FDA Panel Highlights Safety Concerns of Anemia Drugs in Cancer PatientsMay 11, 2007 | Newsinferno.com
In a high-profile meeting this week, an expert panel of the U.S. Food and Drug Administration (FDA) raised significant concerns about the use of the anemia drug erythropoietin in treating cancer patients. According to the findings of the Oncologic Drugs Advisory Committee, the drug, sold by Amgen as Aranesp and by Johnson & Johnson as Procrit, is severely overused in cancer patients and should have new restrictions and guidelines placed on its administration.
Erythropoietin is in a class of drugs known as erythropoiesis-stimulating agents, or ESAs, which are intended to reduce the need for red blood cell transfusions in patients suffering from anemia. (Transfusions are considered a high-risk treatment.) The drug was initially approved for patients suffering from kidney failure, but its approved usage was expanded in 1993 to include cancer patients who were suffering from chemotherapy-induced anemia.
However, in a briefing document released by the FDA ahead of the meeting, the agency said, "Based on data provided to the FDA, there is no evidence that ESAs improve quality of life or cancer outcomes" in these chemotherapy patients. They also note that "data continue to accumulate regarding the increased risks of mortality and of possible tumor promotion from the use of ESAs." They cite a number of recent studies that have found "increased mortality" in ESA patients with cancer. "Given the data from recent clinical studies," the document notes, "it is appropriate to re-assess the safety of ESAs in patients with cancer and to re-evaluate the net clinical benefit of ESAs in this setting."
"As of March 2007," the FDA says, "there are five randomized clinical trials that demonstrated decreased survival times in cancer patients receiving ESAs compared with those receiving transfusion support. There are three randomized studies that demonstrate poorer tumor outcomes in cancer patients receiving ESAs compared with those receiving transfusion support." The FDA also noted that the risks of blood transfusions have lessened significantly since 1993, when it first approved ESAs for use in chemotherapy patients.
In light of these findings, the advisory committee voted to ban the use of these drugs on patients with certain types of cancer. The committee also recommended placing greater restrictions on its overall usage, including stopping the use of ESAs once chemotherapy treatments are over. The committee unanimously decided that more studies were necessary because most of the previous research was conducted on patients receiving higher than recommended dosages of the drug.
There are about a million cancer patients receiving chemotherapy in the Unites States every year, and nearly half of them receive ESAs to treat chemotherapy-induced anemia. When the drugs were approved for use in anemic cancer patients in 1993, their effects on overall survival rates and on tumor promotion were not tested at all. The only test at the time was to see whether or not the drugs reduced the need for blood transfusions.
Over-prescription of Procrit, Aranesp, and a third drug, Epogen, has become a major health-care problem in the United States. In March, a warning was added to labels to make sure that only the minimum dosage necessary to avoid transfusions would be prescribed. "Recently completed studies describe an increased risk of death, blood clots, strokes, and heart attacks in patients with chronic kidney failure when ESAs were given at higher than recommended doses," the FDA said in March. "In other studies, more rapid tumor growth occurred in patients with head and neck cancer who received these higher doses.
"In studies where ESAs were given at recommended doses, an increased risk of death was reported in patients with cancer who were not receiving chemotherapy and an increased risk of blood clots was observed in patients following orthopedic surgery."
The labeling change was the fourth time in the past decade that the products' label warnings were forced to be updated. At the time, Dr. Steven Galson, director of FDA's Center for Drug Evaluation and Research, said, "The new studies provide significant new information for both prescribers and patients, and the new information applies to all ESAs, which share the same mechanism of action. The safety of these products will be discussed when the Oncologic Drugs Advisory Committee (ODAC) meets in May and further revisions to the labeling may occur after that meeting." A meeting addressing the risks of ESAs on kidney patients will take place later this year.
ESAs are "genetically engineered forms of the naturally occurring human protein, erythropoietin." Erythropoietin is produced by the kidneys and increases red-blood-cell levels. Currently, the FDA has only approved these drugs for treating anemia in patients with chronic kidney failure and in patients whose anemia is a result of chemotherapy. Combined domestic sales of ESAs reached approximately $10 billion last year alone. Anemia drugs are currently Medicare's largest drug expenditure.