FDA approves Bosutinib for pediatric Chronic Myelogenous Leukemia patients

On September 26, 2023, the Food and Drug Administration (FDA) granted approval for the use of bosutinib in pediatric patients aged 1 year and older who have chronic phase (CP) Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia (CML). This approval covers cases that are newly diagnosed or those that are resistant or intolerant to prior therapy. Additionally, the FDA approved a new capsule dosage form, available in 50 mg and 100 mg strengths.

The approval followed an assessment of the drug's efficacy in the BCHILD trial (NCT04258943), an open-label, multicenter study. The trial aimed to determine the recommended dose of bosutinib in pediatric patients with newly diagnosed and resistant or intolerant CP Ph+ CML. It also evaluated the drug's safety, tolerability, and pharmacokinetics in this patient population. In total, 28 patients with resistant or intolerant CP Ph+ CML and 21 patients with newly diagnosed CP Ph+ CML participated in the trial.

For pediatric patients with resistant or intolerant CP Ph+ CML, the major cytogenetic response and complete cytogenetic response rates were 82.1% and 78.6%, respectively, with an MMR rate of 50%. Among the 14 patients who achieved major molecular response MMR, two lost MMR after 13.6 and 24.7 months on treatment. The median follow-up was 23.2 months.

The most common adverse reactions in pediatric patients (≥20%) included diarrhea, abdominal pain, vomiting, nausea, rash, fatigue, hepatic dysfunction, headache, pyrexia, decreased appetite, and constipation. The most common laboratory abnormalities that worsened from baseline (≥45%) were increased creatinine, increased alanine aminotransferase or aspartate aminotransferase, decreased white blood cell count, and decreased platelet count.

The recommended dosage for pediatric patients with newly diagnosed CP Ph+ CML is 300 mg/m2 orally once daily with food, while the recommended dose for those with resistant or intolerant CP Ph+ CML is 400 mg/m2 orally once daily with food. For patients who cannot swallow capsules, the capsule contents can be mixed with applesauce or yogurt.