Phases of Clinical Trials (16)
| Phase | Primary purpose | Study participants |
|---|---|---|
| Preclinical | Collect data to determine basic physical, chemical, and biologic characteristics of new compound | Cell studies and animal studies |
| I | Safety in humans | Healthy volunteers or people with the disease or condition (usually 20–100 participants) |
| II | Efficacy in target/disease condition; determination of dose | People with the disease or condition (usually a few hundred participants) |
| III | Efficacy and monitoring of adverse events; comparison to current standard treatment | People with the disease or condition (often thousands of participants) |
| IV | Safety and efficacy over time, usually after FDA approval | People with the disease or condition (usually thousands of participants) |