This study reviewed all publicly available Japanese cost-effectiveness appraisals delivered by the Center for Outcomes Research and Economic Evaluation for Health (C2H) from the national institute of public health (NIPH) and analyzed the relationship between the outcomes of the health-economic assessments and the final price adjustment decisions made by the Ministry of Health, Labour and Welfare (MHLW).

Data were extracted from all official health-economic assessments published by C2H website for the analysis. The extractions were structured based on the following items: indication, assessment methodology, appropriate comparators, health-economic outcomes, and key uncertainties identified by C2H. The analysis was performed on 29th November 2021. A threshold of 5 million JPY per Quality Adjusted Life Year gained (JPY/QALY) was used for the incremental cost-effectiveness ratio (ICER) analysis cut-off.

Up to the time of this analysis, six health-economic assessments had been conducted for five products: three assessments performed cost-effectiveness analysis, one performed cost-minimization analysis and two performed cost-effectiveness and cost-minimization analysis for different comparators and different patient subgroups respectively. Among the five assessments’ reported ICER values, four of them are under the 5 million JPY/QALY threshold, ranging from 328,585 JPY/QALY to 483,056 JPY/QALY. However, price adjustments were still implemented on three out of the four products which were deemed to be cost-effective, ranging from -0.5 percent to -4.3 percent (mean: -3.0%). For the only product deemed to be not cost-effective, a price adjustment of -4.3 percent was implemented.

A price discount could be implemented regardless of whether the ICER value falls under the 5 million JPY/QALY threshold. However, a lower magnitude of price discount is likely to be applied by MHLW for more cost effective treatments. The outcome of this analysis may be limited by the small sample size and continuous monitoring of further HTA publications in Japan is needed.