Clinical trials are research studies that explore whether a new vaccine, drug or medical treatmentis safe and effective for humans. Clinical research produces the best data available for health care decision-making.
Clinical trials are conducted in Phases (a series of steps). Each phase is designed to answer a separate research question. Review and approval by Regulatory Agencies is required before the initiation of each Phase.
Clinical trials follow a typical series from early, small-scale, Phase 1 studies to late-stage, large scale, Phase 3 studies.
• Phase I: Researchers test a new vaccine, drug or treatment (product) in a small group of people (20 to 100 healthy volunteers or people with the disease/condition)for the first time to evaluate its safety, determine a safe dosage range, and identify side effects. The length of the study is for several months.
• Phase II: The product is given to a larger group of people (up to several hundred people with the disease/condition)to see if it is effective and to further evaluate its safety. The length of the study is several months to two years.
• Phase III: The product is given to large groups of people (300 to 3,000 volunteers who have the disease or condition)to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the vaccine, drug or treatment to be used safely. The study length is one to four years.
• Phase IV: Studies are done after the product has been marketed to gather information on the product’s effect in various populations (several thousand volunteers who have the disease/condition), and any side effects associated with long-term use.