Here we show anticancer efficacy of novel dicarboximide denoted BK124.1 (C31H37ClN2O4) in a mouse CML xenograft model and in vitro in two types of chemoresistant CML cells: MDR1 blasts and in CD34+ patients’ stem cells (N = 8) using immunoblotting and flow cytometry. This evidence concerns the gene ABCB1 and chronic myelogenous leukemia, BCR-ABL1 positive.