title: Extended activity in cynomolgus monkeys of a granulocyte colony-stimulating factor mutein conjugated with high molecular weight polyethylene glycol.
abstract: The activity of a granulocyte colony-stimulating factor (G-CSF) mutein (nartograstim; [NTG]) conjugated with an average of two polyethylene glycol (PEG) chains per protein molecule was examined in cynomolgus monkeys following a single s.c. injection. Groups of monkeys were given 10 microg/kg, 30 microg/kg, or 100 microg/kg. For comparison, one group of monkeys was given 5 microg/kg of recombinant human G-CSF (rHuG-CSF) daily for six days. In monkeys given 100 microg/kg of PEG-NTG, neutrophil levels reached a peak one day after injection approximately 20-fold higher than baseline levels. Neutrophil numbers in these animals were still significantly elevated six days after injection. In contrast, peak neutrophil levels in monkeys given six injections of rHuG-CSF reached a peak only on day 6 and were approximately the same as that in monkeys given a single dose of PEG-NTG six days before. Pharmacokinetics of PEG-NTG in these monkeys indicated that the area under the plasma concentration time curve (AUC) increased with increasing the dose from 497 ng x h/ml at 10 microg/kg, 6,140 ng x h/ml at 30 microg/kg to 27,900 ng x h/ml at 100 microg/kg. In a separate study, the effects of single doses of 100 microg/kg of PEG-NTG, rHuG-CSF, and unmodified NTG were compared. In this experiment, peak numbers of neutrophils were reached two days after injection in animals receiving PEG-NTG and one day after in animals given unmodified proteins. The pharmacokinetic parameters demonstrated increased exposure for PEG-NTG relative to the unmodified proteins with an AUC0. of 21,012 ng x h/ml compared with 5,492 ng x h/ml for rHuG-CSF and 5,153 ng x h/ml for NTG. These results demonstrate that conjugation of a G-CSF mutein with high molecular weight PEG results in a preparation that can induce prolonged elevation of neutrophils in normal nonhuman primates following a single injection.
authors.affiliation: Dept. of Internal Medicine, Wayne State School of Medicine, Detroit, Michigan, USA. eliasonj@karmanos.org
authors.forename: J F
authors.initials: JF
authors.lastname: Eliason
authors.forename: A
authors.initials: A
authors.lastname: Greway
authors.forename: N
authors.initials: N
authors.lastname: Tare
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: S
authors.initials: S
authors.lastname: Bowen
authors.forename: M
authors.initials: M
authors.lastname: Dar
authors.forename: M
authors.initials: M
authors.lastname: Yamasaki
authors.forename: M
authors.initials: M
authors.lastname: Okabe
authors.forename: I
authors.initials: I
authors.lastname: Horii
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000493:pharmacokinetics* / Q000494:pharmacology; D006801:Humans; D018655:Lymphocyte Count; D008252:Macaca fascicularis; D008297:Male; D051379:Mice; D008970:Molecular Weight; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology; D011092:Polyethylene Glycols / Q000008:administration & dosage; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D016179:Granulocyte Colony-Stimulating Factor; D011092:Polyethylene Glycols; C072115:nartograstim