According to the news “国際共同治験前の日本人P1は原則不要 医薬局、通知・事務連絡で明確化 | 日刊薬業 – 医薬品産業の総合情報サイト (jiho.jp)” released by NIKKAN YAKUGYO on 26/12/2023, the Ministry of Health, Labour and Welfare in Japan announced on 25/12/2023 that, in principle, there is no need to conduct additional Japanese Phase 1 clinical trials before multi-regional clinical trials (MRCTs) except when deemed necessary. In addition to issuing new administrative communications, the announcement also involves revising and removing previous notices and communications that stipulated the need for Japanese Phase 1 trials before MRCTs. The separate attachment of the new notice dated 25/12/2023, titled “Basic Principles for Conducting Phase 1 Studies in Japanese before Initiating MRCTs Including Japan for Drugs in Which Early Clinical Development is Preceding Outside Japan,” states that Phase 1 trials do not need to be conducted separately for each race, ethnicity, country, or region. It further clarifies that except when deemed necessary, in principle, there is no requirement to conduct additional Japanese Phase 1 trials.