Abstract LB120: Stem cell-derived ACUA CAR-NKT allogeneic cell therapies harness orthogonal mechanisms of action for the treatment of solid tumors

Abstract

Abstract Despite the remarkable success of chimeric antigen receptor T cell (CAR-T) therapies in treating hematological malignancies, their use in solid tumor indications has been met with distinct challenges. The immunosuppressive tumor microenvironment (TME) and tumor antigen heterogeneity are two significant factors that may adversely impact the efficacy of these ground-breaking therapies. Engineered natural killer T (NKT) cells harbor biological features distinct from CAR-T cell or CAR-NK cell therapies and thus represent a novel therapeutic approach to deploy “off the shelf” to patients. Appia Bio’s ACUA platform is capable of generating large quantities of highly pure CAR-NKT cells from cord blood CD34+ hematopoietic stem and progenitor cells (HSPCs) for clinical use. We have demonstrated that multiple distinct mechanisms of anti-tumor activity are operative in CAR-NKT cells, including CAR-mediated killing, NK receptor-mediated killing, adjuvant effects on antigen-specific T cells and immature dendritic cells, as well as the ability to deplete of pro-tumorigenic macrophages.When transduced with a CAR, ACUA-derived CAR-NKT cells show potent CAR-mediated tumor cell killing, similar to CAR-T cells. In contrast to conventional T cells, CAR-NKT cells also demonstrate potent CAR antigen-independent tumor cell killing, mediated partially through NKG2D and DNAM-1 activating NK receptors. CAR-NKT cells, but not conventional CAR-T cells, enhanced the function of NY-ESO specific T cells in controlling multiple rounds of tumor rechallenge, through the secretion of soluble components. In regard to other adjuvant effects which may provide additional benefit in vivo, ACUA-derived NKT cells enhanced the activation of peripheral blood monocyte-derived dendritic cells, which can regulate beneficial Th1 type immune responses. To explore how ACUA-derived NKT cells could reshape the TME, we generated immunosuppressive M2-polarized macrophages and observed that ACUA-derived NKT cells can either kill or reprogram these cells to a pro-inflammatory phenotype following co-culture. Notably, these immune cell adjuvant mechanisms are specific to ACUA-derived NKT cells and are not observed with conventional CAR-T cells. In summary, these mechanistic studies underscore the advantages of ACUA-derived NKT cells over conventional CAR-T cells and highlight their potential as a promising differentiated allogeneic therapy for the treatment of solid tumors. Citation Format: Xi Wang, Andrew J. Hou, Michael A. Christopher, Yannick Bulliard, Jason S. Damiano. Stem cell-derived ACUA CAR-NKT allogeneic cell therapies harness orthogonal mechanisms of action for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB120.