|
Phase |
Purpose |
Time |
|
Preclinical |
Assessing the safety and biological activity using animal models in the laboratory No participants |
3- 6 years |
|
Phase 1 |
Determining which dose is safe, how often it should be given and the best form of treatment Few participants |
1-2 years |
|
Phase 2 |
Assessing the effectiveness of the treatment, its side effects and tolerance levels More participants |
2-4 years |
|
Phase 3 |
Determine whether the new treatment works better than an alternative current standard treatment Most participants - often 100+ |
3-5 years |
|
Phase 4 |
Phase 4 studies are done once the drug or treatment is available on the market. They usually involve new participants and are done to gather long term safety information on the new treatment. |
2-5 years |