These warnings specifically relate to Epoetin alfa (marketed as Procrit, Epogen), Darbepoetin alfa (marketed as Aranesp). Aranesp and Epogen are manufactured by Amgen while Procrit is manufactured by Johnson & Johnson.

Procrit and Epogen are artificial forms of erythropoietin or epo, which is present in human kidney and boosts the production of hemoglobin. Many analysts believe that the drugs are prescribed unnecessarily as it provides a source of revenue to kidney dialysis centers and oncologists.

These drugs had been marketed as having potential to reduce feeling of fatigue in cancer patients, those suffering from HIV and chronic kidney failure. But the new labels will say that there is no evidence to back these claims.

However many studies, including one conducted by Amgen, have shown that over usage of these drugs could lead to serious health problems for patients.

A study published last November in the New England Journal of Medicine revealed that patients who were suffering from kidney disease and were treated with high doses of Procrit were more prone to heart attacks compared to other patients.

Over 1 million Americans use any of the three drugs, with sales of the drugs totaling more than $10 billion last year.

Dr. Richard Pazdur, the FDA's director of the Office of Oncology Drug Products at the Center for Drug Evaluation and Research, said yesterday that this is the fifth time the FDA is warning about these drugs.

"Today's labeling changes are being made to make clear recommendations about the safe and effective use of these products and to strengthen the information about the risks that these drugs pose to patients with cancer and to patients with chromic kidney failure," he added.

Following is the public advisory for these drugs released by the FDA
Patients with cancer who are currently using or considering the use of an ESA should know the following:

    * ESAs may shorten your survival time or may cause your tumors to grow faster.
    * ESAs should only be used to treat anemia caused by chemotherapy and not other  anemia from other causes in patients with cancer.
    * ESAs should not be used to treat the symptoms of anemia, such as fatigue or improve the quality of life in patients with cancer.  The goal of treatment with ESAs is to avoid blood transfusions.
    * Treatment with an ESA should be stopped after you complete your course of chemotherapy

Patients with chronic kidney failure (this includes both patients on dialysis and those not on dialysis) who are currently using an ESA should know the following:

    * Your hemoglobin level should be checked regularly to make sure it stays between 10 and 12 g/dL.
    * ESAs can increase your chance of heart attack, stroke, blood clots, heart failure, and death when they are given to maintain higher hemoglobin levels.
    * If you are not responding to treatment with an ESA (your hemoglobin levels are not increasing) ask your doctor if you need to be checked for other causes of anemia.