Laura Rego Alvarez, Head of Science Policy & Regulation at Cruelty Free International, discusses the science and ethics behind alternatives to animal testing
Animal testing remains a contentious topic in the science community and beyond. Some argue its benefits outweigh its ethical failures, others argue that it is morally wrong and, therefore, the practice should be stopped altogether.
Why do scientists test on animals?
A major reason why scientists continue to test on animals is the current way that hypotheses are tested in science. The process is one of testing models of increasing complexity with growing confidence in the hypothesis as it successfully passes each hurdle.
Therefore, the common justification for using animals is the apparent need to test a substance or idea in a ‘complex, whole being’ before there is enough confidence that it can be tested safely in humans. The assumption behind this is that the complex – that the whole being will capture all possible, unforeseen ways in which the substance or idea could be harmful (or not work), avoiding harm (or wasting time) to human volunteers. This ‘complexity’ argument is one reason for the lack of support for cell-based techniques, as these are seen as less complex and, therefore, inferior. This desire to capture all possible interactions appears to override the very real possibility that many of these interactions are the wrong ones by the very nature of testing in the wrong species. This is very frustrating for those that support non-animal approaches. There appears to be a real gap between the two groups regarding what is more important; complexity or relevance.
When it comes to animal-free research and testing, a chasm between what’s possible and what’s used exists for various reasons, including a lack of trust in less familiar methods, complicated and slow regulatory uptake and inadequate funding.
Cruelty Free International maintains the Replace Animal Tests (RAT) List – a list of ten animal tests that still occur despite having widely accepted animal-free replacements, using an estimated 1.5 million animals each year in the EU alone. The RAT list highlights the fact that the existence of a non-animal replacement method isn’t enough to secure its use – practical, social and political factors must also be addressed.
Is animal testing our only option?
On top of the ethical question, testing on animals is neither our only option nor our best option. Due to the undeniable species differences between humans and animals, for example, major structural and physiological differences, data from animal tests cannot be a reliable basis for predicting the likelihood of specific effects in humans.
Even variations between humans make it difficult to extrapolate from one human sub-population to another. Therefore, the focus in medicine is shifting towards the individual patient, personalised medicine and the development of modern non-animal methods more directly applicable to human patients.
Non-animal methodologies focus on human biology and use advanced cell-based and computational technologies to investigate diseases and potential treatments
Alternatives to animal testing focus on human biology and use advanced cell-based and computational technologies to investigate diseases and potential treatments. These new methods, therefore, have the potential to deliver safer and more effective medicines more quickly and at less cost. Redirecting continued investment in failing animal experiments into human-specific medicine is urgently needed.
What are the alternatives to animal testing?
The last 30 years have seen a dramatic increase in alternatives to animal testing.
Non-animal methods include tissues and mini-organs grown in the laboratory from human cells, organs-on-chips, research conducted using human volunteers and advanced computer simulations
Non-animal methods include tissues and mini-organs grown in the laboratory from human cells, organs-on-chips (USB drive-sized devices that emulate human organs using cells connected by blood vessel-like channels), research conducted using human volunteers and advanced computer simulations.
These methods are already widely used in drug discovery and development because pharmaceutical companies recognise that they are more reliable and human-specific than animal tests. For example, a type of organ-on-a-chip known as a “Liver-Chip” can detect drug-induced liver injury missed by animal tests.
Is animal testing effective?
The scientific process, being iterative, inevitably involves failure, but animal tests – due to two inherent weaknesses – far exceed this expected level of failure.
Tests on animals frequently fail to predict human outcomes
Firstly, tests on animals notoriously lack reliability, meaning that repeats of the same tests often produce conflicting results. Secondly – due to profound biological differences between humans and other animals, compounded by the sterile, standardised conditions of the laboratory – tests on animals frequently fail to predict human outcomes.
