Preclinical studies can also guide the outcome of the project. If the studies show that a chemical does not work as it is supposed to work, researchers can take a different route of action. They can alter the formulation, modify the dose, try another delivery system, or simply drop the chemical.
What is preclinical research?
Preclinical research involves laboratory and, where appropriate, animal studies carried out to gather evidence about a potential treatment. The exact work depends on what is being developed. A small-molecule drug, antibody, vaccine or gene-based treatment will not necessarily follow the same pathway.
Some studies use cells, tissues or other laboratory-based systems. These studies are commonly known as in vitro studies. There are other experiments that involve the use of living organisms. These experiments are referred to as in vivo studies. Researchers may also resort to methods such as using computers, models of tissues and other ways of carrying out experiments in their quest to understand how a certain treatment would work.
The aim is to answer practical questions before human testing begins. Does the treatment have the intended biological effect? How does the body absorb, distribute, break down and remove it? What dose might be suitable? Are there signs of toxicity? Which organs or biological systems could be affected?
The answers do not guarantee what will happen to people, but they help researchers make more informed decisions.
Why is preclinical research needed?
Developing a medicine involves considerable uncertainty. A compound may look promising in an early laboratory experiment but behave very differently in a living system. Preclinical research helps reduce some of that uncertainty before scientists give a treatment to human volunteers or patients.
Safety is one of the major concerns. It is important that scientists investigate potential adverse impacts and see if the discovered impacts are associated with the treatment amount or treatment duration. Depending on the type of product used, the studies can include various areas such as the functioning of organs, cardiovascular impacts, the nervous system, reproductive biology, or the immune system.
As well, the preclinical studies can provide information about the mechanism of action of the investigated product. Scientists can check if the product reaches the target, how long it stays active and whether it delivers the desired biological effect.
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What happens during preclinical studies?
No particular preclinical study can suit each therapy or drug. Research generally hinges on the candidate’s attributes and the questions it must answer.
The initial stages of laboratory research may examine the interaction of the compound with the specific cells or biological target. Researchers may assess the substance’s efficiency, the potency and possible mechanisms.
Pharmacokinetic studies focus on what happens to the compound in the body. Researchers analyse absorption, distribution, metabolism and excretion, abbreviated as ADME. By doing so, they take the role of determining the rate and degree of the compound getting into the body, its movement inside the body, metabolic changes and toxicity.
Pharmacodynamic studies differ from pharmacokinetic studies. The focus is on the physiological action of the compound and its pharmacological effects on the human body. The combination of the two analyses provides the opportunity to understand the correlation between the dose and reaction of the organism to the treatment.
One of the major elements of preclinical testing is toxicology. Toxicology studies aim to identify any possible negative effects of the treatment and to find the safe dose for a particular compound.
The role of animal studies
For many years, animals have been an essential part of preclinical testing. Usually, the animal species used to address a particular research question or FDA regulations have been selected because they provide specific valuable insights into relevant biological or physiological phenomena.
Animal studies allow scientists to obtain information that cannot always be acquired from isolated cell investigations. They provide insight into the effects of a particular treatment on various organs or systems in living organisms.
Nevertheless, animal study results may not always lead to reliable predictions for humans, as metabolic processes, physiology, and immune system activities differ from those in humans. Thus, the findings obtained from animal studies should be interpreted in conjunction with other available information, instead of treating them only as predictions of what is happening with humans.
Today, there is a growing interest in alternatives and complementary options that involve the use of organoids, human cells, tissues, and computational modelling. They can sometimes yield information that is more applicable to humans compared to what can be obtained from animal studies.
Preclinical research and clinical trials
Preclinical research is preceded by clinical studies, and these two stages in drug development are interdependent. Insights gathered from preclinical studies can assist researchers in preparing for clinical studies, as important decisions related to dose and safety testing are made based on preclinical data.
When researchers accumulate enough data, they can go ahead with the application for marketing authorisation. The clinical development phase consists of several stages with a focus on safety, dose, efficacy of the new cure, its merits/drawbacks, etc.
The fact that the medicine has entered clinical trials does not imply that it has been proved. Data from preclinical studies may help to move to human trials, but clinical trials are necessary to measure the effects of the medicine on people.
The reliability of preclinical studies depends on factors like study design and experiment quality. Other significant determinants of reliability include sample size, control, experimental methods, biological differences and reproducibility of the results.
Reproducibility is also important. If suitable conditions prevent the repetition of a finding, confidence in that result may diminish. Excellent laboratory practice, appropriate controls and transparent reporting all help make preclinical evidence more useful.
In simple terms
Preclinical research is the evidence-gathering stage between an early scientific idea and testing a treatment in people. It brings together laboratory experiments, biological models, pharmacology and, where appropriate, animal studies to investigate how a potential treatment works and whether there are safety concerns.
It does not tell researchers exactly what will happen in humans. However, it does provide useful information that helps determine how prepared a particular applicant might be for future progress.
In the realm of drug development and medical research, clinical trials are not concerned with providing proof of effectiveness. Instead, they serve to identify the present state of knowledge, what remains unknown, and what matters require further research before proceeding with clinical trials.
Research Use Only. This glossary explains terminology used in published research. It is not medical advice and does not describe any product for human or animal use.