Statements By Scientists

Research with animals has consistently failed to produce effective and reliable results for human biomedical research. This is best illustrated by the number of scientists and clinicians who over the years have acknowledged the shortcomings of animal research, many of whom themselves conduct animal experiments. This listing is just a sampling of many such statements, and could be greatly expanded.

Unfortunately, awareness of the failings of animal research is not new. Read here about statements from scientists going back a century.

“It is well known that mice are typically the animal model of choice for preclinical research. Even if there is a high percentage of gene homology and both species are mammals, the long history of differing pharmacological responses between mice and humans tells a different story. No matter how many experiments were performed in mice or how successful they were, the failure percentage when transitioning from mouse to human trials is incredibly high.”

--Francina Agosti, Ph.D., Freelance science communicator,  October 15, 2021

​​“Animal models are still standard in preclinical studies. But the high failure rates of drugs in these clinical trials suggest that the differences between animals and humans are too big. Laboratory animals are therefore neither reliable models of humans disease nor good predictors of the effectiveness and toxicity of drugs”.

--Dr. Alirez Mashaghi, October 5, 2021

“Recreating models of Parkinson’s disease in animal models is hard as these do not show the progressive and selective loss of neurons that produce the neurotransmitter dopamine, a major feature of Parkinson’s disease. Another limitation is that experimental mouse models of Parkinson’s disease do not develop characteristic clumps of proteins called Lewy bodies, which are often seen in the brain cells of people with Parkinson’s disease and a type of progressive dementia known as Lewy body dementia.”

--Dr. Ng Huck Hui, September 7, 2021

“Preclinical research in this arena [Alzheimer's disease] predominantly uses animal models, but there is a huge difference between humans and animals such as rodents, especially when it comes to brain architecture”.

--Dr. Yanhong Shi, August 4, 2021

"This is mostly because drugs that work perfectly in preclinical inbred models, such as laboratory mice, that are genetically or otherwise identical to each other, don't translate to patients in the clinic, where each individual and their disease is unique. It is this variability in the clinic that is believed to be the Achilles heel for any drug discovery program."

--Dr. Pradipta Ghosh, July 12, 2021

''We have to share case study examples of where non-animal methods are being applied to demonstrate that we don’t need to use animals. The science is already there. We need to use it.”

--Paul Russell, chemistry science leader at Unilever’s SEAC, June 1, 2021


“If you talk to the leading scientists in the field, animal models are now archaic. The standard rat toxicity study has not moved on for more than half a century.”

--Steve Gutsell, a computational scientist and team leader in Unilever’s Safety and Environmental Assurance Centre (SEAC), June 1, 2021

“New therapies for metastasized cancer are typically tested in models of primary tumors, often established in animals that are not representative of metastatic lesions. At the same time, industry-compatible in vitro solutions are missing. We are honored to have received this grant as it will accelerate development of a more physiologically-relevant in vitro model of metastatic potential that can be applied in compound screens and drug testing. Once established, we envision this model, based on our Akura™ Flow technology platform, will be evaluated in multiple cancer types.”

--Olivier Frey, Ph.D., Vice President of Technology and Platforms at InSphero, May 10, 2021

“Until now, the laboratory animal model is still often the standard within health research and in some cases even required by law. Despite the movement towards other models, their application often lags behind due to the lack of suitable alternatives. We will now change this by stimulating public-private partnerships for the development of humane measurement models. In this way, we will be able to prevent or cure illnesses better in the long term, so that more people can live healthily for longer.”

--Olivier Frey, Ph.D., Vice President of Technology and Platforms at InSphero, May 10, 2021

“The attrition rate between data developed on animals and the correlation in the clinic is extremely low, and the majority of research projects fail before they ever get tested in humans.”

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin, April 27, 2021 

“Time after time it has been proven that animals are an insufficient predictor of drug safety, or efficacy in humans. Consider the statistics. More than 90% of drugs entering clinical trials fail, despite positive results in preclinical animal tests. In part, this is because animals do not have the same immune systems, nor do they contract many of the same diseases humans do, such as major types of heart disease, some cancers, HIV, Parkinson’s, and Schizophrenia.”

