Most people are unfamiliar with the research process, and there are misconceptions about the way that animals are used in medical and scientific research. Science can seem meaningless out of context and the lengthy processes of clinical drug trials is sometimes misinterpreted as repeating the studies already carried out in animals. Some of the more common rumors are addressed below.
Microdosing can replace animal safety tests.
Microdosing is intended to study how very small doses of potential medicines behave in human volunteers (sometimes called Phase 0 human trials). It should make the drug discovery process more efficient by highlighting earlier whether a compound is suitable. New, urgently needed medicines could be available sooner and more cheaply as a result.
If microdosing shows that certain potential medicines are poorly suited for people, it should reduce the number of animals used by eliminating these compounds from further development and testing in animals. But compounds that look promising would need further development, including animal tests.
Microdosing has limitations like any other method of testing. There is no guarantee that the body's reaction to a microdose will be the same as it is to a full dose. It is a relatively new method and has yet to be fully validated, although encouraging moves in this direction are being made by scientists and regulatory authorities.
The side-effects and subsequent withdrawal of the arthritis treatment Vioxx was due to animal tests.
Vioxx was extensively studied in thousands of human patients in clinical trials both before and after it was approved by over 70 regulatory agencies around the world. For any new medicine, animal and other tests are meant to help work out if the medicine is safe enough for human trials. In the case of Vioxx, the answer was yes - animal tests did their job well.
Only when over 80 million patients around the world had taken this medicine and some long-term patient studies had been conducted was the increased risk of heart attack firmly established.
The answer to the problem of rare drug side effects lies in better surveillance after approval. This would help to predict which patients might react badly - because of their genetic make-up, multiple illnesses or interactions with other medication.
The clinical trial tragedy at Northwick Park hospital in the UK shows that animal tests don't work.
TGN1412 is one of the newer ‘biological' medicines. None of the tests done before the clinical trial predicted its tragic side-effects. The expert inquiry described the human blood cell tests as a "striking failure". Testing the safety and effectiveness of such treatments is more difficult than most medicines. But many biologicals which have been developed in animals, like Herceptin, are already saving lives.
There are around 300 clinical trials every year in the UK. Yet the kind of problems seen at Northwick Park Hospital are very rare, partly because animal and other tests are so good at discovering problems. To suggest that we abandon some tests because they are not 100% perfect is like saying that we should stop wearing seat belts because they do not prevent all injuries.
Systematic reviews like those reported in the British Medical Journal (BMJ) demonstrate that animal studies are meaningless for human health.
Systematic reviews can help to tell us whether studies are being properly carried out and published. For example, a systematic review in the respected journal The Lancet showed that none of the 500 human clinical trials for an illness called tardive dyskinesia produced any useful data.
An editorial in the British Medical Journal called ‘The scandal of poor medical research' claimed that all types of research can suffer from insufficient quality control.
Systematic reviews have shown that all types of study can be improved. Where they have been carried out, systematic reviews and other independent studies have shown that animal studies can be relevant for human medical advances.
However, systematic reviews do not resolve all questions about the applicability and relevance of animal studies to humans. A lot depends on how studies are selected for review. For much animal research, the objective is not to predict the outcomes of human trials, but to discover new knowledge or make advances in understanding diseases. Animal data may thus be too diverse for meaningful comparison with results from human trials.
Magnetic resonance imaging can now be used on humans to get the same level of information as invasive studies of brain cells in animals.
This technique measures blood flow in different parts of the brain. It can be used in human volunteers without ill effect. But it does not give anything like the same level of detailed information that can be achieved by painlessly inserting electrodes into brain tissue in animal or human studies.Back to the top
HIV & AIDS research
HIV and AIDS have been difficult to tackle because the virus targets the body's immune system, and because it mutates rapidly. Leading researchers have recently recommended that more basic research should be done to help us understand the virus better, before further vaccine trials are carried out in volunteers. While we do not yet have an effective vaccine, animal studies have been crucial in identifying the virus, developing diagnostic tests, and for producing therapies that have prolonged millions of lives.
HIV was identified in the early 1980s as a retrovirus - the class of virus that had been studied in animals, but had only been found to infect humans a short time previously. The blood test (to test blood for transfusion as well as to diagnose the disease) was developed using animals. The first treatment for HIV was shown to have activity against retroviruses in animals, and once it was shown to also be active against HIV went directly into clinical trials.
By studying monkeys with a related virus, SIV, in the first few weeks after infection, scientists were able to understand more about the virus and develop better antiretroviral medicines for HIV patients. Many now take two or three pills a day to stop the virus from reproducing while helping the immune system to recover. Animal research also played a key role in the development of post-exposure prevention that has saved many victims of needlestick injuries and other exposures to HIV.