FDA Approves Bosutinib for Pediatric Chronic Myelogenous Leukemia

Findings from the phase 1/2 BCHILD study (NCT04258943)—in which 28 patients with PH-positive resistant or intolerant CML and 21 patients with newly diagnosed, chronic phase disease received bosutinib—supported the approval.

The FDA has granted approval to bosutinib (Bosulif) for the treatment of pediatric patients aged 1 year or older with newly diagnosed or resistant/previous treatment intolerant chronic myelogenous leukemia (CML) that is Philadelphia chromosome (Ph) positive and in chronic phase, according to a press release from the FDA.¹

Findings from the phase 1/2 BCHILD study (NCT04258943)—in which 28 patients with PH-positive resistant or intolerant CML were treated with 300 mg/m2 to 400 mg/m² and 21 patients with newly diagnosed, chronic phase disease received 300 mg/m²—supported the approval.² The recommended doses were 400 mg/m² and 300 mg/m², respectively.

In the newly diagnosed population, the major cytogenetic response rate was (MCyR) was 76.2% (95% CI, 52.8%-91.8%) and the complete cytogenetic response rate (CCyR) was 71.4% (95% CI, 47.8%-88.7%). Additionally, investigators reported a major molecular response (MMR) rate of 28.6% (95% CI, 11.3%-52.3%) with a median duration of response of 14.2 months (range, 1.1-26.3).

In the resistant/intolerant population, the MCyR and CCyR rates were 82.1% (95% CI, 63.1%-93.9%) and 78.6% (95% CI, 59.0%-91.7%), respectively. Moreover, investigators reported an MMR of 50.0% (95% CI, 30.6%-69.4%) in this population. Of 14 patients, 2 lost an MMR following 13.6 months and 24.7 months of treatment with bosutinib, respectively. The median follow-up was 23.2 months (range, 1-61.5 months).

In terms of safety, frequent adverse effects included diarrhea, abdominal pain, vomiting, nausea, rash, fatigue, hepatic dysfunction, headache, pyrexia, decreased appetite, and constipation. Additionally, investigators reported several frequent laboratory abnormalities, including increased creatinine, increased alanine aminotransferase or aspartate aminotransferase, decreased white blood cell count, and decreased platelet count.

References

1. FDA approves bosutinib for pediatric patients with chronic myelogenous leukemia. News release. FDA. September 26, 2023. Accessed September 27, 2023. https://bit.ly/46madME
2. Pennesi E, Brivio E, Willemse ME, et al. Preliminary results from the first-in-child phase II trial (ITCC-054/COG-AAML1921) of bosutinib in pediatric patients with newly diagnosed (ND) chronic myeloid leukemia (CML). J Clin Oncol. 2023; 41(supp 16):10017. doi:10.1200/JCO.2023.41.16_suppl.10017