EPO 2026 Revised Examination Guidelines Take Effect: Antibody Patentability Standard Overhauled, PACE Search Abolished

The European Patent Office (EPO) brought its 2026 consolidated Guidelines for Examination into force on April 1, 2026, superseding the April 2025 editions and folding the European Patent Guide and the Euro-PCT Guide into a unified framework. The former guides remain accessible only through May 31, 2026, leaving patent practitioners a narrow window to update internal workflows before the older materials are withdrawn entirely. The 2026 revision makes substantive changes to antibody patentability standards, abolishes accelerated search under the PACE programme, and formally incorporates two landmark Enlarged Board of Appeal rulings.

The most consequential substantive change for the life sciences sector concerns the inventive step standard for antibodies targeting known antigens. The prior version of the guidelines (Part G, Chapter II, Section 6.2) imposed a negative presumption: a novel antibody directed to a known target was presumed to lack inventive step unless the applicant demonstrated a surprising technical effect. The 2026 guidelines eliminate this negative framing entirely. According to the Solve Intelligence analysis of the 2026 guidelines, the revised text states in affirmative terms that inventive step will be acknowledged if a surprising technical effect is demonstrated in the application, removing the procedural burden of overcoming a presumption of non-inventiveness at the outset of examination.

The 2026 guidelines also introduce two additional bases on which antibody-related claims may be found inventive. First, inventive step may be recognized where the application overcomes technical difficulties in generating or manufacturing the antibody. Second, a novel type of functional antibody format may independently support an inventive step finding. These additions are significant for applicants developing next-generation antibody modalities such as bispecific antibodies, antibody-drug conjugates, and novel scaffold proteins, where the contribution often lies in the structural or manufacturing innovation rather than purely in the identification of a new therapeutic target. As Mathys and Squire noted in their preview of the updated guidelines, the change represents a genuine improvement in the prospects for obtaining broad antibody claims at the EPO.

On the procedural side, the 2026 guidelines confirm the abolition of accelerated search under the Programme for Accelerated Prosecution of European Patent Applications (PACE), a change that took effect in February 2026. EPO guidance issued ahead of the February 2026 effective date confirmed that acceleration is now available only in the examination phase; the search phase proceeds at the standard pace. The restriction is intended to improve the quality of prior art searches by ensuring that searches are conducted without the artificial time pressure created by applicant-driven PACE requests. For applicants who previously used PACE requests to obtain rapid search results ahead of filing national phase entries or making commercial decisions, the change requires a reappraisal of accelerated prosecution strategies in Europe.

Two decisions of the EPO Enlarged Board of Appeal are formally incorporated into the 2026 guidelines. G 1/24, addressing claim scope and its relationship to novelty assessment, and G 1/23, concerning enablement requirements under Article 83 EPC, both have direct implications for how European patent claims should be drafted and supported by the description. According to Prism News, the incorporation of these rulings is expected to have a particular impact on prosecution strategies for U.S.-based applicants entering the European regional phase via the PCT route, who may need to revisit claim scope and example density in their PCT applications to align with the EPO’s post-G 1/24 and post-G 1/23 expectations.

The consolidation of the European Patent Guide and the Euro-PCT Guide into the main examination guidelines is primarily an administrative rationalization, but it has practical significance. Both companion documents had accumulated substantial procedural guidance over many years, and their integration into the core guidelines makes them subject to the same annual revision cycle, reducing the risk of procedural guidance falling out of alignment with current EPO practice. Practitioners relying on either guide as standalone reference tools should transition to the 2026 consolidated guidelines before May 31, 2026.

Taken together, the 2026 EPO examination guidelines represent one of the more significant revisions in recent years. For pharmaceutical and biotechnology companies maintaining European patent portfolios, the revised antibody patentability standard warrants a review of pending applications and any pending opposition proceedings where the negative presumption had been raised. For all EPO applicants, the PACE restriction and the incorporation of G 1/24 and G 1/23 call for updated prosecution playbooks before the next filing cycle. The full 2026 EPO Guidelines for Examination are available on the EPO official website.