In this blog post, we will look at the scientific validity and ethical issues of animal testing for drug verification, as well as possible alternatives and their limitations.
As the development of new drugs and the medical industry have advanced dramatically along with industrialization, various cases of evaluating the effectiveness of drugs have emerged. At the same time, the validity of “animal testing,” which is currently the most widely used drug evaluation standard, is also being questioned. Animal testing refers to experiments conducted on all animals except humans, and about 200 million animals are sacrificed for experiments every year around the world. In particular, it is said that about 3 million animals are sacrificed in South Korea alone. This is because many countries, including South Korea, use animal testing as a criterion for evaluating pharmaceuticals. But is animal testing really an effective method?
In fact, the DNA sequence differences between humans, even if they differ in gender, race, and region of birth, are less than 1%, but the DNA differences between humans and monkeys, which are known to be similar to humans, are about 16%. In addition, diseases common to humans and animals account for only about 1.16% of all diseases, and most cancers, AIDS, and dementia are diseases that only occur in humans. Dr. Klausner of the National Cancer Institute in the United States said, “The history of cancer treatment in humans is the same as the history of cancer treatment in mice, and we have been treating cancer in mice for decades, but frankly, it has not worked for humans.” As such, it is questionable whether the results of experiments on animals with large differences in gene sequences and few common diseases can be applied to humans.
The problems of animal testing have not only been theoretical, but have also been shown in real cases. Thalidomide, which was developed in Germany in 1953 to prevent morning sickness in pregnant women, was proven to be safe through several animal tests and was exported to more than 50 countries and was called the “miracle drug.” However, 12,000 deformed babies were born in one year after the drug was used. Side effects that had not been found in animal testing were found in humans. Pharmaceutical companies claimed that no harmful effects had been found in experiments on rats, rabbits, and pigs, but it was eventually discovered that thalidomide’s optical isomer difference caused serious deformity side effects only in humans.
In addition to the thalidomide case, there are many drugs that show different effects in humans and animals. For example, penicillin, a commonly used treatment for bacterial diseases, is beneficial to humans but can be poison to guinea pigs. Also, morphine, which is used as a sedative in humans, acts as an stimulant in cats. As such, it is not appropriate to apply the results of animal experiments to humans, as the effects of drugs vary depending on the animal.
In addition, animal experiments are inefficient compared to the cost of input. As the author of “Animal Experiments of Greed and Arrogance” expressed, “Rats are animals that spit out papers when they are given drugs,” and although animal experiments are often used in academic research, their usefulness is questioned. Every year, 200 million animals are used in animal testing, but only 25 new drugs are registered with the US Food and Drug Administration (FDA) each year. The act of writing papers by repeating ineffective animal testing may also lead to the dissemination of incorrect research results, causing a second thalidomide incident.
Another problem is that animal testing should be prohibited from an ethical perspective. Animal testing is justified by applying different ethical standards to animals and humans. The ethical basis for animal testing is the presence or absence of “moral will.” This is the willingness to abide by the norms that should be observed based on social interest, public opinion, and customs. Two contradictions arise here. First, even though it is difficult to consider a newborn baby or a person in a state of brain death to have the ability to think or a moral will, they are excluded from being used as subjects in animal experiments. This shows that the ethical standards of animal testing cannot be used as a basis for distinguishing between humans and animals. Second, even though research has consistently shown that animals such as monkeys and dogs have a moral will, these animals are still used as sacrificial victims in experiments.
In addition, there are many cases where animal testing is conducted in violation of regulations. According to the Animal Testing Code, “Research using animals should be conducted after examining whether the potential impact of the research, which is against the welfare and well-being of animals, can be justified by the educational value or scientific importance of the research, and the researcher should consider the welfare of the animals and treat them with respect when planning and conducting the research.” However, in reality, experiments are being conducted that are against the code. For example, even at the beginning of the 21st century, when the harmfulness of smoking was clearly established, experiments were conducted in which dogs and monkeys were pierced through the neck and exposed to cigarette smoke. This cannot be considered to satisfy educational value or to be respectful of animals. It is necessary to re-evaluate not only the practicality of animal testing, but also its ethical aspects.
Currently, many excellent methods have been developed to replace animal testing. In vitro studies and mathematical modeling are representative examples. In vitro studies are a method of culturing a target organ in a test tube to observe whether a drug causes side effects. Since certain cancers that occur only in humans cannot be tested on animals, cancer cells are transplanted into a target organ cultured in a test tube to conduct research. Mathematical modeling is a method of predicting whether a drug will cause side effects in the human body by substituting mathematical formulas into a computer. In fact, the side effects of thalidomide, which were not revealed in animal experiments, could be confirmed through mathematical modeling. It is irrational to insist on animal experiments when there are practical and ethical alternatives available.
Interest in and development of pharmaceuticals will continue. While animal testing has undoubtedly contributed to the advancement of medicine, it is also true that incidents such as thalidomide have caused victims in the process. With the side effects of new drugs unknown, preventing a second thalidomide is a priority. Of course, stopping animal testing now could temporarily lead to a setback in medicine. However, if we blindly pursue animal testing, which has ethical and practical limitations, there is a high possibility of a second Thalidomide incident. Therefore, we must gradually reduce animal testing and expand research methods that can replace it. In addition, when animal testing is unavoidable, the experimenter must strictly comply with the code and conduct the experiment with the utmost responsibility for the animals. It is also necessary to strictly control the regulations on animal testing and thoroughly control compliance.