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin, April 27, 2021 

“Most of these drugs fail because of toxicity or loss of efficacy, which can’t be detected in animals. Even an animal’s laboratory conditions may be a factor in the success of experiments, with test results differing based on the animals age, sex, and diet. Consequently, results may vary from lab to lab. Non-human primates are close, but they are not humans. Even if there is a 1% difference, that is significant when testing for efficacy in humans. The best way to get human data is from humans.”

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin, April 27, 2021 

“Alternatives to animal testing are not a trend anymore. They are here to stay. Faster, more accurate, and safer drug development is driving this shift in pharma and biotech, and eventually alternatives to animal testing, such as our technology, will be the norm.”

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin, April 27, 2021 

“Indeed, many drugs first go through animal models before reaching clinical trials, and the large majority of those drugs fail in the clinic. Of course, there are also ethical considerations when it comes to animal models.”

--Dr. Don Ingber, Founding Director of Wyss Institute for Biologically Inspired Engineering at Harvard University, April 26, 2021 

“... We are now at a point at which we have much more complex in vitro models available, ranging from organoids to multiphysiological systems and organs-on-chips. Some of these in vitro models are as good or even better than animal models.”

--Dr. Don Ingber, Founding Director of Wyss Institute for Biologically Inspired Engineering at Harvard University, April 26, 2021 

“Asking for animal models is often a reflex, because this is how it’s been done for many years, even in cases, in which animal models are known to not replicate human physiology or pathophysiology.”

--Dr. Don Ingber, Founding Director of Wyss Institute for Biologically Inspired Engineering at Harvard University, April 26, 2021 

 “Novel drug discovery efforts suffer from increasing costs and low probability of clinical trial success, largely due to a lack of predictive preclinical in vitro models and reliance on animal testing which often fails to accurately capture human response. Organ-on-chip technology has the potential to greatly aid the development of new therapies,”

--authors. Coauthors are employees of Draper, Pfizer and Boston University. Principal investigators are Hesham Azizgolshani, Jonathan Coppeta, Brett Isenberg and Else Vedula of Draper.

April 13, 2021 

“Most commonly used strategies for drug repurposing are based on pre-clinical studies, such as experiments in cells or animal models. However, those types of studies may have problems of reproducibility or difficulties in translating their findings to humans. That usually leads to higher rates of failure in clinical trials”.

--Dr. Juan P. Casas, physician epidemiologist at the VA Boston Healthcare System, April 9, 2021 

“Another key challenge is that the immune system of animals and human is different. Since many toxic reactions in humans are mediated by the immune system, these reactions cannot be predicted by animals. One example is drug-induced liver injury (DILI) which can cause fatal liver damage in humans.”

--Prof. Armin Wolf, chief scientific officer at InSphero, April 7, 2021 

“Animal disease models demonstrated strong limitations in terms of translatability to human and particularly to patients. There is a definite need for more human-specific models.”

--Prof. Armin Wolf, chief scientific officer at InSphero, April 7, 2021 

“Anti-steatotic or anti-NASH drugs tested in healthy animals could strongly deviate from the toxic effects in patients. Toxicity testing in 3D microtissues in the respective in vitro disease model would allow a much better assessment for this fragile patient population.”

--Prof. Armin Wolf, chief scientific officer at InSphero, April 7, 2021 

“Testing drugs in mouse models that typically have brain deposits of either plaques or tangles, but not both, takes more than a year and is very costly. With our three-dimensional model that recapitulates both plaques and tangles, we now can screen hundreds of thousands of drugs in a matter of months without using animals in a system that is considerably more relevant to the events occurring in the brains of Alzheimer’s patients. … This new system – which can be adapted to other neurodegenerative disorders – should revolutionize drug discovery in terms of speed, costs and physiologic relevance to disease.”

Rudolph Tanzi, Joseph P. and Rose F. Kennedy Professor of Child Neurology and Mental Retardation at Harvard Medical School and Massachusetts General Hospital and the hospital’s Genetics and Aging Research Unit. Retrieved April 2021

[Drug development] “is a long and expensive endeavor that is defined by multiple failures. The main reason for this failure is that clinical experiments are ultimately based on minimal information gained from animal experiment which often fail to replicate the human response.”

--Dr. Nahmias Hebrew University of Jerusalem 

March 9, 2021

“It can sometimes take 15 to 20 years for a drug discovery to happen. The reason is these animals do not replicate human genomics or physiology”.

--Dr. Deepak Kalaskar, Professor, Division of Surgery and Interventional Science. University College London.

