Researchers have been growing tiny clumps of human organs, known as organoids, for more than a decade. Tests show that pieces smaller than a millimeter can mirror key features of full-scale organs and tissues, including how they falter with disease and respond to drugs. Armed with organoids grown from diseased human tissues, scientists can investigate whether new drug candidates reverse pathological changes in all or a subset of patients, and quickly identify ineffective drugs early in the process. Historically, more than 90% of drugs that clear animal testing go on to fail in human trials, raising questions about the value of the tests. US and European medicines regulators now encourage other approaches if available. “It’s going to have a major impact on the numbers of animals used and the way we develop new drugs in the future,” said Matthias Zilbauer, a clinical professor of paediatric gastroenterology at the Cambridge Stem Cell Institute. “We’re not saying there won’t be any animal use in the near or foreseeable future, because there are still certain issues that cannot be tested in these new models, but the reduction is very real.”
“A lot of human diseases either do not occur in animals or occur in a different way because they’re not human,” added Zilbauer. “We want tests and models that can tell us which treatments work, and in what patients, and a mouse cannot tell us that.”
