Tuspetinib (HM43239) is an orally active and selective FLT3 inhibitor with IC 50 s of 1.1 nM, 1.8 nM and 1.0 nM for FLT3 WT, FLT3 internal tandem duplication (ITD) and FLT3 D835Y kinases, respectively. Tuspetinib inhibits the kinase activity of FLT3 as a reversible type I inhibitor and modulates p-STAT5, p-ERK, SYK , JAK1/2, and TAK1. Tuspetinib inhibits the proliferation and induces the apoptosis of leukemic cells In Vitro Tuspetinib potently inhibits the growth of acute myeloid leukemia cell lines harboring FLT3 ITD mutation, such as MV4-11 (IC 50 : 1.3 nM), MOLM-13 (IC 50 : 5.1 nM), and MOLM-14 (IC 50 : 2.9 nM). Tuspetinib also inhibits KG1a cells (CD34+/CD38- cells) proliferation. Tuspetinib induces the caspase 3/7-dependent apoptosis of leukemic stem cell (LSC) marker-expressing KG1a cells (CD34+/CD38- cells). Tuspetinib potently inhibits phosphorylation of SYK, STAT3, and STAT5 in KG1a cells. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo Tuspetinib shows the excellent dose proportional antitumor activity in mouse models xenografted with both MV4-11 and MOLM-13 cell lines without any significant toxicity . Tuspetinib prolongs survival in FLT3 ITD/TKD double mutated xenograft mouse models. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:FLT3 WT 1.1 nM (IC 50 ) FLT3 ITD 1.8 nM (IC 50 ) FLT3 D835Y 1.0 nM (IC 50 )