February 11, 2021  

"Many promising drug candidates successfully tested in preclinical models on rodents have failed when tested in humans due to differences between the species and in the expression of a lung disease. This is why, in the long term, we aim to reduce animal testing and provide more patient-relevant systems for drug screening with the possibility of tailoring models to specific patients [by seeding organs-on-chip with their own cells]."

Dr. Olivier Guenat ARTORG Center for Biomedical Research of the University of Bern

February 8, 2021

“… Animal data are not very reliable, or they are very difficult to interpret” … “the functions we can interrogate with a live animal are very different from the functions we can interrogate with cell assays”.

--Dr. Marcel Leist, Professor of Toxicology and Biomedicine, University of Konstanz

December 8, 2020

“Drug-induced injury to the kidney is a major side effect and difficult to predict using animal studies; bioprinting human kidneys are a practical approach to testing for toxicity before use”.

--Dr. Melissa Little, Murdoch Children’s Research Institute (MCRI)

December 1, 2020 

“The industry currently spends probably over three billion dollars a year to go from a discovery at the lab bench to an approved drug … as a result, there’s been a search … for better models that could actually mimic human organ-level function,” and “But the ultimate goal of all of this is to recapitulate human pathophysiology and predict human responses to drugs using clinically relevant dose measures,”

-Dr. Don Ingber, Founding Director of Wyss Institute for Biologically Inspired Engineering at Harvard University,

Nov 23, 2020 

“Animal experiments are no way to learn about the impacts of chemicals on human biology, as they differ biologically. Non-animal methods with a mechanistic toxicology focus can answer these questions in a scientifically superior way.  While scientific excellence drives alternatives to animal testing, the moral argument that animal experimentation is wrong helps turn this drive into a passion”.

--Dr. Timothy Allen, PhD. University of Cambridge

November 11, 2020

“When studying diseases or performing drug screenings, it is critical to have access to a human test system such as human organoids in order to prevent obtaining species specific test results.  Over the course of the last few years, organoids have become one of the most promising in vitro models due to their high physiological relevance; they also present a human-based alternative method to animal experiments”. 

--Dr. Tamara Zietek, Technical University of Munich (TUM) 

October 13, 2020

“ … animal models are physiologically irrelevant when considering human disease”, 

--Dr. Don Ingber, Founding Director of Wyss Institute for Biologically Inspired Engineering at Harvard University,

October 12, 2020 

“You learn a lot more about how human beings respond to the virus and how drugs might work in them when you infect human lung cells, not kidney cells from monkeys”.  … “Our organoids…are engineered from stem cells – they’re not identical to the living, breathing cells inside our bodies, but they are the closest thing to it”.

--Darrell Kotton, MD. Professor, of Medicine and Director, Center for Regenerative Medicine, Boston University School of Medicine.

September 24, 2020

“The main advantage to EVIDENT is speed and throughput, since we obtain an answer in seven days as compared to six weeks in a mouse, and we can run 12 experiments in EVIDENT versus one in a mouse”.   

--Vienna Mott, Bioengineer, Charles River Laboratories (CRL), September 10, 2020

“Our most widely used model is in animals but there are many differences between a mouse respiratory system as opposed to the human anatomy”.

--Choi-Fong Cho, assistant professor of neurosurgery at Harvard Medical School 

August 19, 2020

“Pharma and cosmetics industries as well as research institutes are beginning to realize that animal testing is an insufficient predictor of drug safety and/or efficacy in humans. Additionally, animal testing is often cruel and inhumane.”

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin,

August 24, 2020

“Animal testing is an insufficient predictor of drug safety or efficacy, most of these drugs fail because of toxicity, which is not detected in animals”.

--Dr. Pascal Descargues, Ph.D., founder of biotechnology company Genoskin,

August 13, 2020

 “As the physiology of humans and animals differs, the insight gathered from testing in these model systems does not often reflect how the drug will behave in humans, resulting in many clinical failures”.

--Katrin Hoeck, Head of Marketing at Lonza, a health solutions and technology company 

July 27, 2020

“You need a model when you study regeneration.  Traditionally we have used the mouse model, and, unfortunately what happens in mice in the lab often doesn’t pan out in humans.  This work is revolutionary because using these human pancreatic slices we can witness and monitor regeneration in a human model that resembles a real organ.  That was not possible before because the tissue simply didn’t live long enough”. 

