手法を比較

	後向き第II相臨床試験	第I相臨床試験
分野	疫学	疫学
系統	Process / pipeline	Process / pipeline
提唱年	1980s–1990s (with growth in oncology retrospective analyses)	1960s (formal regulatory framework established ~1963–1970s)
提唱者	Adapted from standard Phase II trial methodology; retrospective variant formalized in oncology practice	Regulatory and clinical pharmacology community; formalized in U.S. FDA IND regulations (1963) and ICH guidelines
種類	Observational retrospective study	Interventional clinical study design
原典	Simon, R. (1989). Optimal two-stage designs for phase II clinical trials. Controlled Clinical Trials, 10(1), 1–10.	Storer, B. E. (1989). Design and analysis of phase I clinical trials. Biometrics, 45(3), 925–937.
別名	retrospective Phase II study, historical Phase II analysis, retrospective efficacy study, Phase II retrospective analysis	Phase 1 trial, first-in-human study, FIH study, dose-escalation study
関連	5	6
概要	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 I clinical trial is the first stage of human testing for a new drug, biologic, or intervention. Its primary objective is to evaluate safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) rather than therapeutic efficacy. Small cohorts of participants — typically healthy volunteers or patients with advanced disease — receive sequentially increasing doses to identify the maximum tolerated dose (MTD) and the dose-limiting toxicities (DLTs) that define the boundary for subsequent trials.