First-line nivolumab plus chemotherapy versus chemotherapy alone for advanced gastric cancer, gastroesophageal junction cancer, and esophageal adenocarcinoma: a cost-effectiveness analysis

BACKGROUND: The CheckMate-649 trial compared nivolumab plus chemotherapy (NC) with chemotherapy alone as first-line treatment for advanced gastric cancer (GC), gastroesophageal junction cancer (GEJC), and esophageal adenocarcinoma (EAC) and showed significant benefits to progression-free survival and overall survival. This study evaluated the lifetime cost-effectiveness of NC versus chemotherapy alone in patients with GC/GEJC/EAC from the perspective of the US payers. METHODS: A 10-year partitioned survival model was constructed to evaluate the cost-effectiveness of NC and chemotherapy alone and measured the health achievements in quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios (ICERs), and life-years. Health states and transition probabilities were modeled from the survival data from the CheckMate-649 clinical trial (NCT02872116). Only direct medical costs were considered. One-way and probabilistic sensitivity analyses were conducted to assess the robustness of the results. RESULTS: On comparing the chemotherapy, we found that NC incurred substantial health costs, resulting in ICERs of $240,635.39/QALY, $434,182.32/QALY, and $386,715.63/QALY for the model of patients with programmed cell death-ligand 1 (PD-L1) combined positive score (CPS) ⩾5, PD-L1 CPS ⩾1, and all-treated patients, respectively. All ICERs were significantly higher than the willingness-to-pay threshold value of $150,000/QALY. The main influencing factors were the cost of nivolumab, the utility value of the progression-free disease, and the discount rate. CONCLUSION: Compared with chemotherapy alone, NC may not be a cost-effective option for treating advanced GC, GEJC, and EAC in the United States.