--Dr. Juan Domínguez-Bendala, University of Miami Miller School of Medicine

July 9, 2020

 “I’ve become increasingly convinced that the animal model of the future will live not in a cage but in a computer chip: By simulating biological systems rather than experimenting with them, we can make drug development and biomedical research safer, more efficient, and more effective.” 

Lindsay Gray, rodent surgeon at the University of California, San Francisco

July 2, 2020

“The hearts of rats and mice beat five to 10 times faster than those of humans.  How those mechanisms work physically – the electrophysiology and the pumping action – is just different because of the scale”.

 --Dylan Richards, PhD, Computational Biologist at The Janssen Pharmaceutical Companies of Johnson & Johnson

June 12, 2020

“No single animal model can ever recapitulate the human disease condition … This is why we have had such big failures”

Dr. Charu Chandraskera, executive director of the Canadian Centre for Alternatives to Animal Methods (CCAAM)

May 4, 2020

“If I give a drug to a mouse, I can have a positive impact on that animal’s symptoms, but it’s not a great predictor of when you give that drug to a person”.

Zhan Shu, a postdoctoral scholar at the Semel Institute for Neuroscience and Human Behavior

February 11, 2020 

“Organoids give us the opportunity to study brain tumors without using experimental animals in a context that is similar to a real-patient scenario. They can be a reliable tool for developing personalized therapies.”

--Luca Tiberi, PhD, University of Trento in Italy

January 29, 2020 

“Non-communicable diseases - like cardiovascular diseases, cancers, diabetes and chronic lung diseases – are complex and for novel drug discovery, it is crucial to understand human genetic and physiological responses. At present, there is a tremendous reliability on animal testing, and this results in adverse events being reported late in clinical trials, leading to expensive drug failures”.

--Dr. Ruchi Sharma, CEO Stemnovate

January 18, 2020  

“Humans, as incidental hosts, are a big part of the disease process in the life cycle of Borrelia,” … “How the pathogen enters the vasculature is a critical event because the pathogen is still only present in a small number. And you can’t study this using animal models. Human tissues are too different, and Borrelia can’t cross the blood-brain barrier in rodent models the way it can in humans”.

Utpal Pal, professor in Veterinary Medicine at the University of Maryland

November 15, 2019 

"In contrast to animal model training, which requires expensive labs, the advantages of non-biologic simulators include increased availability, ease of set-up, flexibility (accommodating interrupted practice), low cost, low maintenance, lack of biological hazards, portability, potential for repeated use, and easy storage. It also reduces animal use and is overall more ethical."

--Jad Abi-Rafeh, a medical student at McGill University and the paper's first author.

October 25, 2019 

"Today, the Food and Drug Administration (FDA) stands as a gross outlier in the federal government as it relates to their outdated requirement to unnecessarily test and kill dogs. While other agencies in the FDA's regulatory ecosystem have aggressively sought to leverage technological advances to eliminate their reliance on animal testing, the FDA lags behind them, the broader science community, and the American public. By not changing its outmoded approach of forcing companies to conduct unnecessary tests on dogs, the FDA not only misses the opportunity to improve safety, but also pointlessly impedes the delivery of innovative new drugs to patients who need them."

-Mihael H. Polymeropoulos, M.D., Vanda's President and CEO.

September 11, 2019

“Clinical studies take years to complete and testing a single compound can cost more than $2 billion. Meanwhile, innumerable animal lives are lost, and the process often fails to predict human responses because traditional animal models often do not accurately mimic human pathophysiology.”

Wyss Institute for Biologically Inspired Engineering at Harvard University Retrieved January 2019.

“Animal experiments represent to date the gold standard in drug toxicology studies. However, the high failure rates of drugs in the preclinical stages, as well as the high cost of animal studies points to the need of more efficient alternative technologies for preclinical drug screening.”

--Charalampos Pitsalidis, Research Associate, Department of Chemical Engineering and Biotechnology, Cambridge.

December 14, 2018

“The causes for drug failure are likely due to the biological differences between the current animal models and cell lines used for drug discovery and human biology. The solution to this problem is to integrate human cell models early into the drug development process.” [Biotech company Elpis] “provides the first robust and scalable solution of functional biologically-relevant cells for drug development,” … “Elpis human cells can fix the broken drug discovery process by replacing animal experiments.” 

