Phases in Clinical Trails

Clinical trials "are generally considered to be biomedical or health-related research studies in human beings that follow a pre-defined protocol," according to the U.S. National Institutes of Health. Members of the community can participate in a clinical trial if they meet the requirements set forth. Some participants even receive payment for participating. There are four different steps or phases to a clinical trial.

Phase I Trials

• Phase I trials consists of researchers conducting a test for a new experimental drug or treatment for the first time in a group of 20 to 80 people. Researchers review for the safety of the drug or treatment and identify a proper safe dosage. In addition, during this phase researchers began to recognize various types of side effects.

Phase II Trials

• Researchers in Phase II trials expand the scope of the initial Phase I trial. A group of 100 to 300 people test an experimental treatment or drug to determine whether it is effective in the treatment of a particular condition. Additionally, researchers continue to evaluate the safety of the drug on the clinical trial participants.

Phase III Trials

• Researchers increase the participants in a Phase III trial to 1,000 to 3,000 people. The trial allows researchers to verify the drug's usefulness, observe the previously noted side effects and identify additional side effects. Additionally, investigators compare the new drug or new treatment with the currently marketed drugs or treatments. Researchers also continue to gather data that allows patients to use the new treatment or drug in a safe manner.

Phase IV Trials

• Phase IV trials consist of additional studies after the new drug or treatment hits the market; these are used to collect data on the effects it has on a particular population on long-term usage. Researchers note additional threats, benefits and best possible uses.