Background and importance The high cost of immunotherapy makes it necessary to evaluate the results in real life, and the study of costs and economic evaluation can be useful tools to guide clinical decisions.

Aim and objectives To make an incremental cost-effectiveness ratio (ICER) analysis among the different available immune checkpoint inhibitors to treat non-small cell lung cancer (NSCLC) as second-line monotherapy.

Material and methods Retrospective and observational study. All patients with locally advanced or metastatic NSCLC treated with nivolumab, pembrolizumab and atezolizumab monotherapy as second-line treatment between April 2017 and April 2020 were included. Outcomes collected: treatment start and end date, administered mean dose, and mean number of cycles administered.

The drug costs were calculated based on the notified price. A 7.5% discount was applied for these prices as laid down in Spanish Royal Decree 8/2010 and 4% was charged as VAT (value add tax). In addition to the pharmacological costs, resource use was estimated: treatment administration in day hospital. Cost/cycle and overall cost (mean number of cycles administered multiplied by pharmacological and associated costs) were calculated. The endpoint was overall survival (OS).

Data were collected from the electronic clinical history, electronic prescribing software and pharmacy management programme. The Kaplan-Meier method was used to calculate OS. SPSS v17 was used to perform statistical calculations. We calculated the ??? for each strategy.

Results 104 patients were included in this study: N=40 nivolumab, N=29 pembrolizumab and N=35 atezolizumab.

Regarding effectiveness: the median OS was 6.4 (95% CI 2.81 to 9.98) months for patients treated with nivolumab; pembrolizumab-treated patients reached 8 months median OS (95% CI 3.05 to 12.94) and atezolizumab-treated patients achieved 6.33 months median OS (95% CI 4.4 to 9.1).

The overall cost of each treatment was: €49 640.19 for pembrolizumab, €42 887 for nivolumab and €28 678.44 for atezolizumab.

ICER: nivolumab vs atezolizumab: €2 435 753.14/life years gained (LYG); pembrolizumab vs atezolizumab: €150 623.35/LYG; pembrolizumab vs nivolumab: €50 648.92/LYG.

Conclusion and relevance The need to promote efficiency in the selection of treatments is one more reason to carry out an exhaustive comparative drug evaluation that includes the economic one. The effectiveness in terms of OS was greater for pembrolizumab; however, the cost analysis showed a greater benefit for atezolizumab.

Conflict of interest No conflict of interest