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Browse by Phase

Clinical Trials by Phase

Clinical trials progress through four phases, each with different goals, sizes, and risk profiles. Browse active recruiting trials at each stage of development.

Trials Indexed
9,849
Phase 1
Safety
Phase 2
Efficacy
Phase 3
Approval
Phase 4
Monitor
Phase 1
604

Safety & dosing in 20–80 participants. First-in-human studies.

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Phase 2
1,071

Efficacy & side effects in 100–300 participants.

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①② Phase 1 / Phase 2
361

Combined early safety + preliminary efficacy assessment.

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Phase 3
514

Large-scale comparison vs. standard of care. 300–3,000+ participants.

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②③ Phase 2 / Phase 3
104

Bridging efficacy assessment with large-scale comparison.

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Phase 4
326

Post-market surveillance. Long-term safety in general population.

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N/A
6,869

Early-phase, observational, or studies not requiring phase designation.

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Phase data is sourced directly from ClinicalTrials.gov and reflects the trial's registered phase designation. Some trials span multiple phases (e.g. Phase 1/2). Counts reflect currently recruiting and active studies only.