The use of beagle dogs in research and testing of human drugs.
By Andre Menache BSc (Hons) BVSc MRCVS
Please read the title again. As a veterinary surgeon, I find this title very strange. Why on earth are beagle dogs being used to see what pharmaceutical drugs do to people? I would certainly never use a parrot to test drugs for horses, so why use dogs (or any other animal) to test human drugs? The short answer is that the law requires it. UK and EU laws require pharmaceutical drugs to be tested on a rodent (usually a rat) and a non-rodent species (usually a beagle dog) before human clinical trials can begin.
This may sound like a reasonable idea to some people. It certainly seemed a reasonable principle 65 years ago when the laws governing drug testing and clinical trials were first formulated. After all, rats, dogs and people all have two eyes, two ears, a brain, a heart and so forth. Animals are similar to people. But how scientific is the word “similar” when one considers that humans share 50 percent of their DNA with a banana? Humans, rats and dogs share the gene for a tail. However, in people the gene is switched off, while in rats and dogs, the gene is switched on. We know that mice and people both share about the same 23 000 genes, but so what? Mice don’t resemble people. It’s less about the genes we share and more about what those genes do and how they network and interact with each other. That helps to explain why one complex system (the dog or the rat) cannot predict what will happen in another complex system (the human).
In other words, science has moved forward by 65 years since those early laws were written, but the laws have not yet caught up with the science (1). For example, we now have knowledge of the human genome, which we didn’t have 65 years ago. This new knowledge plus our expanding knowledge of how genes work, make animal tests look really out of place in the 21st century. Data published by the pharmaceutical industry confirm this. The chance of an animal test correctly predicting how a human will respond to a drug or a chemical is about as reliable as tossing a coin. Wow, that’s quite an accusation. Yes, indeed, and there is plenty of published scientific evidence to back that statement. See references 2 through to 19 below.
Let’s look at a real-life example of what we are talking about. Drug-induced liver damage in people is the most frequent reason cited for the withdrawal from the market of an approved drug, and it also accounts for more than 50 percent of acute liver failure in the United States (20). The figures for the UK are almost the same, where toxicity to the human liver is reported to be the second most common cause of drug failure through adverse effects in clinical trials of potential drugs (2, 21).
In other words, liver damage to people is caused by drugs after they were tested on rats and beagle dogs, as required by law. Based on data from the pharmaceutical industry, the rat and dog experiments reveal liver damage approximately 50% of the time (22). That’s exactly the same result one would expect from tossing a coin.
Could it get any worse than that? Yes, it gets worse. The results of drug testing may be different on male rats and male beagle dogs compared with females, due to differences in liver function in males and females (23, 24). That makes animal testing even less reliable than tossing a coin.
Most of us by now would realise that animal tests don’t work when it comes to human drugs. And most people would say, “Well if you don’t test on rats and beagle dogs, how do you test new drugs?” There are two answers to this question.
The scientific evidence shows that testing on rats and beagle dogs (or any other animal) is less reliable than tossing a coin, so we should stop doing it, regardless of whatever else is available to test drugs.
To comply with the law the pharmaceutical industry continues to test drugs on animals but the industry is well aware that animals cannot predict human outcome, which is why it is investing resources into human-based research methods that are relevant to people. These include human cell studies, human DNA studies, the use of donated human tissues, computer studies and much more. Most of these human-based methods are being improved upon all the time, to make them reliable for human drug testing. Most of these methods are not yet 100 percent predictive, but they are better than a coin toss (= animal tests) and they are relevant to people (25).
In the 65 years since the animal testing laws were introduced, scientific research has revolutionised our understanding of human biology and how it differs from other species. As a result of what we now know about the human body, the consequences of these 65 year old safety laws mandating animal tests, are not just that they have become outdated but are in fact recklessly and negligently exposing thousands of the population to the risk of death by their own medication (197,000 Adverse Drug Reaction deaths a year in Europe) (26).
The solution is quite simple. Our government and health authorities must remove the legal requirement for animal tests and replace them with test methods that are relevant to humans. And the sooner the better, for human health and animal welfare.
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