieved (see also G-II, 3.3.1 and F-III, 12).”   

Clarity

Part F, Chapter IV, section 4.1 includes revised wording based on EPO Enlarged Board of Appeal decision G1/24:

“Art. 84 provides that the claims must define the matter for which protection is sought. It further provides that the claims must be clear and concise and supported by the description.

In view of the function of claims in defining the matter for which protection is sought, their clarity is of the utmost importance for reasons of legal certainty. The meaning of the terms of a claim must, as far as possible, be clear for the skilled person from the wording of the claim alone (see also F-IV, 4.2). There should be no doubt as to which subject-matter is covered by the claims. The skilled person should be able to establish the scope of the claim without undue burden. Otherwise, the claim lacks clarity.

The requirement that the claims must be clear applies to individual claims, i.e. to independent and dependent claims alike, and also to the claims as a whole. Given the differences in the scope of protection which may be attached to the various claim categories, the division must ensure that the wording of a claim leaves no doubt as to its category.

The correct response to any lack of clarity in a claim is amendment (G 1/24; see also F-IV, 4.2 and F-IV, 4.3).”

Part F, Chapter IV, section 4.2 “Interpretation” includes the following new text:

“The claims are the starting point and the basis for assessing the patentability of an invention under Arts. 52 to 57. The description and any drawings are always referred to when interpreting the claims, and not just in the case of a lack of clarity or ambiguity (G 1/24).

However, when assessing patentability, the description and drawings cannot be relied on to read into the claim a restrictive feature not suggested by the wording of the claim.

If, on the other hand, the description provides a special broad definition of a term used in a claim, the claim must be interpreted in the light of that broad definition when assessing patentability, provided this interpretation is technically meaningful.”

Part F, Chapter IV, Section 4.7.2 has also been amended to state that if the application suggests that terms such as “about”, “approximately” or “substantially” extends the interval claimed by a value or range outside the error margins of the measurement system or manufacturing/other tolerances, this “leads to an objection under Art. 84 because the presence of this wording raises doubts as to which subject-matter is covered by the claims and thus prevents the skilled person from establishing the scope of the claim.”

We are pleased to see the explicit confirmation in Part F, Chapter IV, section 4.22 that “Broad claims are therefore not unclear per se. In particular, the clarity of a claim is not affected by the mere breadth of a term contained in it, if the meaning of the term is clear to the skilled person”. Section 4.22 goes on to explain that “However, objections to such claims may be raised for various reasons. A broad claim lacks clarity if the skilled person cannot determine the demarcation of the scope of the claim without undue burden. Moreover, where there are discrepancies between the claims and the description, the claims may not be supported by the description (Art. 84) and also the invention may not be sufficiently disclosed over the whole of the broad field claimed (Art. 83) (see T 409/91, F-IV, 6.1 and F-IV, 6.4).” The last sentence appears to be a softening of the previous wording, which suggested that such discrepancies would in most cases lead to a lack of sufficiency.

Patentability of antibodies

Having significantly amended the Guidelines on patentability of antibodies in recent years, the 2026 change is a small one. Part G, Chapter II, section 6.2 “Inventive step of antibodies” has this added text: “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 is a helpful addition.

Oppositions

Part D, Chapter VI, section 7.1 has been expanded to explain when decisions may be made immediately by EPO Opposition Divisions without oral proceedings, with examples. We will assess the suitability of the described conditions and procedures with interested clients.

Part E, Chapter VI, section 2.2.1 regarding new facts and evidence includes this new comment:

“When considering exercising its discretion to refuse to admit a further auxiliary request under Rule 116, the opposition division must first review the contents of the request. This is done to ensure that the review includes an assessment of whether the amendments are a fair attempt to overcome the objections and whether the request is prima facie allowable.

Refusing any further amendment may be appropriate if there are signs of procedural abuse, for example if it becomes evident after various unsuccessful amendments that the proprietor is not seriously trying to overcome the objections but is only delaying the procedure.

In order to prevent the subsequent filing of various consecutive requests, the division may ask the proprietor to simultaneously present the complete set of requests addressing a specific issue that has already been discussed.”

