Darbepoetin alfa (INN) is a re-engineered form of erythropoietin containing 5 amino acid changes (N30, T32, V87, N88, T90) resulting in the creation of 2 new sites for N-linked carbohydrate addition. It has a 3-fold longer serum half-life compared to epoetin alpha and epoetin beta. It stimulates erythropoiesis (increases red blood cell levels) by the same mechanism as rHuEpo (binding and activating the Epo receptor) and is used to treat anemia, commonly associated with chronic kidney failure and cancer chemotherapy. Darbepoetin is marketed by Amgen under the trade name Aranesp. The medication was approved in September 2001, by the US Food and Drug Administration for treatment of anemia in patients with chronic kidney failure by intravenous or subcutaneous injection. In June 2001, it had been approved by the European Medicines Agency for this indication as well as the treatment of anemia in cancer patients undergoing chemotherapy. Dr. Reddy's Laboratories launched darbepoetin alfa in India under the brand name ‘Cresp’ in August 2010. This is the world's first follow-on biologic of darbepoetin alfa. Darbepoetin is produced by recombinant DNA technology in modified Chinese hamster ovary cells. It differs from endogenous erythropoietin (EPO) by containing two more N-linked oligosaccharide chains. It is an erythropoiesis-stimulating 165-amino acid protein. It is on the World Health Organization's List of Essential Medicines. Contraindications Use of darbepoetin alfa is contraindicated in patients with hypersensitivity to the drug, pre-existing uncontrolled hypertension, and pure red cell aplasia. Adverse effects Darbepoetin alfa has black box warnings in the United States for increased risk of death, myocardial infarction, stroke, venous thromboembolism, thrombosis of vascular access, and tumor progression or recurrence. To avoid side effects, it is recommended for patients with chronic kidney failure or cancer to use the lowest possible dose needed to avoid red blood cell (RBC) transfusions. In addition to those listed in the black box warning, use of darbepoetin alfa also increases the risk of cardiovascular problems, including cardiac arrest, arrhythmia, hypertension and congestive heart failure, and edema. A recent study has extended these findings to treatment of patients exhibiting cancer-related anemia (distinct from anemia resulting from chemotherapy). Other reported adverse reactions include increased risk of seizure, hypotension, and chest pain. Pregnancy and lactation Darbepoetin alfa is not assigned a pregnancy category in the United States. It is not known if darbepoetin alfa is excreted in breast milk. Mechanism of action Darbepoetin alfa binds to the erythropoietin receptor