Long-term cardiac, vascular, hypertension, and effusion safety of bosutinib in patients with Philadelphia chromosome–positive leukemia resistant or intolerant to prior therapy

Introduction: Long-term follow-up (≥4 years) demonstrated a low incidence of cardiac and vascular treatment-emergent adverse events (TEAEs) with bosutinib treatment. We evaluated cardiac, vascular, hypertension, and effusion TEAEs after ≥ 7 years of follow-up in patients with Philadelphia chromosome–positive (Ph+) leukemia. Methods: This retrospective analysis of a phase I/II study and its ongoing extension study included data from patients with chronic phase chronic myeloid leukemia (CML) treated with bosutinib after resistance/intolerance to imatinib (CP2L) or to imatinib plus dasatinib and/or nilotinib (CP3L), and those with accelerated/blast phase CML or acute lymphoblastic leukemia after treatment with, at a minimum, imatinib (ADV). Results: In all, 570 patients were treated with bosutinib; median treatment duration was 11.1 months (range: 0.03-133.1). The incidence of cardiac, vascular, hypertension, and effusion-related TEAEs was 10.9%, 8.8%, 9.1%, and 13.3%, respectively. Few patients had maximum grade 3-4 TEAEs (cardiac, 3.9%; vascular, 4.0%; hypertension, 3.0%; effusion, 4.6%). Grade 5 TEAEs occurred in the cardiac (0.7%) and vascular (1.8%) clusters only. In years 5-7, fewer than 5% of patients each year had newly occurring cardiac, vascular, hypertension, or effusion TEAEs. The exposure-adjusted TEAE rates (patients with TEAEs/total patient-year) pooled across CP2L, CP3L, and ADV cohorts were as follows: cardiac, 0.044; vascular, 0.035; hypertension, 0.038; and effusion, 0.056, of which, correspondingly, 0.9%, 1.2%, 0%, and 2.1% required treatment discontinuation. Conclusions: The incidence of cardiac, hypertension, vascular, and effusion events was low in patients with Ph+ CML resistant or intolerant to prior therapy who were treated with bosutinib.