Bosutinib effective and well tolerated in newly diagnosed CP-CML

The final efficacy and safety results from the phase 3 open-label BFORE trial confirm that bosutinib can be used as standard of care in patients with newly diagnosed chronic-phase chronic myeloid leukaemia (CP-CML).

Bosutinib is approved for patients with Philadelphia chromosome-positive (Ph+) CML resistant or intolerant to prior therapy and patients with newly diagnosed Ph+ CP CML. Approval of first-line bosutinib was based on the primary results from the BFORE trial (NCT02130557), which showed superior efficacy versus imatinib in the modified intent-to-treat (ITT) population after ≥12 months of follow-up [1]. Prof. Tim Brümmendorf (RWTH Aachen University, Germany) reported the final efficacy and safety results from the BFORE trial after 5 years of follow-up [2].

First-line bosutinib continued to demonstrate superior efficacy compared with imatinib, as evidenced by earlier and deeper molecular responses (MR; see Table). An improvement in MR with bosutinib was demonstrated across Sokal risk groups, with the greatest benefit versus imatinib observed in Sokal high-risk patients.

Table: Efficacy outcomes with first-line bosutinib versus imatinib after 5 years of follow-up [2]MR, molecular response

A higher percentage of patients achieved BCR-ABL1 transcripts ≤10% at 3 months in the bosutinib versus imatinib arm. “That translated into a higher rate of later achievement of cumulative major MR,” Prof. Brümmendorf added. Cumulative major MR by 60 months was higher in patients with transcripts ≤10% versus >10% in both treatment arms (bosutinib HR 2.67; imatinib HR 3.12). A substantial proportion of patients receiving bosutinib or imatinib achieved a 2-year sustained MR. The 60-month overall survival rates were similar (94.5% and 94.6%). Long-term adverse events were generally manageable and consistent with previous reports and the known safety profiles of both drugs.

1. Cortes JE, et al. J Clin Oncol. 2018;36:231-7.
2. Brümmendorf TH, et al. Bosutinib (BOS) Versus Imatinib for Newly Diagnosed Chronic Phase (CP) Chronic Myeloid Leukemia (CML): Final 5-Year Results from the Bfore Trial. 62^nd ASH Annual Meeting, 5-8 December 2020. Abstract 46.

Posted on 18 February 202122 February 2021