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Alternatives To Animal Testing In Clinical Research

Updated: Oct 19, 2023

✍🏻 Aoife Delany | Lead Clinical Information Designer & Scientific Writer


What is clinical research? 🐀

Clinical research involves the study of health and disease in humans to assess the safety and effectiveness of potential treatments. There are two main types of clinical research:

  • Clinical trials: Where new treatments are tested in patients to determine their safety and efficacy

  • Observational studies: Where patients are observed under normal circumstances and changes are documented. No treatments are tested in observational studies, but observation can identify future treatments and strategies

Before clinical research can commence, preclinical research must first be conducted to predict potential outcomes in humans. Animals are frequently used during the preclinical phase to predict if a treatment could be both safe and successful.

They are quite biologically similar to humans (for example, mice share 97.5% of their DNA with us) and are susceptible to many of the same diseases. Animal research is desirable due to their short life span, allowing researchers to follow reactions over their entire life and to study the impact of treatments and diseases across multiple generations.

However, despite our similarities, animal models cannot accurately predict how drugs will interact with the human body.

clinical trials

What is animal testing? 🐀

Animal testing refers to the use of live animals in research and industry to assess potential human reactions.

Procedures are performed on animals for the following reasons:

· Biological and disease research

· Drug efficacy and toxicity testing

· Environmental, health and safety testing of consumer products (e.g. cosmetics, food additives, industrial and agri-chemicals etc.)

There are a number of ethical concerns about the pain and suffering that animals endure during testing where most test subjects are euthanised at the conclusion. Thanks to the successful lobbying of animal rights activists, the cosmetic industry has largely banned and/or restricted the use of animals in cosmetic testing in many countries, opening the door to cruelty-free testing alternatives.

However, animal testing remains a necessary evil in the field of clinical research.

Animal testing

Is animal testing really necessary? 🐁

Animal testing has been used extensively throughout history for biomedical research.

Early Greek and Roman scientists such as Aristotle, Galen and Erasistratus all performed experiments on animals to advance our understanding of human biology and pharmacology. Testing in animals became highly important to drug development in the 20th century following mass poisonings in 1937 from untested ‘Elixir Sulfanilamide’ and the foetal deformities caused by thalidomide after a failure to test the drug in pregnant animals during the 1950s/1960s.

Such disasters led to legislation requiring animal testing by the FDA for all human drugs, in addition to other international ethical guidelines such as the Declaration of Helsinki where human studies are required to be based on animal research where applicable. However, to mitigate unnecessary animal suffering in mandated research, the 3Rs were established in 1959:

1. Replacement of animals with alternative models (where possible)

2. Reduction in the amount of animals used in research

3. Refinement of research methods to minimize distress and improve animal welfare

Animal testing has undoubtedly played an important role in the production of vital pharmaceuticals, but 90% of drugs don’t make it out of clinical research, and a further 95% that test safe in animals fail in human trials. As such, it is vital that better alternatives are found to animal testing for clinical research. In January of this year, the FDA have overturned the requirement for drugs to be tested on animals when other viable options are available, paving the way for new and exciting alternatives to animal testing.


What alternatives are there to animal testing? 💻

Computer Models

Technological advances have enabled researchers to create sophisticated computer systems that can predict how drugs will interact with the human body. Computer Aided Drug Design (CADD) software can predict where drugs will most likely interact in the body to determine if the drug will be hazardous or if a drug candidate will even have any biological effect, all without the need for animal testing. Researchers are even working on producing a virtual human to predict drug interactions in minutes, cutting down on years of both animal and human research.


While it may sound like science fiction, organ-on-chip technology is one of the most favourable alternatives to animal testing. Chips are comprised of a series of chambers each containing tissues from different organs of the body. The chambers are linked by microchannels through which a blood substitute flows. This allows the different organ tissues to communicate with each other as they would in the human body. Drugs are added to the blood substitute during testing, allowing researchers to test potential drug interactions without the use of animals.


Mini Organs

Advances in stem cell research in recent decades are allowing scientist to grow their own organs! Organoids (or ‘mini organs’) are grown from human stem cells to make organ-like models for drug testing. Most recently a team in Australia, driven by a passion to find viable alternatives to animal testing, created mini human lungs (both healthy and diseased) by growing human lung cells in a carefully curated environment that accurately mimicked conditions within the human body.

3D Printed Tissues

3D printing technology can also be used to print out tissues for drug testing. Bioprinters are loaded with bioink just like an ordinary printer, but instead of coloured ink, each cartridge is loaded with different cell types. The bioprinter then builds up tissues and organs layer by layer which can then be used as a viable alternative to animal testing during drug development.

An added advantage for many of these alternatives to animal testing, is that the technology can be used for personalized medicine. Researchers can take a biopsy from a patient and use their unique tissue to determine personalised treatment options. Drugs are not one size fits all, so having the ability to predict how someone will respond to a drug in advance could revolutionize the future of drug development.

Alternative models are not without their limitations, as tissues studied in isolation cannot give an accurate representation of how drugs will interact once released into the whole body. Scientists are however looking into new models and ways to connect tissues to better mimic the activity of entire systems within the body.

There’s still a long way to go, but scientists are hopeful that one day soon clinical research will be animal-free.

Isobel Thompson, Content Writer at Write in the Loop

Written by: Aoife Delany (Content Writer)

Grace Pountney, Founder and Director at Write in the Loop

Edited by: Grace Pountney (Founder and Director)


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