Nigar Sofiyeva, MD with honors, completed Obstetrics and Gynecology residency at Istanbul University. Nigar is certified in Clinical Research from Harvard, holds a master's from Dresden. In this article she shares her opinion on FDA changes in animal testing requirements.
“I am not a guinea pig,” a well-known idiom states. How did the name of the animal enter the vocabulary referring to experimentation?
If a homo-sapiens, a human animal with well-developed intellect, can voice their consent or rather dissent in this case, what about non-human animals who are voiceless to the matter? Are we misusing their inarticulate state, or do modern science and medicine really depend on them?
Indeed, animal models are a reliable way to obtain scientific information contributing to human health. The annual use of animals for experimentation is over 115 million worldwide.
The history of living animal testing goes beyond centuries. Pigs, sheep, and goats were among the first tested animals; perhaps, because they were more available to scientists. Dogs, famously known from Pavlov’s conditioning experiments, were used for their close nature to the human organism. Most of those animal studies aimed to understand human anatomy, physiology, and disease pathology.
However, animal testing mandated by FDA aimed to make every newly developed drug safe for humans; prevent massive human casualties from medicines that aim to heal and not kill. Lessons learned from the 1937 Elixir Sulfanilamide incident and Thalidomide disaster were harsh, resulting in the death of hundreds of people or the disability of thousands of newborns.
As heartless as animal testing without their consent may sound, we must admit that today humanity owes a lot to those science heroes. When we think about the number of medicines available on the market, we also must acknowledge the number of drugs withdrawn from development halfway through, thanks to animal testing.
At the same time, it is well-known that humans and animal physiology, genetics, and diseases, even with the closest nature, have differences.
Therefore, animal results are not 100% applicable to humans. While the drug is safe for animals, further tests are needed to validate its safety in human participants.
Does it mean we could skip the animal phase and start directly with a small group of human participants? This is the point creating dilemma; while animal ethics asks, “Why not?” human ethics and science presents several "whys" for the great majority of drugs. Hence, the FDA amendment tries to find mutual ground without compromising safe drug development and replacing animal testing with alternative methods when available.
Considering the increasing requests by animal rights advocates and given the irreplaceable role of scientific results from animal experiments, FDA amended the 80-year-old FDA mandate.
This amendment lifted the “mandatory animal testing for each drug” development, replacing it with “nonclinical tests.” Nonclinical tests include alternative tests in addition to animal tests.
Another interesting perspective is whether we should always rely on negative animal results while knowing the existing difference. One side of the dilemma accepts that animal testing results are better than the absence of information, regardless of the potentially misleading information and waste of resources.
On the other hand, history shows that some drugs were found toxic in animals after a successful application in humans. For example, tamoxifen, one of the most successful drugs used in breast cancer treatment, is toxic to rat liver. Gleevec, a miracle drug for chronic myeloid leukemia, shows severe liver damage in dogs. Experience shows that modern medicine would have been paying a dear price if these drugs had been removed from the development for animal toxicity concerns.
The use of laboratory animals is not limited to drug development.
Numerous research areas involve animal experiments, including but not limited to cancer treatment, immunology, neurological and behavioral studies, and hormone and metabolism pathways.
Compared to the alternative methods, animal models provide several dimensions together. Cell cultures provide one-layered cells that are limited to providing cell-cell interaction information. The 3D cell cultures close this gap generating a tissue-like environment; however, they are limited to creating the environment for tissue groups, namely organs, to work together.
Animal models show apparent superiority in this regard. They have organ systems with an active metabolism and blood circulation. These advantages make animal models preferred not only for understanding human biology and diseases but also for drug research studies.
However, laboratory animals experience pain, distress, and death during these tests. Additionally, animals are kept in the laboratory environment, which might affect their natural biology, especially for behavioral, hormonal, and stress-related experiments.
It must be remembered that research facilities have very serious, as serious as in human cases, regulations to protect animal right.
All researchers are involved in animal training which educates the protection of animal rights as much as the scientific aspects. Also, animals’ well-being is strictly controlled by veterinarians. Any medical condition and emergency are handled immediately. Any signs or symptoms that the animal is in stress or pain are evaluated carefully. If the situation is not curable, animals are withdrawn from the study, and, depending on the condition, a peaceful sacrifice might be indicated.
With all these pros and cons, where should we stand? All opinions are valid and correct.
Considering the impact of such research on humanity, cures for life-threatening diseases, improved prognoses for aggressive conditions, and discoveries of new disease pathways and treatment options, science and medicine still and for some time will depend on animal research. In the meantime, as a “3R rule” priority, animals are used as minimally as possible and replaced with non-animal methods when available in scientific research.