Each type of clinical trial promotes patient safety by providing researchers with important information about the treatment being studied to determine whether it should move on to the next phase.
Phase I – Is it safe?
A new treatment is tested with a group of 20–80 participants for the first time to evaluate safety.
Phase II – Does it work?
The treatment is tested in a larger group (100–500 participants) to determine its effectiveness in treating the condition or illness.
Phase III – Is it better than what we have now?
The new treatment is compared to existing treatments for safety and effectiveness. The FDA reviews the data for approval. (Typically includes 3,000+ participants.)
Phase IV – What else can we learn?
After FDA approval, studies continue with 5,000+ participants to confirm long-term safety and explore other potential uses.