A recombinant analog of the endogenous cytokine erythropoietin, an erythropoiesis-stimulating protein. Due to the addition of two carbohydrate chains, darbepoetin alfa exhibits a three-fold greater half-life than does erythropoietin. Similar to erythropoietin, darbopoietin alfa binds to and activates epoetin receptors, thereby inducing the differentiation and maturation of erythrocyte progenitors, stimulating endothelial cell proliferation, and stimulating B-cell proliferation and immunoglobulin production. OR A drug used to treat multiple myeloma. It is used in patients whose cancer was treated with at least three anticancer therapies, including a proteasome inhibitor and an immunomodulating agent. It is also being studied in the treatment of other types of cancer. Darzalex binds to a protein called CD38, which is found on some types of immune cells and cancer cells, including myeloma cells. Darzalex may block CD38 and help the immune system kill cancer cells. It is a type of monoclonal antibody. Also called daratumumab.