Real-World Outcomes of Nivolumab, Pembrolizumab, and Atezolizumab Treatment Efficacy in Korean Veterans with Stage IV Non-Small-Cell Lung Cancer

SIMPLE SUMMARY: In clinical settings, patients receiving immune checkpoint inhibitors (ICIs) have different treatment criteria than those enrolled in clinical trials. There are concerns regarding the efficacy of ICIs in older adults due to age-associated decline in the immune system, and no study has directly compared the efficacy of different ICIs for the elderly in a real-world setting. We aimed to analyze ICIs’ use and treatment outcomes in Korean veterans with stage IV non-small-cell lung cancer (NSCLC). Three cohort groups were derived based on the ICI type (pembrolizumab, nivolumab, and atezolizumab treatment groups), and their clinical characteristics and survival outcomes were compared. There was no difference in the overall survival (OS) rate among the groups, no treatment-specific OS benefit was observed relative to the tumor PD-L1 expression, and bone metastasis was a poor prognostic factor for OS. Our study demonstrates that all three agents may be appropriate treatment options for elderly patients. ABSTRACT: Purpose: To provide a comprehensive analysis of ICI usage and treatment outcomes in elderly Korean veterans with stage IV NSCLC. Methods: Patients diagnosed with stage IV NSCLC between 2016 and 2021 were included, and three cohorts were derived according to the type of ICI received. Thereafter, the clinical characteristics and survival outcomes were compared. Results: Of the 180 patients with NSCLC (median age, 76 years) included in this study, 49 (27.7%), 61 (33.9%), and 70 (38.9%) received pembrolizumab, nivolumab, and atezolizumab, respectively, and 19.4%, 36.1%, and 34.4% had PD-L1 expressions < 1%, 1–49%, and ≥50%, respectively. The pembrolizumab, nivolumab, and atezolizumab groups, the objective response rates (ORR), and the disease control rates (DCR) were 22.4%, 8.2%, and 4.3% (p = 0.004), and 59.2, 55.7%, and 30.0% (p = 0.001), respectively. However, no difference in the overall survival (OS) rate was noted among the groups (12.6 months vs. 8.4 months vs. 7.7 months, p = 0.334). Similarly, there was no treatment specific OS benefit with respect to the tumor PD-L1 expression status. Interestingly, multivariate analysis identified bone metastasis as a significant poor prognostic factor for OS (HR = 2.75 [95% CI, 1.31–5.76], p = 0.007). Conclusion: Pembrolizumab and nivolumab showed stronger associations with increases in ORR and DCR than atezolizumab, but no statistically significant differences were observed with respect to OS.