World Animal Laboratory Day 24th April: The failure of the animal testing model

This is a small section of my analysis of the animal testing model which is taken from chapter nine of my recent book Eastern Orthodox Christianity and Animal Suffering: Ancient Teachings in Modern Theology.

When we examine the available research on the animal testing model, such as Linzey and Linzey (2017)[1], Bailey and Taylor (2016)[2] Kathrin Herrmann and Kimberley Jayne (2019) (2a),  we find that there are few systematic studies examining the validity of this model.

In answer to the question posed in their article entitled “Is animal research sufficiently evidence based to be a cornerstone of biomedical research?” Pound and Bracken (2014) conclude that it is:

…nearly impossible to rely on most animal data to predict whether or not an intervention will have a favourable clinical benefit-risk ratio in human subjects.[3]

Knight (2011)had already alerted us to this problem:

…the utility of many animal experiments in advancing human healthcare or even biomedical knowledge of significance is poor. [4]

These two statements alone ought to concern us. The obvious question arising is whether these statements can be verified? If this were not the case, we would expect the licensing of a large percentage of the drugs tested on animals for human use.

The American Food and Drug Administration (FDA) is a well-respected and authoritative body and their comments here address this specific point:

Overall, in the US, 92% of drugs that pass pre-clinical tests, mostly animal tests, fail to make it to the market because they are proven to be ineffective and or unsafe in people. [5]

This report also concludes that if topical medicines are excluded the failure rate is around 97%. The first observation from the FDS report is that the failure rate of the animal testing model is extraordinarily high. The second observation is that the animal testing model is unreliable and thus flawed.

The model fails the caveat that the animal testing model is essential for the advancement of human health. In fact, such conclusions ought to lead us to ask whether the model is a benefit or a hindrance to human health. My argument here is that its use is an example of the “predetermined conclusion” that the model is “not harmful to humanity.”

The next question is to ask why the failure rate is so high. There are several contributing factors and the most obvious is that the species of animals used are not human; we are not dogs, rabbits, monkeys etc. This in and of itself ought to raise considerable doubt on the efficacy of the model.

An equally pertinent point is that animals experience physical pain and mental suffering, which includes fear, trauma, stress, distress, anticipation and terror, all of which alter their physiology; if one or a combination of these factors affects the animal, the results will be suspect.[6]

Knight (2011) includes several other factors in calculating stress and suffering, such as capture from the wild, transportation, housing etc., which he concludes, alter the physiology and mental capacities of the animals over time. [7] He states that these factors, in addition to creating significant animal welfare and ethical problems distort a wide range of experimental outcomes, such as those dependent on accurate determination of physiological, behavioural, or cognitive characteristics in animal models.[8] This also raises serious doubts over the efficacy of this model and this too ought to concern us.

There is another factor to consider which again brings us back to H. A. H. Bartholomew’s point on the dangers of the “predetermined conclusion that these are not harmful to humans” and the ethicist’s caveat that they are “necessary.” If we examine the evidence, the drugs that are licensed are not universally safe for humans and the tragedy of giving thalidomide to pregnant women is a well-known case in point. This sadly, is not the only example.

As I write this chapter the scandal of the epilepsy drug, sodium valproate (Epilim) is breaking news. Since its license, circa 20,000 children in the UK have physical abnormalities, autism, low IQ and learning disabilities after being exposed to the drug while in the womb. The Medicines and Healthcare Products Regulatory Agency (MHRA) have now changed the licensing because up to four in ten babies are at risk of developmental disorders and one in ten are at risk of birth defects.[9]

This is not a lone example. The organisation Nurses Movement for Responsible Medicine provides further examples and comments of licensed drugs that have caused considerable damage to humans. I condense their commentary:

