I have written several times that loving animals does not make you a scientist. I have no illusions that merely pointing out this obvious fact will change behaviour but such could be said about pointing out many such facts. There is a wealth of commentary from scientists, as well as scientific evidence and supporting theory, regarding the factual nature of evolution yet many, if not most, Americans simply dismiss it. Some adults do not even vaccinate their children despite the scientific evidence of efficacy. Nevertheless, this does not excuse the scientific community from continuing to point out and defend the facts of vaccination and evolution. Likewise, I will continue to point out nonsense from vivisection activists as well as members of the animal protection community.
One problem with nonscientists thinking they are scientists is that occasionally someone with a modicum of power will listen to them. The latest manifestation of this occurred in London in the form of David Amess, a conservative member of parliament. In a speech delivered on December 7, Amess gave us an excellent example of why people who don’t know the difference between a molecule and cell should be very careful from whom they take science advice.
Amess is a self-proclaimed animal welfarist who has supported legislation improving the welfare of certain groups of animals. This is a good thing from my perspective but, as I have said, loving animals does make you a scientist or even competent to discuss science on an elementary level. Amess did state some sound scientific principles in his speech: “animal models are not reliable indicators of how a drug will behave in humans. . . . [animals] cannot predict mechanisms of the disease, risk factors or potential adverse reactions. According to the US Food and Drug Administration, the world’s largest drug regulator, 92% of potential new drugs fail in humans trials (either because they do not work or are not safe in humans) after appearing safe and effective in animal tests. . . . Of course why should animals be indicators of human response? Animals and humans are evolved complex systems and as such should be expected to demonstrate different responses to drugs and disease. For example, mutations that cause genetic disease in humans are the norm in some animals.” (Sound familiar?) All of that is true!
Unfortunately, Amess then exposes his ignorance of science, and his complete dependence on others almost as ignorant as he, as he proceeds to ask the parliament to pass the Safety of Medicines Bill, which would require a study to determine whether newer, nonanimal testing modalities are superior to animal tests. As I have explained once or twice, tests in medical science are either predictive or they are not. For example, if I was an oncologist, I would not administer certain very toxic anti-neoplastic drugs unless I was at least 99% certain that you had cancer. I would try to be 100% certain by ordering predictive tests, such as taking a biopsy of the tissue. Blood tests, CT scans, and tissue biopsies are predictive for certain conditions and that is why they are used as opposed to a simple and inexpensive physical examination. The positive predictive value (PPV) and negative predictive value (NPV) for a physical exam are not high enough to diagnose the condition with the precision required in medical science.
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Granted, there are tests that are imperfect with a PPV of say 0.8 and a NPV of about the same, and yet we use them. But no one uses them as authoritative or definitive for a condition, only as a screening tool. And 0.8 is much higher than the PPV and NPV of tests on animals eg toxicity. Furthermore, animal tests in drug development are used as authoritative and definitive. Drugs are withdrawn from development because of results from unreliable animal models. That is why the US National Cancer Institute thinks society has lost cures for cancer; animal tests led to the drug not being developed. (Gura 1997) The gray areas of some medical tests notwithstanding, very high standards in medical science must be met in order for a test to be considered predictive. If the test does not meet those standards, then it is not predictive. Period. And in medical science it is not used as a predictive test.
This is not complicated.
Animal models for drug development have been studied and they are not predictive for humans; therefore they should not be used. It is immaterial to say that there are, or that there are not, other tests with a better or worse track record. If animal models have a PPV of 0.5 for hepatotoxicity and another test has a PPV of 0.6, neither is acceptable. Neither is predictive. Even if those are the only two tests in the universe, they should not be used as predictive tests. Tests that do not use animals should be judged on the basis of whether they have a high PPV and NPV, not on how they compare to other tests that do not fulfil the criteria. Being marginally better than animal tests does not mean a test should replace the animal test, it means that test is also not predictive. Neither test should be used as a definitive test or even as a screening tool for that matter. Asking for a study to compare animal tests with other tests is the position of someone with pretensions to sophistication but who in fact does not understand the fundamentals.
Challenging the status quo is seldom easy, however the Safety of Medicine Bill merely heaps bad logic on top of bad science. Sadly, the animal rights movement is usually a cacophony of opinions, not all of which are even consistent with the philosophy of animal rights. One area where the movement should be able to get it right is science. There are actual right and wrong answers in science and when one ignores these answers in order to advance a personal agenda, one is not helping the situation.
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Gura, T. 1997. Cancer Models: Systems for identifying new drugs are often faulty. Science 278 (5340):1041-2.