Novel Erythropoiesis-Stimulating Agents

Nearly two decades ago, recombinant human erythropoietin transformed the management of chronic kidney disease anemia by allowing a more sustained increase in hemoglobin than was possible by intermittent blood transfusion. The treatment was highly effective, but because of the fairly short half-life of the molecule at approximately 6 to 8 h, injections usually had to be administered two to three times weekly. A second-generation erythropoietin analogue, darbepoetin alfa, was then created, with a longer elimination half-life in vivo that translated into less frequent dosing, usually once weekly or once every 2 wk. More recently, another erythropoietin-related molecule has been produced called Continuous Erythropoietin Receptor Activator with an even greater half-life, and other molecules are in development or are being licensed, including biosimilar epoetin products and Hematide. The latter is a synthetic peptide-based erythropoietin receptor agonist that, interestingly, has no structural homology with erythropoietin, and yet is still able to activate the erythropoietin receptor and stimulate erythropoiesis. The search goes on for orally active antianemic therapies, and several strategies are being investigated, although none is imminently available. This article reviews the latest progress with these novel erythropoietic agents in this new era in anemia management.