Pharmacokinetics of metronomic temozolomide in cerebrospinal fluid of children with malignant central nervous system tumors.

Abstract

PURPOSE:

Although temozolomide is widely used in the treatment of childhood central nervous system (CNS) tumors, information on its pharmacokinetic profile in the brain or cerebrospinal fluid (CSF) is sparse. This study aimed at investigating whether measurable and clinically relevant concentrations of temozolomide are reached and maintained in CSF for continuous oral administration in pediatric patients. A population pharmacokinetic model was developed to quantify CSF penetration of temozolomide.

METHODS:

Eleven pediatric CNS tumor patients (aged 4-14 years) treated with oral temozolomide using a metronomic schedule (24-77 mg/m2/day) were included. Temozolomide concentrations in 28 plasma samples and 64 CSF samples were analyzed by high-performance liquid chromatography. Population pharmacokinetic modeling and simulations were performed using non-linear mixed effects modeling (NONMEM 7.4.2).

RESULTS:

Median temozolomide concentrations in plasma and CSF were 0.96 (range 0.24-5.99) µg/ml and 0.37 (0.06-1.76) µg/ml, respectively. A two-compartment model (central/plasma [1], CSF [2]) with first-order absorption, first-order elimination, and a transit compartment between CSF and plasma adequately described the data. Population mean estimates for clearance (CL) and the volume of distribution in the central compartment (Vc) were 3.29 L/h (95% confidence interval (CI) 2.58-3.95) and 10.5 L (8.17-14.32), respectively. Based on simulations, we found a median area under the concentration vs. time curve ratio (AUCCSF / AUCplasma ratio) of 37%.

CONCLUSION:

Metronomic oral temozolomide penetrates into the CSF in pediatric patients, with even higher concentration levels compared to adults.

• Authors: Sören Büsker, Walter Jäger, Stefan Poschner, Lisa Mayr, Valentin Al Jalali, Johannes Gojo, Amedeo A Azizi, Sami Ullah, Muhammad Bilal, Lobna El Tabei, Uwe Fuhr, Andreas Peyrl
• Journal: Cancer chemotherapy and pharmacology (Cancer Chemother Pharmacol) Vol. 89 Issue 5 Pg. 617-627 (05 2022) ISSN: 1432-0843 [Electronic] Germany
• PMID: 35355137 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2022. The Author(s).

Chemical References

• Temozolomide

Topics

• Adult
• Animals
• Area Under Curve
• Central Nervous System Neoplasms (drug therapy)
• Child
• Chromatography, High Pressure Liquid
• Humans
• Macaca mulatta
• Temozolomide