Unlike BCR-ABL kinase inhibitor drugs like imatinib, Bisindolylmaleimide IX targets topoisomerase and B-Raf and takes advantage of pro-DNA damage activity of BCR-ABL and the oncogene addiction Raf-Erk pathway in BCR-ABL positive CML cells. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.