Methoxy polyethylene glycol-epoetin beta is an injection that is being given subcutaneously or intravenously for the treatment of anemia. It is a continuous erythropoietin receptor activator, and works to stimulate the production of red blood cells through interaction with the erythropoietin receptor on progenitor cells in the bone. There is an increase in RBC production. It is similar to epoetins but it has a longer duration of action.