Safer Medicines - putting patient safety first

Putting patient safety first

Spiked 03/03/05

Animal testing for drug safety is unreliable

At the spiked-event 'Drugs and health' that took place at the Society of Chemical Industry on 22 February 2005, Diarmuid Jeffreys, Charles Medawar, and Richard Sullivan gave excellent presentations, in which they raised many disturbing facets of drug regulation and safety that are worthy of attention.

All three speakers agreed that society needs new drugs, but that we need a culture change in the pharmaceutical enterprise. There was unanimous concern about the lack of openness and transparency, and the corrosive influence of the commercial imperative. There is, however, one component of drug safety testing which has a significant impact on safety but which has so far fallen outside the radar of the debate. That component is animal testing.

The primary safety screen for all new drugs is animal tests, from which the regulatory authorities require evidence of safety in one rodent and one non-rodent species. These tests were mandated in the wake of the thalidomide tragedy, in the hope that they would prevent another such disaster. But have they lived up to their promise?

In the light of recent tragedies such as Vioxx - where a drug shown to be safe and even beneficial to the heart in animals has gone on to cause as many as 140,000 heart attacks and strokes in humans - it appears that animals are an inadequate safety screen. Many studies, comparing drug side effects in humans and in animals, have found animal tests to be less predictive than tossing a coin. Even the Handbook of Laboratory Animal Science admits that 'uncritical reliance on the results of animal tests can be dangerously misleading and has cost the health and lives of tens of thousands of humans'.

State-of-the-art human-based tests could have prevented the Vioxx tragedy. In order to protect the public from another Vioxx in future, an assessment needs to be made of the relative performance of the various methods of safety testing available. Substantial evidence exists that animal tests are inadequate for the task, but incredibly, this has never been systematically investigated. The only responsible course of action is to evaluate animal testing scientifically, in an independent and transparent manner. 83 per cent of GPs in a 2004 survey would 'support an independent scientific evaluation of the clinical relevance of animal experimentation'. Many MPs are currently calling for such an evaluation, in an early day motion on Animal testing of drugs.

Meanwhile, there are many superior methods of assessing drug safety, which should be required during the safety testing of new drugs. These include micro-dose studies, endorsed by the European Agency for the Evaluation of Medicinal Products in January 2003; pharmacogenetic analyses, using DNA chips; and human clinical pharmacology assessments, employing human tissues in slico modelling and sensitive and appropriate biomarkers, before and during clinical trials.

If these methods were employed in place of animal testing, we would see significant reductions in the number of drugs failing in clinical trials, and in the numbers of adverse drug reactions.

Kathy Archibald, director, Europeans for Medical Progress, UK

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