Another Animal Model Success Fails in Humans


According to a February 3, 2012, press release from the American Heart Association: “ A new drug that showed promise in animal studies and an early clinical trial didn't improve disability among stroke patients, according to late-breaking research presented at the American Stroke Association's International Stroke Conference 2012.” The drug was AX200, which is a form of granulocyte colony stimulating factor (G-CSF). G-CSF appears to protect the brain in ischemia conditions. The press release quoted Bernd Ringelstein, M.D., lead author of the study as saying: “These top line results are disappointing and unexpected to us because AX200 showed signs of efficacy in a previous clinical trial with a limited number of patients, as well as in numerous animal studies.”

The above should come as no surprise considering that hundreds if not thousands of drugs have been effective as neuroprotectants in animal models but none have been so in humans. Spedding et al addressed this problem in general in Nature Reviews Drug Discovery in 2005: “Animal models often cannot be transposed to Phase I and Phase II clinical testing, and Phase I/II clinical testing is often not transposable to Phase III trials and the general population.” (Spedding et al. 2005) The inability of very small human studies to predict outcomes for large groups of humans is equally problematic. Once again, we get back to the fact that human-based testing based on genotype is the only solution for this problem.

Compare the above to the following from hepatitis researcher Christopher Walker who uses chimpanzees: “If you have an idea for an entirely new approach to vaccination, but can't get proof of that principle in animals, my fear is that it will never move ahead into human trials.” Thomas Rowell, director of New Iberia Research Center similarly stated: “Much of the work we do is done because the FDA won't allow the drug or vaccine to move into human trials without seeing data in relevant species.” (Harrington 2012)

Proof of concept or proof of principle is an oft-used justification for animal models. Animal modelers seem to have faith that if they can show that a drug or intervention is successful in some animal then they have provided evidence that the concept underlying the intervention is viable for humans. I say they have faith because there is ample scientific evidence that such concepts are usually wrong in that they cannot be applied to humans. When a concept or belief has been proven wrong and yet the community of believers still endorses it, that is faith not reason and as such should not be receiving taxpayer funding.

Rowell’s comment is an attempt to shift the focus and blame from the fact that animal models are not predictive of human response to drugs and disease to “the government made us do it. Bad government!” First, there is no “relevant species.” For some drugs rabbits eventually are shown to reproduce the human effects while for others it is monkeys and yet others no animal at all. The relevant species can only been known in retrospect. Moreover, even when the effect is similar the mechanism responsible for the effect can be different. Second, Pharma has stated that animal models cannot predict human response. Third, the fact that a government agency mandates nonsense does not excuse anyone from accepting such nonsense, especially in science. Fourth, taxpayer money goes to fund basic research, which makes no claims of predictive abilities (Greek and Greek 2010), therefore the basic researchers cannot maintain that they only use animals because the big bad government makes them. Finally, the FDA has allowed drugs to come to market without the usual animal tests.

Unfortunately, as I have said many times, this practice is unlikely to end because of all the money involved. Vivisection activists will continue to spin and use fallacious reasoning to support their cause and justify their faith. Universities that rely on money from animal experimentation will continue to send out press releases loudly proclaiming successes in animal models that never seem to make it to humans. Its all about the money.


Greek, R., and J. Greek. 2010. Is the use of sentient animals in basic research justifiable? Philos Ethics Humanit Med 5:14.

Harrington, Monica. 2012. State of the (research) chimp. Lab Animal 41 (2):31.

Spedding, M., T. Jay, J. Costa e Silva, and L. Perret. 2005. A pathophysiological paradigm for the therapy of psychiatric disease. Nat Rev Drug Discov 4 (6):467-76.


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