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The BYOND study evaluated the efficacy and safety of bosutinib 500 mg once daily in patients with chronic myeloid leukemia (CML) resistant/intolerant to prior tyrosine kinase inhibitors (TKIs). These post-hoc analyses assessed the efficacy and safety of bosutinib by resistance or intolerance to prior TKIs (imatinib-resistant vs dasatinib/nilotinib-resistant vs TKI-intolerant), and cross-intolerance between bosutinib and prior TKIs (imatinib, dasatinib, nilotinib), in patients with Philadelphia chromosome–positive chronic phase CML. Data are reported after ≥3 years' follow-up. Of 156 patients with Philadelphia chromosome–positive chronic phase CML, 53 were imatinib-resistant, 29 dasatinib/nilotinib-resistant, and 74 intolerant to all prior TKIs; cumulative complete cytogenetic response rates at any time were 83.7%, 61.5%, and 86.8%, and cumulative major molecular response rates at any time were 72.9%, 40.7%, and 82.4%, respectively. Of 141, 95, and 79 patients who received prior imatinib, dasatinib, and nilotinib, 64 (45.4%), 71 (74.7%), and 60 (75.9%) discontinued the respective TKI due to intolerance; of these, 2 (3.1%), 5 (7.0%), and 0 had cross-intolerance with bosutinib. The response rates observed in TKI-resistant and TKI-intolerant patients, and low cross-intolerance between bosutinib and prior TKIs, further support bosutinib use for patients with Philadelphia chromosome–positive chronic phase CML resistant/intolerant to prior TKIs. ClinicalTrials.gov: NCT02228382 • Bosutinib was assessed in Ph+ CP CML patients resistant or intolerant to prior TKIs. • Response rates were high in imatinib-resistant and TKI-intolerant patients. • Rates were lower but responses durable in dasatinib/nilotinib-resistant patients. • Cross-intolerance between bosutinib and prior TKIs was low. • Bosutinib is a viable option after resistance or intolerance to prior TKIs. [ABSTRACT FROM AUTHOR]