Selenium in the Treatment of Arsenic Toxicity and Cancers

Summary

Context: Approximately 100 million people throughout the world consume water contaminated with arsenic at levels above carcinogenic thresholds, including 40 million in Bangladesh alone, with up to one-fourth of deaths attributed to arsenic exposure in the worst-affected regions. There are no proven therapies for treating chronic arsenic toxicity or for preventing arsenical cancers. Selenium has been known to counter arsenic toxicity in a variety of animal models. The investigators have recently shown in animals and humans that this effect is mediated by the formation of \[(GS)2AsSe\]- , the seleno-bis(S-glutathionyl) arsinium ion, which is then rapidly excreted via the hepatobiliary system. Concurrently, two Phase II studies in China and Bangladesh have suggested clinical benefit to selenium supplementation in arsenicosis patients.

Objective: To assess whether daily selenium supplementation counters arsenic toxicity in patients exposed to drinking water arsenic. If proven effective, selenium supplementation might be safely and cost-effectively implemented in the worst-affected localities.

Conditions

• Arsenical Melanosis
• Arsenical Keratosis
• Arsenical Cancers
• Arsenicosis
• Arsenic Exposure
• Arsenic Toxicity
• Arsenic Poisoning

Interventions

DRUG

sodium selenite

200 micrograms (µg) of selenium in the form of sodium selenite; capsule form consumed once daily with breakfast.

DRUG

placebo

dicalcium phosphate capsule matching the selenium capsule in appearance; consumed once daily with breakfast

Sponsors & Collaborators

• National Cancer Institute (NCI)

  collaborator NIH

• American Cancer Society, Inc.

  collaborator OTHER

• Texas Tech University

  lead OTHER

Principal Investigators

• Julian E Spallholz, PhD · Texas Tech University

• Paul F La Porte, PhD · Pritzker School of Medicine, The University of Chicago

• Selim Ahmed, MBBS, FCPS · Institute of Child & Mother Health, Dhaka, Bangladesh

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

12 Years

Max Age

55 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2006-12-31

Primary Completion

2009-04-30

Completion

2009-04-30

Countries

• Bangladesh