Abstract
Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, with no current effective treatment options. Chimeric antigen receptor (CAR) T cell therapy represents a powerful immunotherapeutic approach but faces major limitations in PDAC due to complex manufacturing and reduces efficacy within the highly immunosuppressive tumor microenvironment (TME). Small extracellular vesicles (sEVs) derived from CAR-T cells present a novel strategy to address these challenges. Here, CLDN18.2 CAR-T cells are used to generate CAR-sEVs via ultracentrifugation. The purified CAR-sEVs exhibit typical sEV size and morphology, containing established sEV markers, and carry functional CAR proteins along with cytotoxic molecules such as granzyme B. In vitro, CAR-sEVs displays potent cytotoxic activity against murine CLDN18.2+ PDAC cells, whereas no significant effects are observed in CLDN18.2- non-transformed cells. In an aggressive orthotopic murine PDAC model, CAR-sEV administration reduces tumor growth as measured by bioluminescence imaging and significantly extends survival. Notably, CAR-sEVs also significantly prolong survival compared to treatment with conventional CLDN18.2-targeting CAR-T cells, further supporting their therapeutic potential. Moreover, unlike CAR-T cells, CAR-sEVs do not induce systemic IL-6 release in vivo. These findings position CLDN18.2 CAR-sEVs as a promising therapeutic modality for PDAC, offering an innovative and potentially safer platform for solid tumor immunotherapy.