What is the role of bosutinib in the treatment of chronic myelogenous leukemia (CML)?

Updated: May 23, 2021
  • Author: Emmanuel C Besa, MD; Chief Editor: Sara J Grethlein, MD, FACP  more...
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Answer

Approval of bosutinib was based on a single-arm, open-label, multicohort, phase I/II study of more than 500 patients with imatinib-resistant or -intolerant Ph+ CML. Separate cohorts were established for chronic-, accelerated-, and blast- phase CML previously treated with 1 or more prior tyrosine kinase inhibitors (ie, imatinib, imatinib followed by dasatinib and/or nilotinib).

In 118 patients with chronic-phase CML, a major cytogenetic response was attained in 32% of patients, a complete cytogenetic response was attained in 24%, and a complete hematologic response was attained in 73%. At 2 years, the progression-free survival rate was 73% and the estimated overall survival rate was 83%. Responses were seen across Bcr-Abl mutations, including those associated with dasatinib and nilotinib resistance, except T315I. [50]

After granting accelerated approval in December 2017, in May 2021 the FDA issued standard approval of bosutinib for newly diagnosed chronic-phase Ph+ CML. Approval was based on the BFORE study, a multinational, phase III study enrolling 536 patients with newly diagnosed chronic-phase CML. Cumulative major molecular response (MMR) by Month 60 in the modified intent-to-treat (mITT) population was 74% (95% CI: 69-80%) in the bosutinib arm and 66% (95% CI: 60-72%) in the imatinib arm. After 60 months of follow-up, the median time to MMR in responders was 9 months for bosutinib and 11.9 months for imatinib. [51, 52]


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