Article
Author: Pacheco, Yedra ; Velasco-Sidro, Miriam ; Jiménez-Reinoso, Anaïs ; Díez-Alonso, Laura ; Falgas, Aida ; Bueno, Clara ; Álvarez-Vallina, Luis ; Menéndez, Pablo ; Juan, Manel ; Jiménez-Matías, Beatriz ; González-Navarro, Europa Azucena ; Aguilar-Sopeña, Óscar ; Gómez-Rosel, Marina ; Blanco, Belén ; Muñoz-Sánchez, Guillermo ; Roca-Ho, Heleia ; Ramírez-Fernández, Ángel ; Orfao, Alberto ; Arroyo-Ródenas, Javier ; Martinez-Moreno, Alba ; Pérez-Pons, Alba ; Roda-Navarro, Pedro ; Bravo-Martín, Clara ; Gil-Etayo, Francisco J
Background:CD19-directed cancer immunotherapies, based on engineered T cells bearing chimeric antigen receptors (CARs, CAR-T cells) or the systemic administration of bispecific T cell-engaging (TCE) antibodies, have shown impressive clinical responses in relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, more than half of patients relapse after CAR-T or TCE therapy, with antigen escape or lineage switching accounting for one-third of disease recurrences. To minimize tumor escape, dual-targeting CAR-T cell therapies simultaneously targeting CD19 and CD22 have been developed and validated both preclinically and clinically.
Methods:We have generated the first dual-targeting strategy for B-cell malignancies based on CD22 CAR-T cells secreting an anti-CD19 TCE antibody (CAR-STAb-T) and conducted a comprehensive preclinical characterization comparing its therapeutic potential in B-ALL with that of previously validated dual-targeting CD19/CD22 tandem CAR cells (TanCAR-T cells) and co-administration of two single-targeting CD19 and CD22 CAR-T cells (pooled CAR-T cells).
Results:We demonstrate that CAR-STAb-T cells efficiently redirect bystander T cells, resulting in higher cytotoxicity of B-ALL cells than dual-targeting CAR-T cells at limiting effector:target ratios. Furthermore, when antigen loss was replicated in a heterogeneous B-ALL cell model, CAR-STAb T cells induced more potent and effective cytotoxic responses than dual-targeting CAR-T cells in both short- and long-term co-culture assays, reducing the risk of CD19-positive leukemia escape. In vivo, CAR-STAb-T cells also controlled leukemia progression more efficiently than dual-targeting CAR-T cells in patient-derived xenograft mouse models under T cell-limiting conditions.
Conclusions:CD22 CAR-T cells secreting CD19 T-cell engagers show an enhanced control of B-ALL progression compared with CD19/CD22 dual CAR-based therapies, supporting their potential for clinical testing.