Phases & Purpose: Trials move through Phase I (first‑in‑human safety, ~20–100 participants; median duration ~1.6 years), Phase II (proof‑of‑concept efficacy, ~100–300 participants; median ~2.9 years), and Phase III (pivotal confirmatory, hundreds–thousands of subjects; median ~3.8 years). Each phase ups the scale, statistical rigor, and safety monitoring intensity.
Regulatory Oversight: All trials adhere to ICH‑GCP E6 plus local authority rules (e.g., FDA, EMA, PMDA, MHRA).
Timelines: From final protocol sign‑off to First Patient In (FPI), the global median is ~227 days (~7.5 months), with regional spans of 4–15 months. Key segments: ~53 days to regulatory approval, ~56 days to ethics sign‑off, and ~118 days from ethics to FPI.
Costs & Complexity: A mid‑sized Phase II trial worldwide averages US $8.6 million (Phase I ~$3.4 M; Phase III ~$21.4 M). Major cost drivers: patient recruitment (~30% of budget), site activation, monitoring, and central lab services.
