La letteratura scientifica è ricca di riferimenti alla sperimentazione animale. Un crescente numero di articoli critica esplicitamente l’uso del modello animale, definendolo quanto meno “discutibile”, “mai validato”, “da revisionare urgentemente”, “inattendibile”. Alcune pubblicazioni sono delle revisioni sistematiche atte a validare/falsificare l’ipotesi di predittività, altre sono semplicemente degli utili approfondimenti sia nel campo dei metodi alternativi che nella critica alla sperimentazione animale e alla validazione basata su di essa. Questo elenco non è esaustivo ed è in continuo aggiornamento: per approfondire ulteriormente riferirsi direttamente a Pubmed ed agli articoli del presente blog, nonché alla relativa bibliografia.
1)
Glazko G, Veeramachaneni V, Nei M, Makałowski W.
Eighty percent of proteins are different between humans and chimpanzees.
Gene. 2005 Feb 14;346:215-9.
Abstract: The chimpanzee is our closest living relative. The morphological differences between the two species are so large that there is no problem in distinguishing between them. However, the nucleotide difference between the two species is surprisingly small. The early genome comparison by DNA hybridization techniques suggested a nucleotide difference of 1-2%. Recently, direct nucleotide sequencing confirmed this estimate. These findings generated the common belief that the human is extremely close to the chimpanzee at the genetic level. However, if one looks at proteins, which are mainly responsible for phenotypic differences, the picture is quite different, and about 80% of proteins are different between the two species. Still, the number of proteins responsible for the phenotypic differences may be smaller since not all genes are directly responsible for phenotypic characters.
Link to the article: http://www.personal.psu.edu/nxm2/2005%20Publications/2005-glazko-etal.pdf
2)
ALTEX. 2010;27(1):43-51.
First alternative method validated by a retrospective weight-of-evidence approach to replace the Draize eye test for the identification of non-irritant substances for a defined applicability domain.
Hartung T, Bruner L, Curren R, Eskes C, Goldberg A, McNamee P, Scott L, Zuang V.
Abstract: A replacement alternative to the rabbit eye irritation test has been sought for many years. First published in 1944 by FDA toxicologist J. H. Draize, the test, now known as the Draize Eye Test, has been used extensively to assess eye safety. It has also been a focal point for concern regarding its animal use. In 1992, Molecular Devices developed the Cytosensor Microphysiometer (CM) technology, an automated potentiometric online measurement of pH changes in cells, and evaluated it also for chemically induced irritation. The method was included in some of the six major validation studies for eye irritation from 1991-1997. The results for CM were inconclusive as were those from other tests evaluated as stand-alone methods to fully replace the animal test. In 2002, the European Centre for the Validation of Alternative Methods (ECVAM) started applying concepts from evidence-based medicine, and opened validation to retrospective meta-analysis. This activity was done in collaboration with US counterpart ICCVAM/NICEATM, and the European Cosmetics Association, Colipa. After a new, comprehensive evaluation of the prior available data, the ECVAM scientific advisory committee (ESAC) has recently accepted the CM as capable of identifying non-irritants for testing limited to water-soluble surfactants and water-soluble surfactant-containing mixtures. This 25-year development is remarkable and instructive in many respects. The authors see this as opening the door, at last, for an end to the use of animals as a standard requirement for eye irritation. Here, several of the people critically involved in this processes have summarized the important aspects of this history.
Link to the article: http://www.altex.ch/resources/Altex_1_10_Hartung.PDF
3)
PNAS 2013 ; published ahead of print February 11, 2013, doi:10.1073/pnas.1222878110
Genomic responses in mouse models poorly mimic human inflammatory diseases
Junhee Seok, H. Shaw Warren, Alex G. Cuenca, Michael N. Mindrinos, Henry V. Baker, Weihong Xu, Daniel R. Richards, Grace P. McDonald-Smith, Hong Gao, Laura Hennessy, Celeste C. Finnerty, Cecilia M. López, Shari Honari, Ernest E. Moore, Joseph P. Minei, Joseph Cuschieri, Paul E. Bankey, Jeffrey L. Johnson, Jason Sperry, Avery B. Nathens, Timothy R. Billiar, Michael A. West, Marc G. Jeschke, Matthew B. Klein, Richard L. Gamelli, Nicole S. Gibran, Bernard H. Brownstein, Carol Miller-Graziano, Steve E. Calvano, Philip H. Mason, J. Perren Cobb, Laurence G. Rahme, Stephen F. Lowry, Ronald V. Maier, Lyle L. Moldawer, David N. Herndon, Ronald W. Davis, Wenzhong Xiao, Ronald G. Tompkins, and the Inflammation and Host Response to Injury, Large Scale Collaborative Research Program
Abstract: A cornerstone of modern biomedical research is the use of mouse models to explore basic pathophysiological mechanisms, evaluate new therapeutic approaches, and make go or no-go decisions to carry new drug candidates forward into clinical trials. Systematic studies evaluating how well murine models mimic human inflammatory diseases are nonexistent. Here, we show that, although acute inflammatory stresses from different etiologies result in highly similar genomic responses in humans, the responses in corresponding mouse models correlate poorly with the human conditions and also, one another. Among genes changed significantly in humans, the murine orthologs are close to random in matching their human counterparts (e.g., R2 between 0.0 and 0.1). In addition to improvements in the current animal model systems, our study supports higher priority for translational medical research to focus on the more complex human conditions rather than relying on mouse models to study human inflammatory diseases.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3587220/
4)
Arch Toxicol. 2013 Apr;87(4):563-7. doi: 10.1007/s00204-013-1038-0. Epub 2013 Mar 19.
Inflammatory findings on species extrapolations: humans are definitely no 70-kg mice.
Abstract: Modern toxicology has embraced in vitro methods, and major hopes are based on the Omics technologies and systems biology approaches they bring along (Hartung and McBride in ALTEX 28(2):83-93, 2011; Hartung et al. in ALTEX 29(2):119-28, 2012). A culture of stringent validation has been developed for such approaches (Leist et al. in ALTEX 27(4):309-317, 2010; ALTEX 29(4):373-88, 2012a; Toxicol Res 1:8-22, 2012b), while the quality and usefulness of animal experiments have been little scrutinized. A new study (Seok et al. 2013) now shows the low predictivity of animal responses in the field of inflammation. These findings corroborate earlier findings from comparisons in the fields of neurodegeneration, stroke and sepsis. The low predictivity of animal experiments in research areas allowing direct comparisons of mouse versus human data puts strong doubt on the usefulness of animal data as key technology to predict human safety.
