The ideal way to design clinical trials and establishment of evidence for human cellular and tissue-based products in Japan.

In Japan, the Pharmaceuticals and Medical Devices (PMD) Act established in 2014 included an additional chapter dedicated to frameworks for human cellular and tissue-based products. To further evaluate the product considered to have "likely to predict efficacy" at the time of receiving "conditional and time-limited marketing authorization," a system has been introduced to determine whether the product is eligible for "full marketing authorization" through statistical "confirmation of the efficacy" in a postmarketing surveillance study using a registry. A movement similar to this regulation has been seen among Western nations. For example, in the United States, Regenerative Medicine Advanced Therapy Designation was introduced in 2017 as a provision of the 21st Century Cures Act. This is similar to Japan's conditional and time-limited marketing authorization, which presumes efficacy of a product based on surrogate endpoints in life-threatening diseases. It is true that the current study design has limitations, and study designs that are beyond our imagination should be developed in the future.