IL3RA and acute myeloid leukemia: The in vitro functionality of iCasp9 was assessed by treating CAR+ T cells for 24 hours with 1μM AP20187, a synthetic CID, which rapidly eliminated T cells in the CID-treated group (Fig 4E). These results indicate that T cells genetically modified to express a CD123-specific CAR kill AML tumor targets in an antigen-specific manner, and can be deleted effectively through iCasp9 suicide switch activation.