A Pilot Study on the Drug Price Revision Strategy in Japan: A Comparison Among Fiscal Years 2018, 2020, and 2022.

Japan has resumed its health technology assessment to decide how to reduce high-cost drug prices. While drug price rules in Japan are comprehensive, they do not necessarily capture differences in product characteristics. This study examined the drug price revision strategy in Japan using migraine treatment with triptans as an example. Cost data from fiscal years (FY) 2018, 2020, and 2022 were utilized. A cost-utility analysis was conducted from the perspective of healthcare payers, focusing on Japanese patients aged over 18 years experiencing migraines. The study employed a base-case model with probabilities derived from a network meta-analysis. Direct costs included medical and drug costs. Effectiveness was assessed using the European Quality of Life 5-dimensions-3-level questionnaire. Deterministic and probabilistic sensitivity analyses were conducted to examine the level of uncertainty. In FY2018, sumatriptan and eletriptan were cost-effective; however, the other triptans were dominated by sumatriptan. In FY2020, sumatriptan and eletriptan were cost-effective, and rizatriptan was extended-dominated; nevertheless, the other triptans were dominated by sumatriptan. In FY2022, naratriptan and eletriptan were cost-effective; however, the other triptans were dominated by naratriptan. The hierarchy of triptan strategies varied in each fiscal year. This study provides valuable insights into the drug price revision strategy in Japan. The variations could be problematic because in Japan, formulary management of triptans, for example, those for migraine, may face revaluation every other year. Discussions regarding this issue will be further explored in the future.