The largest alternative-medicine study the government has ever launched has stopped enrolling people while officials investigate whether participants were fully informed of the risks and are being adequately protected.
More than 1,500 heart-attack survivors are involved in the research, which tests a controversial treatment called chelation. It is mainly used to treat lead poisoning.
More than two people have died, although the Miami doctor leading the study said the deaths were not a direct result of the treatments.
He also acknowledged that some doctors who had been involved in the study have been disciplined by state boards or have criminal records and have been asked to drop out.
“We think we have a safe and ethical trial and we’re protecting our patients,” said the leader, Dr. Gervasio Lamas of the University of Miami.
Federal officials confirmed their probe of the $30 million study Thursday. The research is being conducted at 100 sites across the U.S. and Canada.
The research was designed to test very high doses of vitamin and mineral supplements and chelation, which has not been proved effective for heart disease. Chelation involves intravenous doses of a drug, in this case disodium EDTA, that proponents claim will bind to calcium built up in artery walls and help flush it from the body.
When the study was approved in 2002, federal officials said many heart patients were exploring chelation therapy, and the research would give answers about whether the treatment was safe and effective.
A similar philosophy was behind an effort to test chelation on autistic children. However, the government recently scrapped that plan, citing safety concerns as one reason.
