PEDIATRICS Vol. 122 No. 2 August 2008, pp. 383-391 (doi:10.1542/10.1542/peds.2007-2711)
ARTICLE |
A Phase I/II Trial of High-Dose Erythropoietin in Extremely Low Birth Weight Infants: Pharmacokinetics and Safety
a Departments of Pediatrics
b Pharmacy and Laboratory Medicine, University of Washington, Seattle, Washington
OBJECTIVES. High-dose recombinant erythropoietin is neuroprotective in animal models of neonatal brain injury. Extremely low birth weight infants are at high risk for brain injury and neurodevelopmental problems and might benefit from recombinant erythropoietin. We designed a phase I/II trial to test the safety and determine the pharmacokinetics of high-dose recombinant erythropoietin in extremely low birth weight infants.
METHODS. In a prospective, dose-escalation, open-label trial, we compared 30 infants who were treated with high-dose recombinant erythropoietin with 30 concurrent control subjects. Eligible infants were <24 hours old,
1000 g birth weight, and
28 weeks of gestation and had an umbilical artery catheter in place. Each infant received 3 intravenous doses of 500, 1000, or 2500 U/kg at 24-hour intervals beginning on day 1 of age. Blood samples were collected at scheduled intervals to determine recombinant erythropoietin pharmacokinetics. Safety parameters were also evaluated. In the concurrent control group, only clinical data were collected.
RESULTS. Mean erythropoietin concentrations 30 minutes after recombinant erythropoietin infusion were 5973 ± 266, 12291 ± 403, and 34197 ± 1641 mU/mL after 500, 1000, or 2500 U/kg, respectively. High-dose recombinant erythropoietin followed nonlinear pharmacokinetics as a result of decreasing clearance from the lowest dosage (17.3 mL/hour per kg for 500 U/kg) to the highest dosage (8.2 mL/hour per kg for 2500 U/kg). Steady state was achieved within 24 to 48 hours. Both 1000 and 2500 U/kg recombinant erythropoietin produced peak serum erythropoietin concentrations that were comparable to neuroprotective concentrations that previously were seen in experimental animals. No excess adverse events occurred in the recombinant erythropoietin–treated infants compared with control infants.
CONCLUSIONS. Early high-dose recombinant erythropoietin is well tolerated by extremely low birth weight infants, causing no excess morbidity or mortality. Recombinant erythropoietin dosages of 1000 and 2500 U/kg achieved neuroprotective serum levels.
Key Words: neonate preterm neuroprotection
Abbreviations: ELBW—extremely low birth weight ICH—intracranial hemorrhage Epo—erythropoietin rEpo—recombinant erythropoietin ROP—retinopathy of prematurity PVL—periventricular leukomalacia PDA—patent ductus arteriosus AUC—area under the curve NEC—necrotizing enterocolitis TAOC—total antioxidant capacity t1/2—half-life Epo-R—erythropoietin receptor HSD—honestly significant differences
Accepted Dec 4, 2007.
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