Abstract
BACKGROUND: While immune checkpoint inhibitors (ICIs) in combination with chemotherapy have improved outcomes for patients with extensive-stage small cell lung cancer (ES-SCLC), elderly patients (≥70 years) are often underrepresented in clinical trials, and real-world evidence on their efficacy and safety remains scarce. We conducted a real-world study to supplement data on using serplulimab [a programmed cell death protein 1 (PD-1) inhibitor] with chemotherapy as first-line treatment for elderly (≥70 years) ES-SCLC patients. METHODS: We gathered data on ES-SCLC patients aged 70 and above treated with first-line serplulimab, focusing on progression-free survival (PFS) as the primary endpoint. Secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs). Kaplan-Meier survival curves were used for PFS and OS, and Cox proportional hazards models and accelerated failure time (AFT) models were used for the subgroup analyses. The baseline and post-4-cycle neutrophil-to-lymphocyte ratio (NLR) levels were also collected as exploratory endpoints. RESULTS: Forty-three ES-SCLC patients with a median age of 73 years were included. Median PFS was 7.0 months [95% confidence interval (CI): 6.1-12.5]. Subgroup analysis indicated a significantly higher risk of disease progression in female patients (P=0.04) and those who had brain radiotherapy (P<0.001). OS rate was 94.7% (95% CI: 87.9-100.0%) at 6 months and 65.8% (95% CI: 50.0-86.5%) at 1 year. The ORR was 65.12% (95% CI: 49.07-78.99%), and the DCR was 97.67% (95% CI: 87.71-99.94%). AEs occurred in 19 patients (44.19%), mostly grade 1-2 (14 patients, 32.56%), with grade ≥3 AEs in 11.63% (5 patients). There was no significant difference in NLR levels before and after patient treatment. CONCLUSIONS: This study showed that combining serplulimab with chemotherapy improved survival and reduced toxicity in elderly ES-SCLC patients. Additionally, NLR may not be suitable as a biomarker for the elderly ES-SCLC population.