Treatment of Lead-Exposed Children Trial

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

COMPLETED

Clinical Phase

PHASE3

Total Enrollment

780 participants

Study Classification

INTERVENTIONAL

Study Start Date

1994-07-15

Study Completion Date

2015-06-10

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

The Treatment of Lead-Exposed Children (TLC) clinical trial compared the effect of lead chelation with succimer to placebo therapy. TLC was a randomized, double-blind, placebo-controlled clinical trial with sites in Cincinnati and Columbus, Ohio, Philadelphia, Pennsylvania, Baltimore, Maryland and Newark, New Jersey. The study was designed to test outcomes in IQ, neuropsychological function, behavior, physical growth and blood pressure three years after initiation of treatment. Enrollment was conducted between 1994 and 1997, with completion of the initial three-year follow-up in 2000.

Related Clinical Trials

Explore similar clinical trials based on study characteristics and research focus.

A Study to Determine the Safety, Pharmacokinetics, and Pharmacodynamics of DNL343 in Participants With Amyotrophic Lateral Sclerosis

NCT05006352

Amyotrophic Lateral Sclerosis

COMPLETED PHASE1

A Study to Assess the Efficacy and Safety of Pagoclone for Adults With Stuttering

NCT00830154

Stuttering

COMPLETED PHASE2/PHASE3

A Study to Assess NEU-627 in Healthy Participants

NCT06900751

Healthy

COMPLETED PHASE1

AMX0035 in Patients With Amyotrophic Lateral Sclerosis (ALS)

NCT03127514

Amyotrophic Lateral Sclerosis Motor Neuron Disease Neuromuscular Diseases +5 more

COMPLETED PHASE2

Neural Stem Cell Treatment for Amyotrophic Lateral Sclerosis (STEMALS)

NCT06344260

Amyotrophic Lateral Sclerosis

RECRUITING PHASE2

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

At TLC enrollment, the children were between 12 and 33 months of age with baseline blood lead levels (PbB) between 20 and 44 microg/dl. Of 1,854 referred children who were screened for eligibility, 780 were randomized to the active drug (oral succimer) and placebo groups, stratified by clinical center, body surface area, blood lead level and language spoken at home; only the New Jersey Clinical Center enrolled Spanish-speaking participants. Up to three 26-day courses of succimer or placebo therapy were administered depending on response to treatment in those who were given the active drug. Eighty-nine percent of children had finished treatment by six months, with all children finishing by 13 months after randomization. Residential lead clean-up and nutritional supplementation with multivitamins and minerals were provided to all study children, irrespective of treatment group. Children were followed for three years, with regular physical exams, psychological and developmental testing, and measurement of lead concentration in venous blood. Treatment and follow up are closed for this trial; it is open for scientific analysis and report writing only.

Although succimer lowered blood lead levels much more effectively than placebo, there was no difference between the two groups on any of the psychological tests at three years post randomization, when most children were about five years old. Follow up of TLC children continued into school age. At age seven, 647 of 780 subjects remained in the study. Children were tested at age seven and again at seven and a half on standardized neuropsychological batteries that tap cognition, behavior, learning and memory, attention, and neuromotor skills. While chelation therapy with succimer had lowered average blood lead levels for approximately six months, it resulted in no benefit in cognitive, behavioral and neuromotor endpoints when measured at school ages in these children. These additional follow-up data confirm our previous finding that the TLC regimen of chelation therapy is not associated with neurodevelopmental benefits in children with blood lead levels between 20 and 44 microg/dL.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Lead Exposure

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

TRIPLE

Participants Caregivers Investigators

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

1

Scuccimer Treatment Group

Group Type EXPERIMENTAL

Succimer

Intervention Type DRUG

Succimer (2,3-meso-dimercaptosuccinic acid) is an orally active dithiol compound that is a relatively specific chelating agent for heavy metals, especially lead, arsenic and mercury. The drug undergoes limited absorption in the gastrointestinal tract and then is rapidly metabolized to mixed disulfides which are eliminated in the urine. Blood levels decline slowly with an apparent elimination half-life of about 48 hours in adults.

2

In order to provide placebo with an odor comparable to that of succimer, the Drug Distribution Center will place a small canister containing 200 mg of active drug into each bottle of placebo drug. A canister containing 200 mg of placebo will be placed inside each bottle of succimer so that all bottles will appear the same.

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type DRUG

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Succimer

Succimer (2,3-meso-dimercaptosuccinic acid) is an orally active dithiol compound that is a relatively specific chelating agent for heavy metals, especially lead, arsenic and mercury. The drug undergoes limited absorption in the gastrointestinal tract and then is rapidly metabolized to mixed disulfides which are eliminated in the urine. Blood levels decline slowly with an apparent elimination half-life of about 48 hours in adults.

Intervention Type DRUG

Placebo

Intervention Type DRUG

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

The study population will reflect the population known to be at greatest risk to lead exposure, i.e., low income, urban, African-American children.

Exclusion Criteria

Linguistic minorities will be excluded in all centers except Newark, where Hispanic children make up a sizable portion of the population and will be included.

Minimum Eligible Age

12 Months

Maximum Eligible Age

33 Months

Eligible Sex

ALL

Accepts Healthy Volunteers

No