Link to the article: http://caat.jhsph.edu/publications/70kg_final2013.pdf
5)
Int J Med Sci. 2013; 10(3): 206–221. Published online 2013 January 11. doi: 10.7150/ijms.5529 – PMCID: PMC3558708
Systematic Reviews of Animal Models: Methodology versus Epistemology
Abstract: Systematic reviews are currently favored methods of evaluating research in order to reach conclusions regarding medical practice. The need for such reviews is necessitated by the fact that no research is perfect and experts are prone to bias. By combining many studies that fulfill specific criteria, one
hopes that the strengths can be multiplied and thus reliable conclusions attained. Potential flaws in this process include the assumptions that underlie the research under examination. If the assumptions, or axioms, upon which the research studies are based, are untenable either scientifically or logically, then the results must be highly suspect regardless of the otherwise high quality of the studies or the systematic reviews. We outline recent criticisms of animal-based research, namely that animal models are failing to predict human responses. It is this failure that is purportedly being corrected via systematic reviews. We then examine the assumption that animal models can predict human outcomes to perturbations such as disease or drugs, even under the best of circumstances. We examine the use of animal models in light of empirical evidence comparing human outcomes to those from animal models, complexity theory, and evolutionary biology. We conclude that even if legitimate criticisms of animal models were addressed, through standardization of protocols and systematic reviews, the animal model would still fail as a predictive modality for human response to drugs and disease. Therefore, systematic reviews and meta-analyses of animal-based research are poor tools for attempting to reach conclusions regarding human interventions.
Link to the article: http://www.medsci.org/v10p0206.htm
6)
BMJ. 2004 February 28; 328(7438): 514–517.
doi: 10.1136/bmj.328.7438.514PMCID: PMC351856
Where is the evidence that animal research benefits humans?
Pandora Pound, research fellow,1 Shah Ebrahim, professor,1 Peter Sandercock, professor,2 Michael B Bracken,professor,3 Ian Roberts, professor,4 and Reviewing Animal Trials Systematically (RATS) Group
Summary: Clinicians and the public often consider it axiomatic that animal research has contributed to the treatment of human disease, yet little evidence is available to support this view. Few methods exist for evaluating the clinical relevance or importance of basic animal research, and so its clinical (as distinct from scientific) contribution remains uncertain.1 Anecdotal evidence or unsupported claims are often used as justification—for example, statements that the need for animal research is “self evident”2 or that “Animal experimentation is a valuable research method which has proved itself over time.”3 Such statements are an inadequate form of evidence for such a controversial area of research. We argue that systematic reviews of existing and future research are needed.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC351856/
7)
Contemp Top Lab Anim Sci. 2004 Nov;43(6):42-51.
Laboratory routines cause animal stress.
Balcombe JP, Barnard ND, Sandusky C.
Abstract: Eighty published studies were appraised to document the potential stress associated with three routine laboratory procedures commonly performed on animals: handling, blood collection, and orogastric gavage. We defined handling as any non-invasive manipulation occurring as part of routine husbandry, including lifting an animal and cleaning or moving an animal’s cage. Significant changes in physiologic parameters correlated with stress (e.g., serum or plasma concentrations of corticosterone, glucose, growth hormone or prolactin, heart rate, blood pressure, and behavior) were associated with all three procedures in multiple species in the studies we examined. The results of these studies demonstrated that animals responded with rapid, pronounced, and statistically significant elevations in stress-related responses for each of the procedures, although handling elicited variable alterations in immune system responses. Changes from baseline or control measures typically ranged from 20% to 100% or more and lasted at least 30 min or longer. We interpret these findings to indicate that laboratory routines are associated with stress, and that animals do not readily habituate to them. The data suggest that significant fear, stress, and possibly distress are predictable consequences of routine laboratory procedures, and that these phenomena have substantial scientific and humane implications for the use of animals in laboratory research.
Link to the article: http://animalexperiments.info/resources/Studies/Animal-impacts/Stress.-Balcombe-et-al-2004./Stress-Balcombe-et-al-2004.pdf
8)
Philos Ethics Humanit Med. 2010 Sep 8;5:14. doi: 10.1186/1747-5341-5-14.
Is the use of sentient animals in basic research justifiable?
Greek R, Greek J.
Abstract: Animals can be used in many ways in science and scientific research. Given that society values sentient animals and that basic research is not goal oriented, the question is raised: “Is the use of sentient animals in basic research justifiable?” We explore this in the context of funding issues, outcomes from basic research, and the position of society as a whole on using sentient animals in research that is not goal oriented. We conclude that the use of sentient animals in basic research cannot be justified in light of society’s priorities.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2949619/
9)
ALTEX. 2008;25(3):213-31.
Non-animal methodologies within biomedical research and toxicity testing.
Knight A.
Abstract: Laboratory animal models are limited by scientific constraints on human applicability, and increasing regulatory restrictions, driven by social concerns. Reliance on laboratory animals also incurs marked – and in some cases, prohibitive – logistical challenges, within high-throughput chemical testing programmes, such as those currently underway within Europe and the US. However, a range of non-animal methodologies is available within biomedical research and toxicity testing. These include: mechanisms to enhance the sharing and assessment of existing data prior to conducting further studies, and physicochemical evaluation and computerised modelling, including the use of structure-activity relationships and expert systems. Minimally-sentient animals from lower phylogenetic orders or early developmental vertebral stages may be used, as well as microorganisms and higher plants. A variety of tissue cultures, including immortalised cell lines, embryonic and adult stem cells, and organotypic cultures, are also available. In vitro assays utilising bacterial, yeast, protozoal, mammalian or human cell cultures exist for a wide range of toxic and other endpoints. These may be static or perfused, and may be used individually, or combined within test batteries. Human hepatocyte cultures and metabolic activation systems offer potential assessment of metabolite activity and organ-organ interaction. Microarray technology may allow genetic expression profiling, increasing the speed of toxin detection, well prior to more invasive endpoints. Enhanced human clinical trials utilising micro- dosing, staggered dosing, and more representative study populations
and durations, as well as surrogate human tissues, advanced imaging modalities and human epidemiological, sociological and psycho- logical studies, may increase our understanding of illness aetiology and pathogenesis, and facilitate the development of safe and effective pharmacologic interventions. Particularly when human tissues are used, non-animal models may generate faster, cheaper results, more reliably predictive for humans, whilst yielding greater insights into human biochemical processes. Greater commitment to their development and implementation is necessary, however, to efficiently meet the needs of high-throughput chemical testing programmes, important emerging testing needs, and the ongoing development of human clinical interventions.
