Bosutinib for CML After Progression With First-line TKI

Bosutinib, a dual Src/Abl tyrosine kinase inhibitor (TKI), has shown promise in patients with Philadelphia-positive (Ph+) chronic phase chronic myeloid leukemia (CML-CP) who have progressed on conventional TKIs such as imatinib and dasatinib, according to a study published in the American Journal of Hematology.¹

Patients who have been treated with first- or second-generation TKIs may experience increased recurrence or may not tolerate the adverse effects associated with these medications, such as fluid retention or bleeding disorders. The objective of this study was to analyze the efficacy and safety of bosutinib among patients with CML who progressed on first-line TKI therapy.

In this ongoing, prospective, phase 1/2 trial, researchers evaluated 119 patients who had Ph+ diagnosis, and who had received first and second generation TKIs. Efficacy endpoints included complete hematologic response (CHR), complete cytogenetic response (CCyR), and major cytogenetic response (MCyR). If present, these measures were analyzed at baseline.

Patients on bosutinib had a confirmed CHR rate of 74% (95% CI, 65-81%); for patients who had CHR at baseline, 87% had at least a 4-week maintenance period. Among patients who acquired a new or maintained a MCyR for 4 weeks, the cumulative MCyR rate was 40% (95% CI, 31-50%).

The researchers conclude that bosutinib might be beneficial for patients who have progressed on imatinib or dasatinib/nilotinib as first-line options. The adverse effects of bosutinib were minimal and tolerable compared to other TKIs used for CML-CP.

Reference

1. Cortes JE, Khoury HJ, Kantarjian HM, et al. Long-term bosutinib for chronic phase chronic myeloid leukemia after failure of imatinib plus dasatinib and/or nilotinib. Am J Hematol. 2016 Sep 15. doi: 10.1002/ajh.24536 [Epub ahead of print]