Aranesp, Epogen and Procrit, drugs given to anemia patients suffering end-stage kidney failure, will be taken up by a Food & Drug Administration (FDA) advisory panel tomorrow. Earlier this year, the FDA added a black box warning to the products’ labels recommending that the drugs be used at the lowest dose possible. But what constitutes the minimum dose for these medications has been a subject of controversy.
Aranesp, Epogen and Procrit are all erythropoiesis-stimulating agents (ESAs) given to anemia patients suffering kidney failure and undergoing chemotherapy treatment. Prior to the development of these drugs, such anemia was treated with blood transfusions. In March, a black box warning was added to the drugs’ labels after the FDA discovered that doctors were using the medications to increase red blood cell counts to unsafe levels. The new warning labels advised that the ESAs should be administered at the lowest dose possible in order to bring red blood cell counts to the lowest level necessary to avoid transfusions. The warning labels said hemoglobin (red blood cell) levels should not be allowed to go above 12 grams per deciliter of blood. But the label recommendation did not specify what the lowest hemoglobin should be. Now, no one can agree on what the lowest possible hemoglobin level is, and the FDA is looking to the advisory panel for answers.
The FDA has not pinpointed a proper dosing for ESAs, but has said that there is evidence that a minimum hemoglobin level of 11 could benefit patients. However, an FDA review of the drugs’ safety found that more research focusing on proper dosing is needed. Amgen, the maker of Aranesp and Epogen, claims that a target hemoglobin range should be 11 to 12 grams per deciliter for kidney patients, and that hemoglobin in kidney failure patients should not be allowed to fall below 10.
The dispute over proper ESA dosing came to head a month after the black box warning was added. Because the treatment of kidney patients is a major expense for Medicare, the addition of the warning prompted the program to decide that it would not pay for Aranesp, Epogen and Procrit in patients whose hemoglobin levels were at 10 grams per deciliter. That decision sparked controversy among doctors and members of Congress. As a result, Medicare has been waiting for the outcome of tomorrow’s FDA advisory panel meeting before enforcing its new dosing regulations.
Muddying the waters even more, the FDA says that studies indicating that ESAs significantly improved a patient’s quality of life did not “supply sufficient evidence of efficacy to retain these claims” on the drug labels. The FDA also said that those studies may not meet current regulatory guidelines. But Amgen insists that the data involving quality of life is conclusive.
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