Anemia Drugs Up Cancer Death Risk
Study Shows More Deaths, Blood Clots in Cancer Patients Taking Procrit, Epogen, Aranesp
Feb. 26, 2008 -- Cancer patients die 10% more often -- and have a 57% higher risk of dangerous blood clots -- if they take the anemia drugs Procrit, Epogen, or Aranesp to fight the side effects of chemotherapy.
The findings come from a careful analysis of data from 13,611 cancer patients enrolled in 51 different placebo-controlled clinical trials of the anemia drugs. These drugs -- Procrit, Epogen, and the newer Aranesp -- are known as erythropoiesis-stimulating agents or ESAs because they stimulate the growth of red blood cells.
"In our report we show these drugs increase the risk of thromboembolism [blood clots] by 57%, a number that's been reported before," Northwestern University professor Charles Bennett, MD, tells WebMD. "What is new is the mortality findings. We don't know the risk for an individual cancer patient -- but the more concerning thing is there is a safety problem here."
Bennett and colleagues aren't the first researchers to suspect that cancer patients taking Procrit, Epogen, and Aranesp do worse than those not taking the drugs. But their paper shows that the risk is real.
Only last November, the FDA insisted that the makers of the drugs put stronger warnings on their labels. Since then, the manufacturers notified the FDA that breast and cervical cancers got worse in patients taking the drugs during clinical studies. The studies also found that patients taking the drugs had more life-threatening blood clots than those not taking anemia drugs.
The FDA's oncology-drug advisory panel will meet on March 12-13 to discuss these reports -- and the Bennett study. The panel will decide whether the FDA should put further restrictions on the use of the anemia drugs.
Anemia Drug Benefits Overrated, Risks Underrated?
Both cancer itself and cancer chemotherapy can cause anemia, a condition in which the blood has too few oxygen-carrying red blood cells. Cancer patients often require blood transfusions. But with the introduction of the first ESA in 1989, doctors were able to avoid blood transfusions by using what seemed to be a safe medication.
This could not have been a more timely development. In the early 1990s, there were grave concerns about the safety of the blood supply. And as far as anybody knew, the drugs were extremely safe. That's because Procrit, Epogen, and Aranesp are designed to stimulate a growth receptor found on blood stem cells, says study researcher Stephen Lai, MD, PhD, a head and neck surgeon at the University of Pittsburgh Cancer Institute.