A clinical trial, also called a research study, is a process scientists use to test the value and safety of various interventions in people. Clinical trials are meant to find new and improved methods of evaluating or treating a condition or it can test a new way to prevent diseases.
Clinical trials are conducted in phases and may span long periods of time.
Phase I clinical trials involve giving a new treatment to a small number of participants. The researchers determine the best way to give the new treatment and how much of it can be given safely. Participants are usually people who would not be helped by other known treatments or alternatively, a phase I trial is performed in healthy volunteers to determine the safety of a particular treatment.
Phase II clinical trials focus on learning whether the new treatment has an effect on a specific condition. Additional information regarding the side effects of the treatment is also obtained. A small number of people are included because of the risks and unknowns involved.
Phase III clinical trials compare the new treatment with the standard treatment. In this phase, researchers determine which study group has fewer side effects and is undergoing the most improvement.
Phase IV clinical trials, also called post-marketing studies, are conducted after a treatment has been approved. The purpose of these trials is to learn more details about the treatment and to address questions that may have come up during other phases of trials.
Understanding Clinical Trials
Clinical trial participants are assigned at random (a process similar to flipping a coin) to either the new treatment (treatment group) or the current standard treatment (control group). Randomization helps to avoid bias (having the study's results affected by human choices or other factors not related to the treatments being tested). When no standard treatment exists for a condition, some studies compare a new treatment with a placebo (a look-alike pill/infusion that contains no active drug). Participants do not know if they receive the drug or placebo.
In a clinical trial, patients receive treatment and researchers observe how the treatment affects patients. The patient's progress is closely monitored during the trial. Once the treatment portion of the trial has been completed, researchers may continue to follow patients in order to gather more information about the effects of a treatment.
Such trials can involve risks, and there is no guarantee regarding a trial's outcome.