Extended dosing intervals with erythropoiesis-stimulating agents in chronic kidney disease: a review of clinical data.

The recombinant human erythropoietins epoetins alfa and beta have relatively short half-lives ( approximately 24 h by subcutaneous route) and have traditionally been administered 2 or 3 times a week for the treatment of anaemia in patients with chronic kidney disease. However, multiple weekly injections are inconvenient for both the patient and the healthcare provider. With the introduction of the longer-acting erythropoiesis-stimulating agent darbepoetin alfa, there has been growing interest in longer dosing intervals for erythropoiesis-stimulating agents. Data from several randomized studies have shown that darbepoetin alfa is effective in maintaining haemoglobin levels when administered (subcutaneously, intravenously or both) every 2 weeks in dialysis patients, and every 2 weeks or monthly in patients with chronic kidney disease not yet receiving dialysis. Moreover, intravenous administration with darbepoetin alfa does not require a higher dosage compared with the subcutaneous route. Epoetins alfa and beta have also been studied in similar schedules, although few data from well-designed studies are available. Current data suggest that once-weekly administration of these forms of epoetin is feasible in dialysis patients, but dose increases are often required when switching patients from traditional twice- or thrice-weekly schedules. Also, administration of epoetins every other week is feasible in selected patients with chronic renal insufficiency. Further study is required to clarify the optimum schedule for epoetins in these settings.