Short-term manufacturing of IL-7/CCL19-expressing CAR-T cells enhances and prolongs therapeutic effects in solid tumor models.

CAR-T cell therapy has achieved remarkable success in the treatment of certain blood cancers, but its efficacy against solid tumors remains limited. One of the key strategies is the improvement of manufacturing methods for the rapid production of high-functioning CAR-T cells. We have improved the manufacturing method for CAR-T cells simultaneously expressing IL-7 and CCL19 (referred to as 7×19 CAR-T cells), armored CAR-T cells which we developed for treating solid tumors. We generated 7×19 CAR-T cells using a short-term culture method without expansion phase (referred to as Swift 7×19 CAR-T cells), then compared them with regular culture methods (referred to as Standard 7×19 CAR-T cells). Swift CAR-T cells are distinguished by a high frequency of early memory phenotypes, including stem cell memory and central memory T cells, which showed superior effector functions over Standard CAR-T cells. In a stress test in which effector cells are repeatedly stimulated by target-positive tumor cells, Swift 7×19 CAR-T cells and Swift conventional CAR-T cells initially exhibited similar antitumor effects. However, after repetitive stimulations, only Swift 7×19 CAR-T cells maintained a robust response. Furthermore, Swift 7×19 CAR-T cells demonstrated in vivo antitumor activity by substantially fewer cells compared to Standard 7×19 CAR-T cells, and conferred a long-term resistance to tumor rechallenge without autonomous proliferation indicative of malignant transformation. These results highlight the potential of the innovative "Swift" short-term culture methods combined with 7×19 CAR-T technology to provide a new treatment option for refractory solid tumors.