An Extended Terminal Half-Life for Darbepoetin Alfa: Results from a Single-Dose Pharmacokinetic Study in Patients with Chronic Kidney Disease not Receiving Dialysis

Background and objective Anaemia is a major and persistent manifestation of chronic kidney disease (CKD) caused by the deficient production of erythropoietin in the kidneys, the prevalence of which is proportional to the deterioration in kidney function. Darbepoetin alfa, an erythropoiesis-stimulating protein, exhibits a lower clearance and longer terminal half-life in serum than recombinant human erythropoietin, thereby allowing for a reduced dosing frequency. A recent study in patients with CKD, using a 4-week sampling period, suggested that the terminal half-life of darbepoetin alfa in serum is longer than that reported in previous studies, which were based on a 1-week sampling period. This study was conducted to characterise the pharmacokinetic profile of a single subcutaneous dose of darbepoetin alfa 1 µg/kg in patients with CKD, using a sampling duration of 4 weeks, which was hypothesised to allow better characterisation of the terminal half-life in serum.