About Clinical Trials

A clinical trial is a study of a medical treatment in humans. The treatment being studied can be a drug, device or technique. The purpose of the trial is to answer questions about the safety and effectiveness of that treatment. In this way, clinical trials can help determine whether the best treatments are being used, and they can help the FDA determine whether or not to approve a new treatment for general use.

Clinical trials are a critical part of the research process because through these studies, people help doctors find ways to improve healthcare. Each study tries to answer scientific questions and find better means of preventing, diagnosing and treating a disease. Clinical trials are the way we gain knowledge of diseases and make progress against them.

Clinical Trial Phases

A clinical trial has four phases:

  • Phase I: This first stage of a clinical trial must assess the safety of the study treatment. Only a small number of people, usually 20 to 80, participate at this stage. Phase I studies aim to find a safe dosing range, decide how the treatment should be given and see how the treatment affects the human body. Some information may be gathered on the effectiveness of the treatment. Often, the participants in Phase I trials are healthy individuals who volunteer for the study.
  • Phase II: As soon as the initial safety of the treatment is ensured in Phase I, Phase II trials are initiated. At this stage, a slightly larger group of individuals are enrolled to receive the study treatment. Phase II trials seek to determine if the treatment has an effect on a certain disease and continue to monitor how the treatment affects the individual.
  • Phase III: As opposed to earlier stages, Phase III trials involve a very large group of participants and are conducted in more than one clinical setting. Multicenter trials include more participants and a wider range of participant groups from different geographic locations, which enhances the ability to compare results among centers. This phase assesses the effectiveness of the study treatment by comparing the new treatment (or new use of a treatment) with the current standard of treatment. After a successful Phase III trial, a treatment is eligible for review by the FDA to be marketed to the public.
  • Phase IV: This phase of “post-marketing surveillance” begins after the treatment is made available for the general public. These trials can be carried out for many reasons, such as to find a new market for the treatment, to study its interactions with any other treatments, and to further assess the long-term safety and effectiveness of the treatment.

In order for a treatment to become a standard treatment, it must go through Phase III and Phase IV clinical trial phases. As a participant, you do not have to take part in all phases. Remember that the early phase clinical trials make sure that the treatment is safe, and the later phase clinical trials show if the treatment works better than the current standard treatment.