ABSTRACT
In recent years, multi-regional clinical trials, e.g., a trial that incorporates clinical trials simultaneously in the Asian-Pacific region, Europe, and the United States, have become very popular for global pharmaceutical development. The purpose of multi-regional clinical trials is to shorten the time for pharmaceutical development and regulatory development, submission, and approval around the world. In practice, however, clinical results observed from some regions (sub-population) may not be consistent with the results from other regions and/or all regions combined (entire population). It is a concern for regulatory review and approval of the clinical results of the region that is inconsistent with those of all regions. The inconsistency may be due to: ethnic differences in different regions and/or similar but different regulatory requirements; study protocol/designs; and different study endpoints and time points of assessment. In this chapter, critical issues that are commonly encountered in a multi-regional clinical trial are discussed. It may be by random chance due to small sample size for the region. Several statistical tests for consistency (similarity) between clinical results observed from a specific sub-population and the entire population are proposed. These methods are compared through extensive simulation. A simulated example concerning a consistency in some countries was presented to illustrate the proposed methods.
