on erythroid progenitor cells, stimulating RBC production and differentiation. Safety advisories in anemic cancer patients Amgen sent a "dear stockholders" letter in January, 2007, that highlighted results from a recent anemia of cancer trial, and warned doctors to consider use in that off-label indication with caution. Amgen advised the U.S. Food and Drug Administration (FDA) as to the results of the DAHANCA 10 clinical trial. The DAHANCA 10 data monitoring committee found that 3-year loco-regional control in subjects treated with Aranesp was significantly worse than for those not receiving Aranesp (p=0.01). In response to these advisories, the FDA released a Public Health Advisory on March 9, 2007, and a clinical alert for doctors on February 16, 2007, about the use of erythropoeisis-stimulating agents (ESAs) such as epoetin alfa (marketed as Epogen) and darbepoetin alfa. The advisory recommended caution in using these agents in cancer patients receiving chemotherapy or off chemotherapy, and indicated a lack of clinical evidence to support improvements in quality of life or transfusion requirements in these settings. According to the 2010 update to clinical practice guidelines from the American Society of Clinical Oncology (ASCO) and the American Society of Hematology (ASH), use of ESAs such as darbepoetin alfa in cancer patients is appropriate when following stipulations outlined in FDA-approved labeling. Society and culture Like EPO, darbepoetin alfa has the potential to be abused by athletes seeking a competitive advantage. Its use during the 2002 Winter Olympic Games to improve performance led to the disqualification of cross-country skiers Larisa Lazutina and Olga Danilova of Russia and Johann Mühlegg of Spain from their final races. Economics Epogen and Aranesp had more than $6 billion in combined sales in 2006. Procrit sales were about $3.2 billion in 2006. References External links Antianemic preparations Growth factors Erythropoiesis-stimulating agents World Anti-Doping Agency prohibited substances Orphan drugs