title: Achieving target voriconazole concentrations more accurately in children and adolescents.
abstract: Despite the documented benefit of voriconazole therapeutic drug monitoring, nonlinear pharmacokinetics make the timing of steady-state trough sampling and appropriate dose adjustments unpredictable by conventional methods. We developed a nonparametric population model with data from 141 previously richly sampled children and adults. We then used it in our multiple-model Bayesian adaptive control algorithm to predict measured concentrations and doses in a separate cohort of 33 pediatric patients aged 8 months to 17 years who were receiving voriconazole and enrolled in a pharmacokinetic study. Using all available samples to estimate the individual Bayesian posterior parameter values, the median percent prediction bias relative to a measured target trough concentration in the patients was 1.1% (interquartile range, -17.1 to 10%). Compared to the actual dose that resulted in the target concentration, the percent bias of the predicted dose was -0.7% (interquartile range, -7 to 20%). Using only trough concentrations to generate the Bayesian posterior parameter values, the target bias was 6.4% (interquartile range, -1.4 to 14.7%; P = 0.16 versus the full posterior parameter value) and the dose bias was -6.7% (interquartile range, -18.7 to 2.4%; P = 0.15). Use of a sample collected at an optimal time of 4 h after a dose, in addition to the trough concentration, resulted in a nonsignificantly improved target bias of 3.8% (interquartile range, -13.1 to 18%; P = 0.32) and a dose bias of -3.5% (interquartile range, -18 to 14%; P = 0.33). With the nonparametric population model and trough concentrations, our control algorithm can accurately manage voriconazole therapy in children independently of steady-state conditions, and it is generalizable to any drug with a nonparametric pharmacokinetic model. (This study has been registered at ClinicalTrials.gov under registration no. NCT01976078.).
authors.affiliation: Laboratory of Applied Pharmacokinetics and Bioinformatics, The Saban Research Institute and the Division of Pediatric Infectious Diseases, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA mneely@usc.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Neely
authors.affiliation: Division of Pediatric Hematology/Oncology, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Margol
authors.affiliation: Pathology and Laboratory Medicine, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Fu
authors.affiliation: Laboratory of Applied Pharmacokinetics and Bioinformatics, The Saban Research Institute and the Division of Pediatric Infectious Diseases, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: van Guilder
authors.affiliation: Laboratory of Applied Pharmacokinetics and Bioinformatics, The Saban Research Institute and the Division of Pediatric Infectious Diseases, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: David
authors.initials: D
authors.lastname: Bayard
authors.affiliation: Laboratory of Applied Pharmacokinetics and Bioinformatics, The Saban Research Institute and the Division of Pediatric Infectious Diseases, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Schumitzky
authors.affiliation: Pharmacy Department, University of Southern California Children's Hospital Los Angeles, Los Angeles, California, USA.
authors.forename: Regina
authors.initials: R
authors.lastname: Orbach
authors.affiliation: Department of Clinical Pharmacy and Pharmaceutical Economics & Policy, University of Southern California School of Pharmacy, Los Angeles, California, USA.
authors.forename: Siyu
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Clinical Pharmacy and Pharmaceutical Economics & Policy, University of Southern California School of Pharmacy, Los Angeles, California, USA.
authors.forename: Stan
authors.initials: S
authors.lastname: Louie
authors.affiliation: Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, United Kingdom.
authors.forename: William
authors.initials: W
authors.lastname: Hope
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D065819:Voriconazole / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D065819:Voriconazole