Part E, Chapter VIII, section 5 discusses acceleration of opposition proceedings, if requested by one of the parties when an action for infringement or revocation of a European patent is pending before the Unified Patent Court or the national court of competent authority of an EPC contracting state. A new paragraph has been added:

“For reasons of legal certainty, the accelerated processing of opposition proceedings is maintained even if the EPO is informed about the termination of parallel court proceedings. However, if the information about the termination of parallel court proceedings reaches the EPO before it invites the proprietor under Rule 79(1) to submit observations, the opposition proceedings will not be accelerated. In such a case, even though the EPO has already informed the parties about the intention to accelerate the opposition proceedings, the acceleration has effectively not started and there is no longer any reason for accelerated proceedings. The parties will then be informed that the opposition proceedings are not being accelerated.”

A selection of other changes

Multiple changes have been made in an effort to make the Guidelines as clear and complete as possible.

Parts A and C

The Guidelines at Part A, Chapter IV-4 reflect the 1 October 2025 confirmation that electronic filing of colour and greyscale drawings is now permitted, including for European divisional applications. This was a welcome change. However, drawings filed to remedy deficiencies notified by the Receiving Section must adhere to the format of the original drawings (i.e. they may contain colour or greyscale only to the same extent as the original drawings.

There is a large section providing guidance on the practice currently followed by the EPO when acting as a designated or elected office in the European regional phase of the PCT, in Part A (Chapters XII, XIII, XIV and XV). This has been moved from Part E of the Guidelines. It explains Article 153 EPC and its implementing regulations (Rules 159 to 163 and Rules 70a(2) and 141). Additional sections at Part C, Chapter II, sections 1.2.1 to 1.2.2.1 helpfully explain the different procedures for Euro-PCT applications with and without a supplementary European search report, and the option to accelerate proceedings by waiving the right to receive a specific communication and then proceeding directly to the supplementary European search. These sections provide a very clear explanation of established EPO procedures.

Another helpful addition is in Part C, Chapter III, section 3.2.4 which explains the procedures for re-evaluation of the unity requirement in substantive examination for applications filed directly at the EPO and for Euro-PCT applications for which an EPO search is carried out. This reminds us that applicable principles are set out in the EPO Enlarged Board of Appeal decision G2/92 and explains that fee refunds will sometimes be available or additional searches may be carried out, if an earlier finding of lack of unity was incorrect, but also explains when Examiners can require an applicant to excise unsearched subject matter from the claims.

Part C, Chapter III, section 4 confirms that communications under Rules 161, 162 and 70a are not regarded as the “first communication from the Examining division”. This has been clarified because of the important principle that the Examining Division will only issue a negative decision or a summons to oral proceedings as its first communication in exceptional circumstances, and there will normally be at least one substantive examination report following an applicant’s response to the search opinion before a negative decision or summons issues. Also in Part C, Chapter III, new section 4.1.3 explains that the first communication from the Examining Division will usually be based on the International Preliminary Examination Report and the applicant’s response to it (which may change the EPO’s opinion or may introduce new deficiencies), when that IPER was drawn up by the EPO. Also, examination reports drawn up by other IPEAs must be examined and sound reasoning in those reports must not be disregarded.

There is a helpful new reminder to Examiners in Part C, Chapter IV, section 3 which respects the applicant’s right to oral proceedings: “If the examining division is considering refusing the application immediately because the applicant has not dealt with all the main objections and there is no prospect of overcoming them, due care should be taken to verify that there is no pending request for oral proceedings on file” and if a request for oral proceedings is on file, “oral proceedings must be held” (as determined by decision J12/15). It is very important to request oral proceedings, to avoid waiving the applicant’s right to attend oral proceedings before a refusal. For some applications, written submissions and oral proceedings after receiving a summons can be essential for success at the EPO, and this opportunity is increasingly important now that EPO policy is to try to achieve a resolution with as few examination reports as possible.

Part C, Chapter V, section 4.10 explains the procedure for a summons to oral proceedings following repeated requests for amendments after an EPO approval of text, in response to a second or subsequent communication under Rule 71(3) EPC, and the possibility of refusal if there is no agreed text at the end of oral proceedings.

Part C, Chapter VII, section 3.3 already noted that email exchanges should be documented in the EPO’s publicly accessible file. This section now adds that “it is not necessary to remove personal data (such as email addresses, postal addresses or telephone numbers) from emails annexed to the minutes of personal consultations unless there is an explicit request”. The desire for transparency for communications during consultations should be kept in mind by applicants and their representatives, as should the need for a request if personal data should be removed/redacted.

