Nationwide trends in utilization and expenditure of biologic agents approved for asthma in Japan: Insights from the national database (2014-2023)

Biologics have transformed the management of severe asthma; however, nationwide data on their use in Japan remain limited. We conducted a descriptive analysis using the NDB Open Database from fiscal years 2014-2023 to examine trends in the prescription volumes and costs for five approved biologics. Total prescriptions increased markedly from 81 450 in 2014 to >2 million in 2023, while total costs rose from 24.1 million to 973.3 million U.S. dollars. The proportion of outpatient self-injection prescriptions accounted for more than half of the prescriptions by 2023. These findings reflect the broader adoption of biologics supported by biomarker-driven treatment and expanded access through home administration. Although biologics offer clinical benefits, their growing use highlights the need to monitor their long-term costs and ensure their appropriate utilization. This study provides a nationwide overview of the biologics approved for asthma treatment and highlights key trends relevant to clinicians and policymakers.