Laura Rubio-Pérez, Rodrigo Lázaro-Gorines, Seandean L. Harwood, Marta Compte, Rocío Navarro, Antonio Tapia-Galisteo, Jaume Bonet, Belén Blanco, Simon Lykkemark, Ángel Ramírez-Fernández, Mariola Ferreras-Gutiérrez, Carmen Domínguez-Alonso, Laura Díez-Alonso, Alejandro Segura-Tudela, Oana Hangiu, Ainhoa Erce-Llamazares, Francisco J. Blanco, Cruz Santos, José L. Rodríguez-Peralto, Laura Sanz, Luis Álvarez-Vallina, Ministerio de Ciencia e Innovación (España), Instituto de Salud Carlos III, Fundación CRIS contra el Cáncer, Asociación Española Contra el Cáncer, Fundación 'La Caixa', Fundación de Investigación Biomédica Hospital 12 de Octubre, Universidad Francisco de Vitoria, Comunidad de Madrid, Rubio-Pérez, Laura, Lázaro-Gorines, Rodrigo, Harwood, Seandean Lykke, Compte, Marta, Navarro, Rocío, Tapia-Galisteo, Antonio, Bonet, Jaume, Blanco, Belén, Lykkemark, Simon, Ramírez-Fernández, Ángel, Ferreras-Gutiérrez, Mariola, Domínguez-Alonso, Carmen, Díez-Alonso, Laura, Segura-Tudela, Alejandro, Hangiu, Oana, Erce-Llamazares, Ainhoa, Blanco, Francisco J., Santos, Cruz, Rodríguez-Peralto, J. L., Sanz, Laura, and Alvarez-Vallina, Luis
Immune checkpoint blockade (ICB) with antibodies has shown durable clinical responses in a wide range of cancer types, but the overall response rate is still limited. Other effective therapeutic modalities to increase the ICB response rates are urgently needed. New bispecific antibody (bsAb) formats combining the ICB effect and a direct action on cancer cells could improve the efficacy of current immunotherapies. Here, we report the development of a PD-L1/EGFR symmetric bsAb by fusing a dual-targeting tandem trimmer body with the human IgG1 hinge and Fc regions. The bsAb was characterized in vitro and the antitumor efficacy was evaluated in humanized mice bearing xenografts of aggressive triple-negative breast cancer and lung cancer. The IgG-like hexavalent bsAb, designated IgTT-1E, was able to simultaneously bind both EGFR and PD-L1 antigens, inhibit EGF-mediated proliferation, effectively block PD-1/PD-L1 interaction, and induce strong antigen-specific antibody-dependent cellular cytotoxicity activity in vitro. Potent therapeutic efficacies of IgTT-1E in two different humanized mouse models were observed, where tumor growth control was associated with a significantly increased proportion of CD8+ T cells. These results support the development of IgTT-1E for the treatment of EGFR+ cancers., L.A-V. was supported by grants from the MCIN/AEI/10.13039/ 501100011033 (PID2020-117323RB-100 and PDC2021-121711-100), the Instituto de Salud Carlos III (DTS20/00089), the CRIS Cancer Foundation (FCRIS-2021-0090), the Spanish Association Against Cancer (PROYE19084ALVA), the Fundación ‘‘La Caixa’’ (HR21-00761 project IL7R_LungCan) and the Fundación de Investigación Biomédica 12 de Octubre Programa Investiga (2022-0082). B.B and L.S. were supported by grants PI20/01030 and PI19/00132 from the Instituto de Salud Carlos III (PI20/01030). FJB and MF-G were supported by grants PID2020- 113225GB-I00 and PRE2018-085788 funded by MCIN/AEI/10.13039/ 501100011033. L.R-P. was supported by a predoctoral fellowship from the Immunology Chair, Universidad Francisco de Vitoria/Merck. C. D-A. was supported by a predoctoral fellowship from the MCIN/AEI/ 10.13039/501100011033 (PRE2018-083445). L.D-A. was supported by a Rio Hortega fellowship from the Instituto de Salud Carlos III (CM20/ 00004). O.H. was supported by an industrial PhD fellowship from the Comunidad de Madrid (IND2020/BMD-17668). AE-L was supported industrial PhD fellowship from the Instituto de Salud Carlos III (IFI18/ 00045)