Clinical trials are defined by the World Health Organisation as:

“Any research study that prospectively assigns human participants or groups of humans to one or more health-related interventions to evaluate the effects of health outcomes.”

According to the International Committee of Medical Journal Editors (ICMJE), health-related interventions include any intervention used to modify a biomedical or health-related outcome (for example, drugs, surgical procedures, devices, behavioural treatments, dietary interventions, and process-of-care changes). Health outcomes include any biomedical or health-related measures obtained in patients or participants, including pharmacokinetic measures and adverse events. Purely observational studies (those in which the assignment of the medical intervention is not at the discretion of the investigator) are not clinical trials. It is worth noting that all clinical trials must be registered with a public registry before the enrolment of the first subject in order to be eligible for publication in journals that adhere to ICMJE standards. ICMJE use the WHO definition of a clinical trial and offer the following advice:

“Those who are uncertain whether their trial meets the expanded ICMJE definition should err on the side of registration if they wish to seek publication in an ICMJE journal.”

However, according to the WHO definition, if a trial does not involve an intervention then it is not considered to be a ‘clinical trial’. Examples of non-intervention research studies that are not clinical trials include sampling, questionnaire-based and observational studies.

Other organisations have slightly different definitions of a clinical trial. According to ICH-GCP, a clinical trial is any research on human subjects that involves an investigational medicinal product. Investigational medicinal products include unlicensed drugs or drugs being used outside of the product license (e.g. for a new indication). And yet another definition is provided by the UK’s Medical Research Council which broadly defines clinical trials as any research that involves human participants and the administration of an intervention (drug, vaccine or other type of disease management) as part of research. Finally, some extend the definition of clinical trials to include, in addition to investigational products, the administration of established therapies, vaccines or patient management processes that go beyond standard care and are being given to answer a research question.

Global Health Trials follows the WHO definition and exists to support all such clinical trials. However we also offer our documents, guidelines, support and advice to any other form of clinical research. The straightforward goals of collecting of high quality and reliable data and working to high ethical standards should be applied broadly to all research. To that end we invite researchers to pick what they want from this site, whether they are running a clinical trial or another form of clinical research study.

In many regions (such as Europe and the US) it is a legal requirement to conduct a trial to ICH-GCP standards. This must also be a consideration for trials conducted outside of these areas if they involve a product being developed for use in a region where ICH-GCP is a legal requirement. Furthermore most funding agencies require that trials be conducted to ICH-GCP and it is unlikely a trial will be published unless a statement is made confirming that this trial was conducted to these standards.


This article originally appears on the Global Health Trials resources. Please visit us for more resources relating to trials.


  • opgupta opgupta March 22, 2017

    The clinical trials must be conducted based onICH-GCP guidelines, whether an unlicensed drug, vaccine, a device or repurposing of the known and lecensed drug is consisdered for trial., or a different method is being used for the disease management.

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