Korean J Physiol Pharmacol. 2016 May;20(3):245-51. doi: 10.4196/kjpp.2016.20.3.245. Epub 2016 Apr 26.

Prospective validation of a novel dosing scheme for intravenous busulfan 

in adult patients undergoing hematopoietic stem cell transplantation.

Cho SH, Lee JH, Lim HS, Lee KH, Kim DY, Choe S, Bae KS, Lee JH.

Abstract

The objective of this study was to externally validate a new dosing scheme for busulfan. Thirty-seven adult patients who received busulfan as conditioning therapy for hematopoietic stem cell transplantation (HCT) participated in this prospective study. Patients were randomized to receive intravenous busulfan, either as the conventional dosage (3.2 mg/kg daily) or according to the new dosing scheme based on their actual body weight (ABW) (23×ABW(0.5) mg daily) targeting an area under the concentration-time curve (AUC) of 5924 µM·min. Pharmacokinetic profiles were collected using a limited sampling strategy by randomly selecting 2 time points at 3.5, 5, 6, 7 or 22 hours after starting busulfan administration. Using an established population pharmacokinetic model with NONMEM software, busulfan concentrations at the available blood sampling times were predicted from dosage history and demographic data. The predicted and measured concentrations were compared by a visual predictive check (VPC). Maximum a posteriori Bayesian estimators were estimated to calculate the predicted AUC (AUCPRED). The accuracy and precision of the AUCPRED values were assessed by calculating the mean prediction error (MPE) and root mean squared prediction error (RMSE), and compared with the target AUC of 5924 µM·min. VPC showed that most data fell within the 95% prediction interval. MPE and RMSE of AUCPRED were -5.8% and 20.6%, respectively, in the conventional dosing group and -2.1% and 14.0%, respectively, in the new dosing scheme group. These fi ndings demonstrated the validity of a new dosing scheme for daily intravenous busulfan used as conditioning therapy for HCT.

KEYWORDS:

Adult; Busulfan; Drug dosage calculations; Hematopoietic stem cell transplantation; Pharmacokinetics

PMID:

27162478

PMCID:

PMC4860366

DOI:

10.4196/kjpp.2016.20.3.245