--Dr Jonathan Milner, life science investor and backer of UK company Elpis Biomed.

October 26, 2018

“With continued pressure from governments, societies, and animal welfare groups, pharmaceutical organizations are exploring ways to [decrease animal testing],” 

Dr. Matthew Clark, Senior Director, Scientific Services at Elsevier, September 3, 2018

“Organs on a chip have the potential to significantly speed drug discovery and development timelines, … Using organ chips, it is possible to demonstrate how the molecular biology of toxicology is actually taking place. You can understand pharmacokinetics and other features you can’t understand from animals. … This is a timely addition and hopefully a replacement for laborious, ill-predictive animal models.”

--Robert G. Urban, PhD, Global Head of Johnson & Johnson Innovation

Feb. 21, 2018

"It's very difficult to distill out specific mechanisms inside an animal, and a lot of work in toxicology or drug discovery fails when it goes to human clinical trials. In vitro models like our Thrombosis-on-a-Chip are made from the ground-up, so you can build them to be exactly as complex as you need for the problem you want to study."

Abhishek Jain, Ph.D., Assistant Professor of Biomedical Engineering at Texas A&M University.

May 22, 2017 

“Cancer has been cured a thousand times [in mice].”

--Christopher Austin, MD, Former director of the National Center for Advancing Translational Sciences of NIH

May 11, 2017

“Target validation only happens in humans – not cell lines or animal models. …. This is what new technologies, like organ-on-chips, are working on improving.  We need to move away from animal models.”

--Chas Bountra, Professor of Translational Medicine; Chief Scientist, Structural Genomics Consortium Oxford December 22, 2016

"Right now, preclinical drug development is carried out in animal models. But many of these models are terrible. They're not testing a drug on actual human cells, and in many cases drugs that don't show toxicity in animals eventually do in humans."

--Dr. Donald Ingber, Founding Director, Harvard's Wyss Institute for Biologically Inspired Engineering

October 12, 2016

“Researchers developed individual tissue chips that could mimic human organ structure, function, and physiological and drug responses more accurately than traditional cell- and animal-testing methods.”

--Christopher P. Austin, M.D., Director, National Center for Advancing Translational Sciences

Sept. 29, 2016

“A human organoid-on-a-chip, because it consists of human cells, would actually be more predictive about the effect of a drug candidate than animal testing.”

--Ron Weiss PhD, Professor of Biological Engineering at MIT.

Jan 8, 2016

The fact that [the cells are] human is really important. There can be very different responses to drugs in a mouse and a human.”

--James Wells, professor of pediatrics at Cincinnati Children’s Hospital Medical Center

Jul 19, 2016

“In addition, using the patient’s own cells is going to give you all the genes that are modified [in the disorder].  

You’ll never get that in a mouse.”

Cell biologist Melissa Little of Murdoch Children’s Research Institute in Australia

-- Melissa Little, BSc PhD GAICD, FAAHMS, FAA, Professor and Theme Director of Cell Biology at the Murdoch Children's Research Institute in Melbourne, Australia. 

Jul 19, 2016

"Our work provides a rigorous set of criteria for comparing naïve human stem cells to their counterparts in the early human embryo. Previous studies mainly relied on comparisons with mouse stem cells, which are highly divergent from human."

--Thorold Theunissen, a postdoctoral fellow at the Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology.

July 14, 2016

 “I predict that ten years from now, safety testing for newly developed drugs as well as assessment of the potential toxicity of numerous environmental exposures will be largely carried out using human biochips that are loaded with cells accurately representing heart, liver, kidney, muscle, brain and other tissues. This approach, made possible by the dramatic development of induced pluripotent stem cells (IPS cells), will mostly replace animal testing for drug toxicity and environmental sensing, giving results that are more accurate, at lower cost, and with higher through-put.”

--NIH Director Francis Collins MD, Testimony before a Senate hearing for the Labor, Health & Human Services Subcommittee

April 7, 2016

“We want to demonstrate the possibility of leveraging micro-engineered physiological organ models to challenge a century-long tradition of using animals as human surrogates in life sciences.”

--Don Huh, PhD, Assistant Professor of Bioengineering. University of Pennsylvania

Dec 28, 2015

“Petri dish and animal models often fail to provide good ways to mimic disease or predict how drugs will work in humans, resulting in much wasted time and money while patients wait for therapies. To address that challenge, NIH, DARPA, and FDA are collaborating to develop 3D platforms engineered to support living human tissues and cells, called tissue chips or organs-on-chips. An integrated body-on-a-chip is the ultimate goal.”

