2011 年 32 巻 Special_Issue_2 号 p. S121-S132
The Japanese ‘drug lag,’ where drugs approved in US and EU are not approved in Japan, has been aggravated for many years. The bridging strategy has been accepted to utilize foreign clinical trial data in a new drug application since ICH E5 guideline was published in 1998, but the ‘drug lag’ was not improved. Instead of the bridging strategy, multinational clinical trials including Japan have been encouraged to promote efficient and rapid development of new drugs in Japan for recent several years. Although a global drug development strategy including Japan was changed, it is a fundamental issue that foreign clinical data have to be accepted as full or partial support for approval of a new drug application in Japan. For assuring that foreign clinical data can be extrapolated in other regions, it needs to consider what ethnic factors might affect on efficacy and safety of experimental drugs, how the influence from each ethnic factor should be evaluated, how many patients should be enrolled in each region participated in a global clinical trial, and so on. In this article, these issues are discussed from the point of view of a statistician working in a Japanese pharmaceutical company.