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Studies on anemia drug trigger safety concerns

Recent trials of a cancer treatment sold by Amgen and J&J show increased risk of death.

March 01, 2007|Daniel Costello | Times Staff Writer

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.

Patients with anemia, which can cause sluggishness in its early stages and can be fatal in advanced phases, can get blood transfusions, typically every few weeks, instead of using EPO.

But that alternative is time consuming and increases the chance patients may become exposed to a blood-born pathogen.

In January, Amgen disclosed that one of its trials showed some cancer patients given Aranesp had a higher risk of dying.

Last month, the Cancer Newsletter reported that Danish researchers stopped a separate Aranesp trial in October because it showed a higher recurrence of tumors in some cancer patients using the drug.

Amgen said it learned about the study's closure soon after but did not disclose it publicly, something Chief Executive Kevin Sharer later said he regretted.

Last week, the Journal of Clinical Oncology published an online paper about a Canadian trial in lung cancer patients that was stopped early because some patients receiving the drug were dying earlier.

And on Friday, Roche Pharmaceuticals suspended the second phase of its trial of Cera, a similar EPO product that it sells abroad and was hoping to bring to the U.S. The move stemmed from "an imbalance in the number of deaths in the study," Roche said.

Many doctors and industry analysts say they now are eagerly awaiting the results, expected later this year, of a large Amgen-sponsored trial involving lung cancer patients using Aranesp.

Amgen said its "top priority is patient safety. We strongly believe that Aranesp and Epogen are safe and effective medicines when used in approved populations consistent with label dosing recommendations."

The pace and the similarity of the recent research findings have raised the anxiety level within the oncology community and among industry regulators.

In a letter to members of the American Society of Clinical Oncology last week, the Food and Drug Administration said it would be reviewing the safety and efficacy of such anemia medications at an oncology subcommittee meeting this month.

The recent findings come after a series of other bad news for EPO manufacturers.

Last fall, a study published in the New England Journal of Medicine found that patients with kidney disease who were treated aggressively with Procrit had a 34% higher risk of heart problems or death than those treated less aggressively.

A panel of doctors for the National Kidney Foundation is assessing whether to change guidelines for how patients should be treated.

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daniel.costello@latimes.com

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