2003 年 24 巻 Special_Issue 号 p. S99-S104
For bridging clinical data, a study is additionally conducted in new region to demonstrate some similarity in treatment effects between two regions. An alternative bridging strategy is that new region participates in a multi-regional study as one site. This paper focuses on a possibility of bridging through joining multi-regional study, and statistical inference for an interaction term between treatment and region to detect non-similarity of treatment effects among regions/countries. Applying a logistic model with the terms of treatment effect, regional effect and their interaction to dichotomous response data, a simulation study is performed to investigate statistical power to detect significant treatment-by-region interaction, and treatment effect for a variety of sample size configurations. The result suggests that moderate or large sample sizes are required in new region to achieve sufficient power, if a substantial (qualitative or quantitative) interaction exists.