An Overdue Overhaul of Safety Testing

by Karen Lange

A proposed Human Toxicology Project, which would allow researchers to assess the potential impact on human health of each of the many chemicals used in commerce, took a step forward last month, when scientists at an HSUS-organized workshop laid the groundwork for a steering committee to coordinate global efforts.

The HTP would rival the size of the Human Genome Project, costing $2 to 3 billion, but within 10 to 15 years it would assemble all the tools needed for scientists to begin reliably gauging the risks of human exposure to 80,000 to 100,000 chemicals—without the routine use of animal testing. Safety data is available for only a small percent of those chemicals, and is accruing slowly given the limitation of current testing methods.

Rather than testing chemicals in pesticides, cosmetics, household cleaners, and other potentially hazardous substances on rats, mice, and other animals, as has been common practice for decades, the new approach would test them on human cells and tissues, providing faster, cheaper, more humane—and more accurate—results. But first scientists need to map “pathways,” or biological processes and systems, in the human body that can be disrupted by chemicals. This and related activities will require a massive undertaking.

Pathways to humane testing

“The Human Genome Project shows how it can be done,” Andrew Rowan, chief scientific officer for the Humane Society of the United States, told more than 60 scientists and others gathered Nov. 9 and 10 at Gallaudet University in Washington, D.C., for the conference “Accelerating Implementation of the NRC Vision for Toxicity Testing in the 21^st Century.”

“The technological elements are available in concept. We need to grasp the vision. And we will do it.”

In 2007, the National Research Council[, part of the National Academy of Sciences,] published a report that called for an overhaul of chemical toxicity testing. The NRC’s vision  for the future includes a sharp reduction in the use of animals. The HSUS has coined the phrase “Human Toxicology Project” to refer to the effort needed, and it spearheaded the formation  a consortium of organizations and corporations dedicated to implementing the NRC vision.

Robotics, not rabbits

Government agencies, research groups, and industries in the United States and Europe already spend $200 million annually on developing alternative toxicity tests that do not involve animals.

Researchers have begun adopting new techniques, such as high-speed robotic tests that expose cells and molecules on plastic grids—high-tech equivalents of the petri dish—to chemicals, as well as computer modeling that interprets the data gathered. But to date the new methods and approaches are generally used only to predict health effects in animals, not people, and are regarded as identifying which chemicals look hazardous enough to warrant animal testing, which is typically expensive and time-consuming. Yet the animal experiments often provide misleading data. Some chemicals that are safe in animals harm people. Some chemicals that hurt animals at high doses are harmless for people.

The Human Toxicology Project would assemble information on biological processes within the body, so that researchers could begin to rapidly and systematically test chemicals and determine at what levels people can safely be exposed to them. Science is already taking steps in this general direction, but unless there’s an organized effort it could take up to five decades to map these pathways, rather than one or two.

A revolution in the making

“We’re hoping to instill a sense of buy-in and urgency,” said Martin Stephens, HSUS vice president for animal research issues.

The conference brought together people concerned with improving public health, safeguarding the environment, and advancing animal protection. Many at the event were simply excited about the promised advances in science.

“It’s a once-in-a-lifetime opportunity,” said Thomas Hartung, director of the Center for Alternatives to Human Testing at Johns Hopkins University. “A revolutionary change.”

Karen Lange is Senior Writer for HSUS Publications.