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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
9,847

Clinical Trial Phase Overview

Phase 1
Safety
Phase 2
Efficacy
Phase 3
Approval
Phase 4
Monitor
Phase 1
611

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

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Phase 2
1,056

Efficacy & side effects in 100–300 participants.

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①② Phase 1 / Phase 2
386

Combined early safety + preliminary efficacy assessment.

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Phase 3
495

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

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②③ Phase 2 / Phase 3
122

Bridging efficacy assessment with large-scale comparison.

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Phase 4
350

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

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N/A
6,827

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.

ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer  ·  Last Reviewed: April 2026  ·  Data Methodology