With the growing number of BCR–ABL inhibitors available for patients with CML-CP and the lack of head-to-head clinical trials across second-generation BCR–ABL inhibitors, choosing a treatment requires consideration on a patient-to-patient basis, and therefore, information regarding the efficacy and use of these agents in the real-world setting is of increasing interest. This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.