2026 EPO Guidelines Updates: Part 1

The European Patent Office (EPO) has published a preview of the 2026 edition of the Guidelines for Examination, which will enter into force on 1 April 2026. 

The 2026 update introduces several substantive revisions that are likely to be of practical relevance to applicants and practitioners before the EPO.

In view of these developments, we will be releasing a series of articles that examine the most significant amendments to the 2026 Guidelines. Each article will focus on a specific area in which the guidance has been revised, outlining the nature of the changes and considering their potential implications for practice. 

Novelty 

1) New approach to selection inventions (Part G, Chapter VI, section 7)

One of the most significant updates concerns the assessment of novelty for selection inventions, such as the selection of a sub-range from a broader numerical range disclosed in the prior art. 

Under previous practice, the EPO applied several specific criteria developed in case law. In particular, a selected sub-range was considered novel only if it was:

• Narrow compared to the known range
• Sufficiently far removed from specific examples disclosed in the prior art, and
• Not something the skilled person would “seriously contemplate” working within. 

The 2026 Guidelines abandon these traditional tests. Instead, the assessment now follows the general novelty standard applied elsewhere in EPO practice - namely, whether the claimed subject-matter is clearly and unambiguously disclosed in the prior art. This revision simplifies the legal framework and aligns the treatment of selection inventions with the broader “gold standard” reflected in established EPO case law (for example, G2/10).

2) Clarification on marketed products as prior art (Part G, Chapter IV, section 2)

The Guidelines have also been updated to reflect the Enlarged Board of Appeal Decision G1/23, which concerns products placed on the market. 

Traditionally, a prior disclosure only formed part of the state of the art if it was enabling - that is, if the skilled person could reproduce the disclosed subject-matter based on the information made available. 

Earlier case law (following G1/92) suggested that, for products placed on the market, their composition or internal structure belonged to the state of the art only if the skilled person could analyse and reproduce the product. 

The revised Guidelines now clarify that this enablement requirement does not apply to products placed on the market.  In particular, a product that has been made publicly available by being placed on the market forms part of the state of the art.  This includes the product itself and all properties of the product that can be analysed or determined by the skilled person. Crucially, reproducibility of the product is no longer required. The requirement of “enablement” is considered inherently satisfied by the skilled person’s ability to obtain and possess the marketed product. 

Technical information about a marketed product (for example, a technical brochure, non-patent or patent literature) also forms part of the state of the art if it was publicly available before the effective filing date, regardless of whether the product could be reproduced at that time.  

This revision broadens the potential scope of the prior art arising from commercially available products and underscores the importance of filing patent applications before making any public disclosure including placing a product on the market or publishing technical information about the product. 

3) Further medical use claims (Part G, Chapter VI, sections 6.1.2.1 and 6.1.2.2)

Under European patent practice, a known substance or composition may still be patentable if claimed for a new therapeutic application as a second or further medical use. 

The 2026 update to the Guidelines introduces clarifications on how novelty is assessed for second or further medical use claims, particularly regarding clinical trial disclosures and patient subgroups to be treated. 

Clinical trials and preclinical data in the prior art

According to the revised Guidelines, a prior disclosure destroys the novelty of a specific medical use claim only if two cumulative criteria are met:

i) The prior art must unambiguously disclose the substance or composition, the medical indication, and any essential aspects of the treatment. Without these conceptual elements, the claimed therapeutic use is not considered to have been made available to the public.

ii) The prior art must provide a plausible basis for the claimed therapeutic effect. This can be shown through experimental data or scientifically credible reasoning. 

Importantly, no explanation of the mechanism of action is required. 

Consequently, clinical trial disclosures – including Phase I, II or III studies – that merely announce that an investigation is planned or ongoing, without providing any positive results, are unlikely to render the therapeutic use publicly available because criterion ii) is not fulfilled.  

Patient subgroups as a basis for a new specific medical use

A further route to the novelty of further medical use claims lies in defining a new patient subgroup for the treatment of an already known clinical indication. The 2026 Guidelines provide clarification on how a new patient subgroup may be defined. 

Relevant characteristics of a new patient subgroup may include age, gender, body weight, physiological or pathological parameters, presence of a particular biomarker or specific genetic mutations. 

The subgroup may be defined passively by reciting the relevant characteristic (for example, patients aged at least 60 years, patients expressing gene X, patients having mutation Y in gene X) or actively by explicitly including a selection step (for example, comprising determining mutation Y in gene X and selecting a patient having the mutation Y). 

Claims directed to well-defined patient subgroups therefore offer strategic opportunities for pursuing further medical use protection.