We recently synthesized and discovered a new compound (17f) that inhibits STAT5 phosphorylation and transcriptional activity in various CML and AML cells, without detectable effects on other signal transduction molecules, such as STAT3 and the protein kinases ERK1/2 and AKT [23]. This evidence concerns the gene STAT5B and chronic myelogenous leukemia, BCR-ABL1 positive.