How clinical trials work
Phases
| Phase | What it tests |
|---|---|
| Phase 1 | Safety and dosing, small group |
| Phase 2 | Whether it works and side effects, larger group |
| Phase 3 | Comparison against standard care before approval |
| Phase 4 | Long-term monitoring after approval |
| Not applicable | Many observational and device studies |
Study types
| Type | Meaning |
|---|---|
| Interventional | Participants receive a specific treatment |
| Observational | Researchers observe without assigning treatment |
Eligibility
| Criterion | Meaning |
|---|---|
| Inclusion | Requirements to take part (age range, diagnosis) |
| Exclusion | Factors that rule you out (other conditions, medications) |