Link to the article: http://www.andrewknight.info/publications/anim_expts_overall/non-anim-methods/AK%203Rs%20ALTEX%202008%2025(3)%20213-231.pdf
10)
van Meer PJ, Kooijman M, Gispen-de Wied CC, Moors EH, Schellekens H.
The ability of animal studies to detect serious post marketing adverse events is limited.
Regul Toxicol Pharmacol. 2012 Dec;64(3):345-9. doi: 10.1016/j.yrtph.2012.09.002. Epub 2012 Sep 12.
Abstract: The value of animal studies to assess drug safety is unclear because many such studies are biased and have methodological shortcomings. We studied whether post-marketing serious adverse reactions to small molecule drugs could have been detected on the basis of animal study data included in drug registration files. Of 93 serious adverse reactions related to 43 small molecule drugs, only 19% were identified in animal studies as a true positive outcome, which suggests that data from animal studies are of limited value to pharmacovigilance activities. Our study shows that drug registration files can be used to study the predictive value of animal studies and that the value of animal studies in all stages of the drug development should be investigated in a collaborative endeavour between regulatory authorities, industry, and academia.
Link to the abstract: http://www.ncbi.nlm.nih.gov/pubmed/22982732
11)
Langley G, Evans T, Holgate ST, Jones A.
Replacing animal experiments: choices, chances and challenges.
Bioessays 2007; 29(9): 918-26.
Abstract: Replacing animal procedures with methods such as cells and tissues in vitro, volunteer studies, physicochemical techniques and computer modelling, is driven by legislative, scientific and moral imperatives. Non-animal approaches are now considered as advanced methods that can overcome many of the limitations of animal experiments. In testing medicines and chemicals, in vitro assays have spared hundreds of thousands of animals. In contrast, academic animal use continues to rise and the concept of replacement seems less well accepted in university research. Even so, some animal procedures have been replaced in neurological, reproductive and dentistry research and progress is being made in fields such as respiratory illnesses, pain and sepsis. Systematic reviews of the transferability of animal data to the clinical setting may encourage a fresh look for novel non-animal methods and, as mainstream funding becomes available, more advances in replacement are expected.
Link to the article: http://www.animalexperiments.info/resources/Studies/Alternatives/Replacement.-Langley-et-al.-2007./Replace-Langley-et-al-2007-Bioessays.pdf
12)
ALTEX. 2007;24(4):320-5.
Animal experiments scrutinised: systematic reviews demonstrate poor human clinical and toxicological utility.
Knight A.
Abstract: The assumption that animal models are reasonably predictive of human outcomes provides the basis for their widespread use in toxicity testing and in biomedical research aimed at developing cures for human diseases. To investigate the validity of this assumption, the comprehensive “Scopus” biomedical bibliographic databases were searched for published systematic reviews of the human clinical or toxicological utility of animal experiments. Of 20 reviews examining clinical utility, authors concluded that the animal models were substantially consistent with or useful in advancing clinical outcomes in only two cases, and the conclusion in one case was contentious. Included were reviews of the clinical utility of experiments expected by ethics committees to lead to medical advances, of highly-cited experiments published in major journals, and of chimpanzee experiments – the species most likely to be predictive of human outcomes. Seven additional reviews failed to clearly demonstrate utility in predicting human toxicological outcomes such as carcinogenicity and teratogenicity. Consequently, animal data may not generally be assumed to be substantially useful for these purposes. Possible causes include interspecies differences, the distortion of experimental outcomes arising from experimental environments and protocols, and the poor methodological quality of many animal experiments evident in at least 11 reviews. No reviews existed in which a majority of animal experiments were of good quality. While the latter problems might be minimised with concerted effort, given their widespread nature, the interspecies limitations are likely to be technically and theoretically impossible to overcome. Yet, unlike non-animal models, animal models are not normally subjected to formal scientific validation. Instead of simply assuming they are predictive of human outcomes, the consistent application of formal validation studies to all test models is clearly warranted, regardless of their animal, non-animal, historical, contemporary or possible future status. Expected benefits would include greater selection of models truly predictive of human outcomes, increased safety of people exposed to chemicals that have passed toxicity tests, increased efficiency during the development of human pharmaceuticals, and decreased wastage of animal, personnel and financial resources. The poor human clinical and toxicological utility of most animal models for which data exists, in conjunction with their generally substantial animal welfare and economic costs, justify a ban on animal models lacking scientific data clearly establishing their human predictivity or utility.
Link to the article: http://www.andrewknight.info/publications/anim_expts_overall/sys_reviews/AK%20Sys%20rev%20ALTEX%202007%2024(4)%20320-325.pdf
13)
Schnabel J.
Neuroscience: Standard model.
Nature. 2008 Aug 7;454(7205):682-5. doi: 10.1038/454682a.
Summary: The results of drug tests in mice have never translated perfectly to tests in humans. But in recent years, and especially for neurodegenerative diseases, mouse model results have seemed nearly useless. In the past year, for example, three major Alzheimer’s drug candidates, Alzhemed (3-amino-1-propanesulphonic acid), Flurizan (tarenflurbil) and bapineuzumab, all of which had seemed powerfully effective in mouse models, have performed weakly or not at all in clinical trials involving thousands of human Alzheimer’s patients.
Link to the article: http://www.nature.com/news/2008/080807/full/454682a.html
14)
ATLA 28, 315–331, 2000
Volunteer Studies Replacing Animal Experiments in Brain
Research
Report and Recommendations of a Volunteers in Research and Testing Workshop
Gill Langley, Graham Harding, Penny Hawkins, Anthony Jones, Carol Newman, Stephen Swithenby, David Thompson, Paul Tofts and Vincent Walsh
Link to the article: http://eprints.ucl.ac.uk/6440/1/6440.pdf
15)
Nature 2005 Nov 10;438(7065):144-146
Animal testing: more than a cosmetic change.
Abbott, Alison.
