ORIGINAL RESEARCH article
Front. Immunol.
Sec. Cancer Immunity and Immunotherapy
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1642454
This article is part of the Research TopicBispecific Antibodies and their Conjugates in Solid Tumors and Hematological MalignanciesView all 9 articles
Trispecific eFab-eIg T-cell engagers targeting HER2 and HER3
Provisionally accepted
- University of Stuttgart, Stuttgart, Germany
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Trispecific antibodies have emerged as molecules for enhanced cancer immunotherapy by addressing the complexity of cancer cell biology and anti-cancer immune responses. Here, we present a novel approach to generate trispecific antibodies based on the previously developed eIg technology. These trispecific antibodies comprise one Fab and two eFab moieties, fused to obtain an asymmetric eFab-eIg molecule. The design principle employs two different eFab building blocks, characterized by divergent arrangements of heterodimerizing hetEHD2 domains. Specifically, the first (inner) eFab arm comprises the hetEHD2-1 domain in the heavy chain and the corresponding hetEHD2-2 domain in one of the light chains, while in the second eFab (outer) this arrangement is reversed. The feasibility of this approach was demonstrated for a trispecific eFab-eIg T-cell engager (TCE) targeting HER2, HER3, and CD3. Importantly, the trispecific TCE retained binding activity for all three antigens and was capable of recruiting Tcells to HER2 and/or HER3-expressing cancer cells and mediating effective cancer cell killing, as shown in 2D and 3D model systems. Due to the modular architecture, this approach should be suitable to generate trispecific antibodies of any specificity and for a multitude of applications.
Keywords: Trispecific antibody, T-cell retargeting, Antibody engineering, HER2, HER3, CD3, hetEHD2
Received: 06 Jun 2025; Accepted: 04 Aug 2025.
Copyright: © 2025 Loeffler, Huber, Olayioye, Kontermann and Seifert. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Oliver Seifert, University of Stuttgart, Stuttgart, Germany
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