What Is the Expected Clearance of Methotrexate? A Therapeutic Drug Monitoring Reference Guide for High-Dose Methotrexate Use in Pediatric Malignancies.

Abstract

High-dose methotrexate dosage and infusion durations differ across treatment protocols for pediatric leukemia, lymphoma, and osteosarcoma. Supportive care interventions are dependent on a patient's elimination of methotrexate (MTX). Therefore, it is important to establish the expected MTX elimination across protocols. Using modeling and simulation of real-world data, we determined the expected MTX concentrations at common time points from the start of infusion (24, 36, 42, 48, 60, and 72 hours) and the time that each patient would reach a typical discharge threshold (0.4, 0.2, 0.15, and 0.10 µM). These data provide a reference for MTX concentrations for common pediatric protocols.