Studies in non-human animals have led to “countless” treatments for various diseases, according to a recent article on The Conversation.
But the author, Gavan McNally, provided no scientific references to support his claim. In this, of course, he’s not alone: there’s an intriguing history of animal researchers making insufficiently substantiated claims about the value of their work.
The best available evidence
Those in positions of authority who publicly claim important social benefits from research upon which their careers are dependent have a moral obligation to ensure those claims are supported by sound evidence.
The best evidence we have about the social utility of animal research comes from systematic reviews. Such analyses aim to include all relevant scientific publications (such as animal studies), and include multiple steps to minimise bias.
The research question being investigated must be clearly defined in advance, and at least two scientific literature databases must be comprehensively searched, using a thorough and transparent search strategy, to minimise any risk of missing relevant reports.
Criteria for excluding publications, such as lack of relevance or poor quality, must be clearly specified in advance.
Hundreds of reports of animal experiments are commonly identified in these reviews — sometimes more than 1,000. Where resource constraints prevent examination of all experiments located, any subsets selected for examination must be chosen using randomisation, or similarly impartial and methodical means.
Finally, the whole process must be conducted with a level of scientific rigour sufficient to ensure subsequent publication of the review in a peer-reviewed scientific journal.
In 2007 I comprehensively searched the scientific literature to locate successfully published systematic reviews. Among the 20 I found that examined human clinical utility, animal models appeared to demonstrate significant potential to contribute toward the development of new clinical interventions in only two cases, one of which was contentious because the study results did not support the conclusions.
Included among those 20 reviews were animal experiments that should have been most likely to yield tangible benefits — such as experiments expected by ethics committees to lead to medical advances, highly-cited experiments published in major journals, and chimpanzee experiments — that investigated the species most generally predictive of human outcomes.
In each of seven additional reviews I located that examined toxicity prediction, animal models failed to reliably predict the most important human toxicities — carcinogenicity or teratogenicity, the propensity to cause cancer or birth defects, respectively. Results in animal models were frequently ambiguous or inconsistent with human outcomes.
Weighing costs and benefits
Nevertheless, Professor McNally was correct to assert some value may accrue from animal research. Unless experimental results are not obtained, or are unreliable or duplicative, animal research can usually be argued to have advanced scientific knowledge in some way and, therefore, to have some degree of scientific merit.
But this ignores the costs incurred by such research.
Those costs may include animal lives, the consumption of considerable financial and scientific resources and, potentially, even adverse impacts on patients and consumers, when human results differ from those predicted by animal models.
Keeping it real
Overestimation of the social benefits of invasive animal research appears widespread. This was exemplified in a 2011 review of research using non-human primates (NHPs), in which a panel of eminent scientists examined virtually all UK primate research conducted during a recent decade, only to report that:
In most cases […] little direct evidence was available of actual medical benefit in the form of changes in clinical practice or new treatments.
The same report, again with regards to research on NHPs, stated that:
the Panel’s assessments of medical and other benefits were made with difficulty and often could be no more than informed guesses. This contrasts with the emphatic public statements about the medical benefits of NHP research made by some of the funding bodies and by grant applicants.
The panel — comprising experts in neurobiology, neurology, psychology, zoology, reproductive biology and translational research — recommended that:
In their public engagement, the funders and researchers should avoid overstating and generalising the medical benefit of NHP research, since this cannot be substantiated in many cases.
If the arguments made by researchers such as McNally are to be believed, Australia’s extensive regulatory framework should prevent such problems. “The institution, its animal ethics committee and researchers are subject to inspections”, he assures us; they are part of a framework that ensures “regulatory compliance and continual improvement in animal welfare”.
McNally points to other “independent checks” in the Australian system:
[R]esearchers seek funding from independent agencies such as the National Health and Medical Research Council and the Australian Research Council. These funds are exceptionally hard-won. The idea that research funded via these agencies lacks significance and scientific excellence is absurd.
At first glance, it appears McNally may be right. As scientists in this field, our main regulatory instrument is the Australian Code for the Care and Use of Animals for Scientific Purposes.
On paper, the Code does seem to require a reasonable ethical assessment of proposed research, and appears committed to the implementation of the famous “three Rs”:
- Replacement of animals with non-animal models
- Reduction of animal numbers
- Refinement of experimental procedures to decrease suffering, wherever possible
But unfortunately, as I have described in detail elsewhere, the protection actually afforded to laboratory animals differs significantly from its prima facie appearance.
As outlined above, a large and remarkably consistent body of evidence indicates that resultant social benefits are rarely, if ever, sufficient to justify the costs incurred by animals subjected to invasive research.
Therefore, rigorous regulatory adherence should result in minimal invasive animal use. And yet, Australia is one of the leading international users of laboratory animals.
To date, global comparisons have only been published for 2005. Despite data from multiple Australian states or territories remaining publicly unavailable, my calculations have revealed that, even when limited to states releasing figures, Australia was still the fourth largest user of laboratory animals worldwide, both overall and per capita. Only the US, Japan and China used more animals, overall.
It seems clear that the fundamental regulatory requirement to ensure animal research is “adequately justified” is honoured more in the breach than the observance.
Significant bias of ethics committees in favour of animal research is the obvious, and most likely, cause. Animal welfare representatives invariably constitute a small minority, and documented irregularities have included disproportionate numbers of researchers on committees, and supposedly independent representatives appointed from within the university concerned.
Although animal ethics committees allow researchers to claim their research has “ethical approval”, in truth I would argue such systemic biases render the process fundamentally unethical.
In short, contrary to the poorly-substantiated claims of animal researchers, the overwhelming majority of invasive animal experiments do not pass the cost-benefit test required by regulations and expected by society.
- Animals in research: benefits, ethics and assessment, by Gavan McNally
- More Conversation articles on animals in research.