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Taking the animals out of testing

Janet Babin May 24, 2007
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KAI RYSSDAL: Not many people really like to think about this, but where would science and medicine be without animal testing?

Many argue not nearly as far along as they are today. But animal testing does have its limits, ethical and practical — because animals aren’t people. They can respond differently to drugs and chemicals.

So scientists are working on a new breed of experimentation that’s cheaper, it’s faster, and sometimes even more accurate. Janet Babin reports now from the Marketplace Innovations Desk at North Carolina Public Radio.


JANET BABIN: Humans have used animals as predictors of toxicity for at least a century. The old saying “canary in a coal mine” is more than a mere axiom.

Since then, billions of animals have died to advance science. And millions will be used this year, too, to test the safety of everything from household products to new cancer drugs.

Toxicologist Bruce Fowler says there are about 100,000 chemicals in commercial use, and 1,000 new ones crop up every year. Of that number, less that 10 percent are known entities.

BRUCE FOWLER: That means that there is a huge backlog of chemicals that need to be evaluated — not only as individual chemicals, but as mixtures of chemicals which we’re all exposed to.

But even with the backlog, Dr. Fowler says in general, the number of animals used in research has declined by about 50 percent over the past 25 years.

The reason isn’t tied to animal rights issues. Fowler says it’s about time and money.

FOWLER: Semi-purified rat chow is about $10 per pound.

And food is just the beginning. To test one chemical to see if it’s carcinogenic usually requires 500 to 1,000 animals. It takes about two years, and costs companies millions of dollars in care, housing and research staff. Not to mention how much fun it must be for the animals.

So scientists have been quietly developing alternatives that have begun to take off. One uses computer programs to figure out if a substance is dangerous to humans.

Dr. Gilles Klopman pioneered the software and explains how it works:

GILLES KLOPMAN: You enter into the computer everything you know about carcinogenicity in animals and humans, et cetera. And the computer uses a special methodology to identify what is common about these molecules, that is probably the cause for the cancer.

Klopman says in many cases where data already exist, his software is a better predictor of toxicity than animals are. Still, he says it took decades to convince researchers that they could trust his computer models.

KLOPMAN: I encountered a lot of problems from some toxicologists who were afraid that they would lose their jobs.

Klopman’s company, Multicase, charges anywhere from $500 to $100,000 for computer modeling — far less than animal experiments. Clients include the Food and Drug Administration and Eli Lilly, among others. Last year, Multicase billed $2 million in sales, and expects that number to grow exponentially this year.

But Dr. Mark Dewhurst, at Duke University Medical Center, says computer models will never replace animal testing.

MARK DEWHURST: Because there’s no way to model the entire biology of a living animal or person.

Dewhurst’s cancer research program at Duke uses several hundred animals each year in dozens of experiments. He says modeling can be a piece of the research puzzle.

DEWHURST: It helps us to do the right experiment, so that you don’t waste a lot of time doing experiments that don’t tell you what you want to know.

But Gilles Klopman says old ideas just die hard.

KLOPMAN: The people of course who do the animal tests will never really accept the fact that you can do something else that is as good or better than what they do.

But Klopman says if data are needed on new illnesses, animal tests will be necessary.

And while the FDA accepts computer models in the early stages of a drug’s development, it still requires that the final product be tested on animals before it’s tested in humans.

In Durham, N.C., I’m Janet Babin for Marketplace.

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