Background: Darbepoetin alfa, a glycoprotein that stimulates erythropoiesis by the same mechanism as endogenous erythropoietin, has a 3-fold longer terminal half-life than recombinant human erythropoietin, allowing for an extended dosing interval. Darbepoetin alfa is currently recommended for once-weekly and once every 2 weeks administration in patients with chronic renal failure (CRF). The objective of this study was to explore once-monthly administration in this patient population.
Methods: Clinically stable dialysis patients (mean haemoglobin concentration, 10.0-13.0 g/dl) receiving stable darbepoetin alfa therapy administered once every 2 weeks in a long-term treatment study were converted to darbepoetin alfa once every 3 weeks for 20 weeks and then, if haemoglobin concentrations were successfully maintained between 10.0 and 13.0 g/dl, were converted to darbepoetin alfa once every 4 weeks for 20 weeks. The darbepoetin alfa dose was titrated to maintain haemoglobin within a target range (-1.0 to +1.5 g/dl of baseline haemoglobin, and between 10.0 and 13.0 g/dl). Success with the extended dosing interval was defined as maintenance of mean haemoglobin >/=10.0 g/dl during a 4-week evaluation at the end of the dosing period.
Results: Of the 54 patients who entered the study, 38 patients were converted to darbepoetin alfa administered once every 4 weeks. Of these, 36 patients were considered evaluable and 30 (83%) of those evaluable patients successfully maintained the target haemoglobin. For successful patients the mean (SD) haemoglobin during evaluation was 11.16 (0.60) g/dl, and the mean change in haemoglobin from baseline to evaluation was -0.26 g/dl (95% CI: -0.51, -0.01). The median change from baseline in average weekly darbepoetin alfa dose was 1.61 microg (95% CI: 0.00, 4.75). Adverse events were consistent with those expected for this patient population.
Conclusions: Darbepoetin alfa, administered once monthly, maintained haemoglobin effectively and safely in most dialysis patients stabilized previously on once every 2 weeks dosing. Once-monthly dosing may optimize anaemia management for patients with CRF and for health care providers.