Principles of conducting clinical trials


Which unites the vast majority of companies requesting clinical trials in Poland, have developed, together with the association, a document entitled “Principles for conducting clinical trials” in the self-regulatory framework. Processes ”, whose provisions they undertook to comply with. In some cases, these principles go beyond the applicable law, imposing additional obligations on companies.  Learn about the principles for clinical trials, adopted by INFARMA member companies and the Association for Good Clinical Practice

Stages of clinical trials

Phase I

First, the safety of the test substance is assessed initially. In a group of several dozen healthy volunteers, metabolism, absorption, excretion, possible toxicity and interaction with other substances (food, drugs) are tested. At the end of this step, the dose of test substance can be determined. The research takes place in specialized centers, which most often belong to pharmaceutical companies or research institutions.  In research on substances used to treat cancer, Phase I is combined with Phase II to avoid exposing healthy volunteers to highly toxic compounds.

Phase II

At this stage of the study, it is determined whether the drug works for a specific group of patients and whether it is safe for them. The relationship between dose and effect of the substance is also assessed, which leads to the determination of the dose used in the later stages of the study. The efficacy and safety of the investigational medicinal product are also evaluated on an ongoing basis. In stage II, data on the absorption, metabolism and excretion of drugs by sex and age are subject to a detailed assessment.

At this stage of the study, the effect of the new medicine is compared to that of a placebo or a medicine used to treat the disease. The comparison is performed in a blind manner, which provides the most objective measure of performance. With this method, neither the patient nor the investigator knows whether the patient is receiving the test substance or a placebo. The study group is randomly selected and includes several hundred volunteers, including patients with a specific medical condition.

A positive evaluation of phase II studies is made when the balance of benefits and risks of a substance is clearly higher. After obtaining such a result, the next step appears.  

Phase III

Phase III clinical trials aim to definitively confirm the efficacy of the investigational substance in the treatment of this disease. This stage includes investigations into the relationship between the safety of the medicine and its effectiveness in short- and long-term use. A group of up to several thousand patients is involved in studies, their duration varies from one year to several years. As in phase II, it uses double-blind and random selection of patients. After successful completion of the third stage of the study, the drug can be registered and placed on the market.

The documentation for a medicinal product, which is submitted to the registrar, shall contain all data collected during preclinical and phase I – III clinical trials. This is a necessary documentation, which can have even a few thousand pages. In order to determine exactly what data should be included in the documentation, before the launch of research programs, drug manufacturers should consult with the pharmaceutical agencies in these countries. This allows you to accurately determine the group of patients who will be given the medicine and reduces the risk of refusing documentation due to the omission of important data.

Phase IV

The last phase of clinical trials concerns registered and marketed medicines, ie medicines that are commercially available. This step is to determine the safety of the medicine for all indications recommended by the manufacturer and for all groups of patients. At this stage, the results obtained in the previous stages are further verified. Phase IV also explores new indications for an already approved drug.