Regulators have approved a less-frequent dosing schedule for Aranesp, the anemia drug from biotech giant Amgen ( AMGN). The Food and Drug Administration approval will make the treatment for chemotherapy-induced anemia the first drug of its kind to be given every three weeks. Similar drugs are generally administered weekly. "In clinical studies, Aranesp has proven effective in reducing the incidence of red blood cell transfusions and boosting and maintaining target hemoglobin levels when administered every three weeks," said Dr. Ralph Boccia, the director of clinical research at the Center for Cancer and Blood Disorders in Bethesda, Md. "This offers improved convenience for patients and less injection-related burden for patients and healthcare professionals compared to weekly anemia treatment," said Willard Dere, Amgen's chief medical officer. Less-frequent injections are generally believed to improve patients' compliance with doctors' orders. Amgen's shares fell 74 cents to $72.44 Monday.