Abstract 4813: Multi-armored allogeneic CD5 γδ CAR T cells enhance anti-tumor efficacy in T cell malignancies

T cell malignancies, such as T cell lymphoma and leukemia (T-NHL/T-ALL), present substantial challenges to conventional first-line therapies, highlighting an urgent need for novel therapeutic approaches. CAR-T therapies targeting T-cell-specific antigens have emerged as promising strategies against these cancers. However, the risk of tumor contamination by patient-derived T cells underscores the necessity for developing allogeneic, blast-free CAR-T therapies. Healthy donor-derived γδ T cells are attractive candidates for allogeneic CAR-T cell therapy due to their blast-free nature and the minimal risk of inducing Graft-versus-Host Disease (GvHD). Nevertheless, the difficulties in large-scale expansion and limited in vivo efficacy remain substantial obstacles to clinical application. To overcome these limitations, we aimed to enhance both the expansion and in vivo efficacy of anti-CD5 γδ CAR-T (γδCAR5) cells by incorporating “signal-3” supplement. A membrane-bound cytokine approach was employed to ensure targeted “signal 3” supplement specifically to CAR-T cells, promoting controlled expansion and activation. Among various cytokines engineered in membrane-bound forms (IL-2, IL-12, IL-15, IL-18, IL-21, and IL-36γ), only membrane-bound IL-18 (mbIL-18) induced a more than 10-fold increase in γδCAR5 cell expansion in vitro and demonstrated robust anti-tumor efficacy in a T-ALL xenograft model. Furthermore, knockdown of CD5 and PD-1, which are associated with fratricide and immunosuppression, respectively, further maximized the anti-tumor activity of γδCAR5-mbIL-18. Consequently, this multi-armoring strategy, which integrates enhanced proliferative capacity, fratricide resistance, and immune checkpoint evasion, represents an innovative approach to maximizing the therapeutic efficacy of allogeneic cell therapies for T cell malignancies. This study provides a promising framework for the advancement of more effective CAR-T therapies against challenging T cell cancers. Citation Format: Yu Ri Seo, Hyeong Ji Lee, Seung Rok Yu, Hyo Bhin Lee, Je Ho Lee, Hyung Cheol Kim, Youngho Lee. Multi-armored allogeneic CD5 γδ CAR T cells enhance anti-tumor efficacy in T cell malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4813.