--NIH-Wide Strategic Plan, page 38

December 16, 2015

“To improve the efficiency, relevance, and accuracy of preclinical research, NIH will catalyze powerful innovations, including molecule cross-coupling methods that will open a vast new frontier of “chemical space” and human 3D organoid technologies that will be better than animal models.”

--NIH-Wide Strategic Plan, page 22

December 16, 2015

“The animal models used to understand the safety and efficacy of drugs are flawed. Human systems could predict, more effectively, safety and efficacy of drug molecules.”

--Bill Murphy PhD, Professor biomedical engineering, University of Wisconsin- Madison 

Dec 21, 2014

“They [animals] don’t behave exactly like people behave under those circumstances. That is why I like the simulation, especially the simulations based on fundamental human physiology.”

--Dr. John Pawlowski, assistant professor at Harvard Medical School and codirector of the Shapiro Simulation and Skills Center at Beth Israel Deaconess Medical Center

Discussing the use of human simulators for medical training

November 11, 2014

‘We’ve struggled for a long time trying to solve complex brain disease problems that cause tremendous pain and suffering. The power of this brain model bodes very well for human health because it gives us better and more relevant options to test and develop therapeutics other than rodents.”

-- Rene Anand PhD, Professor Biological Chemistry and Pharmacology, Ohio State University School of Medicine

September 30, 2015

“There are sufficient [non-animal] simulation models available to meet medical education and training needs”.

--Dr. Jonathan Woodson, the assistant secretary of defense for health affairs

November 11, 2014

"Murine [mouse] models have been extensively used in recent decades to identify and test drug candidates for subsequent human trials. However, few of these human trials have shown success. The success rate is even worse for those trials in the field of inflammation, a condition present in many human diseases. To date, there have been nearly 150 clinical trials testing candidate agents intended to block the inflammatory response in critically ill patients, and every one of these trials failed. … The prevailing assumption—that molecular results from current mouse models developed to mimic human diseases translate directly to human conditions—is challenged by our study. …  our study supports higher priority to focus on the more complex human conditions rather than relying on mouse models to study human inflammatory diseases."

--Seok J, et al. 2013 Genomic responses in mouse models poorly mimic human inflammatory diseases. Proc Natl Acad Sci U S A. 2013 Feb 26;110(9):3507-12.

“We have moved away from studying human disease in humans. We all drank the Kool-Aid on that one, me included. With the ability to knock in or knock out any gene in a mouse—which can’t sue us, researchers have over-relied on animal data. …The problem is that it hasn’t worked, and it’s time we stopped dancing around the problem…We need to refocus and adapt new methodologies for use in humans to understand disease biology in humans.”

--Dr. Elias Zerhouni, Former NIH director, 2002 – 2008, speaking before the NIH Scientific Review Management Board on June 4, 2013 as reported in NIH Record.   

“To date, almost all of these [toxicity] studies have been performed on animals. Until more research is done on women, we can’t rule out an environmental link. This is something we’re investigating now at the Dr. Susan Love Research Foundation, including ways to set up virtual human models to study the effect of potential carcinogens in the milk duct. That’s the kind of research that will help clarify this complex issue.”

--Susan Love, MD, founder and president of the Dr. Susan Love Research Foundation and clinical professor of surgery UCLA School of Medicine, speaking about the impact of environmental toxins on breast cancer: Quoted in Better Homes and Gardens, October 2012

"No [animal]model is ideal as each has its own advantages and limitations with respect to manipulation of the atherogenic process and modeling human atherosclerosis or lipoprotein profile. "

--Arterioscler Thromb Vasc Biol., May 2012

"Mice are mice, and people are people. If we look to the mouse to model every aspect of the disease for man, and to model cures, we're just wasting our time.... [The mouse] has cost us a new generation of medicines... The vast majority of the money that we spend in clinical trials based on mouse data is completely wasted... We keep getting led down the garden path. We've had thousands of mouse studies of tuberculosis, yet not one of them has ever been used to pick a new drug regimen that succeeded in clinical trials. This isn't just true for TB; it's true for virtually every disease. We're spending more and more money and we're not getting more and more drug candidates."

