Cost-Effectiveness Analysis of Mirvetuximab Soravtansine in FRa-Positive Platinum-Resistant Ovarian Cancer in Japan

OBJECTIVES: Current treatments for platinum-resistant ovarian cancer primarily involve nonplatinum chemotherapy, such as weekly paclitaxel, pegylated liposomal doxorubicin, or topotecan, administered either as a single agent or in combination with bevacizumab. However, none significantly improved overall survival. Mirvetuximab Soravtansine (MIRV) treatment offers clear clinical advantages and is expected as a new treatment. This study aimed to evaluate the cost-effectiveness of MIRV from the payer’s perspective in Japan.
METHODS: A partitioned survival analysis model was developed to predict costs and quality-adjusted life years (QALYs) in MIRV and chemotherapy groups. Survival data were derived from the phaseIII MIRASOL study. Drug prices for MIRV were estimated based on foreign prices. Other cost parameters were estimated by using the JMDC claims database. Lifetime horizon and discount rate of 2% were applied. Utility weights were estimated based on previous studies. The incremental cost-effectiveness ratio (ICER) of MIRV compared with chemotherapy was estimated. Sensitivity analysis was performed to assess parameter uncertainty.
RESULTS: Compared with chemotherapy, MIRV incurred an additional cost of JPY 32,217,876 and conferred an additional 0.281 QALY. This resulted in the ICER of JPY 114,646,442/QALY gained. Sensitivity analysis showed that the parameter with the largest influence was utility of MIRV group in progression-free state, and the ICER ranged from JPY 84,476,936 to JPY 17,336,193/QALY.
CONCLUSIONS: At the current price, MIRV was not cost-effective compared to chemotherapy. However, there is a high possibility that this treatment will become an innovative treatment by reducing the cost.