THURSDAY, May 10 (HealthDay News) -- A U.S. Food and Drug Administration advisory panel on Thursday called for new warnings and additional safety studies on anemia drugs commonly used to treat patients undergoing kidney dialysis or chemotherapy.
These medications have been the subject of controversy since some of their dangerous side effects -- including the risk of heart attacks and stroke -- came to light earlier this year. In March, the FDA issued stronger label warnings for the popular drugs.
On Thursday, the agency's advisory panel of experts voted 15-2 in favor of new prescribing restrictions and 17-0 for new clinical trials to prove the safety of Amgen's Aranesp and Johnson & Johnson's Procrit, Bloomberg reported.
"Many of us are concerned on the committee and have a lot of questions," said advisory panel chairwoman Gail Eckhardt, an oncologist at the University of Colorado in Aurora, according to Bloomberg.
Eckhardt said the questions concerned the design of trials, why regulators have limited access to results from company studies, and why the drugs have been marketed for improving quality of life if there isn't sufficient evidence for the claim.
Amgen, of Thousand Oaks, Calif., claims that 4 million patients have taken the medicines since they were introduced in 1989, and more than 9,000 people have been studied in clinical trials with cancer patients, the Bloomberg report said.
"We want to consider the totality of the evidence and consider what's best for patients," Roger Perlmutter, Amgen's head of research and development, told the panel. The anemia drugs don't shorten patients' life spans or make tumors spread more rapidly, based on the findings of 55 studies, he added.
The FDA isn't required to follow the recommendations of its advisory panels but typically does.
Recent research has shown that these erythropoiesis-stimulating agents can lead to blood clots, strokes, heart attacks and death in patients with chronic kidney failure who receive them at higher-than-recommended doses, a practice that is becoming increasingly common. Other studies have discovered that higher doses might produce more rapid tumor growth in patients with head and neck cancer.
"There has clearly been an issue raised about the efficacy, the effectiveness and safety of these drugs when used to treat anemia from cancer," said Dr. Len Lichtenfeld, deputy chief medical officer at the American Cancer Society, before the panel voted.
Another expert said he thinks the FDA needs to carefully define when and for whom these drugs should be used.
"The FDA needs to provide a strong message and guidelines about under what circumstances, and for what populations, patients need to be treated with these drugs," said Dr. Ajay Singh, clinical chief of the renal division and director of dialysis at Brigham and Women's Hospital in Boston.
"In addition, we need updated and independent guidelines that advise doctors how to use these drugs that support what the FDA is recommending," Singh said.
The drugs include darbepoetin (Aranesp) and epoetin alfa (Epogen and Procrit). They are genetically engineered versions of a natural protein, erythropoietin, that boosts red blood cell counts to combat anemia. Anemia is a common side effect with certain forms of kidney disease, especially for patients undergoing dialysis, and for cancer patients undergoing chemotherapy.