Abstract: Commercial and political pressures are pushing for a halt to the use of animals in toxicology tests in Europe. This change will also mean a move towards better science, says Alison Abbott.
Every time you reach for an eyedrop or reapply a lip salve, you do so confident that the chemicals they contain are safe to use. But the toxicology tests on which regulators rely to gather this information are stuck in a time warp, and are largely based on wasteful and often poorly predictive animal experiments.
Link to the article: http://ethics.ucsd.edu/journal/2006/readings/Animal_Testing_More_than_a_cosmetic_change.pdf
16)
Biogenic Amines 2005; 19(4-6): 235–255.
Non-human primates in medical research and drug development: a critical review.
Bailey J
Abstract: There is much current debate surrounding the use of non-human primates (NHPs) in medical research and drug development. This review, stimulated by calls for evidence from UK-based inquiries into NHP research, takes a critical view in order to provide some important balance against papers supporting NHP research and calling for it to be expanded. We show that there is a paucity of evidence to demonstrate the positive contribution or successful translation of NHP research to human medicine, that there is a great deal of often overlooked data showing NHP research to be irrelevant, unnecessary, even hazardous to human health and to have little or no predictive value or application to human medicine. We briefly discuss the reasons why this may be so, reflect upon the consequences for future medical progress and, on the basis of our findings, suggest a more scientifically robust and promising way forward.
Link to the article: http://www.safermedicines.org/pdfs/reportbiogenic.pdf
17)
Balls, M. (2004)
Are animal tests inherently valid?
ATLA: Alternatives to Laboratory Animals, 32(Suppl. 1B), 755–758.
Abstract: The proposition that animal tests are inherently valid, merely because they are animal tests, is discussed and is rejected. It is concluded that there is no justifiable reason for subjecting new or substantially modified animal test procedures or testing strategies to a validation process that is any less stringent than that applied to non-animal tests and testing strategies.
Link to the article: http://www.frame.org.uk/atla_article.php?art_id=734&pdf=true
18)
Barnard, Neal D., Kaufman, Stephen R.,
Animal research is wasteful and misleading . Scientific American, 00368733, Feb97, Vol. 276, Issue 2
Summary: The use of animals for research and testing is only one of many investigative techniques available. We believe that although animal experiments are sometimes intellectually seductive, they are poorly suited to addressing the urgent health problems of our era, such as heart disease, cancer, stroke, AIDS and birth defects. Even worse, animal experiments can mislead researchers or even contribute to illnesses or deaths by failing to predict the toxic effects of drugs. Fortunately, other, more reliable methods that represent a far better investment of research funds can be employed.
The process of scientific discovery often begins with unexpected observations that force researchers to reconsider existing theories and to conceive hypotheses that better explain their findings. Many of the apparent anomalies seen in animal experiments, however, merely reflect the unique biology of the species being studied, the unnatural means by which the disease was induced or the stressful environment of the laboratory. Such irregularities are irrelevant to human pathology, and testing hypotheses derived from these observations wastes considerable time and money.
The majority of animals in laboratories are used as so-called animal models: through genetic manipulation, surgical intervention or injection of foreign substances, researchers produce ailments in these animals that “model” human conditions. This research paradigm is fraught with difficulties, however. Evolutionary pressures have resulted in innumerable subtle, but significant, differences between species. Each species has multiple systems of organs–the cardiovascular and nervous systems, for example–that have complex interactions with one another. A stimulus applied to one particular organ system perturbs the animal’s overall physiological functioning in myriad ways that often cannot he predicted or fully understand Such uncertainty severely undermines the extrapolation of animal data to other species, including humans.
Link to the article: http://msherzan.pbworks.com/f/Animal+Research+is+Wasteful+and+Misleading.pdf
19)
Brady C.A .
Of mice and men: the potential of high resolution human immune cell assays to aid the preclinical to clinical transition of drug development projects. Drug Discovery world 2008/9:74-78.
Abstract: The effort to develop drugs that interact with the human immune system (whether by accident or design) has been dogged by a mismatch between the data derived from animal models (mice in particular) and that found in man. Although the mouse provides the most common model for many aspects of the human immune system, the 65 million years of divergence has introduced significant differences between these species, which can and has impeded the reliable transition of pre-clinical mouse data to the clinic.The industry is littered with examples of delays, reiterations or even abandoned drug programmes arising from poor translation of animal responses to man. This article highlights some of the species differences and forwards the rationale to utilise high-resolution human immune cell assays to improve the successful transition from pre-clinical project to proof-of-concept in clinical trial.
Link to the article: http://ddw.net-genie.co.uk/enabling_technologies/261930/of_mice_and_men.html
20)
Knight A, Bailey J, Balcombe J.
Which drugs cause cancer? Animal tests yield misleading results.
BMJ USA 2005; 331: E389-E391.
Link to the article: http://www.andrewknight.info/publications/anim_expts_tox/carcino/AK%20et%20al%20Carcino%20BMJ%20USA%202005%20331%20E389-391.pdf
21)
Davis MM.
A prescription for human immunology.
Immunity. 2008 Dec 19;29(6):835-8.
Abstract: Inbred mice have been an extremely successful tool for basic immunology, but much less so as models of disease. Thus, to maximize the use of immunologic approaches to improve human health, we need more strategically directed efforts in human immunology. This would also open up new opportunities for basic research.
Link to the article
: http://www.wissenschaftsdialog.de/728%20Davis%20mouse%20model.pdf
22)
Greek R., Pippus A. and Hansen A.L.
The Nuremberg Code subverts human health and safety by requiring animal modeling BMC Medical Ethics 2012
Abstract:
Background
The requirement that animals be used in research and testing in order to protect humans was formalized in the Nuremberg Code and subsequent national and international laws, codes, and declarations.
Discussion
We review the history of these requirements and contrast what was known via science about animal models then with what is known now. We further analyze the predictive value of animal models when used as test subjects for human response to drugs and disease. We explore the use of animals for models in toxicity testing as an example of the problem with using animal models.
Summary
We conclude that the requirements for animal testing found in the Nuremberg Code were based on scientifically outdated principles, compromised by people with a vested interest in animal experimentation, serve no useful function, increase the cost of drug development, and prevent otherwise safe and efficacious drugs and therapies from being implemented.
Link to the article: http://www.biomedcentral.com/1472-6939/13/16
23)
Hartung T.
