Epitope Claims Persist at European Patent Office
Despite the U.S. Supreme Court effectively ending the genus antibody claim in the Amgen v. Sanofi case, the concept continues to thrive in Europe, with a few recent setbacks at the European Patent Office (“EPO”) and the Unified Patent Court (“UPC”).
The aftermath of the Amgen v. Sanofi decision saw a shift in antibody applications drafted in the United States, focusing on structural characterization through complementarity-determining regions and variable domains. However, functional antibody claiming, which offers a broader scope of protection and economic efficiency by grouping multiple antibodies under a common property, remains of interest to companies developing therapeutic antibodies.
Functional antibody claiming includes defining an antibody by its epitope, a type of claiming that garnered attention in Europe when Amgen’s PCSK9 epitope claims faced challenges in multiple EPO oppositions. While Amgen managed to navigate potential negative decisions on epitope claims in the first opposition against EP 2215124 by narrowing the claims to structurally defined antibodies (T 845/19), the epitope claims of the divisional patent EP 3666797 are currently under scrutiny in an ongoing opposition and before the UPC. The rejection of the epitope claims by the Munich Central Division of the UPC on July 16, 2024 (UPC 1/2023) marked a significant moment in the ongoing discussion.
In light of the Amgen case and the recent decision in T 435/20 that dismissed a claim to IL-23 antibodies defined by a conformational epitope, the ruling in T 326/22 during oral proceedings on August 1 this year has been a game changer. The Board of Appeal confirmed the validity of epitope claiming, particularly conformational epitope claiming, as long as the patent provides sufficient information on antibody generation.
The case EP 2812443 centered on CD47 antibodies characterized by their binding to a conformational epitope defined by its sequence using open “comprising” language. An objection of insufficiency was raised, citing the alleged burden associated with producing antibodies that bind to a conformational epitope. The opponent stressed the complexity of antibody generation through classical methods like hybridoma or phage display, as well as the labor-intensive X-ray crystallography (“XRC”)-based epitope screening. However, the board disagreed, stating that generating antibodies to a specific antigen and determining the epitope, particularly through XRC, is a routine albeit time-consuming process.
This decision in T 326/22 has provided a significant boost to epitope claiming in Europe. When drafting patent applications, applicants should consider the benefits of epitope claims.
Jones Day, representing the patentee in T 326/22, has provided valuable insights into the legal aspects of these developments. The views expressed by Jones Day should be understood as general information and not as legal advice on specific circumstances.
The Impact of the Amgen v. Sanofi Decision
The Amgen v. Sanofi case marked a pivotal moment in the discussion surrounding epitope claiming. While the U.S. Supreme Court’s decision effectively shut down the genus antibody claim, it sparked a shift towards structurally defined antibodies in the United States. However, functional antibody claiming, particularly epitope claiming, continued to gain traction in Europe.
The rejection of Amgen’s PCSK9 epitope claims in multiple EPO oppositions set the stage for a broader debate on the validity and scope of epitope claiming. Despite some setbacks, epitope claiming persisted, with ongoing challenges in opposition proceedings and before the UPC.
Recent Developments and Game-Changing Decisions
The recent decision in T 326/22 has been hailed as a game changer in the realm of epitope claiming. By confirming the validity of epitope claiming, particularly conformational epitope claiming, the Board of Appeal has provided a significant boost to this approach in Europe.
The case EP 2812443, which focused on CD47 antibodies characterized by their binding to a conformational epitope, highlighted the importance of providing sufficient information on antibody generation in patent applications. The decision reaffirmed the EPO’s position that generating antibodies to a specific antigen and determining the epitope, even through methods like XRC, is a routine albeit time-consuming exercise.
The ruling in T 326/22 has not only clarified the validity of epitope claiming but also underscored the advantages of this approach in drafting patent applications. As companies continue to develop therapeutic antibodies, epitope claiming offers a broader scope of protection and economic efficiency.
Looking Ahead: The Future of Epitope Claiming
As epitope claiming continues to evolve in Europe, applicants should consider the benefits and challenges associated with this approach. While the recent decision in T 326/22 has provided a welcome boost to epitope claiming, ongoing developments and challenges in opposition proceedings and before the UPC will shape the future of this practice.
Jones Day’s representation of the patentee in T 326/22 highlights the legal complexities and nuances surrounding epitope claiming. As the discussion unfolds, it is crucial for applicants to stay informed and adapt their strategies accordingly to navigate the evolving landscape of epitope claiming in Europe.
