Some doctors say they have begun curtailing use of one of the nation's most popular cancer drugs, erythropoietin, after four studies released since January have shown it may increase the risk of death in some patients.
The medication, also called EPO, stimulates the body's production of oxygen-carrying red blood cells and is used to treat anemia caused by chemotherapy or kidney failure. It is sold under the brand names Procrit by Johnson & Johnson, and Epogen and Aranesp by Thousand-Oaks-based Amgen Inc. The drugs account for nearly half of Amgen's revenue.
Doctors say the studies raise concerns that EPO may increase patients' chance of forming fatal blood clots and may separately shield cancer tumors from treatments such as chemotherapy and radiation.
Amgen and Johnson & Johnson say they believe the medication is safe and effective when used as directed. The drug is used by more than 1 million patients in the U.S. each year and is the largest medication expense for the federal Medicare program.
But some doctors are cautious.
"This is very disconcerting," said Dr. Peter Eisenberg, an oncologist at California Cancer Care in Greenbrae, Calif. "I am worried that after this stuff has been so widely available for more than 10 years, it might hasten the death of some of my patients."
Eisenberg said he still planned to prescribe the medication, especially for gravely ill patients who might not survive their cancer and would clearly benefit from the drug.
But "what do I do now with a 55-year-old patient with early breast or colorectal cancer? Many of them are likely to survive their disease. I'm not sure I feel comfortable giving them something that could do them harm in that case," he said.
Dr. John Glaspy, director of UCLA's Outpatient Oncology Clinic, said he was taking a wait-and-see approach, acknowledging that he would like to see more studies about the drug's safety.
"We have to balance a small chance there might be a risk here against known benefits and years of accumulated experience," Glaspy said. "These drugs will continue to have an important role in medicine."
One complicating factor, experts say, is that oncologists make significant revenue buying cancer drugs from manufacturers and charging patients a higher price for receiving the drugs in their offices. That profit motive could influence some doctors' decisions, experts say.
