Urinary Erythropoietin Concentrations after Early Short-Term Infusion of High-Dose Recombinant Epo for Neuroprotection in Preterm Neonates

BACKGROUND: High-dose recombinant human erythropoietin (rEpo) has first been administered in clinical trials for neuroprotection in very preterm neonates at high risk of brain injury and in (near-) term neonates with hypoxic-ischemic encephalopathy. However, recent trials in adults raised concerns about the safety of high-dose rEpo for neuro- and cardioprotection. OBJECTIVES: To evaluate the putative accumulation or renal leakage of Epo as a function of developmental stage after repetitive early short-term infusion of high-dose rEpo (3 × 3,000 U/kg within 42 h after birth; NCT00413946) for neuroprotection in very preterm infants. METHODS: Epo concentrations were measured using the ELISA technique in the first two consecutive urine specimens after each rEpo infusion. RESULTS: Renal Epo excretion was significantly higher in preterm infants with gestational ages <29 weeks than in more mature infants and reached up to 23% of the administered rEpo within 8 h after each infusion. The urinary Epo concentration did not increase after three repetitive infusions of high-dose rEpo. The ratio of urinary Epo to total protein concentrations was the same in infants with gestational ages <29 weeks and in those with gestational ages ≥29 weeks. CONCLUSIONS: Our data suggest that the higher renal Epo excretion in more immature infants may be attributed to a higher glomerular filtration leakage due to the lower maturation of the kidneys and argue against saturation kinetics after multiple doses of 3,000 U/kg rEpo. This information should be considered in future trials on the use of rEpo for neuroprotection in neonates.