A small molecule, multi-target kinase inhibitor, 4SC-203 (formerly SC-71710), was being developed by 4SC AG for the treatment of cancer, with an focus on acute myeloid leukaemia. 4SC-203 selectively inhibits FMS-related tyrosine kinase 3 (FLT3/STK1), FLT3 mutated forms, and vascular endothelial growth factor receptors (VEGFRs). This may result in the inhibition of angiogenesis and cell proliferation in tumor cells in which these kinases are upregulated. FLT3 (FLK2), a class III tyrosine kinase receptor, is overexpressed or mutated in most B lineage and acute myeloid leukemias (AML). VEGFRs, tyrosine kinase receptors, are overexpressed in a variety of tumor cell types and play key roles in angiogenesis. 4SC has discontinued the development of 4SC-203 (formerly SC-71710), the lead in a series of Flt-3, VEGF protein kinase and aurora kinase A and B inhibitors, for the treatment of acute myeloid leukaemia (AML) as the personnel and financial resources have been allocated preferentially to the development of resminostat.