New publication demonstrates the need to replace animal models in medical research

Further, this not only questions the efficacy and very base argument for using animals, but critically raises the question about the drugs that failed in animals and were discarded: how many might have worked in humans?  How many discarded cures for cancer?  

Let’s consider chimpanzees - the species most closely related to humans. The chimpanzee genome (complete genetic material) is 98.77 percent identical to that of humans, therefore researchers argue that chimpanzees will be the species most likely to replicate human outcomes in scientific (biomedical and toxicity) testing.  However this small genetic variation between human and chimpanzees accounts for very significant differences in the way diseases affect the two species.Chimpanzees are not currently used in Australian research, and those primates that are used have even wider genetic variation to humans, meaning that the differences in results would be greater again.

Despite chimpanzees being the most genetically similar animals to humans, experiments on them have not provided substantial contributions to biomedical research. Therefore, it is logical for us to question, that if the most genetically similar animal to humans is an ineffective model, then how can the use of more genetically distant animals – dogs, mice or fish - assist us?

These concerns are verified in systematic reviews of the literature conducted in the areas of toxicity testing and biomedical research which have shown that scientific alternatives are far more predictive of human outcomes than data obtained from animals.

Such trepidations may well lead to the question; have we been going about medical research all wrong?

A team of international authors expert in innovative toxicology and animal replacement, led by Dr Gill Langley of Humane Society International (HSI), states:

[A] new paradigm is needed for fundamental research into human diseases and for drug discovery. The focus should move decisively away from preclinical animal studies and overly simplistic cell models toward a systems biology framework to integrate new types of scientific data, such as from omics, novel human-specific in vitro models, and clinical studies. Such a framework would help enable a comprehensive and dynamic understanding of disease causation and pathophysiology.

According to Australian co-author and Humane Research Australia scientific advisor, Dr. Brett Lidbury, the article raises the following key issues:

• Closer scrutiny and analyses on the value of pre-clinical animal-models has revealed disappointment in terms of human translation from fundamental research;
• Twenty-first century innovation and technology is now available to provide animal replacement alternatives, particularly through systems approaches (e.g. Integration of external and internal disease-associated processes)
• Fundamental biomedical research can learn much from toxicology and the advances to find alternatives to animal models – a good example is the “adverse outcome pathway” (AOP).

The paper is a welcome development as the current methods of using different species to obtain data for humans is simply not working. We need a different approach – one that focuses on the genetic, anatomic and metabolic intricacies of the species we are trying to study and not erroneous and misleading extrapolations from animal tests.

According to Dr Langley:

It is essential we adopt and utilise human-species specific models in vitro, in vivo (clinical), and in silico (in computer). We need to entirely revise the medical research paradigm, so that novel techniques and their data aren't simply added piecemeal to the existing 'edifice' but are used strategically in a new framework that also eliminates failing animal models.

The article states:

The key driver for a new paradigm in health research is the slow progress scientists have made in understanding human disease. This has resulted in a lack of success in drug discovery and translation of laboratory findings into effective therapies and in the spiraling investment of resources wasted by late-stage drug failures.

Whilst no one wants to harm animals, human medical progress is generally deemed to take priority over animal suffering, and cost/benefit analyses currently allow animal experiments to proceed.  As this recent publication suggests however, it is time we reconsider our approach to medical research and embrace a new paradigm that focuses on the human species and is likely to lead to genuine medical progress.