Per aspirin ad astra…
Altern Lab Anim. 2009 Dec;37 Suppl 2:45-7. CAAT, Johns Hopkins University, Baltimore, USA.
Abstract:
Taking the 110th anniversary of marketing of aspirin as starting point, the almost scary toxicological profile of aspirin is contrasted with its actual use experience. The author concludes that we are lucky that, in 1899, there was no regulatory toxicology. Adding, for the purpose of this article, a fourth R to the Three Rs, i.e. Realism, three reality-checks are carried out. The first one comes to the conclusion that the tools of toxicology are hardly adequate for the challenges ahead. The second one concludes that, specifically, the implementation of the EU REACH system is not feasible with these tools, mainly with regard to throughput. The third one challenges the belief that classical alternative methods, i.e. replacing animal test-based tools one by one, is actually leading to a new toxicology — it appears to change only patches of the patchwork, but not to overcome any inherent limitations other than ethical ones. The perspective lies in the Toxicology for the 21st Century initiatives, which aim to create a new approach from the scratch, by an evidence-based toxicology and a global “Human Toxicology Programme”.
Link to the article: http://www.frame.org.uk/atla_article.php?art_id=1238&pdf=true
24)
Philos Ethics Humanit Med. 2009 Jan 15;4:2. doi: 10.1186/1747-5341-4-2.
Are animal models predictive for humans?
Shanks N, Greek R, Greek J.
Abstract:
It is one of the central aims of the philosophy of science to elucidate the meanings of scientific terms and also to think critically about their application. The focus of this essay is the scientific term predict and whether there is credible evidence that animal models, especially in toxicology and pathophysiology, can be used to predict human outcomes. Whether animals can be used to predict human response to drugs and other chemicals is apparently a contentious issue. However, when one empirically analyzes animal models using scientific tools they fall far short of being able to predict human responses. This is not surprising considering what we have learned from fields such evolutionary and developmental biology, gene regulation and expression, epigenetics, complexity theory, and comparative genomics.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2642860/
25)
van der Worp HB, Howells DW, Sena ES, Porritt MJ, Rewell S, O’Collins V et al.:
Can animal models of disease reliably inform human studies?
PLoS Med 2010, 7: e1000245
Summary points:
– The value of animal experiments for predicting the effectiveness of treatment strategies in clinical trials has remained controversial, mainly because of a recurrent failure of interventions apparently promising in animal models to translate to the clinic.
– Translational failure may be explained in part by methodological flaws in animal studies, leading to systematic bias and thereby to inadequate data and incorrect conclusions about efficacy.
– Failures also result because of critical disparities, usually disease specific, between the animal models and the clinical trials testing the treatment strategy.
– Systematic review and meta-analysis of animal studies may aid in the selection of the most promising treatment strategies for clinical trials.
– Publication bias may account for one-third or more of the efficacy reported in systematic reviews of animal stroke studies, and probably also plays a substantial role in the experimental literature for other diseases.
– We provide recommendations for the reporting of aspects of study quality in publications of comparisons of treatment strategies in animal models of disease.
Link to the article: http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000245
26)
Hackam & Redelmeier.
Translation of research evidence from animals to humans.
JAMA 2006;296(14):1731-2.
Comment. Only about a third of highly cited animal research translated at the level of human randomized trials. This rate of translation is lower than the recently estimated 44% replication rate for highly cited human studies.4
Limitations of this review include a focus on highly cited animal studies published in leading journals, which by their positive and highly visible nature may have been more likely to translate than less frequently cited research. In addition, this study had limited power to discern individual predictors of translation.
Nevertheless, we believe these findings have important implications. First, patients and physicians should remain cautious about extrapolating the findings of prominent animal research to the care of human disease. Second, major opportunities for improving study design and methodological quality are available for preclinical research. Finally, poor replication of even high-quality animal studies should be expected by those who conduct clinical research.
Link to the article: http://animalexperiments.info/resources/Studies/Human-healthcare/Highly-cited-studies.-Hackam-et-al-2006./Translation-Hackam-et-al-2006-JAMA.pdf
27)
David Biello.
Robot Allows High-Speed Testing of Chemicals.
Scientific American October 13, 2011
Summary: Of the more than 80,000 chemicals used in the U.S., only 300 or so have ever undergone health and safety testing. In fact, only five chemicals have ever been restricted or banned by the U.S. Environmental Protection Agency (EPA). But now some 10,000 agricultural and industrial chemicals—as well as food additives—will be screened for toxicity for the first time, with the help of a rapid-fire testing robot.
Link to the article: http://www.scientificamerican.com/article.cfm?id=robot-allows-high-speed-chemical-test
28)
James Kirkpatrick C, Fuchs S, Iris Hermanns M, Peters K, Unger RE.
Cell culture models of higher complexity in tissue engineering and regenerative medicine.
Biomaterials. 2007 Dec;28(34):5193-8. Epub 2007 Aug 29.
Abstract: Cell culture techniques have tended to be used in biomaterial research as a screening method prior to embarking on specific in vivo experimentation. This presentation aims at showing that it is possible to develop more sophisticated in vitro systems using primary human cells in co-culture with other cell types and biomaterials in a three-dimensional setting. While the predictive value of such systems is still not proven these models can be employed to unravel the complexity of biological systems in order to understand molecular mechanisms of cell-cell and cell-material interactions. The brief overview is under the headings of basic principles of relevant culture systems, the study of inflammation and the healing response, scenarios for specific biomaterial applications and future directions. How human endothelial cells can be usefully incorporated into more complex cell culture models is presented as an example of how relevant questions in tissue engineering and regenerative medicine can be addressed. The central tenet of this paper is that it is possible to refine in vitro methodology using cells of human origin to establish relevant assay systems that more closely simulate the cellular and molecular microenvironment encountered in a specific situation of regeneration using biomaterials.
Link to the abstract: http://www.ncbi.nlm.nih.gov/pubmed/17761278
29)
Vinci B, Duret C, Klieber S, Gerbal-Chaloin S, Sa-Cunha A, Laporte S, Suc B, Maurel P, Ahluwalia A, Daujat-Chavanieu M.
Modular bioreactor for primary human hepatocyte culture: medium flow stimulates expression and activity of detoxification genes.
Biotechnol J. 2011 May;6(5):554-64. doi: 10.1002/biot.201000326. Epub 2011 Jan 21.
