Understand what Phase 1, 2, 3, and 4 clinical trials mean. Browse trials by phase with AI-powered analysis and plain English summaries.
93 total clinical trials tracked.
| Phase | Description | Trials | Share |
|---|---|---|---|
| Phase 1 | Safety & dosage (20-80 participants) | 14 | 15% |
| Phase 2 | Effectiveness (100-300 patients) | 25 | 27% |
| Phase 3 | Large-scale pivotal (300-3,000+) | 10 | 11% |
| Phase 4 | Post-approval monitoring (1,000+) | 5 | 5% |
| N/A | Phase not applicable or not specified | 39 | 42% |
First-in-human testing with 20-80 participants. The primary goal is to evaluate safety, determine safe dosage ranges, and identify side effects. About 70% of drugs pass this phase.
Expanded testing with 100-300 patients who have the target condition. Researchers evaluate whether the treatment works and monitor short-term side effects. Only about 33% of drugs pass this phase.
Large-scale studies with 300-3,000+ participants. These trials confirm effectiveness, compare against standard treatments, and collect comprehensive safety data. Successful Phase 3 trials can lead to FDA approval.
Post-marketing studies with 1,000+ participants. These trials monitor long-term safety, effectiveness across diverse populations, and detect rare adverse effects after a drug reaches the market.
Some trials are classified as Early Phase 1 (initial safety/pharmacology studies) or Phase 1/Phase 2 (combined early safety and efficacy studies that blend elements of both phases).