Bosulif Approved for Ph+ CML

September 2012, Vol 3, No 6

The US Food and Drug Administration (FDA) approved the tyrosine kinase inhibitor bosutinib (Bosulif; Pfizer) for the treatment of patients with chronic, accelerated, or blast-phase Philadelphia chromosome–positive (Ph+) chronic myelogenous leukemia (CML) who are resistant to or who cannot tolerate other therapies.

The approval was based on a single clinical trial of 546 patients with chronic, accelerated, or blast-phase CML. All patients were treated with bosutinib; their disease had progressed after treatment with imatinib (Gleevec) or with imatinib followed by dasatinib (Sprycel) and/or nilotinib (Tasigna), or they could not tolerate the side effects of previous therapy.

In patients with chronic-phase CML, 34% of those who had previously received imatinib achieved major cytogenetic response (MCyR) after 24 weeks with bosutinib therapy; of those who achieved MCyR at any time, 52.8% responded for at least 18 months. Among patients previously treated with imatinib followed by dasatinib and/or nilotinib, approximately 27% achieved MCyR within the first 24 weeks of treatment with bosutinib; of those achieving MCyR at any time, 51.4% responded for at least 9 months.

In patients with accelerated CML previously treated with at least imatinib, 33% had complete hematologic response and 55% achieved overall hematologic response within the first 48 weeks of treatment with bosutinib; the rates were 15% and 28%, respectively, in those with blast-phase CML.

The most common side effects with bosutinib were diarrhea, nausea, thrombocytopenia, vomiting, abdominal pain, rash, anemia, fever, and fatigue. (September 4, 2012)

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