So sánh phương pháp

	Thử nghiệm lâm sàng Giai đoạn II hồi cứu	Giai đoạn III Thử nghiệm lâm sàng
Lĩnh vực	Dịch tễ học	Dịch tễ học
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1980s–1990s (with growth in oncology retrospective analyses)	1962 (Kefauver-Harris Amendment formalised phased drug development)
Người khởi xướng	Adapted from standard Phase II trial methodology; retrospective variant formalized in oncology practice	FDA regulatory framework / ICH guidelines
Loại	Observational retrospective study	Confirmatory randomised controlled trial
Công trình gốc	Simon, R. (1989). Optimal two-stage designs for phase II clinical trials. Controlled Clinical Trials, 10(1), 1–10.	Friedman, L. M., Furberg, C. D., DeMets, D. L., Reboussin, D. M., & Granger, C. B. (2015). Fundamentals of Clinical Trials (5th ed.). Springer. ISBN: 978-3319185385
Tên gọi khác	retrospective Phase II study, historical Phase II analysis, retrospective efficacy study, Phase II retrospective analysis	Phase 3 trial, confirmatory trial, pivotal trial, Phase III RCT
Liên quan	5	6
Tóm tắt	A retrospective Phase II clinical trial evaluates a treatment's preliminary efficacy and safety signals using existing archival data — medical records, registries, or electronic health records — rather than prospectively enrolling new patients. It mirrors the objectives of a standard Phase II trial (estimating response rate, tolerability, and early efficacy) but does so by looking backward at patients who have already received the intervention, making it faster and less costly than a prospective design.	A Phase III clinical trial is a large-scale, confirmatory randomised controlled trial designed to establish the efficacy and safety of an intervention in the target patient population before regulatory submission. It builds on the signal identified in Phase II, tests the intervention at its proposed dose under controlled conditions, and provides the primary evidence base for marketing authorisation or guideline adoption.