Imatinib mesylate (IM), a competitive inhibitor of BCR/ABL1 tyrosine kinase activity, is the current standard therapy for chronic myeloid leukaemia (CML) which is caused by the BCR/ABL1 gene fusion encoding a constitutively active tyrosine kinase.     ///    "Usually, IM resistance is due to the presence of BCR-ABL1 mutations but in many cases resistance is far from being completely understood or from being satisfactorily addressed from a therapeutic standpoint. "