Trial to Assess Chelation Therapy in Critical Limb Ischemia (TACT3a)

  • End date
    Mar 25, 2023
  • participants needed
  • sponsor
    Mt. Sinai Medical Center, Miami
Updated on 9 February 2022
fasting blood glucose
hemoglobin a1c
glycosylated hemoglobin
limb ischemia
rest pain
healing ulceration
hypoglycemic agents
oral hypoglycemic


TACT3a is a double blind, placebo-controlled, randomized trial to test a novel therapy, edetate disodium-based chelation of environmentally acquired toxic metals, to reduce cardiovascular events including amputation in high-risk diabetic patients.


TACT3a is a double blind, placebo-controlled, randomized trial to test a novel therapy, edetate disodium-based chelation of environmentally acquired toxic metals, to reduce cardiovascular events including amputation in high-risk diabetic patients.

The study plans to enroll 50 patients with diabetes and critical limb ischemia (CLI) to prevent the major cardiovascular endpoints of major amputation, coronary revascularization, stroke, Myocardial Infarction (MI), or death (all-cause) during an average 1.25 years of follow-up. Patients will be randomly assigned to chelation or placebo with a 3:2 (30 active, 20 placebo) allocation ratio. Treatment will consist of 40 active or placebo infusions over 30 weeks. Active therapy will be the same edetate disodium-based infusion used safely and successfully in a previous published study, Trial to Assess Chelation Therapy (TACT). Baseline and post infusion urine metals will be collected. Following the final infusion, patients will be contacted quarterly until the end of the study.

Condition Critical Limb Ischemia, Diabetes
Treatment Placebo, Edetate Disodium, Edetate Disodium
Clinical Study IdentifierNCT03982693
SponsorMt. Sinai Medical Center, Miami
Last Modified on9 February 2022


Yes No Not Sure

Inclusion Criteria

Age 50 years
History of diabetes, defined as medical record evidence or patient report of currently using insulin or oral hypoglycemic agents, or with a history of fasting blood glucose measurement of 126 mg/dL or higher, or a history of HbA1c of 6.5% or higher
Significant stenosis ( 75%) of two or more infra-popliteal arteries in the affected limb as verified by at least one imaging technique (angiography, magnetic resonance angiogram, coronary computed tomography angiogram, or doppler examination) within 6 months prior to enrollment
History of CLI defined as moderate or high-risk infra-popliteal chronic critical limb ischemia (Rutherford Clinical Severity Score 4 or 5) defined as
The presence of rest pain or non-healing ulceration or gangrene for at least 2 weeks plus documentation of severely compromised tissue perfusion
If there is tissue loss, a resting ankle systolic pressure of 60 mmHg in the affected limb; or a resting toe systolic pressure of 40 mmHg or a tissue perfusion pressure (TPP) <40 mmHg
If there is no tissue loss, a resting ankle pressure of 50 mmHg or resting toe systolic pressure of 30 mmHg or a tissue perfusion pressure (TPP) < 30 mmHg
Not a candidate or a failed candidate for surgical or transcatheter revascularization
Able to give informed consent

Exclusion Criteria

Arterial insufficiency in the lower extremity as the result of a non-atherosclerotic disorder
Subjects with evidence of active infection (e.g., cellulitis, osteomyelitis) or deep ulceration exposing bone or tendon or extensive heel ulceration
Subjects with extensive gangrene extending above the Metatarsophalangeal (MT) joint
Subjects in whom there is severe pain at rest uncontrollable with pain medications
Prior intravenous chelation therapy consisting of > 1 infusion within 5 years; if only 1 infusion took place, patient cannot be enrolled for at least 12 months after said infusion
Oral chelation with an FDA-approved chelating agent within 2 years
Allergy to any components of the study drug
Coronary or carotid revascularization within 3 months
Planned leg revascularization within 1 month of enrollment
Symptomatic or clinically evident acute heart failure
Heart failure hospitalization within 3 months
Blood pressure >160/100
No venous access
Estimated glomerular filtration ratee (GFR) < 30 mL/min per 1.73 m2 or lower (CKD stages 1-3) calculated with the Modification of Diet in Renal Disease Study (MDRD) equation
Known or suspected acute kidney injury using prevalent Kidney Disease: Improving Global Outcomes (KDIGO) criteria
Platelet count <100,000/mm3
Cigarette smoking within the last 3 months
Liver disease or Alanine aminotransferase (ALT), aspartate aminotransferase (AST) > 2.0 times the upper limit of normal (this will require clearance by the Study PI)
Diseases of copper, iron, or calcium metabolism (other than osteopenia or osteoporosis, or simple iron deficiency). These require evaluation by the Study PI
Inability to tolerate the study-required fluid load
Other medical condition likely to affect patient survival within 3 years
Women of child-bearing potential
Any factor that suggests that the potential participant will not be able to adhere to the protocol
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