Living with Chronic Pain

What Are Clinical Trials?


Clinical trials are research studies conducted with human participants to test the safety and effectiveness of medical interventions, such as drugs and medical devices. Clinical trials help the medical community discover better ways to prevent, diagnose or treat a disease. They are often used to determine if a new treatment is more effective than an existing standard treatment.

Researchers typically begin testing new medical interventions in a lab and on animals. If the results are promising and after extensive testing, the intervention is moved into clinical trials. Each clinical trial has a protocol: the goal of the study, the categories of people who can participate, details about procedures and treatments and the information that will be gathered from the study.

Once voluntary participants for a study are chosen, researchers conduct the procedures and treatments outlined in the protocol while collecting data and information in order to draw conclusions. The results of clinical trials are used by the U.S. Food and Drug Administration (FDA) to approve new drugs and medical devices.

Phases of clinical trials

A medical intervention undergoes four different phases of clinical trials to ensure its safety and effectiveness:

  • Phase I trials are conducted on a group of approximately 20 to 80 individuals to test an intervention’s safety and identify any side effects. A safe dosage range is also identified in Phase I.
  • Phase II trials are conducted on a larger group of people (about 100 to 300). While safety remains a priority, phase II also focuses on the effectiveness of the intervention.
  • Phase III trials continue to study the safety and effectiveness of the intervention on an even larger group, typically made up of several hundred to 3,000 people. This phase studies the intervention in different populations and in combination with other drugs or interventions. If the phase III trial results are positive, the FDA approves the drug or device.
  • Phase IV trials take place after FDA approval. The intervention continues to be monitored for safety and effectiveness in large, diverse populations. More information is gathered about the intervention’s risks, benefits and best use.

Safety of clinical trials

Most clinical trials in the United States are approved and monitored by an Institutional Review Board (IRB) consisting of physicians, statisticians and members of the community. The goal of an IRB is to ensure the study is ethical, to protect the rights and welfare of participants and to ensure that the risks of the study are minimal compared to the potential benefits.

Most clinical trials pose minimal risks, such as minor discomfort. However, some participants have experienced complications requiring medical attention. Others have experienced serious injuries or have died as a result of participating in a clinical trial.

The risks for a specific study are disclosed in a document, referred to as an informed consent, which every participant must sign before participating in any study. An individual should always consider the risks and potential benefits before agreeing to participate in a clinical trial.

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