RESUMEN
INTRODUCTION: Esophageal and gastroesophageal junction cancer (EC/GEJC) is a poor prognosis disease with a high risk of recurrence even in patients curatively resected. Adjuvant nivolumab is currently used for patients with completely resected (R0) EC/GEJC who have residual pathologic disease following prior neoadjuvant chemoradiotherapy. This study aimed to determine the cost effectiveness of nivolumab in this indication in France according to the collective perspective excluding indirect costs. MATERIALS AND METHODS: A simplified four-health-state semi-Markov model was developed to model EC/GEJC patients who have residual disease after neoadjuvant chemoradiotherapy followed by R0 over a 15-year time horizon, comparing adjuvant nivolumab versus surveillance, which was the recommended French clinical practice before immunotherapy arrival. Time-to-recurrence (TTR) from CheckMate 577 was used to inform transition from disease-free to post-recurrence health state; patients who recurred were split according to the distribution of type of recurrence observed during the trial. Post-recurrence survival (PRS) according to the type of recurrence was derived from a real-world registry. RESULTS: Adjuvant treatment with nivolumab led to an incremental survival gain of 1.19 years (+ 34%), mostly in the disease-free state, an incremental cost of 48,634 and QALY of 0.98 resulting in an incremental cost-utility ratio (ICUR) of 49,572/QALY with limited uncertainty. 'Cure assumption' at 5 years had an important impact on the results (41,115/QALY; - 17%), as that tends to increase life-years and QALYs while costs remain the same. Probabilistic sensitivity analyses confirmed reference ICUR (52,542/QALY) with 80% probability of nivolumab being cost effective at a willingness-to-pay threshold of 75,000/QALY. CONCLUSIONS: Our analysis suggests that adjuvant nivolumab is cost effective in the treatment of EC/GEJC patients who have residual disease after neoadjuvant CRT followed by R0 resection. Compared with previously evaluated cost-effectiveness analyses for other immune-checkpoint inhibitors indicated in metastatic settings, ICUR appears particularly low in this early setting thanks to the important impact on health outcomes and capped treatment duration.