So sánh phương pháp

	Thử nghiệm lâm sàng Giai đoạn II hồi cứu	Thử nghiệm lâm sàng Giai đoạn II
Lĩnh vực	Dịch tễ học	Dịch tễ học
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1980s–1990s (with growth in oncology retrospective analyses)	1960s–1970s (formalised in US federal drug regulation)
Người khởi xướng	Adapted from standard Phase II trial methodology; retrospective variant formalized in oncology practice	U.S. Food and Drug Administration / ICH E8 guidelines (institutionalised framework)
Loại	Observational retrospective study	Interventional clinical study design
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: 978-3319185392
Tên gọi khác	retrospective Phase II study, historical Phase II analysis, retrospective efficacy study, Phase II retrospective analysis	Phase 2 trial, Phase II study, early efficacy trial, proof-of-concept trial
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 II clinical trial is the second stage in the drug or intervention development pipeline, conducted after Phase I safety testing. Its primary goal is to assess whether the intervention shows preliminary efficacy signals in a relevant patient population at the dose established in Phase I, while continuing to characterise the safety and tolerability profile. Phase II trials are generally smaller than Phase III confirmatory trials and serve as critical go/no-go decision points before large-scale investment.