Few people in the West are aware of the Clioquinol tragedy. Clioquinol caused 30,000 cases of blindness and/or paralysis in Japan alone. This drug also caused a new disease called SMON. “Clioquinol was tested on rats, cats, beagles and rabbits with no evidence of neurotoxicity.” “Oraflex (Opren) an antiarthritic drug meant to alleviate the pain and frequently crippling limitations of arthritis was found safe in nonhuman primates, at 7 times the maximum tolerated human dose for a year. It caused death in a number of elderly patients, mainly from liver damage.” “Butazolidine, a pain killer, caused kidney and red blood cell damage.” “Chloramphenicol caused bone marrow destruction and fatal aplastic anaemia…though human cell culture could have found what animal testing has failed to show.” “Isoprenaline aerosol during the 1960s, thousands of young asthmatics died following the use of Isoprenaline aerosol inhalers. Animal tests did not show nor predict the danger…cats could tolerate 175 times the dose found dangerous to asthmatics and the adverse complications could not be reproduced in guinea pigs, dogs and monkeys at doses much higher than the recommended dosage.” “Eraldin a heart medication; some patients who received it suffered intestinal and eye problems, blindness and many deaths resulted.” “Phenformin, to treat diabetes, caused 1,000 deaths annually until withdrawn from the market.” “Amydopyrine a pain killer caused a nasty blood disease.” “Reserpine to treat hypertension may cause restlessness, nightmares and depression, pancreatitis, severe anaemia and kidney failure. A number of epidemiologic studies pointed to an increased risk of breast cancer in women. It may cause foetal harm when given to pregnant women.” “Methotrexate to treat leukaemia and psoriasis caused intestinal haemorrhage, anaemia and tumours.” “Mitotane for leukaemia caused kidney damage.” “Cyclophosphamide used for cancer and transplants…led to liver and lung damage.” “Urethane for leukaemia caused cancer of the liver, lungs and bone marrow.” “Kanamycin an antibiotic caused deafness and kidney damage.” “Methaqualon a tranquilizer caused severe mental disturbances.” “Maxiton diet pills caused damage to the heart and nervous system.” “Halcion a hypnotic; reports of severe psychic problems with its use are surfacing which prompted Britain to ban its use.” “Tegretol for epilepsy, two potentially fatal blood diseases: aplastic anaemia and agranulocytosis are 5-8 times more likely to occur in patients on Tegretol than in the general population. Epidemiologic findings suggest an increased incidence of birth defects when pregnant women used Tegretol.[10]

The bold sections draw attention to the fact that alternatives are available and can offer data that is more reliable. Despite the animal testing model, all these licensed products resulted in injury, suffering and in some cases human death.

In addition to the poor ratio of usable drugs to animals used, there is now the additional problem of human safety for those drugs that are licensed.

An obvious criticism here is that I am simply selecting evidence from scientists that have a bias against animal testing. This statement from a report from leaders in the drug development industries addresses that criticism:

The poor predictability of animal experiments is one of the major challenges facing the drug discovery industry.[11]

This would not be the first time that manufacturers were aware of problems but failed to inform the public.

A forensic question to ask here is if this level of failure arose in any other industry, would we expect industry to continue with the model’s use or substitute it with procedures that are more reliable? The answer is obvious.

Why there has not been greater investment in alternative procedures is probably due to economics/profit and the lack of any challenge to the animal testing model by those other than animal protectionists. Many in society still believe philosophical and theological teachings that God created animals solely for our use but this is part of the second discussion and so I put this aside for the moment.

There is evidence of change. Sir David Attenborough, along with 20 other scientists, calls for an end to animal testing on primates and urges the use of currently available alternatives:

The recognition that apes, certainly, and to an extent other primates, are so akin to ourselves, and can suffer so much, as we can, has transformed our attitude, or should have transformed our attitude, to using them for our own benefit. They are sentient beings that have mental lives comparable to ours, and sensitivities, and pain and deprivation mean things to them, just as they mean things to us.[12]

We, the undersigned, are concerned at the level of suffering involved in many neuroscience experiments on non-human primates, especially where fluid deprivation and movement restraint are involved, and believe that there has now been sufficient progress in human-based alternatives to call into serious question whether further research of this type is necessary. We note the recent research in this area published in ATLA [Bailey J & Taylor K. (2016). Non-human Primates in Neuroscience Research: The Case Against its Scientific Necessity. ATLA 44, 43-69]. We therefore call on bodies responsible for the funding and licensing of this type of research to review their policies and specifically to end support for experiments involving deprivation of fluids and movement restraint.[13]

The words in bold type, bring into focus the scientific community’s recognition that there are human-based alternatives to primate testing already available.

