Efficacy and Safety of First-line Pembrolizumab Plus Platinum and Pemetrexed in Elderly Patients with Non-squamous Non-small-cell Lung Cancer.

Objective Pembrolizumab plus platinum and pemetrexed (Pemb-Plt-PEM) combination therapy is an effective first-line treatment for advanced non-squamous non-small-cell lung cancer (NSCLC), regardless of programmed death ligand 1 expression. However, the effectiveness and feasibility of first-line Pemb-Plt-PEM therapy in elderly patients (≥75 years old) remain unclear. Therefore, this study investigated the safety and efficacy of first-line Pemb-Plt-PEM in elderly patients with nonsquamous NSCLC. Methods We retrospectively evaluated the data of patients ≥75 years old with non-squamous NSCLC who were treated with first-line Pemb-Plt-PEM from December 2018 to December 2020 at 10 institutes in Japan. Data on patient characteristics, efficacy of pemb-Plt-PEM therapy, and the type and severity of adverse events were reviewed. Results Thirty patients [20 men and 10 women; median age: 76 (range: 75-82) years old] were included in the analysis. The overall response rate, disease control rate, median progression-free survival (PFS), and median overall survival (OS) were 40.0%, 66.7%, and 7.5 and 24.0 months, respectively. The treatment-related deaths were caused by pneumonitis. First-line Pemb-Plt-PEM was associated with the PFS, based on the neutrophil-to-lymphocyte ratio (NLR). The PFS for low and high NLR values was 10.1 and 2.0 months, respectively. Furthermore, the sex and NLR influenced the association between Pemb-Plt-PEM and the OS. The OS for low and high NLR values was 32.8 and 2.6 months, respectively. Conclusion First-line pemb-Plt-PEM therapy is effective and feasible in elderly patients with non-squamous NSCLC.