Presentation (CTI)

OBJECTIVES: Single-agent chemotherapy is the standard treatment for metastatic or recurrent triple-negative breast cancer (TNBC), but its efficacy is unsatisfactory. Although tripalimumab, showed superiority over chemotherapy in improving overall survival, it is not approved in Japan and its cost-effectiveness is not necessarily clear. This study aimed to evaluate the cost-effectiveness of tripalimumab 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 tripalimumab and chemotherapy groups. Survival data were derived from a multicenter, randomized, double blind trial, TORCHLIGHT (NCT04085276). Drug prices for tripalimumab were estimated based on foreign prices. Other cost parameters were estimated by using the JMDC calims database. Lifetime horizon and discount rate of 2% was applied. Utility weights were estimated based on previous studies. The incremental cost-effectiveness ratio (ICER) of tripalimumab compared with chemotherapy was estimated. Sensitivity analysis (SA) was performed to assess parameter uncertainty.
RESULTS: Compared with chemotherapy, tripalimumab incurred an additional cost of JPY 28,020,378 and conferred an additional 1.3914 QALY. This resulted in the ICER of JPY 20,137,646/QALY gained. SA showed that the parameter with the largest influence was the progression-free survival (PFS) utility values for the intervention group phase, and the ICER ranged from JPY 15,616,987 to JPY 28,341,751/QALY.
CONCLUSIONS: Applying a willingness-to-pay (WTP) threshold of JPY 15 million/QALY, tripalimumab was not cost-effective compared to chemotherapy at its current price. In the future, it would be necessary to incorporate a cost-effectiveness perspective in the pricing of cancer treatment in Japan.