The Four Phases of a Clinical Research Study


The testing of an experimental drug involves four phases:

  • Phase I clinical research studies are the first stage of testing in human volunteers. A small group of these otherwise healthy volunteers are screened. This phase assesses the safety and tolerability of a drug.
  • A Phase II clinical research study occurs after Phase I studies have been completed successfully. The investigational drug is tested for safety and effectiveness in a larger population of people who have the disease or condition.
  • A Phase III clinical research study is the last round of pre-approval testing for an investigational drug. The drug is tested in comparison to a standard or an approved treatment and/or placebo for the disease or condition for which the drug is being researched. The results of these studies usually provide the information for the drug's package insert and label.
  • A Phase IV clinical research study occurs after a drug has been approved by the FDA. The drug may be compared with similar medications; it may be evaluated for additional patient populations; or it may be studied for any specific, unusual, or unexpected side effects.

The GAP Study is a Phase III study. It is designed to evaluate the effectiveness, safety, and tolerability of an investigational drug for Alzheimer's. About 360 patients with mild-to-moderate Alzheimer's will participate in this research study.

See If You May Be Eligable
Please call 1-800-438-4380 and mention the Gap Study
For you, for them, for now, for the future. Living with Alzheimer’s is often about more than just one life. It’s about partnership and possibilities for people living with Alzheimer’s.