Study shows testing new drugs in any one animal species cannot reliably predict results in other animal species – including humans
A new scientific paper published today raises serious questions about whether any animal test – including on monkeys, the species closest to us – can predict human responses.
The key findings of the new analysis, Predicting Human Drug Toxicity and Safety via Animal Tests: Can Any One Species Predict Drug Toxicity in Any Other, and Do Monkeys Help?, demonstrate that any one animal species is a highly inconsistent predictor of toxic responses in any other (eg, rats for dogs, dogs for monkeys, and so on). Further, it finds that test results from any one species are no better than a coin-toss at predicting the absence of toxic responses in another species (how likely a new drug is to be free from adverse effects).
Approximately 250,000 animals (including around 3,000 dogs) were used in such experiments in 2014 in Great Britain alone. Despite these numbers, drug development is facing serious difficulties: new drugs and drug pipelines are at all-time lows.
The analysis also highlights that drug tests involving monkeys—the ‘least different’ species to humans—are as poor as those using any other commonly used species in predicting human responses.
The findings of the new peer-reviewed study, authored by FRAME Life President Professor Michael Balls and Dr Jarrod Bailey and Michelle Thew, of Cruelty Free International, and published in the scientific journal ATLA (Alternatives to Laboratory Animals), raise two major concerns. If tests on any one animal species cannot reliably predict results in any other, then how can any animal tests predict human drug responses and safety? And, if tests in monkeys are poorly predictive for humans, how can tests using species such as rats be of value?
The paper concludes “…animal testing of human drugs is not fit-for-purpose… the preclinical testing of pharmaceuticals in animals cannot currently be justified, ethically or scientifically.”
This latest paper builds on two previous reports by the authors, which showed that using dogs—and other animals such as mice, rabbits and rats—in experiments to predict the safety of new drugs in humans is not scientifically justifiable.
Together, these papers constitute the most comprehensive published analyses to date of the value of using animals for predicting drug safety in humans, and are based on the largest publicly available database of animal toxicity studies yet compiled.
Laws and regulatory agencies worldwide currently require that drugs are tested on animals prior to clinical trials on humans. To date, however, very little research has been carried out examining whether experiments on animals really are useful in advancing the development of drugs for humans.
The authors’ three studies address this knowledge gap, and should have widespread implications for the pharmaceutical industry.
Michelle Thew, CEO of Cruelty Free International, said: “We have always known that animal experiments are not ethically justifiable, and this latest peer-reviewed paper adds to our rigorous body of work demonstrating that using animals to test drugs for humans is not scientifically justifiable either. We call on governments, regulators and the pharmaceutical industry to recognise the failure of animal research and to embrace humane and human-relevant methods for developing drugs.”
The authors hope the paper will encourage the pharmaceutical industry and other stakeholders to engage fully in constructive discussion and debate, to increase the search for more reliable testing methods not involving the use of animals, and to more fully adopt and embrace alternative approaches that already exist.
References:
Bailey J, Thew M, Balls M. (2015). Predicting Human Drug Toxicity and Safety via Animal Tests: Can Any One Species Predict Drug Toxicity in Any Other, and Do Monkeys Help? Alternatives to Laboratory Animals (ATLA) 43, 393–403.
Bailey J, Thew M, Balls M. (2014). An Analysis of the Use of Animal Models in Predicting Human Toxicology and Drug Safety. Alternatives to Laboratory Animals (ATLA) 42, 181–199.
Bailey J, Thew M, Balls M. (2013). An Analysis of the Use of Dogs in Predicting Human Toxicology and Drug Safety. Alternatives to Laboratory Animals (ATLA) 41, 335–350.
