Clinical Medicine Insights: Therapeutics

Anemia resulting from a relative deficiency of erythropoietin commonly complicates chronic kidney disease (CKD). With the introduction of recombinant erythropoietin two decades ago, there has been a dramatic reduction in the need for blood transfusions in CKD patients. Epoetin alpha is a first generation erythropoiesis stimulating agent (ESA) that needs to be administered frequently because of its short half-life. Methoxy ethylene glycol-epoetin beta is a longer acting ESA that acts as a continuous erythropoietin receptor activator and is given once every 2 to 4 weeks. In short term clinical studies, Methoxy polyethylene glycol-epoetin beta has been observed to be comparable with other ESAs with regard to safety and efficacy in maintaining hemoglobin levels in the target range. However, hemoglobin is no longer a clinically valid surrogate for safety i.e. correction of anemia does not translate into better clinical outcome. Long term studies evaluating hard end-points such as death and cardiovascular events are lacking. Methoxy polyethylene glycol-epoetin beta has been approved for use in the European Union since 2007 while its use in the United States is prohibited on legal grounds.