API-192, an Allogeneic CD19/20 CAR-NKT Cell Product Derived from Cord Blood CD34+ HSPCs for the Treatment of B-Cell Malignancies

Autologous chimeric antigen receptor (CAR)-T cell therapies induce durable remissions and improve survival in patients with advanced B cell malignancies. However, challenges such as manufacturing variability, cost, and time to treatment highlight the need for an allogeneic, off-the-shelf approach that preserves the efficacy of autologous CAR-T. Additionally, antigen escape is one of the established mechanisms of resistance to current CAR-T therapies which target a single antigen. Classical natural killer T (NKT) cells express an invariant T cell receptor (iTCR) that is restricted to the conserved CD1d protein, making it a promising cell type for allogeneic therapies as they do not require TCR gene editing to avoid graft-vs-host (GvH) disease. Furthermore, NKT cells mediate dendritic cell cross-priming, target immunosuppressive myeloid cells/macrophages in the tumor microenvironment, and directly kill CD1d + tumor cells through the iTCR. Endogenous NKT cells are an extremely rare population in the blood (90% iTCR + 19CAR + 20CAR +) with no purification step or gene editing. Phenotypically, API-192 cells are predominantly CD4 -CD8 - or CD4 -CD8 +, express major activating NK receptors, and harbor intracellular stores of cytotoxic molecules, resembling endogenous NKT cells. API-192 kills Raji and Nalm6 tumor cells in a CAR-specific and dose-dependent manner and can control multiple rounds of tumor challenge in vitro. API-192 secretes pro-inflammatory cytokines and proliferates in response to tumor antigen . In human tumor xenograft models in immunocompromised mice, API-192 robustly expands, suppresses tumor growth, and exhibits prolonged persistence, enabling control of a tumor rechallenge 70 days after initial dosing. API-192 expresses lower levels of MHC I and MHC II molecules relative to conventional CAR-T cells and elicits less IFN-γ release by NK and T cells in mixed lymphocyte reaction (MLR) assays, indicative of a more favorable immunogenic profile. Compared to conventional CAR-T cells, API-192 also secretes mi