Antivivisectionists like to talk about science because it makes them sound rational. Judging by their insistence that all animal research is scientifically flawed, they think they know the science better than the overwhelming majority of scientists, doctors and research organisations.
In their bid to sound ever more clever, the antivivisectionists come up with all sorts of claims about alternatives to animal research, from the nonsensical to the merely muddled. For example, here is an extract from a 1979 bulletin of the Lord Dowding Fund, which is a Department of the National Anti Vivisection Society, and supposedly develops alternatives to animal research.
This is plain nonsense.
Now the antivivisectionists have a new buzz-word to make them feel important. It is ‘microdosing’, a technique for measuring how very small doses of potential new drugs move throughout the body. It is carried out in human volunteers.
All of a sudden, microdosing seems to be the answer to every problem. If you were to listen to the antivivisectionists, microdosing can not only replace animal tests in toxicology, it will also pick up side-effects such as the alleged increase in heart attacks in patients taking Vioxx. Never mind that the antivivisectionists had nothing to do with the development of microdosing. According to their view, it’s the ultimate solution, but is resisted by old-fashioned vested interests wedded to animal testing.
It’s all very well the antivivisectionists trotting out this jargon. But what we are lacking from them is a single decent explanation of how microdosing is supposed to detect toxic effects of potential new medicines. It certainly wasn’t designed for that purpose. Microdosing uses a technology called accelerator mass spectrometry (AMS), which allows the accurate analysis of micro-doses of experimental drugs. It is typically carried out at doses one hundredth of what would be a therapeutic dose. This is intended to be so low that it does not cause toxicity, as explained in a simple and comprehensive briefing from the National Centre for the 3rs. Furthermore, it is widely recognised that animal studies are required before microdosing to ensure that the new drug is not severely toxic at very low doses. Imagine the disaster if we tried to microdose humans on a compound like ricin, which is toxic even at exceptionally low doses. This is exactly what animal tests are designed to avoid, although like any method of testing, they cannot guarantee safety.
Unfortunately for the antivivisectionists, microdosing simply doesn’t live up to their claims. If it were possible to devise a test that was guaranteed not to pick up side-effects of medicines like Vioxx, then microdosing would be a good attempt. Vioxx was subject to extensive clinical trials in human volunteers over long periods of time, at high doses and with large numbers of people. Instead, the antivivisectionists are proposing that microdosing carried out over short periods of time, at very low doses, with very small numbers of people, would do better.
The antivivisectionists point to a study carried out by the biotech company Xceleron which claims as a result of preliminary studies that microdosing is or can be predictive of drug behaviour. But that merely confirms that microdosing might work well at what it is supposed to do, namely trace the movement of drugs around the body. This does not mean that that it can pick up toxic effects, a point the antivivisectionists seem to have missed entirely.
Even respected journalists can fall into the trap of misunderstanding microdosing. Science writer Robert Matthews, whose work is much quoted on the website of Europeans for Medical Progress, recently wrote in the on-line journal The First Post: “the hope is that microdosing will weed out toxic drugs faster and more reliably than animal experiments.” To his credit, after further investigation Robert accepted that “the sentence should have avoided the word toxic”.
There is little doubt that microdosing is a technique with enormous potential for picking medicines which behave in a way we might want them to. The technique has not yet been fully validated, however, and doubts remain as to whether drugs in low doses behave in same way as drugs given at therapeutic doses within the body. There is good potential for replacing the use of some, but not all, animal tests in early-stage drug development.
But the idea that microdosing can replace whole scale animal toxicity testing is pie-in-the-sky. Not that the scientific facts have ever stopped the antivivisectionists from making their ill-informed claims. This is what Jan Creamer, Director of the National Anti Vivisection Society, said in a recent interview on the Today programme:
“everyone remembers recently the TGN1412 drug disaster which we had. Now those human volunteers were given the drug 500 times less than the animals. The monkeys had received a 500 times stronger dose and to no ill-effect - there were no adverse side-effects. It was then given to the human volunteers… And this is at a time when we already have available a system, microdosing, that would have avoided that… you go straight to using humans, but in ultra-low safe doses where you don’t get those sorts of horrific side-effects
Let’s go over that again - just to be clear. Jan Creamer is not happy about the results of giving a test drug to humans at very low doses. So instead, she wants to give test drugs to humans at very low doses. If ever there was muddled thinking on microdosing, this is it.
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