title: Population pharmacokinetics of eltrombopag in healthy subjects and patients with chronic idiopathic thrombocytopenic purpura.
abstract: The population pharmacokinetics of eltrombopag were characterized in healthy subjects (n = 111) and patients with idiopathic thrombocytopenic purpura (ITP) (n = 88) using nonlinear mixed-effects modeling. The final model was evaluated via graphical diagnostics and through predictive check and nonparametric bootstrap procedures. A 2-compartment model with dual sequential first-order absorption, absorption lag time, and interoccasion variability in absorption adequately described the data. For a typical 70-kg Caucasian male ITP patient not taking corticosteroids, estimated parameters were apparent clearance (CL/F) = 0.668 L/h, apparent volume of the central compartment (Vc/F) = 8.76 L, apparent volume of the peripheral compartment (Vp/F) = 11.3 L, and distributional clearance (Q/F) = 0.399 L/h. Eltrombopag CL/F, Vc/F, Q/F, and Vp/F increased with body weight. For the range of weights included (43-122 kg), the parameters ranged from 26% lower to 41% higher than for a 70-kg individual. The typical eltrombopag CL/F was 33% lower in East Asians compared with other races, 26% lower in patients taking corticosteroids concomitantly, 19% lower in females compared with males, and 17% higher in healthy subjects compared with ITP patients. There was also a dose effect, with CL/F and Vc/F estimated to be respectively 68% and 55% higher for doses 20 mg or less. In conclusion, East Asian race had the largest impact on eltrombopag exposure with a lower initial dose being recommended.
authors.affiliation: QuantPharm LLC, 49 Flints Grove Drive, North Potomac, MD 20878, USA.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Gibiansky
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhang
authors.forename: Daphne
authors.initials: D
authors.lastname: Williams
authors.forename: Zhao
authors.initials: Z
authors.lastname: Wang
authors.forename: Daniele
authors.initials: D
authors.lastname: Ouellet
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data; D001565:Benzoates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006834:Hydrazines / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000188:drug therapy*; D011720:Pyrazoles / Q000008:administration & dosage / Q000493:pharmacokinetics*; D053628:Receptors, Thrombopoietin / Q000819:agonists*; D012727:Sex Characteristics; D044465:White People / Q000706:statistics & numerical data
chemical_list: D001565:Benzoates; D006834:Hydrazines; D011720:Pyrazoles; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; C520809:eltrombopag