A clinical trial is any research conducted in humans evaluating the performance and safety of an investigational product.
James Lind conducted the first clinical trial in 17471. In that year, the Royal Navy embarked on a long sea voyage. During these long voyages, sailors suffered from gum rot, skin wounds, and some even ended up dying. The disease they were suffering from is what we now know as scurvy, but at the time, the illness’s cause was unknown. In May 1747, Lind decided to treat 12 sick sailors by dividing them into six groups of two. Each group received a different acidic dietary supplement, such as citrus fruits or vinegar. Only the group that consumed lemons and oranges showed any effect of the treatment. This experiment is the first recorded evidence of a clinical trial in our history. Lind could not know he had created a new concept that would revolutionize medicine in the future.
When it comes to defining clinical trials, many definitions are found in the literature. Here we mention some of the most relevant ones.
In the Good Clinical Practice2 a clinical trial/study is defined as
“any investigation in human subjects intended to discover or verify the clinical, pharmacological and/or other pharmacodynamic effects of an investigational product(s), and/or to identify any adverse reactions to an investigational product(s), and/or to study absorption, distribution, metabolism, and excretion of an investigational product(s) with the object of ascertaining its safety and/or efficacy”.
The World Health Organization3 explains that
“Clinical trials are a type of research that studies new tests and treatments and evaluates their effects on human health outcomes. People volunteer to take part in clinical trials to test medical interventions including drugs, cells and other biological products, surgical procedures, radiological procedures, devices, behavioral treatments, and preventive care”.
In ISO 14155 relating to Clinical investigation of medical devices for human subjects4, a clinical investigation is defined as a
“systematic investigation in one or more human subjects, undertaken to assess the clinical performance, effectiveness or safety of a medical device.” It adds that a “clinical trial” or “clinical study” is synonymous with a “clinical investigation.”
The Regulation 2017/745 (EU) on medical devices5 provides an even more narrow and concrete definition where
“Clinical investigation means any systematic investigation involving one or more human subjects, undertaken to assess the safety or performance of a device.”
To summarize, one could say that a clinical trial is any research carried out on humans where the protection of their rights, safety, and well-being is ensured. The objective of these studies is to assess the safety and performance of an investigational product.
Every clinical trial requires a series of successive steps to reach its goal safely. The process of a clinical investigation is highly complex. Therefore, in an attempt to simplify the process, we have created a Gantt chart with the stages that a clinical study should follow. It also indicates the approximate time that each of the steps could take.
With the different definitions and this diagram, our aim is to provide a general idea of what a clinical trial is, as well as the actions and time needed to be able to develop one.
1- James Lind: A Treatise of the Scurvy (1753). Of the Prevention of the Scurvy. Available here: http://www.bruzelius.info/Nautica/Medicine/Lind(1753).html
2- E6(R2) Good Clinical Practice. Available here: https://www.fda.gov/media/93884/download
3- World Health Organization. Clinical trials – Overview. Available here: https://www.who.int/health-topics/clinical-trials/#tab=tab_1
4- International Organization for Standardization. 2018. Clinical investigation of medical devices for human subjects – Good clinical practice. ISO/DIS 14155.
5- Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and repealing Council Directives 90/385/EEC and 93/42/EEC. Official Journal. L 111, 5 May 2017.