Drugs that stimulate red-blood-cell formation also stimulate blood clots in the leg
Procrit, Epogen and Aranesp, drugs that are used to stimulate red-blood-cell production in cancer patients made anemic by chemotherapy, increase the risk of venou thromboembolism, the production of blood clots in the legs that can move to the lungs and elsewhere to create potentially lethal illnesses. The new data, published today in the Journal of the National Cancer Institute, do not show that the drugs increase the risk of death, but they also do not show that the drugs benefit patients.
The drugs already have been under fire because of a 2006 study showing that aggressive treatment of patients with them led to a higher risk of death and cardiovascular complications. In 2007, the Food and Drug Administration required a strong warning on the label of the drugs, known collectively as erythropoiesis-stimulating agents, or ESAs, and suggested limiting their use to patients with unusually low red blood counts. In 2006, U.S. sales of the drugs totaled $20 billion, and they represented the largest expenditure for drugs by Medicare Part B. In the two years following the 2006 report, however, sales of Aranesp and Procrit fell 23% to 24%.
Dr. Dawn L. Hershman of the Irving Comprehensive Cancer Center at Columbia University Medical Center and her colleagues studied more than 56,210 patients who were at least 65 years old and who were given chemotherapy for colon, non-small cell lung or breast cancer between Jan. 1, 1991, and Dec. 31, 2002. The patients were identified in the government's Surveillance, Epidemiology and End Results-Medicare database that covers about 14% of the population. The cancers chosen, which also included large B-cell lymphoma, were those that were thought to be most likely to require ESAs.
About 27% of the patients, 15,346, received an ESA. The proportion receiving the drugs increased from 4.8% in 1991 to 45.9% in 2002. Blood clots developed in 14.3% of those who received the drugs, compared with 9.8% of those who did not, the team found. Overall survival was similar in both groups. Perhaps most damning: The rate of anemia-related transfusions did not change over the course of the study, despite the greatly increased use of the drugs. It remained constant at 22%.
Dr. J. Leonard Lichtenfeld, deputy chief medical officer of the American Cancer Society, told Healthday News that "this study is one more in a list of several that suggests the value of ESAs was less than originally hoped, and the side effects were greater than previously understood."
-- Thomas H. Maugh II