Background: Even after several decades of human drug development, there remains an absence of published, substantial, comprehensive data to validate the use of animals in preclinical drug testing, and to point to their predictive nature with regard to human safety/toxicity and efficacy. Two recent papers, authored by pharmaceutical industry scientists, added to the few substantive publications that exist. In this brief article, we discuss both these papers, as well as our own series of three papers on the subject, and also various views and criticisms of lobby groups that advocate the animal testing of new drugs.

Main text: We argue that there still remains no published evidence to support the current regulatory paradigm of animal testing in supporting safe entry to clinical trials. In fact, the data in these recent studies, as well as in our own studies, support the contention that tests on rodents, dogs and monkeys provide next to no evidential weight to the probability of there being a lack of human toxicity, when there is no apparent toxicity in the animals.

Conclusion: Based on these data, and in particular on this finding, it must be concluded that animal drug tests are therefore not fit for their stated purpose. At the very least, it is now incumbent on—and we very much encourage—the pharmaceutical industry and its regulators to commission, conduct and/or facilitate further independent studies involving the use of substantial proprietary data.