FDA Approves Bosutinib for Children With CML

M. Alexander Otto, PA, MMS

September 27, 2023

The US Food and Drug Administration (FDA) has approved bosutinib (Bosulif, Pfizer) for pediatric patients aged 1 year or older with chronic phase Philadelphia chromosome positive (Ph+) chronic myelogenous leukemia (CML) that is either newly diagnosed or resistant/intolerant to prior therapy.

The agency also approved new 50-mg and 100-mg capsules to help treat children.

For newly diagnosed disease, the dose is 300 mg/m2 once daily with food. For resistant/intolerant disease, the dose is 400 mg/m2 once daily. For children who can't swallow capsules, the contents can be mixed into applesauce or yogurt, the FDA said in a press release announcing the approval.

The tyrosine kinase inhibitor (TKI) was previously approved for adults. Three other TKIs were previously approved for pediatric CML.

The approval was based on the BCHILD trial, a pediatric dose-finding study involving patients aged 1 year or older. Among the 21 children with newly diagnosed chronic phase, Ph+ CML treated with 300 mg/m2, the rate of major cytogenetic response was 76.2%, the rate of complete cytogenetic response was 71.4%, and the rate of major molecular response rate was 28.6% over a median duration of 14.2 months.

Among the 28 children with relapsed/intolerant disease treated with up to 400 mg/m2, the rate of major cytogenetic response was 82.1%, the rate of complete cytogenetic response was 78.6%, and the rate of major molecular response was 50% over a median duration of 23.2 months. Among the 14 patients who had a major molecular response, two lost it — one after 13.6 months of treatment, and the other after 24.7 months of treatment.

Adverse events that occurred in 20% or more of children included diarrhea, abdominal pain, vomiting, nausea, rash, fatigue, hepatic dysfunction, headache, pyrexia, decreased appetite, and constipation. Overall, 45% or more of patients experienced an increase in creatinine, alanine aminotransferase, or aspartate aminotransferase levels, or a decrease in white blood cell count or platelet count.

The full labeling information is available online.

M. Alexander Otto is a physician assistant with a master's degree in medical science. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape and is an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.

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