--Clif Barry, Chief of the Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA, November 16, 2011

"The use of animal models for therapeutic development and target validation is time consuming, costly, and may not accurately predict efficacy in humans. As a result, many clinical compounds are carried forward only to fail in phase II or III trials; many others are probably abandoned because of the shortcomings of the model. Building on a potentially extensive network of collaborations with academic centers and advocacy groups, NCATS [National Center for Advancing Translational Science] will aim to develop more reliable efficacy models that are based on access to biobanks of human tissues, use of human embryonic stem cell and induced pluripotent stem cell models of disease, and improved validation of assays. With earlier and more rigorous target validation in human tissues, it may be justifiable to skip the animal model assessment of efficacy altogether."

--Collins, Francis S., Director, National Institutes of Health, “Reengineering Translational Science: The Time Is Right,” 6 July 2011, Vol. 3, Issue 90, page 1.

"Ultimately, what this means is that many preliminary tests on animal cells -- particularly in medically relevant projects -- may not only be useless, but the findings from this kind of early testing may even be misleading," … "Our latest study demonstrates that animal model systems are inadequate for a great many tests of this kind," Particularly when we're talking about developing safe and effective stem cell therapies, we will still need human ES cells as the gold standard against which to compare everything else. In such cases, lengthy preliminary testing on animal cells risks wasting valuable time and resources."

--Dr. Hans Schöler from the Max Planck Institute for Molecular Biomedicine, as quoted in ScienceDaily, 9 March 2010. Max-Planck-Gesellschaft. "Deceptive model: Stem cells of humans and mice differ more strongly than suspected."

“Although many sophisticated mice APP [*amyloid precursor protein] models exist, none recapitulates AD [Alzheimer’s Disease] cellular and behavioral pathology. The morphological resemblance to AD amyloidosis is impressive, but fundamental biophysical and biochemical properties of the APP/amyloid β produced in Tg mice differ substantially from those of humans. … Transgenic mice were widely used for testing AD therapeutic agents, and demonstrated promising results. Unfortunately, clinical trials resulted in unforeseen adverse events or negative therapeutic outcomes. The disparity between success and failure is in part attributable to evolutionary divergence between humans and rodents. These observations suggest that the pathogenesis of AD is by far more intricate than can be explained by a straightforward accumulation of amyloid β.”

* The amyloid beta protein is considered a precursor to AD.

--Kokjohn TA, Roher AE. Amyloid precursor protein transgenic mouse models and Alzheimer's disease: understanding the paradigms, limitations, and contributions. Alzheimers Dement. 2009 Jul;5(4):340-7., July 2009

“These [non-animal] models have the ability to be far more accurate. I sometimes think it is just tradition — that feeling that if it’s safe in an animal it’s safe in a human — which means so many animal tests are still carried out.”

--Kelly BéruBé, cell biologist, Cardiff University, as quoted in The Times Online (UK), June 5, 2009, accessed at

"The reason we use animal tests is because we have a comfort level with the process . . . not because it is the correct process, not because it gives us any real new information we need to make decisions … Animal tests are no longer the gold standard. It is a marvelously new world."

--Melvin E. Andersen, director of the division of computational systems biology at the Hamner Institutes for Health Sciences near Raleigh, N.C.  as quoted in Gaul, GM, In U.S., Few Alternatives To Testing On Animals, Washington Post, April 12, 2008.

"Some animal tests haven't changed in 60 years. The tests are frozen in time. This is not science. Science is always moving ahead."

-- Thomas Hartung, Head of The European Center for the Evaluation of Alternative Methods (ECVAM) as quoted in Gaul, GM, Washington Post, April 12, 2008.

“Animals don't reflect the reality of cancer in humans. We cure cancer in animals all the time, but not in people."

--Fran Visco, Founder of the National Breast Cancer Coalition and cancer survivor, as quoted in Begley, Sharon, We fought cancer …. and cancer won.” Newsweek, September 15, 2008.

"Animal models have not been very predictive of how well [cancer] drugs would do in people. We put a human tumor under the mouse's skin, and that microenvironment doesn't reflect a person's—the blood vessels, inflammatory cells or cells of the immune system.”

--Paul Bunn MD, Director, International Society for the Study of Lung Cancer, , as quoted in Begley, Sharon, We fought cancer …. and cancer won.” Newsweek, September 15, 2008.

