FDA Approves Bosutinib for Pediatric Patients With CP-CML

• The FDA-recommended dose of bosutinib for the treatment of patients with newly-diagnosed with chronic phase (CP), Philadelphia chromosome-positive chronic myelogenous leukemia (CML) is 300 mg/m² to be administered orally once daily with food.

• The FDA-recommended dose of bosutinib for the treatment of relapsed/refractory CP-CML is 400 mg/m² to be administered orally once daily with food.

• In addition to bosutinib’s latest FDA indication, the FDA approved a capsule form on bosutinib in the dosages of 50 mg and 100mg.

The FDA has granted approval to bosutinib for the treatment of pediatric patients aged 1 year or older with CP-CML that is newly diagnosed or relapsed or refractory to prior therapy.¹

Results from the phase 1/2 BCHILD study (NCT04258943) support the FDA’s decision to grant approval of bosutinib for this indication. The study showed that bosutinib had preliminary efficacy in patients with CP-CML compared with other second-generation tyrosine kinase inhibitors. The agent was also well-tolerated in patients.^1,2

In the newly diagnosed CP-CML population, the median duration of follow-up was 4.2 months (range, 1.1-26.3 months). Bosutinib achieved a major cytogenetic response rate (MCyR) of 76.2% (95% CI, 52.8-91.8) and complete cytogenetic response rate (CCyR) of 71.4% (95% CI, 47.8-88.7). Further, the major molecular response rate was 28.6% (95% CI, 11.3-52.3).

Among patients with relapsed/refractory CP-CML, the median duration of follow-up was 23.2 months (range, 1-61.5 months). MCyR observed with bosutinib was 82.1% (95% CI, 63.1- 93.9), and the CCyR was 78.6% (95% CI, 59-91.7). Fourteen patients from the cohort achieved a MMR, and of them 2 patients lost MMR after 13.6 and 24.7 months on treatment, respectively.

Occurring in at least 20% of patients in the study, the most common adverse events were diarrhea, abdominal pain, vomiting, nausea, rash, fatigue, hepatic dysfunction, headache, pyrexia, decreased appetite, and constipation. Further, increased creatinine, increased alanine aminotransferase or aspartate aminotransferase, decreased white blood cell count, and decreased platelet count were the most common laboratory abnormalities, which were observed in 45% of patients or more.

_REFERENCES:

_{1. FDA approves bosutinib for pediatric patients with chronic myelogenous leukemia. News release. FDA. September 27, 2023. Accessed. September 27, 2023. https://tinyurl.com/bdza5my2}

_{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(suppl 16): 10017. doi:10.1200/JCO.2023.41.16_suppl.10017}