Treatment of Lead‑Exposed Children Trial Repository
A public repository of trial records, publications, archival material, and policy documents concerning the NIEHS-funded Treatment of Lead-Exposed Children Trial.
This repository brings together records of the trial's planning, design, conduct, results, interpretation, and implementation into policy. Documents are organized so readers can review the source record directly.
The Treatment of Lead-Exposed Children Trial was a randomized, double-blind, placebo-controlled study of succimer in toddlers with blood lead levels (BLLs) of 20 to 44 µg/dL.
Background
The TLC Trial
Design and Primary Results
The Treatment of Lead-Exposed Children (TLC) trial was a landmark randomized, double-blind, placebo-controlled study conducted between 1994 and 2003, funded by the National Institute of Environmental Health Sciences and the Office of Research on Minority Health. The trial investigated whether succimer (meso-2,3-dimercaptosuccinic acid), the first oral FDA-approved lead chelating agent, could prevent cognitive decline in toddlers with moderate lead poisoning — at the time defined as blood lead levels (BLLs) of 20–44 µg/dL.
In 2001, the primary results were published in the New England Journal of Medicine, reporting that although succimer significantly lowered BLLs in the short term, no long-term increase in IQ was detected.
NEJM · 2001The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead.PDF
NIEHS · 1992Request for Proposals NIH-ES-92-31, Amendment of Solicitation.PDF
NIH · 2016Walter J. Rogan Oral History, Office of NIH History and Stetten Museum.PDF
Audio, video, and page images: the 2016 Walter Rogan oral history, the audio report “Succimer Found Ineffective for Removing Mercury,” a video of Walter Rogan, courtroom video from Sumpter v. City Homes, and page images of the trial’s solicitation, planning, and contract records.
Court records from Kennedy Krieger Institute lead research litigation, including Grimes, Featherstone, DeShields, White, Thomas, Jones, Ervin, Heckstall, and Partlow, and law-review commentary on the Grimes opinion, 1992–2019.
NIH Record articles, NIH Guide notices, NIEHS intramural annual reports, NIEHS contract listings, the Walter J. Rogan CV and oral history, and NIH RePORTER funding data related to the TLC trial and the NIEHS lead research program.
The NIEHS website for the Treatment of Lead-Exposed Children trial, 1998–2007, recovered from the Internet Archive: trial, investigator, and Epidemiology Branch pages, hosted publications, and IRB and conflict-of-interest records, each linked to its archived captures.
Childhood lead poisoning guidelines from CDC and its Advisory Committee on Childhood Lead Poisoning Prevention, the Agency for Toxic Substances and Disease Registry, the American Academy of Pediatrics, the US Preventive Services Task Force, and state health departments, 1975–2019.
Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) meeting agendas, minutes, and attendance rosters (2001–2013), with related MMWR reports and CDC guidance.
Congressional hearings, reports, bills, and testimony, NIEHS council minutes, White House environmental policy files, and GAO decisions on childhood lead poisoning policy and the TLC trial, 1989–2018.
We proposed to Dr. Olden that we do a clinical trial, because lowering blood lead might be a good thing, but it might not be a good thing in the sense of reversing any effect that lead had already had.
The costs for regulatory compliance as well as for health care costs are enormous, and it seems to me that it would be a wise policy to make the investment to do the science. And as soon as that could be done, with a fraction of the resources that it would take to enforce regulations that may or may not be required, we could rehabilitate or treat humans who have disabilities or diseases as a consequence of these exposures.