Discovery of a Potent and Selective FLT3 Inhibitor ()--(5-((5-Fluoro-2-oxoindolin-3-ylidene)methyl)-4-methyl-1-pyrrol-3-yl)-3-(pyrrolidin-1-yl)propanamide with Improved Drug-like Properties and Superior Efficacy in FLT3-ITD-Positive Acute Myeloid Leukemia.

Overcoming the FLT3-ITD mutant has been a promising drug design strategy for treating acute myeloid leukemia (AML). Herein, we discovered a novel FLT3 inhibitor , which displayed potent inhibitory activity against the FLT3-ITD mutant (IC = 0.8 nM) and achieved good selectivity over c-KIT kinase (over 500-fold). Compound selectively inhibited the proliferation of FLT3-ITD-positive AML cell lines MV4-11 (IC = 23.5 nM) and MOLM-13 (IC = 35.5 nM) and exhibited potent inhibitory effects against associated acquired resistance mutations. In cellular mechanism studies, compound strongly inhibited FLT3-mediated signaling pathways and induced apoptosis by arresting the cell cycle in the sub-G1 phase. In in vivo studies, compound demonstrated a good bioavailability (73.6%) and significantly suppressed tumor growth in MV4-11 (10 mg/kg, TGI 93.4%) and MOLM-13 (20 mg/kg, TGI 98.0%) xenograft models without exhibiting obvious toxicity. These results suggested that compound may be a promising drug candidate for treating FLT3-ITD-positive AML.