OBJECTIVES: The primary objective of this study was to evaluate the incremental cost-utility ratio (ICUR) for the adjuvant treatment of patients with resected EC/GEJC tumour in Canada. This analysis is based on outcomes of the phase 3 clinical trial, CheckMate 577, in which patients with resected EC/GEJC had statistically significant and clinically meaningful improvement in its primary endpoint, disease-free survival (DFS), versus placebo with an acceptable safety profile following neoadjuvant chemoradiotherapy.

METHODS: A three-health state Markov model (pre-recurrence, post-recurrence, and death) was developed to determine the ICUR of nivolumab vs. surveillance over 30 years. CM577 DFS data estimated the transition from pre-recurrence to post-recurrence. As overall survival data were not available, the transition from post-recurrence to death was estimated with IKNL registry data matched to the CM577 population, independent of treatment. The transition from pre-recurrence to death was estimated by combining CM577 and general population mortality data, independent of treatment. Utility data were from CM577 and cost data from clinical input and published literature, costs were based on a maximum nivolumab treatment duration of 1-year, per CM577. Nivolumab and surveillance patients in pre-recurrence from 3-years onwards were assumed to remain in a disease-free health state based on CM577 data.

RESULTS: In the probabilistic-approach reference case, the ICUR of nivolumab versus surveillance was $42,733/QALY gained, at list price. Nivolumab was associated with incremental cost of $71,474 and incremental QALY gain of 1.67. Nivolumab had a 92% probability of being cost-effective at a willingness to pay (WTP) threshold of $100,000/QALY. The ICUR remained below this threshold for all scenarios, with results ranging from $32,854/QALY to $92,681/QALY, when TTR instead of DFS was used for pre-recurrence to post-recurrence transition and time horizon reduced to 10 years, respectively.

CONCLUSIONS: Nivolumab is a cost-effective option in the adjuvant setting for patients with resected EC or GEJC in Canada.