High Doses of Anemia Drugs Can be Fatal, Says FDA

< Mar. 14, 2007 > -- US health officials issued new warnings Friday for the popular drugs Aranesp^TM, Epogen^TM, and Procrit^TM, prescribed to treat anemia, saying they can increase the risk of death and other serious health problems in persons 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, according to officials at the US Food and Drug Administration (FDA).

The drugs included in the new safety update are darbepoetin alfa (Aranesp^TM) and epoetin alfa (Epogen^TM and Procrit^TM ). 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.

In addition to being used to prevent blood transfusions, the ESA drugs have been advertised as a way for cancer patients to feel better during treatment. However, Dr. Richard Pazdur, director of the FDA's Office of Oncology Drug Products, says there is no evidence to back up this claim.

Kidney, Cancer, Surgery, and HIV Patients at Risk

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^TM and Procrit^TM  are approved for patients scheduled for major surgery to reduce potential blood transfusions and for the treatment of anemia in HIV patients, the FDA says.

"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. Pazdur says.

The warning will note that when these drugs are given with a red blood cell count greater than 12 g/dl, they can increase the risk for death, blood clots, and serious cardiovascular events such as heart attack and stroke. Expanding the use of the drugs to patients with higher hemoglobin levels has contributed to the problem.

ESAs Especially Risky in Persons with Cancer

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, according to Dr. Pazdur.

"Moreover, ESAs administered to cancer patients increased mortality in cancer patients not receiving chemotherapy or radiation therapy, when administered to target a hemoglobin of 12 grams per deciliter," Dr. Pazdur says. "ESAs are not indicated for this population," he stresses.

Anemia and Fatigue

Anemia is a common blood disorder that occurs when there are fewer red blood cells than normal, or there is a low concentration of hemoglobin in the blood due to excess fluid.

Hemoglobin is the part of blood that distributes oxygen from the lungs to tissues in the body.

According to the National Comprehensive Cancer Network (NCCN), anemia by itself may or may not cause a person to feel fatigued. People with blood hemoglobin (Hb) levels above 11 grams per deciliter usually do not need treatment.

If your hemoglobin level is low, your physician may order certain tests. These may include blood tests, stool (feces), and bone marrow sampling.

Your physician can use this information, along with the results from your medical history and physical exam, to get an idea of what might be causing the anemia.

Sometimes no cause can be found other than “anemia associated with chronic disease,” which occurs in diseases like cancer and kidney disease.

Always consult your physician for more information.

Online Resources

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American Cancer Society (ACS)

American Heart Association (AHA)

Centers for Disease Control and Prevention (CDC)

National Cancer Institute (NCI)

National Comprehensive Cancer Network (NCCN)

National Institutes of Health (NIH)

National Kidney Foundation (NKF)

US Food and Drug Administration (FDA)