The National Center for Complementary and Alternative Medicine (NCCAM)
and the National Heart, Lung, and Blood Institute (NHLBI), components of
the National Institutes of Health (NIH), have launched the first
large-scale clinical trial to determine the safety and efficacy of EDTA
chelation therapy in individuals with coronary artery disease, the leading
cause of death for both men and women in the United States.
The 5-year Trial To Assess Chelation Therapy (TACT) will involve over
2,300 patients at more than 100 research sites across the country.
"The public health imperative to undertake a definitive study of
chelation therapy is clear. The widespread use of chelation therapy in lieu
of established therapies, the lack of adequate prior research to verify its
safety and effectiveness, and the overall impact of coronary artery disease
convinced NIH that the time is right to launch this rigorous study," said
Stephen E. Straus, M.D., NCCAM Director.
Over 800,000 patient visits were made for chelation therapy in the United
States in 1997. Chelation therapy involves the use of EDTA (ethylene diamine
tetra-acetic acid), a synthetic amino acid that is administered
intravenously (through the veins). EDTA, which effectively speeds removal of
heavy metals and minerals such as lead, iron, copper, and calcium from the
blood, is approved by the U.S. Food and Drug Administration (FDA) for use in
treating lead poisoning and toxicity from other heavy metals. Although it is
not approved by the FDA to treat coronary artery disease, some physicians
and alternative medicine practitioners have recommended EDTA chelation as a
way to treat this disorder.
Coronary artery disease (CAD) is a type of heart disease in which the
coronary arteries (vessels that supply oxygen-carrying blood to the heart)
become blocked by deposits of a fatty substance called plaque. As plaque
builds, the arteries become narrower and less oxygen and nutrients are
transported to the heart for proper function. CAD can lead to serious health
problems such as angina (pain caused by insufficient oxygen-carrying blood
reaching the heart) and heart attack.
There are standard and well-proven ways to reduce the risks or
complications of CAD. These include stopping smoking and controlling high
blood pressure and high blood cholesterol through lifestyle changes and
medication. More invasive procedures are used to treat symptomatic CAD
including balloon angioplasty (dilation of a blocked artery to open it up)
or coronary artery bypass surgery (using arteries or veins from other areas
of the body to create detours for blood flow around areas of blockage in the
heart artery).
"NCCAM's leadership in initiating and supporting this study is to be
commended," said NHLBI Director Claude Lenfant, M.D. "It is important for
heart disease patients to know whether we should add chelation therapy to
the list of proven treatments for coronary artery disease. Scientific
evidence is needed to resolve this issue. And only a large clinical trial
can definitively answer the question of whether chelation treatment is truly
safe and effective," added Lenfant.
The randomized, double-blind study will enroll 2,372 patients aged 50 or
older who have had a heart attack. The $30 million study, led by Gervasio A.
Lamas, M.D., director of cardiovascular research and academic affairs at
Mount Sinai Medical Center-Miami Heart Institute in Miami Beach, Florida,
will test whether EDTA chelation therapy and/or high-dose vitamin therapy is
effective for the treatment of CAD. Vitamin and mineral supplements,
consistent with the regimen used by practitioners who deliver EDTA chelation
therapy, will be used in the study.
Following baseline assessments, about 1,186 patients will be randomly
assigned to receive a standardized chelation solution, and about 1,186
patients will receive a placebo (dummy) solution. Each of these two groups
will additionally be randomized to receive high-dose vitamin/mineral
supplements versus low-dose vitamin/mineral supplements. Study participants
will receive 30 weekly infusions of EDTA chelation therapy followed by 10
bimonthly infusions. All patients enrolled will be followed until the end of
the study to observe any significant clinical benefits or side effects. The
primary study endpoint (a marker of improvement) of this trial will be a
composite of heart attack, stroke, hospitalization for angina (pain
associated with CAD), coronary revascularization, and death. The study will
also evaluate cardiac deaths, nonfatal heart attacks, health-related quality
of life, and cost effectiveness, among other factors.
TACT includes a Data Coordinating Center led by Kerry Lee, Ph.D., and a
Quality of Life Coordinating Center led by Daniel Mark, M.D., M.P.H., both
at the Duke Clinical Research Institute in Durham, North Carolina. In
addition, an independent Data Safety Monitoring Board will oversee the
study.
Patient recruitment for the study is expected to begin in March 2003,
after preparations are completed to enroll participants at the many study
sites.
Questions and answers about this study are located at
www.nccam.nih.gov/news/2002/chelation/q-and-a.htm.
Information about the study, locations, and enrollment will be available
from the NCCAM Web site and from ClinicalTrials.gov,
the NIH Web site for clinical trial information.
Therapeutic
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