Bosutinib in the real-life treatment of chronic myeloid leukemia patients aged > 65 years resistant/intolerant to previous tyrosine-kinase inhibitors

To evaluate the role of bosutinib in elderly patients aged >65 years with chronic myeloid leukemia (CML), a real-life cohort of 101 chronic-phase CML patients followed up in 23 Italian centers and treated with bosutinib in second or a subsequent line was retrospectively evaluated. Starting dose of bosutinib was 500 mg/day in 25 patients (24.8\%), 400 mg/day in 7 patients (6.9\%), 300 mg/day in 33 patients (32.7\%), 200 mg/day in 34 patients (33.6\%), and 100 mg/day in 2 patients (2.0\%). Grade 3/4 hematological toxicity occurred in 7/101 patients (6.9\%) and grade 3/4 extra-hematological toxicity in 19/101 patients (18.8\%). Permanent bosutinib discontinuation due to toxicity was needed in 12 patients (11.9\%). Among the 96 patients evaluable for response, 74 (77.0\%) achieved a complete cytogenetic response (CCyR), while 64 of these 74 patients in CCyR (66.6\% of all 96 evaluable patients) also achieved a molecular response (MR) (major MR {[}MR 3.0] in 21 {[}21.8\%], deep MR {[}MR 4.0/4.5] in 43 {[}44.8\%]). The 3-year event-free survival and overall survival of the whole patients' cohort from bosutinib start were 60.9\% (CI 95\% 49.3-72.5) and 86.4\% (CI 95\% 77.2-95.6), respectively. Our real-life data show that bosutinib is effective, with a favorable safety profile, also in elderly patients with important comorbidities and resistance and/or intolerance to previous tyrosine-kinase inhibitor treatments. As a consequence, it could play a significant role in current clinical practice for frail patients.