Experimental Blood Substitutes Unsafe, Study Finds

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"Outside the cell, hemoglobin scavenges nitric oxide," Wolfe explained. "This causes constriction of arteries that is predictive of increased risk of heart attacks and organ damage."

Wolfe and Public Citizen initiated the inquiries that produced the report, starting in 2006. "We learned from the Federal Register that the FDA would hold an advisory committee meeting about a blood product," Wolfe said. "They decided to keep it secret. We sued the FDA, and they canceled the meeting because it was illegal."

Wolfe contacted Natanson, "because I knew he was on advisory committee of the FDA," and they began a search for information on hemoglobin-based blood substitutes. It was not easy to find, because neither the companies testing the products nor the FDA were forthcoming with information, Wolfe charged. Often, the FDA did not report on trial results, because they were regarded as trade secrets, he said.

The only information available in many cases came from press releases. In the case of one product, Polyheme, a report was not published until December, 2006, six years after the trial ended.

"It took a long amount of time, because a meta-analysis like this, if done appropriately, takes an enormous amount of energy and time," Natanson said.

The FDA itself did not do the kind of meta-analysis that produced the journal report, Wolfe said, but the evidence that the products caused harm should have been evident by the year 2000, he said.

"In the eight countries where there are clinical trials, if they had been aware of the cumulative picture, they would not have allowed the trials to go forward," he said.

The FDA "does not concur that a prior meta-analysis would have modified our assessment or resulted in stopping all studies in 2000," said Karen Riley, a spokeswoman for the agency.

"We discussed the safety of these products at several public meetings and workshops," Riley said. "Because of safety concerns, there are no ongoing studies of hemoglobin-based blood products in the United States and no approved products."