Bosulif Approved for Pediatric Patients With Chronic Phase Ph+ CML

The Food and Drug Administration (FDA) has approved Bosulif (bosutinib) for the treatment of patients 1 year of age and older with chronic phase (CP) Philadelphia chromosome-positive chronic myelogenous leukemia (Ph+ CML) that is newly diagnosed (ND) or resistant or intolerant (R/I) to prior therapy. Previously, the treatment was only approved for adults with newly-diagnosed CP Ph+ CML.

The approval was based on data from the single-arm, open-label phase 1/2 BCHILD trial (ClinicalTrials.gov Identifier: NCT04258943), which was designed to identify the recommended dose of bosutinib in pediatric patients with ND CP Ph+ CML and R/I CP Ph+ CML who received at least 1 prior tyrosine kinase inhibitor therapy. The trial included 28 patients with R/I CP Ph+ CML who received bosutinib 300mg/m² to 400mg/m² orally once daily and 21 patients with ND CP Ph+ CML who received bosutinib 300mg/m² orally once daily.

Results showed that among patients with ND CP Ph+ CML, the major (MCyR) and complete (CCyR) cytogenetic responses were 76.2% (95% CI, 52.8-91.8) and 71.4% (95% CI, 47.8-88.7), respectively. The major molecular response (MMR) was 28.6% (95% CI, 11.3-52.3). Median duration of follow-up was 14.2 months (range, 1.1 to 26.3 months).

Among patients with R/I CP Ph+ CML, the MCyR and CCyR were 82.1% (95% CI, 63.1-93.9) and 78.6% (95% CI, 59-91.7), respectively. The MMR was 50% (95% CI, 30.6-69.4); among the 14 responders, there were 2 patients who lost MMR after 13.6 and 24.7 months of treatment. The MR4.5 (defined as BCR-ABL/ABL IS ≤ 0.0032%) was 17.9% (95% CI, 6.1-36.9). Median duration of follow-up for overall survival was 23.2 months (range, 1 to 61.5 months).

The most common adverse reactions reported in this study population were diarrhea, abdominal pain, vomiting, nausea, rash, fatigue, hepatic dysfunction, headache, pyrexia, decreased appetite, and constipation. Laboratory abnormalities included increased creatinine, increased ALT/AST, decreased white blood cell count, and decreased platelet count.

Bosulif is supplied in a new capsule dosage form in 50mg and 100mg strengths. For those who have difficulty swallowing the capsules, the contents can be mixed with applesauce or yogurt. Bosulif is also supplied as 100mg, 400mg, and 500mg strength tablets.