According to the news “オーファン指定制度の要件明確化 厚労省、優先審査は従前基準のみ | 日刊薬業 – 医薬品産業の総合情報サイト (jiho.jp)” released by NIKKAN YAKUGYO on 16/01/2024, the Ministry of Health, Labour and Welfare in Japan issued a notice on 16/01/2024, informing about the revision of the orphan disease designation system. This revision clarifies that applications that calculate a patient population of less than 50,000 by adding prefixes such as “serious” or qualifiers without clear medical or pharmaceutical reasons, known as “sliced applications,” are not accepted. However, this revision specifies that certain exceptions, particularly for areas with high unmet needs but lacking therapeutic development, do not fall under the “sliced application” category. The exceptions are based on appropriate medical and pharmaceutical grounds, such as age groups (including children), treatment regimens, and the necessity for medication. The notice also refined the criteria for medical needs. It states that a condition satisfies the requirements if multiple treatment or prevention options are clinically necessary and the use of currently approved drugs alone are insufficient. Examples include cases where a new mechanism of action is expected to be effective based on non-clinical trial results or when administration becomes possible for patients who have difficulty using existing drugs.