Patients receive dasatinib orally (PO) once a day (QD) or nilotinib PO twice a day (BID) at the discretion of the treating hematologist. Patients achieving either a 1 log reduction at 3 months or a 2 log reduction at 6 months in their breakpoint cluster region-abelson murine leukemia viral oncogene homolog 1 (BCR-ABL1) transcript levels may switch to imatinib mesylate PO QD.