Erlotinib Pharmacokinetics in Children with High-Grade Glioma: A Study

A recent phase I study published in Clinical Cancer Research has provided valuable insights into the pharmacokinetics of erlotinib, a protein kinase inhibitor, in children with newly diagnosed high-grade glioma. The study aimed to estimate the maximum-tolerated dose (MTD) of erlotinib when administered concurrently with radiotherapy and to describe the pharmacokinetics of erlotinib and its metabolite OSI-420 in patients aged 3 to 25 years. The researchers found that the MTD of erlotinib was 120 mg/m^2 per day, and pharmacokinetic studies showed wide interpatient variability in drug exposure.

Key Takeaways:

• The MTD of erlotinib in children with newly diagnosed high-grade glioma was 120 mg/m^2 per day.
• Pharmacokinetic studies showed wide interpatient variability in drug exposure.
• The pharmacokinetic variables of erlotinib and OSI-420 in children were similar to those described in adults.
• No EGFR kinase domain mutations were observed in the tumor tissue samples.
• Two patients with glioblastoma harbored mutations in PIK3CA (n=1) or PTEN (n=1).
• Dose-limiting toxicities were diarrhea, increase in serum lipase, and rash with pruritus.
• Skin rash and diarrhea were generally well-controlled with supportive care.

Statistics:

• Median age at diagnosis: 10.7 years (range, 3.7-22.5 years).
• Number of patients: 23.
• Erlotinib dosage levels: 70, 90, 120, 160, and 200 mg/m^2 per day.
• Time of therapy: up to 3 years.
• Dose-limiting toxicities: nausea (n=1), increase in serum lipase (n=1), and rash with pruritus (n=1).

Sources:

• Broniscer, A., et al. (2009). Phase I and pharmacokinetic studies of erlotinib administered concurrently with radiotherapy for children, adolescents, and young adults with high-grade glioma. Clinical Cancer Research, 15(2), 701-707.
• St. Jude Children's Research Hospital, Department of Oncology (site not available).
• American Association for Cancer Research (site not available).