Less helpful is an addition to Part C, Chapter III, section 2, which states that any amendment “must comply with the requirements under Rule 49(2) as determined by the President in the decision dated 7 July 2025 on the presentation of application and other documents (OJ EPO 2025, A49)”. We believe this amendment is less clear than the changes made to other sections, as this brief addition to the Guidelines is referencing Rule 49(2) which merely states “The President of the European Patent Office shall determine the presentation requirements of documents making up the application”, and currently requires applicants to refer to a number of different decisions of the EPO President from 2022 and 2024. Also, Part C, Chapter IV, section 5 specifies a short deadline of only 2 months for resolving any non-compliance before the application will be deemed withdrawn or refused or a summons to oral proceedings issued, so clarity is important here.  We congratulate the EPO on investing in an open consultation and thorough review process that allow us to recommend improvements to any sections that should be clarified or updated.

Part E

Part E, Chapter III, section 8.11.1 includes this existing comment indicating a reluctance to postpone oral proceedings for all first instance proceedings before the EPO (the Boards of Appeal have their own rules, but are also reluctant to postpone): “Oral proceedings in examination, limitation or opposition are intended to bring the proceedings to a close, and parties are expected to prepare themselves fully. The division will therefore normally refuse any request from a party that the proceedings be postponed or continued in writing”. This is now followed by the helpful addition: “In exceptional cases, if a new and major objection is unexpectedly introduced shortly before or at the oral proceedings, and the applicant or proprietor cannot reasonably be required to make the necessary amendments there and then, a request for postponement or to continue in writing should be granted”.

Part E, Chapter III, Section 10.1 includes an expanded comment about use of sound recordings and AI:

“Sound recordings are made where evidence is taken (E-IV, 1.7). The recording is kept until the end of any possible proceedings before the EPO. Sound recordings are also made when minutes of oral proceedings held by videoconference before examining and opposition divisions are drawn up with the assistance of artificial intelligence (AI) (OJ EPO 2025, A32). These recordings will be deleted once the minutes of the oral proceedings are issued to the parties to the proceedings. Where sound recordings are made of the taking of evidence or for AI-assisted minutes, copies of the recordings are not made available to the parties”.

There is also a reference to use of the recording functionality of a videoconferencing tool in the taking of evidence in Part E, Chapter IV, section 1.7.

Part E, Chapter VIII, section 1.2 explains which types of objections raised in examination reports and telephone minutes are considered substantive and justify a 4 month time limit, which by omission tells us which other objections are not considered to justify a 4 month response period.  Substantive issues include the exclusions and exceptions from patentability, novelty, inventive step, unity, sufficiency, clarity and unallowable added subject matter, as well as the deletion of redundant features from the claims. The Examining Division will usually set a time limit of only two months for adaptations to the description, if requested separately from an approval communication under Rule 71(3) EPC.

Part E, Chapter VIII, section 4.1 “Accelerated search” has been deleted, as this option is no longer available to applicants. The EPO has concluded that the consistent timeliness of its searches removes the need for accelerated searches.

Use of the EPO’s MyEPO features and AI tools

Part C, Chapter VII, section 2.6 has been clarified and expanded and sections 2.6.1 and 2.6.2 have been added to explain how a secure shared area can be used by an applicant and an Examiner to jointly edit an uploaded document during a consultation or in preparation for an Examiner consultation, with the applicant or their European representative accessing the shared area from MyEPO.  We have found Examiner consultations to be a very helpful option for European patent attorneys to work efficiently with EPO Examiners, and we believe the interactive option and this clarification of the legal and procedural framework are helpful.

On page 11 of the up-front General Part of the Guidelines, expanded Section 5 on ‘The use of artificial intelligence’ states:

“The parties are responsible for the content of their patent applications and submissions to the EPO and for complying with the requirements of the EPC and/or PCT regardless of whether a document has been prepared with the assistance of an artificial intelligence (AI) tool.

Artificial intelligence can improve the quality and efficiency of the EPO and may support its work in many areas. While leveraging AI, the EPO remains mindful of the ethical and legal considerations. Its dedicated AI policy (see epo.org/web/about-us/transparency-portal/en-epo-ai-policy.pdf) clearly defines roles, responsibilities and procedures to ensure a human-centric approach.”

This reiterates that the parties (and their European representatives) remain fully responsible for their patent applications and submissions to the EPO, and of course patent offices must also strictly maintain quality when using AI.