転移性ホルモン感受性前立腺癌に対するエンザルタミドの費用効果分析と財政影響評価

Abstract

We conducted cost-effectiveness analysis and budget impact analysis for androgen deprivation therapy (ADT) plus enzalutamide (ENZ) on patients with metastatic hormone-sensitive prostate cancer (mHSPC) from the publicly-funded healthcare system perspective. Using a partitioned survival model, lifetime costs, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) of ADT＋ENZ were estimated against ADT alone, ADT plus abiraterone (ADT＋ABI), and ADT plus apalutamide (ADT＋APA). Total healthcare cost differences with and without ENZ in mHSPC therapy were estimated for the period from 2022 to 2026. Based on cost-effectiveness analysis, the ICER of ADT＋ENZ versus ADT alone was estimated as ￥7.18 million/QALY gained. ADT＋ABI and ADT＋APA were dominated options (extended dominance). Budget impact analysis showed that incorporation of ENZ had a net budget impact of ￥57.19 billion, an 8.4% increase, over these 5 years. This amounted to a budgetary impact of ￥16, 000 per patient per month at year 5. However, the number of patients with disease progressed to metastatic castration-resistant prostate cancer (mCRPC) would be reduced from 79, 000 (without ENZ) to 65, 000 (with ENZ), resulting in a 17% cost reduction within the mCRPC phase. In conclusion, ADT＋ENZ would be a cost-effective option, at the willingness to pay threshold of ￥7.5 million/QALY gained. Introduction of ENZ in the mHSPC treatment would result in a marginal increase in the total budget. However, ENZ is also expected to provide clinical benefits in reducing the number of patients with disease that would otherwise progress to mCRPC during these 5 years, resulting in cost savings in this phase.