title: Pharmacokinetics of novel erythropoiesis stimulating protein compared with epoetin alfa in dialysis patients.
abstract: Novel erythropoiesis stimulating protein (NESP) is a hyperglycosylated analogue of recombinant human erythropoietin (Epoetin) which has an increased terminal half-life in animal models. The aim of this study was to extend these observations to humans. Using a double-blind, randomized, cross-over design, the single-dose pharmacokinetics of Epoetin alfa (100 U/kg) and an equivalent peptide mass of NESP were compared following intravenous bolus in 11 stable peritoneal dialysis patients. This was followed by an open-label study to determine the single-dose pharmacokinetics of an equivalent peptide mass of NESP by subcutaneous injection in six of these patients. The mean terminal half-life for intravenous NESP was threefold longer than for intravenous Epoetin (25.3 versus 8.5 h), a difference of 16.8 h (95% confidence interval, 9.4 to 24.2 h, P = 0.0008). The area under the serum concentration-time curve was significantly greater for NESP (291.0 +/- 7.6 ng x h per ml versus 131.9 +/- 8.3 ng x h per ml; mean +/- SEM; P < 0.0005), and clearance was significantly lower (1.6 +/- 0.3 ml/h per kg versus 4.0 +/- 0.3 ml/h per kg; mean +/- SEM; P < 0.0005). The volume of distribution was similar for NESP and Epoetin (52.4 +/- 2.0 ml/kg versus 48.7 +/-2.1 ml/kg; mean +/-SEM). The mean terminal half-life for subcutaneous NESP was 48.8 h. The peak concentration of subcutaneous NESP was approximately 10% of that following intravenous administration, and bioavailability was approximately 37% by the subcutaneous route. The longer half-life of NESP is likely to confer a clinical advantage over Epoetin by allowing less frequent dosing in patients treated for anemia.
authors.affiliation: Department of Renal Medicine, King's College Hospital, London, United Kingdom. icm-kru@globalnet.co.uk
authors.forename: I C
authors.initials: IC
authors.lastname: Macdougall
authors.forename: S J
authors.initials: SJ
authors.lastname: Gray
authors.forename: O
authors.initials: O
authors.lastname: Elston
authors.forename: C
authors.initials: C
authors.lastname: Breen
authors.forename: B
authors.initials: B
authors.lastname: Jenkins
authors.forename: J
authors.initials: J
authors.lastname: Browne
authors.forename: J
authors.initials: J
authors.lastname: Egrie
mesh_terms: D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004920:Erythropoiesis / Q000187:drug effects*; D004921:Erythropoietin / Q000031:analogs & derivatives / Q000493:pharmacokinetics*; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins
chemical_list: D011994:Recombinant Proteins; D004921:Erythropoietin