FDA Tightens Warnings on Anemia Drugs
Higher-than-recommended doses can be fatal to kidney, cancer patients
FRIDAY, March 9, 2007 (HealthDay News) -- U.S. health officials issued new warnings Friday for the popular drugs Aranesp, Epogen and Procrit, prescribed to treat anemia, saying they can increase the risk of death and other serious health problems in patients with kidney disease and cancer.
Recent studies showed that the drugs -- called erythropoiesis-stimulating agents (ESAs) -- can lead to blood clots, strokes, heart attacks and death in patients with chronic kidney failure who received them at higher-than-recommended doses. Other studies found that the higher doses can produce more rapid tumor growth in patients with head and neck cancer, the U.S. Food and Drug Administration said.
The drugs included in the new safety update are darbepoetin alfa (Aranesp) and epoetin alfa (Epogen and Procrit). These drugs are genetically engineered versions of a natural protein, erythropoietin, that increases the number of red blood cells to combat anemia. Anemia is a common side effect with certain forms of kidney disease, especially for patients undergoing dialysis, and for cancer patients undergoing chemotherapy.
The three drugs are approved to treat anemia in patients with chronic kidney failure and in patients with cancer whose anemia is caused by chemotherapy. Epogen and Procrit are approved for patients scheduled for major surgery to reduce potential blood transfusions and for the treatment of anemia due to zidovudine therapy in HIV patients, the FDA said.
"The new warning tells physicians to monitor red blood cell levels and to adjust the dose of these drugs to maintain the lowest red cell level needed to avoid blood transfusions," Dr. Richard Pazdur, director of FDA's Office of Oncology Drug Products, said during a teleconference.
The new boxed warning will note that when these drugs are given with a red blood cell count greater than 12 grams per deciliter, they can increase the risk for death, blood clots, and serious cardiovascular events.
Patients with advanced head and neck cancer who are receiving radiation therapy will be warned the drugs can promote tumor progression. And patients with metastatic breast cancer receiving chemotherapy will be told the drugs can shorten survival and increase the likelihood of death from the disease, Pazdur said.
"Moreover, ESAs administered to cancer patients increased mortality to cancer patients not receiving chemotherapy or radiation therapy when administered to target a hemoglobin of 12 grams per deciliter," Pazdur said. "ESAs are not indicated for this population," he said.
The FDA and the drugs' manufacturer, Amgen, have agreed to alter the product labeling to include a new black-boxed warning, and make changes in dosing instructions.
Amgen, based in Thousand Oaks, Calif., said it is cooperating with the FDA on the label change.
"Patient safety is unquestionably our top priority," Dr. Roger M. Perlmutter, executive vice president of research and development at the company, said in a prepared statement. "Amgen is committed to providing timely and appropriate communications to physicians and patients whenever we become aware of new safety information that could affect clinical practice."
Beyond the use of ESAs to prevent blood transfusions, the drugs have been advertised as a way for cancer patients to feel better during treatment. However, Pazdur said there is no evidence to back up this claim.
"For oncology patients, these products have not been shown to improve or relieve the symptoms of anemia, or to improve the quality of life in patients with cancer," Pazdur said. "The FDA is currently reviewing all quality-of-life claims in the product label. The FDA believes these quality-of-life claims should be consistent with current FDA standards."
For more information on ESAs, visit the U.S. Food and Drug Administration.