Enrollment Halted in Trial Studying Chelation Therapy for Treatment of CAD

Enrollment into the Trial to Assess Chelation Therapy (TACT), a five-year, $30-million National Institutes of Health-funded clinical study, has been stopped, according to Heartwire, a professional news service of WebMD.

"The investigators and institutions performing the trial, in conjunction with their institutional review boards, have temporarily and voluntarily suspended enrollment of new participants in the study," Susan Dambrauskas, a media officer at the National Heart, Lung, and Blood Institute, a cosponsor of the study, wrote in an e-mail to the news service.

TACT is a randomized, double-blind, placebo-controlled study evaluating the efficacy of ethylene-diamine-tetra-acetic acid (EDTA) chelation therapy in the treatment of coronary artery disease (CAD). The primary endpoint of the trial is a composite of all-cause mortality, MI, stroke, hospitalization for angina, and hospitalization for congestive heart failure. Enrollment was estimated at around 2,000 patients, and the trial was to be completed in July 2009.

Chelation therapy has been used since 1955 for the treatment of CAD. Agents such as EDTA, which bind metals and are approved by the FDA to treat heavy-metal poisoning, are given intravenously to decalcify atherosclerotic plaque, Heartwire says. While TACT was designed to answer questions about the potential benefit of using chelation to treat CAD, critics have called this trial dangerous, unethical, and a waste of public funds.

The National Center for Complementary and Alternative Medicine is also a study sponsor.