In the combination of PTC596 and S63845 strong cytotoxic effects were detected in two AML and one MDS-AML: AML1, classified as FLT3 mutant adverse de novo AML with 90% blast count; AML6, a relapsed t-AML; MDS-AML5, a DNMT3A, TET2, NPM1 mutant secondary AML. This evidence concerns the gene NPM1 and acute myeloid leukemia.