Clinical trials are studies in which researchers study the effectiveness and safety of new methods of diagnosing and treating diseases with the help of volunteers. Their importance is tremendous as they allow for the use of state of the art scientific and technological discoveries in the treatment of patients. Most clinical trials take place in the field of medicinal products, but we also know clinical trials in the field of medical devices and new methods of treatment. Trials are used by researchers to establish and verify the safety and effectiveness of new medicines, thereby assuring a safe transfer of medicines into daily clinical practice.

Types of clinical trials

Clinical trials are divided into interventional and non-interventional. The latter are based on researchers’ observations and efforts to assess the state of the patient on the basis of a predetermined protocol. In interventional clinical trials the strategy of treatment, examinations and monitoring of participants differ from established clinical practice. Accordingly, they are divided into several phases. Each phase is aimed at gaining specific information and each new phase builds upon the results of the previous phase.

Phases of clinical trials of medicines

Safety is the primary concern throughout the research process. In the first phase researchers under strict supervision administer the new medicine to a smaller group of volunteers participating in the study, determine the best method of administering the new medicine, discover the most common and severe side effects and determine the safe dose of a medicinal product. The second phase monitors the efficiency of the medicinal product in order to confirm or disprove its effects. In these two phases a smaller number of volunteers provides quite reliable results. In the third phase the number of patients included in the trial must be increased, provided the medicine has been proven to be safe and effective.

The third phase is aimed at comparing the new medicine with established treatments, researching the influence of the new medicine on different populations, establishing dosing and combinations with other medicinal products. Data gathered by researchers in the third phase shows whether a new medicine can begin to be used to treat patients in daily clinical practice.

Of course researchers continue to monitor medicinal product safety after receiving authorization for use in clinical practice, normally through the aforementioned non-interventional trials where treatment, examinations and monitoring of patients is no different that regular clinical practice.

Benefits of participating in a clinical trial for patients

Generally clinical trials are intended to expand knowledge on a certain disease which helps improve treatment, but also diagnosing, prevention of diseases and conditions, assessment of risk rates for certain diseases, improvements of the quality of life of chronic patients ...

The greatest benefit of clinical trials is to allow patients who have exhausted other treatment options access to new possibilities for potentially effective treatment before a new medicine reaches the market. Volunteers participating in such trials also receive a greater number of examinations by a physician and more tests as the progression of the disease and treatment must be monitored more closely. This is another welcome advantage for a patient, but it is also true that more frequent trips to the physician can be burdensome for seriously ill individuals.

Who can participate?

Each clinical trial has specific needs and research goals that influence the selection of volunteers. Sometimes researchers require patients with specific diseases while at other times they need healthy persons without symptoms. In every case the trial protocol determines guidelines for volunteers that include criteria such as age, gender, type and stage of the disease, prior treatment and others.

Protection and informing volunteers

Prior to being included in a trial, each patient must be informed of the purpose, course, procedures and duration of a trial, potential adverse effects, risks and expected benefits and associated rights and obligations inherent in participation, both verbally and in writing. Persons deciding on participation have access to materials on the trial and can pose questions to researchers, particularly in relation to potential risks, until they feel they have sufficient data to decide to participate or reject participation. It is important to note that the decision for or against participation is completely autonomous.

Persons who decide do participate must give their written consent by means of an informed consent form. Naturally volunteers are given all relevant information during the trial as well, on the basis of which they can decide on whether to keep participating in the trial or exit the trial. Participation can be terminated at any time, without stating any reason and without consequences. Persons who reject or terminate participation continue to receive all the necessary medical care and treatment within the scope of regular treatment, same as before their inclusion in a trial.

Safety and regulation of clinical trials

The use of medicinal products in trials carries a degree of risk since their safety and effectiveness are still being researched. There is also a risk of adverse effects that have not been seen before, as well as a risk that the medicine will not work. It is therefore very important that volunteers receive all necessary information and educate themselves thoroughly.

The performance of clinical trials is a strictly regulated area due to the necessity for assuring patient safety and rights. In Slovenia clinical trials must be performed in accordance with a protocol that accurately states the objectives, purposes, methodology, statistical processing and organization of each clinical trial. Each trial must also be organized in accordance with international ethical standards, scientific standards and legislation and must first be reviewed and approved by the National Medical Ethics Committee and the Public Agency for Medicinal Products and Medical Devices of the Republic of Slovenia.  

Clinical trials in Slovenia must adhere to:
- The Medicinal Products Act (Official Gazette of RS no. 17/14)
- Rules on clinical testing of medicinal products (Official Gazette of the Republic of Slovenia, No 54/06)
- Helsinki declaration on Ethical Principles for Medical Research Involving Human Subjects
- ICH guidelines of good clinical practice
- Oviedo Convention
- Code of Medical Ethics
- Rules on fees and costs of procedures in the field of medicinal products (Official Gazette of RS, no. 3/07, 25/10 and 37/10)

More on EU legislation pertaining to clinical trials:
- Directives and recommendations of the European Commission: EudraLex - Volume 10 Clinical trials guidelines
- Regulation (EU) no. 536/2014 of the European Parliament and of the Council of 16 April 2014 on clinical trials on medicinal products for human use, and repealing Directive 2001/20/EC