compound 13a

Compound 13a is an optimized indirubin-3'-aminooxy-acetamide derivative developed as a potent and selective inhibitor of Fms-like tyrosine kinase 3 (FLT3) and its D835Y mutant. It is being investigated for the treatment of acute myeloid leukemia (AML), particularly in cases involving secondary TKD mutations like FLT3/D835Y and FLT3-ITD. The compound has demonstrated strong in vitro anticancer activities with single-digit nanomolar GI50 values against several AML cell lines (MV4-11 and MOLM14) and Ba/F3 cell lines expressing mutated FLT3 kinases. Furthermore, it has shown significant in vivo anticancer efficacy in a xenograft animal model implanted with FLT3-ITD/D835Y-expressing MOLM-14 cells. Its selectivity profile indicates inhibitory activities primarily focused on a few members of the receptor tyrosine kinase family and AML versus solid tumor cell lines.