Antivivisection groups are increasingly latching on to a new figure, emerging from drug development studies, in their attempts to undermine the use of animals in research. For example, the animal rights group Europeans for Medical Progress has sent a postcard to MPs stating that ‘there is substantial evidence that animal tests are the weakest link in the safety testing of new drugs: they are so poorly predictive for humans that 92% of candidate drugs fail in clinical trials after success in animal tests.’

The recent report from the British Union for the Abolition of Vivisection (BUAV) on the use of primates in experiments also refers to this figure. It describes the source as being a US Food and Drug Administration (FDA), review of problems facing the development of safe and effective new drugs.

BUAV correctly claims that the main causes of the 92% failure-rate are safety concerns and lack of effectiveness in humans, but adds its own interpretation that this is ‘despite tests on primates and other animals’.

Once again, the anti-vivisection spin on what is a complex problem is simplistic, distorted, and dishonest by omission.

The full 30 page FDA report outlines the problem that ‘the current medical product development path is becoming increasingly challenging, inefficient, and costly’. It goes on to point out how ‘currently, a striking feature of this path is the difficulty, at any point, of predicting ultimate success with a novel candidate. For example, a new medicinal compound entering Phase 1 testing, often representing the culmination of upwards of a decade of pre-clinical screening and evaluation, is estimated to have only an 8% chance of reaching the market’. This reflects a worsening outlook from the historical success rate of about 14%. 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.

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. Recent biomedical research breakthroughs have not improved the ability to identify successful candidates.

The emphasis the antivivisectionists put on the problems of animal testing, to the exclusion of any other issue, is entirely unjustified. Crucially, the FDA confirms that, ‘we are seeing more product candidate failures in the later stages of product development - the most expensive way to fail’. In other words, early-stage human clinical trials are failing to adequately pick up problems which cause medicines to fail later. The FDA explains how ‘clinical testing, even if extensive, often fails to detect important safety problems, either because they are uncommon or because the tested population was not representative of eventual recipients’. By the logic of the antivivisection groups, this would mean clinical tests are scientifically invalid and flawed!

Certainly there is discussion by the FDA of the need to improve animal testing. The report states that ‘although traditional animal toxicology has a good track record for ensuring the safety of clinical trial volunteers, it is laborious, time-consuming, requires large quantities of product, and may fail to predict the specific safety problem that ultimately halts development’.

And when it comes to solutions proposed by the FDA, better animal models come top of the list: the FDA states ‘a new product development toolkit - containing powerful new scientific and technical methods such as animal or computer-based predictive models, biomarkers for safety and effectiveness, and new clinical evaluation techniques - is urgently needed to improve predictability and efficiency along the critical path from laboratory concept to commercial product… strengthening and rebuilding the disciplines of physiology, pharmacology, and clinical pharmacology will be necessary to provide the capacity to develop and evaluate new biomarkers and bridge across animal and human studies’.

The FDA highlights the importance of animal research and clarifies that ‘new genetic technologies may make it possible to develop animal models that are more predictive of human responses to vaccines and treatments for diseases’. As examples, they highlight efforts to develop good animal models for many conditions, including SARS and anthrax infection.

Unsurprisingly, the fuller story gets no mention in the antivivisection material!