Clinical Study Phases

A large group of people are involved in Phase 3 studies. Those who participate in Phase 3 are usually randomly assigned to different groups. In one group, up to a few thousand people will receive the new treatment.

 

Another group receives the standard treatment for the same medical condition, or receives a placebo. This is called the "control" group. The side effects and treatment success in people receiving the new treatment are compared to those in the control group. This helps the researches know if the new treatment is really safer and more effective.

 

During this phase, researchers will continue to collect information about side effects, and also study how often the condition returns and the effects of the treatment on the patient's quality and length of life.

 

After Phase 3 studies are completed, a medicine can be submitted to the government for final approval.

 

Once a new treatment has been approved, there may be additional clinical studies performed. These are called Phase 4 studies. These studies are conducted for a number of reasons. One of these is to find out how effective the treatment is in different groups of people -- such as those of the same race or age group. Information is also gathered about long-term effects of the treatment.