NIH Funds Second Round Of Controversial Chelation Tria

–TACT2 will test chelation in heart attack patients with diabetes.

The NIH has agreed to fund a second round of a highly controversial study testing the possible benefits of chelation therapy in heart attack patients with diabetes. The second Trial to Assess Chelation Therapy (TACT2), now recruiting patients at more than 100 clinical sites, is sponsored by the National Center for Complementary and Integrative Health (NCCIH) and has also received funding from the National Heart, Lung and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases.

The first TACT trial provoked an enormous, long-running controversy. Some mainstream medical critics argued that the NIH was wrong to study chelation, which has been popular in the alternative medicine community for nearly 60 years but, with no data to support its use, had never gained acceptance in the more conventional medical community. Study chairman Gervasio Lamas, chairman of medicine and chief of the Columbia University Division of Cardiology at Mount Sinai Medical Center in Miami Beach, argued that it was ethical to study chelation since many people were continuing to receive the treatment in alternative medicine centers.

To the surprise of many, the first TACT trial found a small but statistically significant reduction in cardiovascular events in patients with a history of myocardial infarction who received chelation. A later substudy, the basis for TACT2, found that nearly all the benefit occurred in the subgroup of patients with diabetes. In this subgroup there was a dramatic 41% reduction in recurrent events and a 43% reduction in death.

“If TACT2 is positive, it will forever change the way we treat heart attack patients and view toxic metals in the environment,” said Lamas, in a press release.

“The results of the original TACT study suggested that chelation of toxic environmentally-acquired metals may reduce cardiac risk, particularly in diabetic patients. If a second TACT study (TACT2) can confirm these interesting and relevant findings, it has great potential to change cardiac therapeutics”, said Valentin Fuster (Mount Sinai Hospital, NY) in the press release.

Lamas acknowledged that acceptance of chelation in mainstream medicine will require a positive trial. “Unless we can show a consistent effect across the two TACT Trials, it will be difficult for chelation to enter the mainstream of other cardiovascular therapies,” he said.

Responding to email questions, Lamas said he hopes to avoid the the long delays and sluggish enrollment that plagued the first TACT trial. TACT2 will include more conventional cardiology sites and endocrine sites and fewer alternative medicine sites, though it is retaining some alternative sites which “had a good track record in TACT1,” said Lamas.

Lamas explained that because the “purpose of this study is to replicate TACT1,” the trial is using the same primary endpoint: time to first occurrence of death from any cause, MI, stroke, coronary revascularization, and hospitalization for unstable angina. The proposed sample size of 1,200 patients gives the trial an 85% power to detect a 30% reduction in the primary endpoint, after an estimated 282 endpoint events.

Lamas said he does not think that the trial will be affected by the increasing use of novel diabetes drugs. “We believe that the mechanism of toxic metal chelation is unique and unlikely to be masked in any way by more novel cardiac and diabetes medications just now entering the market,” he said.


Previous Coverage of the TACT story:

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