Abstract:
The MCmB, fabricated at the University of Pisa, consists of silicone culture chambers (similar shape and dimensions as those of 24-well plates) connected by culture medium flow, so that cell-cell interaction between chambers is mediated by soluble molecules/proteins as in the body.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3123466/
30)
Michael Hopkin
New test could weed out dangerous drug trials.
Published online 7 December 2006 | Nature | doi:10.1038/news061204-13
Summary: Immunologists studying what went wrong in the fateful Northwick Park drug trial in London in March 2006 have developed a test that they say may have spotted the near-deadly effects of the ‘superantibody’ drug TGN1412.
The announcement came at the unveiling of a report by the expert scientific group convened to provide guidelines to the Medicines and Healthcare Products Regulatory Agency (MHRA), which governs UK clinical trials. The group has provided a list of 22 recommendations to minimize the risk from phase-one clinical trials, during which a new drug is tested on humans for the first time.
Six volunteers became critically ill during the phase-one test of TGN1412, developed by now-defunct drug firm TeGenero. Although preclinical research on monkeys had shown no sign of danger, the drug provoked devastating immune reactions in the human subjects.
Immunologist Stephen Inglis a researcher at the National Institute for Biological Standards and Control in London and a member of the expert group, has now developed a lab test using human immune cells that shows the same overactivation and proliferation seen in the volunteers. Although still being refined and developed, he hopes that similar tests could become a routine part of preclinical testing of new drugs that target the immune system.
Link to the article: http://www.nature.com/news/2006/061204/full/news061204-13.html
31)
Ekwall B.
Overview of the Final MEIC Results: II. The In Vitro–In Vivo Evaluation, Including the Selection of a Practical Battery of Cell Tests for Prediction of Acute Lethal Blood Concentrations in Humans.
Toxicol In Vitro. 1999 Aug-Oct;13(4-5):665-73.
Abstract: In MEIC, all 50 reference chemicals were tested in 61 in vitro assays. To provide a background to the in vitro/in vivo evaluation, mouse LD(50) values were compared with human lethal doses, resulting in a good correlation (R(2) 0.65). To study the relevance of in vitro results, IC(50) values were compared with human lethal blood concentrations (LCs) by linear regression. An average IC(50) for the ten 24-hour human cell line tests predicted peak LCs better (R(2) 0.74) than other groups of tests. When IC(50) values for 32 chemicals which rapidly enter brain were divided by a factor of 3.2 and 48-hour IC(50) values were compared with 48-hour human LCs for 10 slow-acting chemicals, the prediction improved considerably. Human toxicity was clearly underpredicted for only four chemicals, namely digoxin, malathion, nicotine and atropine, indicating a high relevance of the human cell line toxicity. All chemicals entering the brain induced a CNS depression, explaining this syndrome as a cytotoxic effect. Multivariate analysis was used to select an optimal combination of assays, resulting in a battery of three 24-hour human cell line tests (endpoints: protein, ATP and morphology/pH) with good direct prediction of human peak LCs (R(2) 0.77).
Link to the article: http://nanotoxcore.mit.edu/tox%20core/nano%20toxicity%20papers/final%20MEIC%20results%20II.pdf
32)
Knight A, Bailey J, Balcombe J.
Animal carcinogenicity studies: 2. Obstacles to extrapolation of data to humans.
Altern Lab Anim. 2006 Feb;34(1):29-38.
Abstract: Due to limited human exposure data, risk classification and the consequent regulation of exposure to potential carcinogens has conventionally relied mainly upon animal tests. However, several investigations have revealed animal carcinogenicity data to be lacking in human predictivity. To investigate the reasons for this, we surveyed 160 chemicals possessing animal but not human exposure data within the US Environmental Protection Agency chemicals database, but which had received human carcinogenicity assessments by 1 January 2004. We discovered the use of a wide variety of species, with rodents predominating, and of a wide variety of routes of administration, and that there were effects on a particularly wide variety of organ systems. The likely causes of the poor human predictivity of rodent carcinogenicity bioassays include: 1) the profound discordance of bioassay results between rodent species, strains and genders, and further, between rodents and human beings; 2) the variable, yet substantial, stresses caused by handling and restraint, and the stressful routes of administration common to carcinogenicity bioassays, and their effects on hormonal regulation, immune status and predisposition to carcinogenesis; 3) differences in rates of absorption and transport mechanisms between test routes of administration and other important human routes of exposure; 4) the considerable variability of organ systems in response to carcinogenic insults, both between and within species; and 5) the predisposition of chronic high dose bioassays toward false positive results, due to the overwhelming of physiological defences, and the unna
tural elevation of cell division rates during ad libitum feeding studies. Such factors render profoundly difficult any attempts to accurately extrapolate human carcinogenic hazards from animal data.
Link to the article: http://www.frame.org.uk/dynamic_files/knight_2.pdf
33)
Robert AJ Matthews
Medical progress depends on animal models – doesn’t it?
J R Soc Med. 2008 February; 101(2): 95–98.
Summary: The scientific community can choose to deal with the current situation in one of three ways. The simplest is to replace the current statement with one which can be formally validated. This need not be a vapid platitude: there is a wealth of evidence to support a statement such as ‘Animal models can and have provided many crucial insights that have led to major advances in medicine and surgery’. The second and most valuable course of action would be to embark on a systematic study of the use of animal models with a view to establishing the weight of evidence they provide. This would undoubtedly be a major undertaking, but it would also bring many benefits – not the least of which would be quantitative support for the claims made for animal models. The third option is simply to turn a blind eye to the continued promulgation of a statement about the importance of animal experiments lacking in logical or evidential support.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2254450/
34)
Knight A.
Systematic reviews of animal experiments demonstrate poor contributions toward human healthcare.
Rev Recent Clin Trials. 2008 May;3(2):89-96.
Abstract: Widespread reliance on animal models during preclinical research and toxicity testing assumes their reasonable predictivity for human outcomes. However, of 20 published systematic reviews examining human clinical utility, located during a comprehensive literature search, animal models demonstrated significant potential to contribute toward the development of clinical interventions in only two cases, one of which was contentious. Included were experiments expected by ethics committees to lead to medical advances, highly-cited experiments published in major journals, and chimpanzee experiments-the species most generally predictive of human outcomes. Seven additional reviews failed to demonstrate utility in reliably predicting human toxicological outcomes such as carcinogenicity and teratogenicity. Results in animal models were frequently equivocal, or inconsistent with human outcomes. Consequently, animal data may not generally be considered useful for these purposes. Regulatory acceptance of non-animal models is normally conditional on formal scientific validation. In contrast, animal models are simply assumed to be predictive of human outcomes. These results demonstrate the invalidity of such assumptions. The poor human clinical and toxicological utility of animal models, combined with their generally substantial animal welfare and economic costs, necessitate considerably greater rigor within animal studies, and justify a ban on the use of animal models lacking scientific data clearly establishing their human predictivity or utility.
