Cancer Health Center

Anemia Drugs Up Cancer Death Risk

Anemia Drug Benefits Overrated, Risks Underrated? continued...

The effect on tumor cells, Lai says, is to help them invade deeper into the body.

Meanwhile, U.S. doctors began using more and more of the drugs. Instead of using the drugs to bring patients' red blood cell counts up to minimum levels, they began using it to bring blood cell counts as close to normal as possible. Fueling the process was a rebate scheme in which the companies making the drugs paid doctors millions of dollars to give the drugs to their patients.

"We had a class of drug approved for a very specific indication. But through a variety of professional concerns and legitimate patient interests -- combined with heavy advertising and doctor-reimbursement policies -- we expanded use of these drugs beyond their original intent," Len Lichtenfeld, MD, deputy chief medical officer at the American Cancer Society, tells WebMD.

The unchecked use of Procrit, Epogen, and Aranesp began to unravel in May 2006, when a research review by the U.S. Agency for Healthcare Research and Quality showed that the drugs increased patients' risk of deadly blood clots.

But Lichtenfeld says what really shocked cancer doctors was the FDA's January 2007 release of a "Dear Health Care Professional" letter from Aranesp maker Amgen. The letter informed doctors that cancer patients no longer on chemotherapy but still taking Aranesp appeared to die more often than patients not taking it.

Now the Bennett study confirms this suspicion -- and strongly suggests that it applies to the entire class of ESA drugs.

Whither Procrit, Epogen, Aranesp?

Procrit, Epogen, and Aranesp are top-selling drugs. Until the mid-March FDA panel meeting, it won't be clear exactly how doctors should use the medications.

"This is like the HRT [hormone replacement therapy] story," Lichtenfeld says. "Several years ago, research suggested HRT had significant side effects and not as much benefit as thought. The pendulum swung from very many women using HRT to very few women using HRT. But now a balance has been achieved, where there is not so much HRT use as in the past, but still a major if limited role for the treatment. With ESAs, we will come to a similar conclusion. But for now, use will be very conservative."

Lai says Procrit, Epogen, and Aranesp have complex effects on tumors -- effects that are not yet fully known. The drugs seem to have different effects on different tumors.

"I don't think these drugs have a huge overall effect on tumor progression, but they definitely do make a contribution to the disease," he says. "The size of that contribution still needs to be completely understood."

Lai worries that while researchers figure this out, oncologists -- and their patients -- will be denied a useful class of drugs.