title: Pharmacokinetics of pegylated recombinant human megakaryocyte growth and development factor in healthy volunteers and patients with hematological disorders.
abstract: OBJECTIVE
  The purpose of this study is to examine the pharmacokinetics of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) in healthy volunteers with normal hematopoiesis and patients with idiopathic thrombocytopenic purpura (ITP), acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and aplastic anemia (AA).
  
  
  METHODS
  PEG-rHuMGDF was intravenously administered to healthy volunteers and patients with ITP, AML, MDS, and AA. The serum concentration of PEG-rHuMGDF was measured and the pharmacokinetics was investigated using non-linear mixed-effects modeling technique.
  
  
  RESULTS
  The systemic clearance (CL) and volume of distribution at steady-state (Vss) consistently decreased in the healthy subjects, when the dose increased. In AML patients, CL and Vss decreased when the dose increased, but the change of CL was not statistically significant. In contrast, no significant dose dependency of these parameter estimates was observed in MDS patients. In AA patients there was no significant change in Vss but the CL of the higher dose groups was slightly smaller than that of the lower dose groups. Relatively smaller CL and Vss in ITP patients than those of healthy volunteers at the same dose were observed.
  
  
  CONCLUSIONS
  This saturable pathway of CL may involve the receptor-mediated endocytosis and degradation by megakaryocyte lineage cells and platelets. The saturable distribution space can be also explained by the receptors on hematopoietic cells. The non-saturable distribution space corresponds to the value of plasma and interstitial fluid volume.
authors.affiliation: Pharmaceutical Division, Kirin Brewery Company, Ltd, Shibuya-ku, Tokyo, Japan. hidejit@kirin.co.jp
authors.forename: Hideji
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Takama
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Arai
authors.forename: Junichi
authors.initials: J
authors.lastname: Azuma
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Ohno
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Hideaki
authors.initials: H
authors.lastname: Mizoguchi
mesh_terms: D016022:Case-Control Studies; D006402:Hematologic Diseases / Q000188:drug therapy*; D006801:Humans; D010919:Placebos; D011092:Polyethylene Glycols / Q000493:pharmacokinetics* / Q000627:therapeutic use; D011994:Recombinant Proteins / Q000493:pharmacokinetics* / Q000627:therapeutic use; D016037:Single-Blind Method; D013926:Thrombopoietin / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D010919:Placebos; D011994:Recombinant Proteins; C103117:polyethylene glycol-recombinant human megakaryocyte growth and development factor; D011092:Polyethylene Glycols; D013926:Thrombopoietin