OBJECTIVES: Trifluridine/tipiracil (FTD/TPI) significantly improved overall survival (OS) compared with a placebo in patients with heavily pretreated metastatic gastric cancer (mGC) in the TAGS trial. Based on the ATTRACTION-2 trial, nivolumab has been approved and recommended in patients with heavily pretreated mGC in Japan. Recently, FTD/TPI was approved in same patients in Japan and US. Our objective was to conduct a cost–utility analysis of FTD/TPI against nivolumab for those patients from the healthcare payer’s perspective.

METHODS: A partitioned survival model (PSM), which consisted of three health states—“pre-progression,” “post-progression,” and “death”—was constructed for this analysis. The PSM calculated the proportion of patients in each state; the cost, life-years, and quality-adjusted life-years (QALYs) were then estimated. Efficacy and safety data were derived from the TAGS and ATTRACTION-2 trials. Weibull and exponential distributions were adopted to estimate survival curves for OS and progression-free survival (PFS). Utility scores were obtained from the phase II “INTEGRATE” trial of regorafenib, as no utility data were collected in the TAGS nor ATTRACTION-2 trials. One-way and probabilistic sensitivity analyses were performed. The threshold value was set to JPY7,500,000/QALY.

RESULTS: The expected median PFS were 1.99 months and 1.55 months for FTD/TPI and nivolumab, respectively. The median OS were 5.59 months and 5.26 months for FTD/TPI and nivolumab, respectively. The QALYs were 0.4379 and 0.5294 for FTD/TPI and nivolumab, respectively. The expected cost per patient was JPY2,054,625 and JPY5,018,148 for FTD/TPI and nivolumab, respectively. The expected median PFS and OS were equivalent between FTD/TPI and nivolumab, whereas QALY of FTD/TPI was slightly lower than that of nivolumab; however, the effect of cost reduction was very high. The incremental cost-effectiveness ratio of nivolumab against FTD/TPI was JPY32,352,489 (EUR265,184) per QALY gained.

CONCLUSIONS: FTD/TPI was thought to be cost-effective against nivolumab for patients with heavily pretreated mGC.