Importantly, their arguments are equally valid for all other species of sentient creatures used in the animal testing model. The obvious question to ask is why scientists are not using suitable alternatives if they are available for use. I have given my answer. There is also the possibility of using ‘irrational’ creatures as units of ‘disposable life’ but again I leave this aside for the moment.

As noted, alternatives to the animal testing model are available and two useful journals are Alternatives to Laboratory Animals[14] and Laboratory Animals.[15]Several animal welfare organisations’ websites list examples of alternatives such as In vitro; Microfluidic chip; Micro-dosing; Imaging studies and computer models and simulations.[16] The Linzey and Linzey (2017) report gives examples of adult stem cell research; human organs-on-a-chip; lab-grown human organs and systems biology and compare the effectiveness of these methods to existing animal models.[17] Sharma (2015) suggests alternatives for use in university Zoology and Life Science courses in India (and elsewhere) and, makes us aware of the link between educational institutions, suppliers and hunters:

I estimate that employing these alternatives will save roughly 19 million animals belonging to a variety of species, from fish to mammals. In addition, the adoption of these non-animal methods will deal a death blow to the well-organised nexus between educational institutions and those who catch, kill and supply animals…inspection of breeding business have discovered ill and wounded animals crammed inside soiled cages, rats embalmed alive and workers who killed frogs by slamming their heads against hard surfaces. [18]

His comments on the link between hunting and experimentation and the abusive conditions and treatment of the animals should not surprise us. He also mentions the reestablishment of the concept of ahimsa in using humane alternatives and Christians may use the same argument using our concept of the non-violent Christ. In his summary of this section of the Linzey report, Andrew Linzey states:

The upshot of these scientific developments in cutting-edge human-based testing models is that it is no longer accurate or reasonable (if it ever was) to say that the only moral choice is between experimenting on animals and giving up on medical progress. This is a false dilemma. The choice instead is the choice between experimenting on animals and using improved human-based methods of testing.[19]

This indicates a further problem in the animal testing model-the phenomenon of publication bias. Knight outlines the problem:

Research demonstrating ‘no effect’ is less likely to be published than research falsely indicating an effect (false positives). When investigators later review the published literature, they find only the latter and draw false conclusions about the drug effects. This is partly why animal research translates so poorly to human patients.[20]

Apart from the false positive/negative problems, scientists are also less likely to publish failures. This in turn, gives a distorted view of the efficacy of the animal testing model.

In light of the above evidence, we gain an insight into why there are serious doubts both inside and outside of the scientific community on the reliability of the animal testing model to predict the suitability of a variety of medicines/drugs for human health and thus its advancement.

In light of the above evidence, I submit that the animal testing model fails several of the previously outlined caveats and parameters for scientific research. It ought therefore, to be rejected.

[1] Linzey and Linzey, The Ethical Case Against Animal Experiments, references over 200 different research papers and reports on the theme. Also, Knight, The Costs and Benefits of Animal Experiments.

[2] Bailey and Taylor, “Non-human Primates in Neuroscience Research: The Case Against its Scientific Necessity.” I am grateful to Prof. Knight for this reference.

2a Kathrin Herrmann and Kimberley Jayne Animal Experimentation: Working Towards a Paradigm Change. 51 experts have contributed to this book. E-Book Availability: Published ISBN: 978-90-04-39119-2 Publication Date: 30 Apr 2019 Hardback Availability: Published ISBN: 978-90-04-35618-4 Publication Date: 04 Apr 2019

[3] Pound and Bracken, “Is animal research sufficiently evidence based to be a cornerstone of biomedical research?” BMJ 348 (3387); also, BMJ editor F. Godlee’s accompanying editorial, “How Predictive and Productive is Animal Research?” BMJ 348: (3719).

[4] Knight, Costs and Benefits, 4, 57-9. For the number of animals used, see 9-17. For species, sources and categories of use, see 18-28; also, USFDA (2004) Innovation or Stagnation: Challenge and Opportunity on the Critical Path to New Medical Products.

[5] My emphasis. USFDA, Innovation or Stagnation: Challenge and Opportunity on the Critical Path to New Medical Products, 2004.

