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.
"We thought that receptor was found only on blood stem cells, so the
drugs' effects would be very precise," Lai tells WebMD. "But then we
saw that brain cells also had the receptor, and that the drugs help some blood
vessels to develop. And then someone got the idea to see if cancer cells have
it. Sure enough, all these different solid tumors express the