Paediatric Drug Development in Japan: Current Status and Future Challenges.

Introduction: Until around 2000, the number of medicinal products labelled for paediatric use was limited worldwide. Regulatory measures to promote paediatric drug development in the US and Europe and the establishment of an international guideline (ICH-E11) have led to an increase in the number of paediatric labels. In Japan, efforts have been made to promote the development of paediatric drugs. This study was aimed to examine whether these supportive efforts are successful in Japan.

Methods: This study examined the number of new drugs approved for paediatric indications in Japan from 2006 to 2023, as well as the clinical data package, that is, characteristics of the approved paediatric drugs and paediatric clinical trials, and the percentage of extrapolation of adult data, in the most recent 9-year period.

Results: The number of paediatric drug approvals showed an increasing trend between 2006 and 2023 with some fluctuations. The proportion of drugs indicated for paediatric patients to the total number of approved drugs was about 30% until 2022, but increased to 48% in 2023. During the period from 2015 to 2023, simultaneous development in adults and children accounted for 59% (159/269) of paediatric development, but the complete extrapolation of adult data to paediatric populations has not been widely utilized (11.2%, 30/269).

Conclusions: The number of paediatric drug approvals has shown an upward trend, suggesting that measures to promote the development of paediatric drugs may have been exerting a favourable effect in Japan. However, there is still a limited number of drugs that have additional indications for paediatric use. Appropriate development strategies, such as the extrapolation of adult data to paediatric populations, should be considered if scientifically justified.