Phases Of Clinical Trials

Clinical Trails are comprised of four distinct phases:

Phase One:

In Phase One the trials only involve a small number of human subjects in which to test a new drug or treatment that has already been extensively tested on animals. Participants usually have not responded to conventional treatments. During this phase, researchers can only document outcomes and any possible side-effects. Researchers determine the most effective dosage and application methods. Some patients see improvements in their condition in Phase One trials.

Phase Two:

Phase Two trials use a larger group of patients. Because more subjects are involved, researchers may discover less common side-effects. They will continue to evaluate the safety of the drug or treatment. In this phase researchers expand on what they learned during Phase One.

Phase Three:

Phase Three trials may involve over a thousand participants at several different medical institutions across the country. In this phase, the study treatment is compared to and/or combined with standard medical treatment methods. There are two groups in this phase, one is the "control group" who receives standard medical treatment or placebo (sugar pill) and the "treatment group" who receives the experimental treatment. Researchers compare the outcomes/results of the two groups.

Phase Four:

Phase Four trials occur after the treatment has been approved for use in the general population. Researchers monitor long-term usage and how it affects certain population groups. If dangerous side-effects are found, the drug or treatment is taken off the market.