Link to the article: http://www.andrewknight.info/publications/anim_expts_overall/sys_reviews/AK%20Sys%20rev%20RRCT%202008%203(2)%2089-96.pdf
35)
Annapoorni Rangarajan, Robert A. Weinberg
Comparative biology of mouse versus human cells: modelling human cancer in mice
Nature Reviews Cancer 3, 952-959 (December 2003) | doi:10.1038/nrc1235
Abstract: Laboratory mice have represented a powerful experimental system for understanding the intricacy of human cancer pathogenesis. Indeed, much of our current conceptualization of how tumorigenesis occurs in humans is strongly influenced by mouse models of cancer development. However, an emerging body of evidence indicates that there are fundamental differences in how the process of tumorigenesis occurs in mice and humans. What are these species-specific differences and how do they affect the use of mice as models of human tumour pathogenesis?
Link to the article: http://www.nature.com/nrc/journal/v3/n12/abs/nrc1235.html
36)
Crabbe JC, Wahlsten D, Dudek BC.
Genetics of mouse behavior: interactions with laboratory environment.
Science. 1999 Jun 4;284(5420):1670-2.
Abstract: Strains of mice that show characteristic patterns of behavior are critical for research in neurobehavioral genetics. Possible confounding influences of the laboratory environment were studied in several inbred strains and one null mutant by simultaneous testing in three laboratories on a battery of six behaviors. Apparatus, test protocols, and many environmental variables were rigorously equated. Strains differed markedly in all behaviors, and despite standardization, there were systematic differences in behavior across labs. For some tests, the magnitude of genetic differences depended upon the specific testing lab. Thus, experiments characterizing mutants may yield results that are idiosyncratic to a particular laboratory.
Link to the article: http://www.sciencemag.org/content/284/5420/1670.full.html
37)
Greek R., Menache A., Rice MJ.
Animal models in an age of personalized medicine.
Personalized Medicine January 2012, Vol. 9, No. 1, Pages 47-64
Abstract:
Personalized medicine is based on intraspecies differences. It is axiomatic that small differences in genetic make-up can result in dramatic differences in response to drugs or disease. To express this in more general terms: in any given complex system, small changes in initial conditions can result in dramatically different outcomes. Despite human variability and intraspecies variation in other species, nonhuman species are still the primary model for ascertaining data for humans. We call this practice into question and conclude that human-based research should be the primary means for obtaining data about human diseases and responses to drugs.
Link to the article: http://www.futuremedicine.com/doi/pdf/10.2217/pme.11.89
38)
Stingl L, Völkel M & Lindl T.
20 years of hypertension research using genetically modified animals: no clinically promising approaches in sight.
ALTEX 2009; 26(1): 41-51.
Abstract: The incidence of essential or primary hypertension is increasing, especially in the northern hemisphere, but although the disease displays clear symptoms, its aetiology appears very complex, and thus no causal treatment is available yet. In the 1990’s, genetically modified animals (GMO) were considered to be the key to solving this problem of high complexity. However, until now, although a few approaches have shown that old, well-known drugs have a positive effect (decrease of blood pressure) on such animal models of hypertension, no approach has appeared in the literature of this area of research which might indicate a direct connection between GMO and a therapeutic strategy to treat or prevent this type of hypertension in humans. Instead, criticism of the GMO approach has accumulated in the last years, arguing that it is misleading as this disease does not have a monogenic cause and so complementary regulatory mechanisms could prevent the true identification of the function of the modified
genes. Furthermore, the technology is best developed in mice, whose physiology of blood pressure is different from that of humans. Because of species specificity, it is not easy to extrapolate the results from animal models of hypertension to human hypertension. Also, in the years 2000 to 2004 a reorientation of the technology and the aims of this kind of research took place. Therefore, although these approaches are without exception deemed “very promising” in the literature, it cannot be expected that research on GMO will make any contribution to a new therapeutic strategy in the near future.
Link to the article: http://www.altex.ch/resources/1_9_Altex_Stingl_.pdf
39)
Benigni R.
Alternatives to the carcinogenicity bioassay for toxicity prediction: are we there yet?
Expert Opin Drug Metab Toxicol. 2012 Apr;8(4):407-17. doi: 10.1517/17425255.2012.666238. Epub 2012 Feb 23.
Abstract:
INTRODUCTION:
For decades, traditional toxicology has been the ultimate source of information on the carcinogenic potential of chemicals; however, with increasing demand on regulation of chemicals and decreasing resources for testing, opportunities to accept ‘alternative’ approaches have dramatically expanded. The need for tools able to identify carcinogens in shorter times and at a lower cost in terms of animal lives and money is still an open issue, and the present strategies and regulations for carcinogenicity prescreening do not adequately protect human health.
AREAS COVERED:
This paper briefly summarizes the theories on the early steps of carcinogenesis and presents alternative detection methods for carcinogens based on genetic toxicology, structure-activity relationships and cell transformation assays.
EXPERT OPINION:
There is evidence that the combination of Salmonella and structural alerts for the DNA-reactive carcinogens, and in vitro cell transformation assays for nongenotoxic carcinogens, permits the identification of a very large proportion of carcinogens. If implemented, this alternative strategy could improve considerably the protection of human health.
Link to the abstract: http://www.ncbi.nlm.nih.gov/pubmed/22360376
40)
Müller U.
In vitro biocompatibility testing of biomaterials and medical devices.
Med Device Technol. 2008 Mar-Apr;19(2):30, 32-4.
Abstract: Biomaterials used for medical devices must be thoroughly tested according to ISO 10993 before their introduction so that any negative effects on the body are known about and prevented. By using in vitro laboratory tests, dangers for patients and unnecessary animal experiments can be avoided. Here, in vitro tests for cell compatibility (cytotoxicity) and blood compatibility (haemocompatibility) are described.
