LAM-003 overcomes intrinsic FLT3 TKI resistance mechanisms. (A) AML cell lines were treated with LAM-003, gilteritinib, or crenolanib for 72 hours in either conditioned medium or nonconditioned medium before cell viability was determined by using CTG. All comparisons were made to LAM-003 by using a 1-way analysis of variance, Dunnett’s multiple comparisons test. For MOLM-13, **P = .007, ****P < .0001; for MOLM-14, ***P = .0002, ****P < .0001; for MV-4-11, **P = .002, ****P < .0001. (B) AML cell lines were treated with LAM-003 or venetoclax for 72 hours in either conditioned medium or nonconditioned medium. For MOLM-13, **P = .001; for MOLM-14, **P < .005; for MV-4-11, **P < .007 compared with LAM-003 using 2-way analysis of variance, Bonferroni’s multiple comparisons test. (C) Normalized isobologram at the EC₇₅ of MV-4-11 cells and MOLM-13 cells with the combination of LAM-003 and venetoclax in nonconditioned (solid symbol) or conditioned (open symbol) medium for 72 hours before viability was assayed by using CellTiter-Glo. Each data point is the average of 2 independent experiments, each performed in duplicate, for each cell line. (D) EC₅₀ values of BA/F3 cells expressing WT-FLT3 or FLT3-ITD supplemented with or without IL-3 and treated with gilteritinib, crenolanib, or LAM-003. Viability was assessed 72 hours later by using CTG. Data in all panels are the mean of at least 2 independent experiments, each performed in duplicate. Bar graphs in panels A-B and D represent the mean ± SD.