Hangiu et al. generated small (47kDa) mouse and human bispecific Fc-free agonist antibodies comprising an EGFR-specific single-domain VHH antibody linked to a 4-1BB-specific scFv and a human albumin sequence (LiTCo-Albu). In vitro, LiTCo-Albu bound specifically to its cognate targets and mediated EGFR-targeted 4-1BB costimulatory activity and its own cellular recycling via FcRn. In mice, mouse LiTCo-Albu had an extended circulatory half-life, and delayed established EGFR+ CRC growth; therapeutic activity was enhanced by a blocking anti-PD-1 mAb. LiTCo-Albu did not display Fc-dependent 4-1BB mAb-associated toxicities.
Contributed by Paula Hochman
ABSTRACT: Costimulation of tumor-infiltrating T lymphocytes by anti-4-1BB monoclonal antibodies (mAbs) has shown anti-tumor activity in human trials, but can be associated with significant off-tumor toxicities involving Fc_R interactions. Here, we introduce albumin-fused mouse and human bispecific antibodies with clinically favorable pharmacokinetics designed to confine 4-1BB costimulation to the tumor microenvironment. These Fc-free 4-1BB agonists consist of an EGFR-specific V(HH) antibody, a 4-1BB-specific scFv, and a human albumin sequence engineered for high FcRn binding connected in tandem (LiTCo-Albu). We demonstrate in vitro cognate target engagement, EGFR-specific costimulatory activity, and FcRn-driven cellular recycling similar to non-fused FcRn high-binding albumin. The mouse LiTCo-Albu exhibited a prolonged circulatory half-life and in vivo tumor inhibition, with no indication of 4-1BB mAb-associated toxicity. Furthermore, we show a greater therapeutic effect when used in combination with PD-1-blocking mAbs. These findings demonstrate the feasibility of tumor-specific LiTCo-Albu antibodies for safe and effective costimulatory strategies in cancer immunotherapy.
Author Info: (1) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Inv
Author Info: (1) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. Department of Antibody Engineering, Leadartis SL, Madrid, Spain. (2) Department of Antibody Engineering, Leadartis SL, Madrid, Spain. (3) Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark. (4) Department of Antibody Engineering, Leadartis SL, Madrid, Spain. (5) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (6) Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark. (7) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (8) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (9) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (10) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (11) Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark. (12) Centro de Investigaciones Biolgicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain. (13) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (14) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. Chair for Immunology UFV/Merck, Universidad Francisco de Vitoria (UFV), 28223 Pozuelo de Alarcn, Madrid, Spain. (15) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (16) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. (17) Centro de Investigaciones Biolgicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain. (18) Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, 28220 Majadahonda, Madrid, Spain. (19) Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark. (20) Cancer Immunotherapy Unit (UNICA), Department of Immunology, Hospital Universitario12 de Octubre, 28041 Madrid, Spain. Immuno-Oncology and Immunotherapy Group, Instituto de Investigacin Sanitaria Hospital 12 de Octubre (imas12), 28041 Madrid, Spain. Chair for Immunology UFV/Merck, Universidad Francisco de Vitoria (UFV), 28223 Pozuelo de Alarcn, Madrid, Spain. Red Espaola de Terapias Avanzadas (TERAV), Instituto de Salud Carlos III (ISCII) (RICORS, RD21/0017/0030), Madrid, Spain.
