ABCB1 and acute myeloid leukemia: Finally, while clinically targeted plasma levels of quizartinib are below those needed for inhibition of ABCB1-mediated transport of chemotherapy drugs in AML cells, levels in the gastrointestinal tract are likely to be sufficient to inhibit ABCB1-mediated intestinal drug transport [35] and thus increase absorption of co-administered ABCB1 substrate drugs, including those that have the potential to prolong the QT interval [70].