For now, these alternative methods are better at predicting relatively simple, short-term outcomes, such as acute toxicity, than complicated, long-term ones, such as whether a chemical might increase the risk of cancer when used over months or years, scientists said.
And experts disagreed on the extent to which these alternative approaches might replace animal models. “We’re absolutely working toward a future where we want to be able to fully replace them,” Dr. Kleinstreuer said, although she acknowledged that it might take decades, “if not centuries.”
But others said that these technologies should be viewed as a supplement to, rather than a replacement for, animal testing. Drugs that prove promising in organoids or computer models should still be tested in animals, said Matthew Bailey, president of the National Association for Biomedical Research, a nonprofit group that advocates for the responsible use of animals in research.
“Researchers still need to be able to see everything that happens in a complex mammalian organism before being allowed to move to the human clinical trials,” he said.
Still, even this more conservative approach could have benefits, said Nicole zur Nieden, a developmental toxicologist at the University of California, Riverside, who said that she thought the wholesale replacement of animal testing was unrealistic.
In particular, she said, the new approaches could help scientists screen out a greater number of ineffective and unsafe compounds before they ever get to animal trials. That would reduce the number of animal studies researchers need to conduct and the limit the chemicals lab animals are exposed to, she said, adding, “We will be able to reduce the suffering of test animals quite tremendously.”
