Cost-Effectiveness of First-Line Pembrolizumab Monotherapy Versus Chemotherapy in High Programmed Death-Ligand 1 Advanced Non-Small Cell Lung Cancer in the Irish Healthcare Setting

Objectives: This study aimed to assess the cost-effectiveness of pembrolizumab monotherapy in the first-line treatment of advanced non-small cell lung cancer (NSCLC) in adults whose tumors expressed programmed death-ligand 1 (PD-L1) with a tumor proportion score (TPS) >= 50% in the Irish healthcare setting.Methods: Effectiveness inputs were derived from the 5-year analysis of KEYNOTE-024 phase III clinical trial. The intervention was pembrolizumab monotherapy; the comparator was a weighted average of the 5 chemotherapy regimens from the trial. The population included those with previously untreated advanced PD-L1 TPS >= 50% NSCLC. A de novo partitioned survival model was developed. Survival modeling was done using Bayesian model averaging on fitted parametric functions. Costs included drug acquisition, treatment initiation, administration and monitoring, adverse events, subsequent treatments, and terminal care. Costs and health state utilities were sourced from the literature and Irish sources. The model had a 20 -year time horizon. The perspective taken was the Health Service Executive. A 4% discount rate was applied. Outcomes were expressed as an incremental cost-effectiveness ratio (ICER), measured in terms of incremental costs per quality -adjusted life-year (QALY). Probabilistic sensitivity analysis and 1-way sensitivity analyses were conducted.Results: The model estimated a base case ICER of euro54 237 per QALY. The probabilistic sensitivity analysis estimated an average ICER of euro54 568 per QALY and a 11% probability of cost-effectiveness at the Irish cost-effectiveness threshold of euro45 000 per QALY.Conclusion: At the current list price, first-line pembrolizumab monotherapy is not considered cost-effective for the treatment of advanced PD-L1 TPS >= 50% NSCLC in the Irish healthcare setting.