What's more, the Epogen website warns of Epogen side effects, and of a study in which patients with kidney failure and cardiac disease taking Epogen showed an increase rate of thrombotic events and fatalities. The company also warns that Epogen should be discontinued in patients with antibody-mediated anemia.
The three anemia drugs, manufactured by Amgen of Thousand Oaks, are genetically engineered versions of the natural protein erythropoietin, which increases the number of red blood cells. Known as erythropoiesis stimulating agents (ESAs), the drugs have recently been linked to cases of severe anemia and pure red cell aplasia (PRCA), a serious condition in which the body's white blood cells begin to attack its own bone marrow.Given that ESAs are administered to kidney patients, and to cancer patients fighting off symptoms of anemia resulting from chemotherapy, this dark side of ESA drugs is the cause for much concern.
And it gets worse.
In March of last year the US Food and Drug Administration (FDA) weighed in with new warning labels for the trio of drugs, over concern for increased risk of blood clots, heart attack and death amongst kidney patients when the drugs were taken in higher doses than those recommended. Cancer patients, with cancer affecting the head and neck, were seen to develop tumor growth in those regions much faster with the higher dosage.
Even when Procrit, Aranesp and Epogen were given at recommended doses, there was an increased risk of death amongst cancer patients not receiving chemotherapy, and an increased risk of blood clots amongst patients having had orthopedic surgery.
Procrit and Epogen are commonly used to reduce the potential need for blood transfusions in patients facing major surgery, as well as the treatment of anemia in HIV patients.
The FDA statement, and the updated warning labels last March advised that the three drugs be given at the lowest possible dosage, and that doctors monitor their patients carefully for red blood cell count. The label updates last spring were the result of six studies, which demonstrated that survival was shorter and tumors progressed more quickly with the use of ESAs.
The November, 2007 black box warnings for Procrit, Aranesp and Epogen pick up where the March label update left off, warning of risks for certain cancer patients, and for patients with chronic kidney failure.
The black box warning also comes with a statement that ESAs in general have not been shown to improve symptoms of fatigue, or quality of life in cancer patients.
"The FDA strongly recommends that doctors talk to their patients about the risk that ESAs might cause cancers to grow more quickly or shorten survival, before they prescribe these drugs or continue ESA therapy. These risks should be weighed against the potential for red cell blood transfusion and their associated risks," the FDA's Richard Pazdur, MD, said in a news conference.
The FDA stressed that EASs should only be used in cancer patients suffering from anemia caused by chemotherapy, and not for other causes of anemia.
Meanwhile, two new studies reveal that breast cancer patients, or patients with advanced cervical cancers who took ESAs experienced more rapid tumor growth compared with similar patients who did not take anemia drugs. Data from the two studies revealed that some cancer patients died sooner.
The FDA is currently reviewing this latest data, as well as the six previous studies from last spring, and plans to convene a panel in March to further study and debate the usefulness and safety of ESAs.
The three drugs in question are manufactured by Amgen Inc. of Thousand Oaks, and markets Aranesp and Epogen. Procrit, meanwhile, is distributed by Ortho Biotech LP, a subsidiary of Johnson & Johnson. Total Amgen sales average around the $5 billion mark annually. Last year Amgen's stock price took a hit over the attention paid to its ESA drug portfoilio, and while fourth quarter performance was positive and the 2008 forecast steady-as-she-goes, Amgen is predicting a dip in earnings for 2008.
Amgen is also under scrutiny from the New Jersey Attorney General's Office after two former sales associates with the company accused Amgen of off-label marketing involving Enbrel, Amgen's top-selling psoriasis drug.
