OBJECTIVES: The study aimed to assess the cost-effectiveness in France of atezolizumab monotherapy as adjuvant treatment following resection and platinum-based chemotherapy for patients with stage II-IIIA non-small cell lung cancer (NSCLC) with PD-L1≥50% of tumour cells vs best supportive care (BSC), excluding EGFR and ALK+.

METHODS: A 5-state Markov model was developed including disease-free survival (DFS), locoregional recurrence (LR), first and second line metastatic recurrence (MR) and death health states, based on extrapolated outcomes from the phase 3 trial IMpower010 and the literature, considering a 20-year time horizon and monthly cycles. Treatment discontinuation and grade 3 and 4 adverse events (AE) were included. DFS and LR utilities were sourced from the literature, and time to death utilities were considered for MR states (IMpower150). Disutilities associated with AE were sourced from the literature. Costs were estimated from a collective perspective, and included treatment acquisition, administration, follow-up, AE hospitalizations, transport, post-progression, and end-of-life costs. The impact of uncertainty was assessed through deterministic and probabilistic sensitivity analyses. A secondary analysis was conducted assuming a proportion of cured patients, based on clinicians’ opinion

RESULTS: The atezolizumab and BSC strategies were associated with 6.4 and 4.7 quality adjusted life years (QALY) respectively. Patients spent 5.8 years in DFS in the atezolizumab arm and 4.0 years in the BSC arm. The incremental cost-effectiveness ratio (ICER) for atezolizumab vs BSC was €21,280/QALY gained. Varying plausible choices of DFS survival curves all produced ICERs below €20,000/QALY. The secondary analysis reduced the ICER by 38.3%.

CONCLUSIONS: This is one of the first modelling studies of immunotherapy in adjuvant treatment of NSCLC. The estimated ICER was lower than those generally observed in oncology in France. The use of external sources to inform utilities was the main study limitation.