Population Pharmacokinetics of Cyclosporine after Hematopoietic Stem Cell Transplantation in Pediatric Patients

ABSTRACT

BACKGROUND: Cyclosporine is an immunosuppressive agent used to treat and prevent graft versus host reaction (GVHR)-a complication associated with stem cell transplantation. This study aimed to develop a population pharmacokinetic model of cyclosporine and investigate factors affecting cyclosporine clearance in pediatric hematopoietic stem cell transplant patients. METHODS: A total of 650 cyclosporine concentrations recorded in 65 patients who underwent hematopoietic stem cell transplantation were used. Data including age, sex, weight, height, body surface area (BSA), type of disease, chemotherapy before stem cell transplantation, type of donor, serum creatinine levels, total bilirubin concentration, hematocrit value, and type of concomitant antifungal agents and methylprednisolone used were retrospectively collected. Data related to cyclosporine dosage, administration time, and blood concentration were also collected. All data were analyzed using the non-linear mixed effect model; a two-compartment model with first-order elimination was used. RESULTS: The population pharmacokinetic model of cyclosporine using the NONMEM program was as follows: CL (L/h) = 5.9 × (BSA / 1.2)0.9, V2 (L) = 54.5, Q (L/h) = 3.5, V3 (L) = 1080.0, ka (h-1) = 0.000377. BSA was selected as a covariate of cyclosporine clearance, which increased with an increase in BSA. CONCLUSION: A population pharmacokinetic model for Korean pediatric hematopoietic stem cell transplant patients was developed, and the important factor affecting cyclosporine clearance was found to be BSA. The model might contribute to the development of the most appropriate dosing regimen for cyclosporine. Further studies on population pharmacokinetics should be carried out, prospectively targeting pediatric patients.