[6] Linzey, “Cruelty to Animals is as if a Man did not Love God.” In The Ark: Journal of Catholic Concern for Animals, 220 (Spring): 5. We may think this is a modern thought but as previously noted, Philo gives similar commentary when condemning practices which cause mental anguish to cows separated from their newly born calves.

[7] I add a personal note here to support Knight’s point. When my dogs were in quarantine in Bahrain I arrived to find three adult Baboons in the same block and that one had escaped. The chaos and the fear and distress of the apes were evident from their screams, their throwing of faeces and the attempt of the escapee to avoid recapture. The process took nearly an hour whereupon the animals were removed to the laboratory at Bahrain University.

[8] Knight, Costs and Benefits of Animal Experiments, 36.

[9] 24th April 2018.  Also, Zack Adesina, BBC Inside Out, London, UK 22 January 2018

[10] My emphasis. See,

[11] Palfreyman, Vinod and Blander, “The importance of using human-based models in gene and drug discovery.” In Drug Discovery World Fall (2002): 33-44.

[12]  Also, 

[13]My emphasis. Signatories: Sir David Attenborough, broadcaster and naturalist; Simon Bearder, PhD, Emeritus Professor, Department of Anthropology, Oxford Brookes University; Marc Bekoff, PhD, Emeritus Professor, Department of Ecology and Evolutionary Biology, University of Colorado. Nedim C. Buyukmihci, VMD, Emeritus Professor, Department of Veterinary Medicine, University of California, Davis; Herbert H. Covert, PhD, Professor, Department of Anthropology, University of Colorado Boulder; Paul Furlong, PhD, Professor of Clinical Neuroimaging, Director, Aston Brain Centre, School of Life and Health Sciences, Aston University. John P. Gluck, PhD, Emeritus Professor, Department of Psychology, University of New Mexico; Research Professor Kennedy Institute of Ethics, Georgetown University; Jane Goodall, PhD, DBE-Founder of the Jane Goodall Institute and UN Messenger of Peace. Colin Groves, PhD, Emeritus Professor of Bio anthropology, Australian National University; Eleonora Gullone, PhD, Affiliate Associate Professor, Centre for Developmental Psychiatry and Psychology, Monash University; Steven Harnad, PhD, Professor of Psychology at Université du Québec à Montréal (UQAM) and Professor of Cognitive Science at the University of Southampton. Catherine Hobaiter, PhD, Lecturer, School of Psychology and Neuroscience, St Andrews University; Jessica A. Mayhew, PhD, Assistant Professor, Department of Anthropology & Museum Studies and Primate Behavior & Ecology Program, Central Washington University; Dr Monika Merkes, PhD, (Public Health) Honorary Associate, Australian Institute for Primary Care & Ageing, La Trobe University. Anna Nekaris, PhD, Professor in Anthropology and Course Leader, MSc Primate Conservation, Oxford Brookes University; Hugh Notman, PhD, Associate Dean, Learning Technologies & Associate Professor, Anthropology, Biological, Athabasca University. Ian Redmond, OBE, Field biologist and conservationist, Ambassador, UNEP Convention on Migratory Species, former Envoy for UN-GRASP; Vernon Reynolds, PhD, Emeritus Professor, School of Anthropology, Oxford University and Founder of the Budongo Conservation Field Station, Uganda; Lori K. Sheeran, PhD, Professor, Department of Anthropology & Museum Studies and Primate Behavior & Ecology Program, Central Washington University. Jo Thompson, PhD, Executive Director, Lukuru Foundation, Democratic Republic of Congo; Richard Wrangham, PhD, Ruth B. Moore Professor and former Chair of Biological Anthropology, Harvard University and President Emeritus, International Primatological Society.




[17] 2015:4.23-29. Published as Linzey & Linzey, 2017.

[18] Dr Sharma is a member of EGC-MHRD Core Expert Committee to Consider Discontinuation of Dissection of animals in Zoology/Life Science in Indian Universities and Colleges, The Ark (Spring 2012):29-30.

[19] Linzey and Linzey, The Ethical Case Against Animal Experiments, 4.29

[20] Discussions at Winchester University in 2017.