Preclinical and Clinical Trials

Considering the discovery of drugs it’s necessary to mention pre- and clinical developments. Pre-clinical development is a stage of research that begins before clinical trials (testing in humans), and during which important feasibility, iterative testing and safety data are collected. The main goals of pre-clinical studies (also named nonclinical studies) are to determine a product's ultimate safety profile. Products may include new or iterated or like-kind medical devices, drug. Each class of product may undergo different types of pre-clinical research. For example, drugs may undergo toxicity testing through animal testing. These data allow researchers to estimate a safe starting dose of the drug for clinical trials in humans. Most pre-clinical studies must adhere to Good Laboratory Practices (the abbreviation is GLP). The information collected from these studies is vital so that safe human testing can begin.

Typically, in drug development studies animal testing involves two species. The most common models to be used are murine and canine, although primate and porcine are also used. The choice of species is based on which will give the best correlation to human trials. But rodents cannot act as models for antibiotic drugs. Most studies are performed in larger species such as dogs, pigs and sheep which allow for testing in a similar sized model as that of a human. Animal testing in the research-based pharmaceutical industry has been reduced in recent years both for ethical and cost reasons. However, most research will still involve animal based testing for the need of similarity in anatomy and physiology that is required for diverse product development.

Clinical trials are a set of procedures in medical research and drug development that are conducted to allow safety (or more specifically, information about adverse drug reactions and adverse effects of other treatments) and efficacy data to be collected for health interventions (e.g., drugs, diagnostics, devices, therapy protocols). Depending on the type of product and the stage of its development, investigators enroll healthy volunteers and/or patients into small pilot studies initially, followed by larger scale studies in patients that often compare the new product with the currently prescribed treatment. As positive safety and efficacy data are gathered, the number of patients is typically increased. Clinical trials can vary in size from a single center in one country to multicenter trials in multiple countries. Clinical trials often involve patients with specific health conditions who then benefit from receiving otherwise unavailable treatments.

During the clinical trial, the investigators: recruit patients with the predetermined characteristics, administer the treatment(s), and collect data on the patients' health for a defined time period. These patients are volunteers and they are not paid for participating in clinical trials. These data include measurements like vital signs, concentration of the study drug in the blood, and whether the patient's health improves or not. The researchers send the data to the trial sponsor who then analyzes the pooled data using statistical tests. The most commonly performed clinical trials evaluate new drugs, medical devices, biology, psychological therapies or other interventions.

The Role of Drugs

Drugs in modern medicine act a very important role. They are a powerful weapon in the struggle with a variety of diseases, in the conduct of preventive measures. Medications are used in almost all areas of medical practice. We make wide use of drugs, such as therapy in the treatment of cardiovascular diseases, tuberculosis, diarrheal diseases, influenza, etc., in dermatology for the treatment of skin diseases, in surgery, pain management, and in ophthalmology at infectious diseases. A number of drugs are used for disinfection.

Great achievements of modern medicine, the development of powerful chemical and pharmaceutical industry, the synthesis of drugs, a broad study of domestic medicinal plants led to the creation of new highly efficient drugs such as antibiotics, sulfa drugs and hormones which further increased the role and value of drugs and expanded the range of applications.

Comprehension Aspect

Ex. 1. Match the expressions in the left-hand column with their definitions in the right-hand column. The expressions appear in the text you have just read.

Ex. 2. Mark the following statements as True or False.

1. Drug discovery is a highly efficient process with a high coefficient of new therapeutic effects.

2. Before Paracelsus extracts produced from plants constituted the main part of traditionally used raw medications in Western medicine.

3. Ziconotide is a toxic substance extracted from plant species to treat nervous disease.

4. The main objectives of pre-clinical studies are to find out if the product to be tested is safe as much as possible.

5. Preclinical trials include tests in humans.

6. In recent years animal testing has expanded.

7. Murine, canine, porcine models are related to rats/mice, dogs and pigs respectively.

8. Patients are involved into clinical trial against their own free will.

9. The number of patients taking part in clinical trials is always the same. 

10. Patients are not paid for participating in clinical trials.