Bridging Studies in Japan and Taiwan: A Dynamic Evolution in Regulating Ethnic Differences

In the past 10 years since the implementation of the E5 guideline, bridging studies have been one of the most controversial ICH concepts for East Asian states. This article reveals the dynamics of bridging studies by comprehensively reviewing their evolution and policy impacts in Japan and Taiwan from a comparative perspective. This article addresses the following. First, the concept of bridging studies has proved to be a diplomatic resolution rather than a scientific consensus. Although it facilitated the making of the E5 guideline, it left the problem of putting it into practice. Second, Japan did not wholeheartedly welcome bridging studies; it believed that a transition to spontaneous global trials would soon follow and exhausted its regulatory means to pursue it. Third, Taiwan captured this controversial concept as an ICH outsider, and showed the ICH the feasibility of bridging studies. It further attempted to extend their feasibility to create a multistate trial scheme, thereby keeping its visibility to the ICH. In addition, based on these findings, this article provides a regulatory outlook on pan-Asian clinical trial schemes.