title: Pharmacokinetics of intravenous recombinant human granulocyte colony-stimulating factor (rhG-CSF) in children receiving myelosuppressive cancer chemotherapy: clearance increases in relation to absolute neutrophil count with repeated dosing.
abstract: Limited evidence suggests increased efficacy of rhG-CSF by subcutaneous (SQ) compared with intravenous (IV) administration. To examine the possibility that rapid elimination of IV rhG-CSF could substantially shorten the duration of systemic exposure and could explain a difference in pharmacodynamics, we characterized the pharmacokinetic profile of IV rhG-CSF for comparison to that previously reported for SQ administration. Twelve children were randomly assigned to receive 10 or more days of IV rhG-CSF at dosages of 5 or 10 microg/kg a day beginning 24 hr after chemotherapy. Enzyme-linked immunosorbent assay (ELISA) was used to measure rhG-CSF concentrations in timed serum samples on days 1 and 10. Pharmacokinetic parameters were estimated by nonlinear, least squares regression. All serum concentration-time profiles were best described by a two-compartment model of elimination. Mean t1/2beta values ranged from 3.68 +/- 0.86 to 22.4 +/- 12.0 hr. ANC was correlated with log CLT (r = 0.72, P < 0.05), and inversely with log dose-adjusted AUC (r = 0.75, P < 0.05) and log dose-adjusted Cmax (r = -0.65, P < 0.05). Estimated duration of serum rhG-CSF concentrations above 1 ng/ml exceeded 24 hr for all but the 5 microg/kg cohort on day 1. Pharmacokinetic parameters of IV rhG-CSF are similar to those previously reported for SQ administration in children treated with myelosuppressive cancer chemotherapy. Daily IV administration should be a suitable alternative route of administration in this patient population.
authors.affiliation: College of Pharmacy, Rutgers, The State University of New Jersey, New Brunswick 08903, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Sturgill
authors.forename: R D
authors.initials: RD
authors.lastname: Huhn
authors.forename: R A
authors.initials: RA
authors.lastname: Drachtman
authors.forename: A G
authors.initials: AG
authors.lastname: Ettinger
authors.forename: L J
authors.initials: LJ
authors.lastname: Ettinger
mesh_terms: D000293:Adolescent; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001853:Bone Marrow / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D007275:Injections, Intravenous; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils / Q000473:pathology*; D011994:Recombinant Proteins
chemical_list: D000970:Antineoplastic Agents; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor