Safer Medicines - putting patient safety first

Putting patient safety first

Telegraph 17/11/04

QED: Animals make poor guinea pigs in drugs tests

By Robert Matthews

In a world where dissent is frequently dealt with by summary execution, the injunction imposed last week by the High Court on anti-vivisection protestors in Oxford seems almost heart-warming.

Despite having been responsible for criminal damage, harassment and much disruption over recent months, activists have been told simply to stay away from those working on the animal testing centre being built in the city. Meanwhile, those who want to make their voices heard can still join the group of 50 allowed to protest from a spot provided by the university near the lab each Thursday afternoon between 1pm and 4pm. The injunction then requires that the protestors then disperse and head for a nominated teashop for pots of Darjeeling and muffins. All right, I made that last bit up, but I think the point is clear: there may be a lot wrong with this country, but dissent is still permitted - as long as we are reasonable about it. The trouble with the animal experimentation debate is that it drives people to be anything but reasonable. Even the most rational can be heard coming out with deeply dubious statements - such as claiming that animal experiments are vital to medical progress.

Distinguished professors of medicine fell over themselves last week hailing the injunction as crucial to their quest for miracle cures. Such unanimity usually implies that the claim being made is backed by plenty of compelling evidence. Certainly there is no shortage of treatments successfully tested on animals proving safe and effective with humans. Indeed, medical scientists routinely wheel them out - only to have them shot down by protestors pointing to equally anecdotal evidence of where animal experiments proved hopelessly misleading.

Recognising the futility of this ya-boo-sucks approach to scientific debate, the Royal Society issued a report earlier this year addressing the key issue: anecdotes apart, what does the scientific evidence tell us about the overall reliability of animals as surrogates for humans? According to the Royal Society, the evidence can be summed up thus: "Animals are normally highly accurate models for humans."

Again, one might expect such a definitive statement to be backed by a wealth of references to the scientific literature; after all, this is the Royal Society speaking, not some bloke in the pub, and as the report states: "The society believes in the importance of evidence-based discussion and debate."

Curiously, its statement is not supported by a single reference. This could, of course, be because the statement is so obviously correct that it no more needs references than does the declaration that the sky is blue.

Cynics will quickly point out another possibility, however: that there are no references because the evidence doesn't exist. Having made extensive efforts to find this evidence myself, I have reluctantly come to side with the cynics.

By chance, just a few weeks after the Royal Society published its report, the journal Nature Drug Discovery carried a review paper that considered the specific question of the predictive value of animals in toxicity testing of new drugs.

After trawling the literature, its authors concluded that the amount of data available was "limited" and "fragmentary". Even so, their overall conclusion was that if a drug is toxic in humans, animal tests will detect it around 70 per cent of the time. Missing around one in three toxic reactions to drugs hardly suggests animals are "highly accurate" surrogates for humans, but that misses a far more important point - and one overlooked by just about everyone working in this scientific Twilight Zone. A proper assessment of the accuracy of any predictive method, from weather forecasting to star charts, must take into account more than just its success rate. It must also include the false alarm rate - and studies show that this is astonishingly high in animal testing. The Nature Drug Discovery paper cites research showing that even with monkeys the false alarm rate exceeds the success rate in two-thirds of the forms of toxicity studied.

In other words, not only is there no evidence that animals are "highly accurate" surrogates for humans, but what data there is suggests their use is actually hampering medical progress, by falsely warning of toxic effects that simply don't affect humans.

Within pharmaceutical companies there is growing alarm about the signal failure of their "breakthroughs" to turn into successful money-spinning drugs. Over 90 per cent fail in tests before getting anywhere near the pharmacy shelves. There may be woefully little evidence about the value of animal testing, but what there is suggests that shareholders of drugs companies should be among those waving placards in Oxford on Thursday afternoons.

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