The U.S. Food and Drug Administration (FDA) expanded the approval of bosutinib – an oral, once-daily tyrosine kinase inhibitor – to include adult patients with newly diagnosed chronic phase, Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML). Bosutinib was first approved in September 2012 for the treatment of adult patients with relapsed or refractory chronic-, accelerated-, or blast phase Ph+ CML.
The FDA based the decision on results of the international, open-label, randomized phase III BFORE trial, which included 536 patients with chronic phase Ph+ CML. Researchers assigned patients 1:1 to receive either bosutinib 400 mg or imatinib 400 mg. A higher percentage of patients assigned to the bosutinib group achieved major molecular response at 12 months (47.2% vs. 36.9%; p value not reported). Results also showed a higher rate of complete cytogenetic response at 12 months in the bosutinib group (77.2% vs. 66.4%; p value not reported).
The adverse events (AEs) observed in the trial were consistent with the known safety profile of bosutinib, and the most common AEs included diarrhea (70%), nausea (35%), thrombocytopenia (35%), rash (34%), increased alanine aminotransferase (31%), abdominal pain (25%) and increased aspartate aminotransferase (23%).
Source: Pfizer press release, December 19, 2017.