For example, 92% of medicines currently fail in human clinical trials even though they passed preclinical tests (including animal tests); 55% of failures are due to lack of efficacy, while 28% are due to toxic effects in humans. This general failure rate is bad enough, but failure is almost a certainty for drugs that treat complex and poorly understood conditions.
For instance, the failure rate of drugs intended to treat Alzheimer’s disease is estimated to be higher than 99%. Only a handful (approximately 20) of novel medicines are released onto the market every year, and withdrawals and warnings of adverse effects commonly follow as the drug is tested in the wider population. This tells us that the animal testing paradigm, on which drug development remains largely based, is failing. The profound inefficiency of animal tests to predict safety and efficacy outcomes in humans, coupled with the huge cost (over $2 billion) and time (over a decade) required for new treatments to reach the market, is causing patients and society to suffer.
Why is animal testing unethical?
We believe there is no rational moral justification for using animals in experiments. Animals used in laboratories are deliberately harmed, not for their own good, and are usually killed at the end of the experiment.
Approximately 3 million experiments are conducted on sentient animals each year in the UK that, by their definition, cause pain, suffering, distress or lasting harm. For example, animal experiments often involve forcing animals to ingest or inhale potentially harmful substances or have them applied to their skin or injected into their bodies, surgically removing animals’ organs or tissues to cause damage deliberately, or subjecting animals to frightening situations to create anxiety and depression.
Some experiments even require the animal to die as part of the test. For example, regulatory tests for Botox, vaccines and some tests for chemical safety are essentially variations of the cruel Lethal Dose 50 test in which 50% of the animals die or are killed just before the point of death.
Life inside a laboratory is no life at all
Outside the tests, animals are usually confined to small, barren, unnatural enclosures that restrict natural behaviour and result in boredom and stress. Some animals in laboratories are confined on their own, without the companionship of others. Our investigations show time and time again that, despite claims by the animal research community, life inside a laboratory is no life at all.
What can individuals do to put a stop to animal testing?
Cruelty Free International works to achieve a world where no one wants or believes we need to test on animals, and we rely on the public globally to help us achieve that.
People in the UK can support our Target Zero campaign by contacting the Secretary of State for Business Energy and Industrial Strategy and their own Member of Parliament to call for an ambitious action plan to bring animal experiments to an end and a ministerial portfolio dedicated to making this happen.
EU residents can email the European Commission to ensure they listen to the results of our ‘End Animal Testing’ European Citizens’ Initiative, signed by over 1.4 million people and currently in its validation process.
We are asking US residents to urge their Representative to become a cosponsor of three federal bills: the Humane and Existing Alternatives to Animals in Research and Testing Sciences (HEARTS) Act, which would prioritise the use and development of non-animal testing methods for generating new information on human biology and illness to deliver better medicines and healthcare products and protect the environment; the Companion Animal Release from Experiments (CARE) Act, which could ensure that animals are put up for adoption rather than killed when no longer wanted for experiments in laboratories that receive taxpayer funding from the National Institutes of Health; and the Humane Cosmetics Act, which would end animal testing for cosmetics in the U.S. and stop the sale of new animal-tested cosmetics.
Caring consumers can choose to help end cosmetics animal testing by only buying from brands approved by our Leaping Bunny Programme. This allows consumers to choose their products, knowing that any Leaping Bunny approved brand has passed the most rigorous global criteria, which extend over and above laws governing animal testing.
What does the law say about animal testing?
While laws in place aim to protect animals in laboratories, they do not go far enough. Over the past decade, the number of animal tests in the UK has fallen by only 1% per year (discounting 2020’s unusual drop due to the COVID-19 pandemic lockdowns).
If the UK continues its current trajectory, animal experiments will remain for at least another 90 years. We desperately need a strategy – including revision of the laws governing animal tests – that will put this country on a fast track to ending animal experiments completely.
This piece was written and provided by Laura Rego Alvarez, Head of Science Policy & Regulation – Medicines, Cruelty Free International
