Linganisha mbinu

	Jaribio la Kliniki la Awamu ya II la Retrospective	Jaribio la Kliniki la Awamu ya III
Nyanja	Epidemiolojia	Epidemiolojia
Familia	Process / pipeline	Process / pipeline
Mwaka wa asili	1980s–1990s (with growth in oncology retrospective analyses)	1962 (Kefauver-Harris Amendment formalised phased drug development)
Mwanzilishi	Adapted from standard Phase II trial methodology; retrospective variant formalized in oncology practice	FDA regulatory framework / ICH guidelines
Aina	Observational retrospective study	Confirmatory randomised controlled trial
Chanzo asilia	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
Majina mbadala	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
Zinazohusiana	5	6
Muhtasari	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.