“This [over reliance on mice] has skewed the field so much that most clinically trained immunologists keep at least a few (and usually a lot more) mice in the “back room” so that they can have a steady flow of papers, grant funding, etc., and some have abandoned human work entirely as a lost cause. But this is just the price of progress, no? Well, except that mice are lousy models for clinical studies. This is readily apparent in autoimmunity and in cancer immunotherapy where of dozens (if not hundreds) of protocols that work well in mice, very few have been successful in humans. Similarly, in neurological diseases, the mouse models have also been disappointing.”

--Davis, MM, Director Stanford University Institute for Immunity, Transplantation and Infection. “A prescription for human immunology.” Immunity. 2008 Dec 19;29(6):835-8.

“Recent advances in systems biology, testing in cells and tissues, and related scientific fields offer the potential to fundamentally change the way chemicals are tested for risks they may pose to humans, says a new report from the National Research Council.  The report outlines a new approach that would rely less heavily on animal studies and instead focus on in vitro methods that evaluate chemicals' effects on biological processes using cells, cell lines, or cellular components, preferably of human origin.  . … Over time, the need for traditional animal testing could be greatly reduced, and possibly even eliminated someday, says the report.” [emphasis added]

--Press release, June 12, 2007. “Report Calls for New Directions, Innovative Approaches in Testing Chemicals for Toxicity to Humans” The National Academies of Sciences report commissioned by the Environmental Protection Agency.

“Despite decades of research using various animal models for type 1 diabetes, we are still struggling to define the initiating autoantigens, the precise mechanisms of beta cell destruction, and suitable immune-based interventions to prevent or treat human diabetes. ... Although [these] animal models of autoimmune diabetes have proved to be valuable tools to study certain aspects of the disease process, they have also led to misconceptions and erroneous extrapolations, as well as false expectations with regard to the efficacy of immunotherapy. It is therefore time to ask ourselves whether we are making major strategic mistakes when employing rodent models for the study of type 1 diabetes.”

--Roep, BO. Are insights gained from NOD mice sufficient to guide clinical translation? Another inconvenient truth. Ann N Y Acad Sci. 2007 Apr; 1103:1-10.

“Finally, poor replication of even high-quality animal studies should be expected by those who conduct clinical research.”

--Hackam DG, Redelmeier DA. 2006. Translation of research evidence from animals to humans. JAMA. Oct 11;296(14):1731-2.

“Currently, nine out of ten experimental drugs fail in clinical studies because we cannot accurately predict how they will behave in people based on laboratory and animal studies”

--Mike Leavitt, Secretary of Health and Human Services, U.S. Department of Health and Human Services (Food and Drug Administration press release, FDA Issues Advice to Make Earliest Stages of Clinical Drug Development More Efficient, January 12, 2006)

"The biomedical model is failing …Even if we know all there is to know about the animal model we don't necessarily know about the disease. …The model becomes what we study, not the human disease. …It's a fundamental flaw. We need a fundamentally new approach."

--Susan Fitzpatrick, Ph.D., vice-president of the James S. McDonnell Foundation in Saint Louis, Missouri, as quoted in Philips, H., The Insider - Focus on Neuroscience. Brainstorming. . New Scientist, 2004. 184(2469): p. 54.

“As therapies for human diseases become ever more sophisticated and specifically targeted, it becomes increasingly important to understand the potential limitations of extrapolating data from mice to humans. The literature is littered with examples of therapies that work well in mice but fail to provide similar efficacy in humans.”

--Mestas J, Hughes CC. 2004  Of mice and not men: differences between mouse and human immunology. J Immunol. Mar 1;172(5):2731-8.

"The clinical trials of nimodipine and low level laser therapy were conducted concurrently with the animal studies, while the clinical trials of fluid resuscitation, thrombolytic therapy, and endothelin receptor blockade went ahead despite evidence of harm from the animal studies. This suggests that the animal data were regarded as irrelevant, calling into question why the studies were done in the first place and seriously undermining the principle that animal experiments are necessary to inform clinical medicine."

--Pound P, et al. Where is the evidence that animal research benefits humans? BMJ. 2004;328(7438):514–517. 

“There isn’t a single genetically manipulated mouse that has been used yet to produce a drug that cures a disease.”

--Kathleen Murray, director of transgenic services at Charles River Laboratories; The Scientist 16 [3]; 22, Feb. 4, 2002