3401 N. Central Avenue Chicago, IL 60634



Clinical research in action

Chicago Research Centers manages clinical trials in all four phases.

Before the Food and Drug Administration (FDA) approves a new drug, a pharmaceutical company must show that the medication is both safe and effective for use in the treatment for which it is intended.

To prove this efficacy and safety, the pharmaceutical company spends many years conducting a series of studies. The clinical testing of experimental drugs is normally done in four phases.

Purpose of each phase:

Phase I – Determines how the drug is absorbed, metabolized and excreted. Investigates side effects as dosage levels change.

Phase II – Usually a randomized trial where one group receives the drug and the second group gets a standard treatment or placebo. Studies are often “blind” where neither patients nor researchers know who receives the experimental drug. Helps the FDA evaluate the effectiveness and safety of the drug and compare to other treatments.

Phase III – Large-scale testing provides the pharmaceutical company and the FDA with a more thorough understanding of the drug’s effectiveness, benefits, and the range of possible side effects. Most phase III studies are randomized and blinded trials. Once a phase III study is successfully completed, a pharmaceutical company can request FDA approval for marketing the drug.

Late Phase III/Phase IV – Once the FDA has granted a New Drug Approval (NDA), pharmaceutical companies conduct post marketing or late phase III/phase IV studies with several objectives:

1.    To compare a drug with other drugs already in the market,

2.    To monitor a drug’s long-term effectiveness and impact on a patient’s quality of life,

3.     To determine the cost-effectiveness of a drug therapy relative to other traditional and new therapies.