Articles renew scrutiny of antianemia drug safetyNov 16, 2006 | Boston Globe
A set of articles to be published today in the New England Journal of Medicine is spurring new scrutiny of the use of antianemia drugs to boost red blood cell counts beyond Food and Drug Administration recommendations.
The FDA said yesterday it will review new data from one of the studies, called CHOIR, which was halted before its completion last year. A safety panel stopped the trial after patients with chronic kidney disease receiving larger doses of Johnson & Johnson's drug Procrit to increase red blood cell counts began dying at an unexpectedly high rate.
FDA officials said they want to see whether they can solve a puzzle: At what point does aggressive anemia treatment increase risk?
"Now we have a new piece, and it is going to be a new thing to consider," said Dr. Douglas Throckmorton , deputy director of the FDA's Center for Drug Evaluation and Research .
The CHOIR study and a second study, CREATE, which showed no cardiovascular benefit from higher hemoglobin but not the same levels of risk found by CHOIR, prompted the New England Journal of Medicine to publish an accompanying editorial cautioning doctors against aggressively raising red blood cell counts.
The studies and editorial add to a growing debate about antianemia drug profits, safety, and the Medicare program.
Medicare, which pays for most dialysis treatments in the United States under a 1972 law, guarantees dialysis clinics a 6 percent profit on their use of Amgen Inc.'s Epogen, which is used exclusively in dialysis. Critics in the medical community and Congress say the guaranteed profit margin encourages excessive use of the drug, and some say excessive use of it may be harming patients.
The Globe reported in September that half of all kidney dialysis patients had their red blood cell counts pushed higher than the limit recommended by the FDA, and about 20 percent of those patients about 65,000 had counts elevated to the potential danger zone revealed in the CHOIR trial. Dr. Barry Straube , Medicare's chief medical officer, said the new study would be reviewed to see whether it contains warning signs that could require a change in reimbursement policy.
In a letter to Medicare yesterday, Republican US Representative Bill Thomas of California, chairman of the House Ways and Means Committee, and Democratic Representative Pete Stark of California, ranking member of the Ways and Means subcommittee on health, said they are concerned Medicare is not doing enough to "stem the systemic abuse of Epogen, resulting in costs to taxpayers and potential health dangers to patients."
The CHOIR study also raises questions about a new set of clinical guidelines produced this year by the National Kidney Foundation , with industry funding. The guidelines say kidney patients can have better health and improve their quality of life if their red blood cell counts are boosted higher than the FDA recommended label. But the CHOIR study authors say in today's Journal article that their study does not support the revised guidelines. Kerry Willis , the kidney foundation's vice president for scientific activities, said the new papers would be analyzed to see if they warrant changing the guidelines.
New data to be released this weekend at the American Society of Nephrology conference in San Diego shows that some clinic chains are giving patients larger Epogen doses than others. In particular, the data, produced by Dr. Allan Collins of the University of Minnesota, a leading expert in anemia treatment in kidney patients, showed that clinics operated by DaVita Inc. tend to most often use Epogen to "overshoot" the FDA anemia treatment limits.
DaVita said its dosing protocols are appropriate, but declined to comment on Collins's findings. "DaVita has the best clinical outcomes, and the lowest mortality," said the company's chief medical officer, Charles McAllister . He said it is inappropriate for physicians to take the CHOIR analysis and apply it to all kidney patients, because it focused on those who suffered from chronic kidney disease, but had not yet progressed to dialysis treatment.
Collins also has produced data that show a large percentage of patients whose red blood cells are boosted above the FDA limit tend to stay at elevated levels for three months. That undercuts previous arguments by Amgen that such fluctuations above the FDA limit are temporary and pose no threat to patients of the kind demonstrated in CHOIR, where patients were maintained at a high level over a long period .
Amgen said the proprietary database that it said showed doctors reducing the dose quickly is more accurate than the public, federally maintained database that Collins used for his analysis.