The tyrosine kinase inhibitor dasatinib acts as a pharmacologic on/off switch for CAR T cells

CAR T cells that is of immediate onset and can be sustained for several days without affecting T cell viability. We show that treatment with dasatinib halts cytolytic activity, cytokine production, and proliferation of CAR T cells in vitro and in vivo. The dose of dasatinib can be titrated to achieve partial or complete inhibition of CAR T cell function. Upon discontinuation of dasatinib, the inhibitory effect is rapidly and completely reversed, and CAR T cells resume their antitumor function. The favorable pharmacodynamic attributes of dasatinib can be exploited to steer the activity of CAR T cells in “function-on-off-on” sequences in real time. In a mouse model of cytokine release syndrome (CRS), we demonstrated that a short treatment course of dasatinib, administered early after CAR T cell infusion, protects a proportion of mice from otherwise fatal CRS. Our data introduce dasatinib as a broadly applicable pharmacologic on/off switch for CAR T cells.