Sample size considerations for Japanese patients in a multi-regional trial based on MHLW guidance.

Since the publication of the International Conference on Harmonization E5 guideline, new drug approvals in Japan based on the bridging strategy have been increasing. To further streamline and expedite new drug development in Japan, the Ministry of Health, Labour and Welfare, the Japanese regulatory authority, recently issued the 'Basic Principles on Global Clinical Trials' guidance to promote Japan's participation in multi-regional trials. The guidance, in a Q&A format, provides two methods as examples for recommending the number of Japanese patients in a multi-regional trial.