04. 2017 | NPR Article: Drugs That Work In Mice Often Fail When Tried In People | Read Full Article
Most potential new drugs fail when they’re tested in people. These failures are not only a major disappointment, they sharply drive up the cost of developing new drugs.
A major reason for these failures is that most new drugs are first tested out in mice, rats or other animals. Often those animal studies show great promise.
But mice aren’t simply furry little people, so these studies often lead science astray. Some scientists are now rethinking animal studies to make them more effective for human health.
When scientists first started using animals in research over a century ago, the animals were not regarded as human stand-ins. Scientists studying rats were initially trying to understand rats, says Todd Preuss, an anthropologist at the Yerkes National Primate Research Center at Emory University.
“As this process went on, people stopped seeing them as specialized animals and started seeing them more and more as prototypical mammals,” Preuss says.
But is a rat really a generic mammal? Preuss says emphatically no. But that’s how rodents were pitched when they became products sold to scientists.
“It wasn’t strictly a financial interest,” he says. The sellers “really believed that you could do almost anything” with these animals. “You could learn about almost any feature of human organization, you could cure almost any disease by studying these animals.”
That was a dangerous assumption. Rats and humans have been on their own evolutionary paths for tens of millions of years. We’ve developed our own unique features, and so have the rodents.
So it should come as no surprise that a drug that works in a mouse often doesn’t work in a person. Even so, Preuss says there’s tremendous momentum to keep using animals as human substitutes. Entire scientific communities are built up around rats, mice and other lab animals.
“Once these communities exist, then you have an infrastructure of knowledge: how to raise the animals, how to keep them healthy,” Preuss says. “You have companies that spring up to provide you with specialized equipment to study these animals.”