Cost-effectiveness analysis of nivolumab plus chemotherapy vs chemotherapy for patients with unresectable advanced or metastatic HER2-negative gastric or gastroesophageal junction or esophageal adenocarcinoma in Japan

BackgroundThis study aimed to evaluate the cost-effectiveness of nivolumab plus chemotherapy (NIVO + Chemo) compared with chemotherapy monotherapy (Chemo) for patients with advanced or metastatic HER2-negative gastric or gastroesophageal junction or esophageal adenocarcinoma (GC/GEJC/EAC) in Japan from the perspective of healthcare payer.MethodsA partitioned survival analysis model was developed to predict costs and quality-adjusted life years (QALYs) for NIVO + Chemo and Chemo. The time horizon of the model was set to 38 years. An annual discount rate of 2% for both costs and QALYs was applied. Data on overall survival and progression-free survival were derived from the CheckMate649 trial. Cost parameters were estimated from a Japanese medical claims database. The incremental cost-effectiveness ratio (ICER) of NIVO + Chemo compared with Chemo was estimated. A subgroup analysis on the level of PD-L1 CPS expression was conducted. In addition, sensitivity analysis was performed to assess the uncertainty in the parameter settings.ResultsThe incremental cost and QALY of NIVO + Chemo compared with Chemo were USD99,416 and 0.30 QALY, respectively. The ICER of NIVO + Chemo was estimated to be USD327,161 per QALY gained. The results of the subgroup analysis showed that ICER was USD247,403/QALY and USD302,183/QALY for PD-L1 CPS >= 5 and >= 1, respectively. Sensitivity analyses showed a relatively robust result that the ICER remained higher than the Japanese cancer threshold of USD75,000-150,000/QALY.ConclusionsApplying the Japanese cancer threshold of USD75,000-150,000/QALY, NIVO + Chemo was not cost-effective for patients with advanced or metastatic HER2-negative GC/GEJC/EAC in Japan from the perspective of healthcare payer.