Clinical Trials Take Place in Phases
For a treatment to become standard, it must first go through 3 or 4 clinical trial phases. The early phases make sure the treatment is safe. Later phases show if it works better than the standard treatment. You do not have to take part in all phases.
|Purpose||Number of people who take part|
|Phase I||15-30 people|
|Phase II||Less than 100 people|
|Phase III||From 100 to several thousand people|
|Phase IV||Several hundred to several thousand people|