WASHINGTON — An analysis concludes that the U.S. Food and Drug Administration approved experiments with artificial blood substitutes even after studies showed the products posed a clear risk of causing heart attacks and death.
The review released Monday of combined data from more than 3,711 patients in 16 studies testing five different types of artificial blood found that the products nearly tripled the risk for heart attacks and boosted the chances of dying by 30 percent.
Researchers questioned why the FDA allowed additional testing of the products to go forward and why the agency is considering letting yet another study proceed.
“It’s hard to understand,” said Charles Natanson, a senior investigator at the National Institutes of Health who led the analysis, released by the Journal of the American Medical Association so the data could be presented at an FDA meeting on the subject. “They already had data that these products could cause heart attacks and evidence that they could kill.”
An FDA official defended the agency, saying it had carefully weighed the risks and benefits of each study individually and had convened this week’s two-day meeting to address the very concerns raised by the analysis.
An artificial blood substitute that has a long shelf life and does not need refrigeration could save untold lives by providing an alternative to trauma patients in emergencies, especially in rural areas and in combat settings.
But attempts to develop such products have been marred by failures and controversy, in part because some products have been studied under rules allowing researchers to administer them without obtaining consent from individual patients.
Such trials were permitted based on the argument that there was no alternative because patients were often unconscious and time too limited to obtain consent from a family member.
Based on the available data, Natanson and his colleagues said, the FDA could have been aware of the risk as early as 2000, after which they allowed five more trials.
