Clinical trials conduct ‘human experiments’. Three fundamental principles apply:
- The trial must address a legitimate question
- The patient must be informed and willing to participate
- The patient may decline entry or withdraw at any stage
Blinding:
- Unblinded: All are aware of the treatment the participant receives
- Single blinding: Only the participant is unaware of the treatment they receive
- Double blinding: The participant and clinician (data collectors) are unaware of the treatment the participant receives
- Triple blinding: Participant, clinician and data analysts – all are unaware of the treatment the participant receives
Phases:
Mnemonic: I SWIM
| Phase | Purpose | Name | Sample | Blinding and control |
|---|---|---|---|---|
| 0 | Initial (Pharmacokinetics and Pharmacodynamics) | Microdosing studies | Healthy volunteers (smaller) | No |
| I | Safe? (Safe maximum dose and tolerability) | Human pharmacology and safety | Healthy volunteers (larger) | No |
| II | Works? (Efficacy) | Therapeutic exploratory | Patients (smaller) | Single |
| III | Improvement from current standard? | Therapeutic safety | Patients (larger) | Double |
| IV | Market suitability? | Post-marketing surveillance | Patients being treated by doctors |