However, not everyone is convinced that these drugs do more harm than good.
"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, La. "Many of the trials that changed the FDA prescribing guidelines were done in Europe and outside the guidelines of the U.S."
"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 new study included 51 phase 3 clinical trials completed between 1985 and 2005. Survival was evaluated in 13,613 people with cancer, and the risk of VTE was evaluated in 8,172 people with cancer. The type of cancer varied widely from study to study.
Overall, Bennett and his colleagues found the risk of VTE increased 57 percent in people taking ESAs, and the risk of mortality increased 10 percent in people on these medications.
"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.
More information
Here's what the U.S. Food and Drug Administration has to say about ESAs.
