A Simple Dosing Scheme for Intravenous Busulfan Based on Retrospective Population Pharmacokinetic Analysis in Korean Patients
A Simple Dosing Scheme for Intravenous Busulfan Based on Retrospective Population Pharmacokinetic Analysis in Korean Patients
- Sangmin Choe Gayeong Kim Hyeong-Seok Lim Sang-Heon Cho Jong-Lyul Ghim Jin Ah Jung Un-Jib Kim Gyujeon
- 대한생리학회-대한약리학회
- The Korean Journal of Physiology & Pharmacology
- 제16권 제4호
- 등재여부 : KCI등재
- 2012.01
- 273 - 280 (8 pages)
Busulfan is an antineoplastic agent with a narrow therapeutic window. A post-hoc population pharmacokinetic analysis of a prospective randomized trial for comparison of four-times daily versus once-daily intravenous busulfan was carried out to search for predictive factors of intravenous busulfan (iBu) pharmacokinetics (PK). In this study the population PK of iBu was characterized to provide suitable dosing recommendations. Patients were randomized to receive iBu, either as 0.8 mg/kg every 6 h or 3.2 mg/kg daily over 4 days prior to hematopoietic stem cell transplantation. In total, 295 busulfan concentrations were analyzed with NONMEM. Actual body weight and sex were significant covariates affecting the PK of iBu. Sixty patients were included in the study (all Korean; 23 women, 37 men; mean [SD] age, 36.5 [10.9] years; weight, 66.5 [11.3] kg). Population estimates for a typical patient weighing 65 kg were: clearance (CL) 7.6 l/h and volume of distribution (V<sub>d</sub>) 32.2 l for men and 29.1 L for women. Inter-individual random variabilities of CL and V<sub>d</sub> were 16% and 9%. Based on a CL estimate from the final PK model, a simple dosage scheme to achieve the target AUC<sub>0-inf</sub> (defined as median AUC<sub>0-inf</sub> with a once-daily dosage) of 26.18 mg/lㆍhr, was proposed: 24.79ㆍABW<sup>0.5</sup> mg q24h, where ABW represents the actual body weight in kilograms. The dosing scheme reduced the unexplained interindividual variabilities of CL and Vd of iBu with ABW being a significant covariate affecting clearance of iBU. We propose a new simple dosing scheme for iBu based only on ABW.