Darbepoetin alfa (Aranesp®, Nespo®) is an amino acid substituted analog of human erythropoietin (EPO) that promotes erythrocyte survival, proliferation, and differentiation. Approved in Europe and the US for the treatment of anemia associated with chronic kidney disease (CKD), it is characterized by delayed clearance and a more prolonged elimination half-life than recombinant human erythropoietin (rhEPO; epoetin alfa and beta), permitting an extended interval between doses.Darbepoetin alfa is generally well tolerated, and clinical trials of 20–52 weeks' duration have demonstrated the efficacy of subcutaneous and intravenous administration at 1- or 2-week intervals in the initial treatment of anemia associated with CKD both in dialysis patients and in patients not yet on dialysis. Trials of up to 52 weeks' duration demonstrated that in the majority of patients with CKD, treatment with darbepoetin alfa at up to 4-week intervals maintained hemoglobin (Hb) levels established by prior erythropoietic treatment, while in patients undergoing dialysis, intravenous or subcutaneous darbepoetin alfa administered at 1- or 2-week intervals was noninferior to rhEPO administered once, twice, or three times per week in maintaining established Hb levels.