The United States Food and Drug Administration (FDA) has announced that it is reviewing new data regarding erythropoiesis-stimulating agents (ESAs). ESAs are drugs used to treat anemia. They include Procrit® (epoetin alfa), Epogen® (epoetin alfa), and Aranesp® (darbepoetin alfa).
Anemia is a common side effect of chemotherapy and cancer. It is characterized by low levels of circulating red blood cells, which are responsible for delivering oxygen to tissues throughout the body. Severe anemia often requires treatment with blood transfusions.
ESAs stimulate the body to produce more red blood cells. Use of ESAs to treat anemia caused by chemotherapy has been shown to decrease the need for blood transfusions.
ESAs are approved for the treatment of anemia in chronic kidney failure patients, in patients with cancer whose anemia is caused by chemotherapy, in patients with HIV whose anemia is caused by AZT (zidovudine), and to reduce the number of transfusions during and after major surgery (except heart surgery).
Serious adverse effects of ESAs have been reported in certain groups of patients, particularly patients who have used ESAs for indications other than for which they are approved. The FDA has recently received additional data from two clinical studies that add to a list of concerns regarding use of ESAs.
The two studies that the FDA is now reviewing include data from the PREPARE study. The first study included 733 patients with breast cancer who were treated with chemotherapy prior to undergoing surgery. A portion of patients received Aranesp, while others did not. At three years 14% of patients who had been treated with Aranesp had died compared with approximately 10% who had not received Aranesp.
The second study includes data conducted by the National Cancer Institute's Gynecologic Oncology Group and includes patients who were being treated with chemotherapy and radiation therapy for advanced cervical cancer. Patients received either Procrit or blood transfusions for anemia. At three years 66% of patients who had not received Procrit were alive compared with 58% of patients who had received Procrit.
It is not clear whether ESAs were actually associated with the reduction in survival in these patients.
The FDA states that they are currently "reviewing these data and may take additional action. In the meantime, FDA recommends that health care providers review the risks and benefits of ESAs outlined in the product label and discuss this information with their patients."
Patients who are undergoing chemotherapy may wish to speak with their healthcare provider regarding their individual risks and benefits of treatment with ESAs.
Reference: The United States Food and Drug Administration (FDA). FDA Receives New Data on Risks of Anemia Drugs. Available at: http://www.fda.gov/bbs/topics/NEWS/2008/NEW01769.html. Accessed January 2008.