Pharmacokinetic Analysis of High Dose Methotrexate in Pediatric Lymphoblastic Malignancies

Pharmacokinetic Analysis of High Dose Methotrexate in Pediatric Acute Lymphoblastic Leukemia: Significant Impact Factors and Establishment of a Clinically Relevant Model

* The pharmacokinetics of MTX were assessed with regards to the relevance of several different patient specific factors in 291 pediatric patients, who were administered with high dose of MTX. Population pharmacokinetics of MTX analysis was performed by using nonlinear mixed effects modeling.

• Methotrexate (MTX) is one of the critical components for treating all forms of acute lymphoblastic leukemia (ALL), which is the most common pediatric cancer. Unfortunately, high dose MTX has several undesirable side effects and MTX toxicity vastly differs from patient to patient.
• The pharmacokinetics of MTX were assessed with regards to the relevance of several different patient specific factors in 291 pediatric patients, who were administered with high dose of MTX. Population pharmacokinetics of MTX analysis was performed by using nonlinear mixed effects modeling.
• The final model was validated using nonparametric bootstrap analysis. Body surface area (BSA), pre-hydration, baseline serum creatinine and 24 h creatinine clearance rate were statistically significant covariates for distributional volume (V) and renal clearance (CL). Herein, is the first report of analysis of the importance of a series of patient factors on pharmacokinetics of MTX by one-compartment model. Using these data, we have established an efficient population pharmacokinetic model for MTX, which can be used to predict safe clinical application of MTX especially in children with ALL.

Inclusion Criteria:

• Acute lymphoblastic leukemia and non-hodgkin's lymphoma younger than 18 years old

Exclusion Criteria:

• Non lymphoblastic malignancies or older than 18 years