Real-world treatment persistence of first-line atezolizumab in elderly patients with PD-L1-high NSCLC: comparison with pembrolizumab.

BACKGROUND: Evidence comparing first-line atezolizumab and pembrolizumab monotherapy in elderly patients with PD-L1-high non-small cell lung cancer (NSCLC) remains limited in routine clinical practice. We compared treatment persistence and clinical outcomes between these two treatment strategies in a real-world setting. METHODS: We conducted a retrospective single-center study of patients aged ≥75 years with PD-L1 tumor proportion score ≥50% who received first-line atezolizumab or pembrolizumab monotherapy. The primary endpoint was time to treatment failure (TTF). Secondary endpoints included real-world progression-free survival (rwPFS), overall survival (OS), treatment discontinuation patterns, and safety. RESULTS: Twenty-nine patients were included (atezolizumab, n = 8; pembrolizumab, n = 21). Patients treated with atezolizumab exhibited greater clinical vulnerability, including older age, a higher burden of comorbidities, and poorer performance status. Despite these less favorable baseline characteristics, time to treatment failure (TTF) appeared broadly similar between the two groups. Similar trends were observed for real-world progression-free survival (rwPFS), while no clear difference in overall survival (OS) was evident. Discontinuation due to immune-related adverse events occurred more frequently in the atezolizumab group, whereas disease progression was the predominant reason for treatment discontinuation in the pembrolizumab group. No treatment-related deaths were observed. CONCLUSIONS: Despite less favorable baseline characteristics, atezolizumab demonstrated descriptively acceptable treatment persistence in elderly and clinically vulnerable patients. These findings suggest that atezolizumab remains a feasible first-line treatment option for selected older patients with PD-L1-high NSCLC.