PFS while on bosutinib treatment. PFS is shown for all patients treated with bosutinib at a median follow-up of 28.5 months. Progression was determined by the investigator and defined as on-treatment transformation to accelerated or blast phase, loss of CHR, loss of MCyR with Philadelphia chromosome rate increased by 30%, doubling of white blood cell count to > 20 × 109/L, or death because of any cause within 30 days of the last study dose. IM indicates imatinib; DAS, dasatinib; NI, nilotinib; and NA, not available. *Includes 3 patients who previously received all 3 inhibitors and one patient with NI intolerance. †PFS rates at 1 and 2 years were based on Kaplan-Meier estimates.