Epogen, Aranesp and Procrit, anemia drugs used to treat cancer patients, have been linked to a higher risk of a potentially fatal type of blood clot. According to a review published in the February 27 issue of the Journal of the American Medical Association, anemia drugs—medications designed to fight fatigue and other symptoms associated with cancer treatment-related anemia—significantly increase the risk of death and serious side effects in cancer patients. The risk of death is increased by 10 percent when taking ESAs — erythropoiesis-stimulating agents—and the risk of blood clots—venous thromboembolisms (VTE)—increased by 57 percent. “What we’ve done here is put together the totality of the evidence and found two things that are concerning: The increased risk of VTE and the increased risk of mortality,” said the review’s lead author, Dr. Charles Bennett, the A.C. Beuhler professor of geriatric medicine at Northwestern University’s Feinberg School of Medicine.
The U.S. National Institutes of Health explains that ESAs—erythropoietin (Epogen, Procrit) and darbepoetin (Aranesp)—work by stimulating bone marrow to produce new red blood cells. Epogen, Aranesp and Procrit are used in the treatment of chemotherapy-related anemia and to treat anemia in people with chronic kidney disease who are also on dialysis.
Health experts have raised concerns about Epogen, Aranesp and Procrit before. In kidney patients, past research showed that if ESAs are used to raise hemoglobin levels above 12 grams per deciliter of blood, the risk of death increases. Also, past cancer research revealed that ESAs may be associated with more rapid tumor growth in addition to an increased risk of death. Because of this, the U.S. Food and Drug Administration (FDA) last year had the drugs’ manufacturers add a “black box” warning to the medications. The black box—the strongest drug warning—indicates that the medications should be used at the lowest possible doses to avoid risks such as blood clots, heart attacks, stroke, congestive heart failure, increased tumor growth, and an increased risk of death. The FDA also recommended that ESAs be prescribed at the lowest possible doses since trials generally indicated an increased risk when blood levels were raised above 12 grams per deciliter.
But there are critics to these findings. “If you use ESAs the way they’re supposed to be used, I really don’t see clinically what they’re talking about in the trials,” said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, Louisiana. “Many of the trials that changed the FDA prescribing guidelines were done in Europe and outside the guidelines of the US. I still think ESAs are extraordinarily useful and safe medications when used in an efficacious manner. I would be treated with these agents if I had cancer,” Brooks said.
The study included 51 phase 3 clinical trials completed in the 20-year period between 1985 and 2005. Survival was evaluated in 13,613 cancer patients; the risk of VTE was evaluated in 8,172 people with cancer. The type of cancer varied widely from study to study. “At the end of the day, these data are very provocative and it’s important for people [that] make clinical guidelines to review the data,” said Bennett, who’s also a hematologist/oncologist at Northwestern Memorial Hospital and the Jesse Brown VA Medical Center in Chicago. “Patients should be informed of the risks and benefits of these drugs,” he added.