Link to the article: http://www.emdt.co.uk/article/vitro-biocompatibility-testing-biomaterials-and-medical-devices
41)
Bailey J, Knight A, Balcombe J.
The future of teratology research is in vitro.
Biogenic Amines 2005;19(2): 97-145.
Abstract: Birth defects induced by maternal exposure to exogenous agents during pregnancy are preventable, if the agents themselves can be identified and avoided. Billions of dollars and manhours have been dedicated to animal-based discovery and characterisation methods over decades. We show here, via a comprehensive systematic review and analysis of this data, that these methods constitute questionable science and pose a hazard to humans. Mean positive and negative predictivities barely exceed 50%; discordance among the species used is substantial; reliable extrapolation from animal data to humans is impossible, and virtually all known human teratogens have so far been identified in spite of, rather than because of, animal-based methods. Despite strict validation criteria that animal-based teratology studies would fail to meet, three in vitro alternatives have done so. The embryonic stem-cell test (EST) is the best of these. We argue that the poor performance of animal-based teratology alone warrants its cessation; it ought to be replaced by the easier, cheaper and more repeatable EST, and resources made available to improve this and other tests even further.
Link to the article: http://www.aknight.info/publications/anim_expts_tox/teratol/JB%20et%20al%20Teratol%20Biog%20Amines%202005%2019(2)%2097-146.pdf
42)
Archibald K, Coleman R, Foster C.
Open letter to UK Prime Minister David Cameron and Health Secretary Andrew Lansley on safety of medicines.
Lancet. 2011 Jun 4;377(9781):1915. doi: 10.1016/S0140-6736(11)60802-7.
Summary: Our reliance on animals to establish safety results in the exposure of clinical volunteers and patients to many treatments that are at best ineffective and at worst dangerous. Take for example the notorious Northwick Park clinical trial drug, TGN1412, that left six young men in intensive care in 2006. This drug was demonstrably safe in monkeys at doses 500 times higher than those that nearly proved fatal to the volunteers.5 Soon after the disastrous trial, an assay that used human cells was developed to predict such an immune system over-reaction.5 Had this assay been in use before human beings were exposed, the trial would never have taken place. Surely the time has come for there to be a rigorous assessment of the ability of such human-based tests to improve on the deeply flawed, animal-based approaches in current use?
Link to the article: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(11)60802-7/fulltext?rss=yes
43)
Vincent J. Lynch
Use with caution: Developmental systems divergence and potential pitfalls of animal models
Yale J Biol Med. 2009 June; 82(2): 53–66.
Abstract: Transgenic animal models have played an important role in elucidating gene functions and the molecular basis development, physiology, behavior, and pathogenesis. Transgenic models have been so successful that they have become a standard tool in molecular genetics and biomedical studies and are being used to fulfill one of the main goals of the post-genomic era: to assign functions to each gene in the genome. However, the assumption that gene functions and genetic systems are conserved between models and humans is taken for granted, often in spite of evidence that gene functions and networks diverge during evolution. In this review, I discuss some mechanisms that generate functional divergence and highlight recent examples demonstrating that gene functions and regulatory networks diverge through time. These examples suggest that annotation of gene functions based solely on mutant phenotypes in animal models, as well as assumptions of conserved functions between species, can be wrong. Therefore, animal models of gene function and human disease may not provide appropriate information, particularly for rapidly evolving genes and systems.
Link to the article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2701150/
44)
Lindl T., Voelkel M.
No clinical relevance of approved animal experiments after seventeen years.
ALTEX. 2011;28(3):242-3.
Link to the article: http://altweb.jhsph.edu/altex/28_3/altex_2011_3_242_244_Letters2.pdf
45)
Gr
eek R, Rice MJ.
Animal models and conserved processes.
Theor Biol Med Model. 2012 Sep 10;9:40. doi: 10.1186/1742-4682-9-40.
Abstract:
Background
The concept of conserved processes presents unique opportunities for using nonhuman animal models in biomedical research. However, the concept must be examined in the context that humans and nonhuman animals are evolved, complex, adaptive systems. Given that nonhuman animals are examples of living systems that are differently complex from humans, what does the existence of a conserved gene or process imply for inter-species extrapolation?
Methods
We surveyed the literature including philosophy of science, biological complexity, conserved processes, evolutionary biology, comparative medicine, anti-neoplastic agents, inhalational anesthetics, and drug development journals in order to determine the value of nonhuman animal models when studying conserved processes.
Results
Evolution through natural selection has employed components and processes both to produce the same outcomes among species but also to generate different functions and traits. Many genes and processes are conserved, but new combinations of these processes or different regulation of the genes involved in these processes have resulted in unique organisms. Further, there is a hierarchy of organization in complex living systems. At some levels, the components are simple systems that can be analyzed by mathematics or the physical sciences, while at other levels the system cannot be fully analyzed by reducing it to a physical system. The study of complex living systems must alternate between focusing on the parts and examining the intact whole organism while taking into account the connections between the two. Systems biology aims for this holism. We examined the actions of inhalational anesthetic agents and anti-neoplastic agents in order to address what the characteristics of complex living systems imply for inter-species extrapolation of traits and responses related to conserved processes.
Conclusion
We conclude that even the presence of conserved processes is insufficient for inter-species extrapolation when the trait or response being studied is located at higher levels of organization, is in a different module, or is influenced by other modules. However, when the examination of the conserved process occurs at the same level of organization or in the same module, and hence is subject to study solely by reductionism, then extrapolation is possible.
Link to the article: http://www.tbiomed.com/content/9/1/40
46)
Innovation or Stagnation: Challenge and Opportunity on the Critical Path to New Medical Products. U.S. Department of Health and Human Services. Food and Drug Administration. March 2004
Summary: For example, a new medicinal compound entering Phase 1 testing, often representing the culmination of upwards of a decade of preclinical screening and evaluation, is estimated to have only an 8 percent chance of reaching the market. This reflects a worsening outlook from the historical success rate of about 14 percent. In other words, a drug entering Phase 1 trials in 2000 was not more likely to reach the market than one entering Phase 1 trials in 1985. Recent biomedical research breakthroughs have not improved the ability to identify successful candidates.
The main causes of failure in the clinic include safety problems and lack of effectiveness: inability to predict these failures before human testing or early in clinical trials dramatically escalates costs.
Link to the dossier: http://www.who.int/intellectualproperty/documents/en/FDAproposals.pdf
In Vivo Veritas? 