First-line serplulimab for locally advanced or metastatic squamous non–small cell lung cancer: Updated survival from the ASTRUM-004R trial.

8581 Background: Although the ASTRUM-004 trial has confirmed that serplulimab plus platinum-based therapy improves survival in patients with locally advanced or metastatic squamous non-small cell lung cancer (sqNSCLC), evidence regarding its efficacy and safety in routine clinical practice remains limited. Previous results from the ASTRUM-004R trial have shown that a serplulimab plus platinum-based therapy exhibits promising antitumor activity in sqNSCLC. Here, we report the updated follow-up results from this study. Methods: The ASTRUM-004R trial is a retrospective, real-world study conducted across 14 centers in China. Patients with locally advanced or metastatic sqNSCLC received first-line serplulimab plus platinum-based therapy, followed by serplulimab maintenance treatment until disease progression, intolerable toxicity, or up to 2 years. This update presents the survival outcomes, including progression-free survival (PFS) and overall survival (OS). Additionally, PFS was assessed across various patient subgroups. Results: A total of 132 patients were enrolled in the analysis, with a median follow-up of 18 months as of October 31, 2025. The median patient age was 69 years. Overall, 92.4% (n = 122) were male, 71.2% (n = 94) were aged 65 or older, 19.7% (n = 26) had an ECOG performance status of 2, and 47.0% (n = 62) had stage IV disease. Maintenance therapy was administered to 50.8% (n = 67) of the patients. The median PFS for all patients was 14.8 months (95% CI: 11.9-19.6), with a 6-month PFS rate of 78.5% (95% CI: 71.5%-86.2%). The median PFS benefit was comparable between patients receiving nab-paclitaxel and those receiving paclitaxel (17.5 vs. 15.2 months, P = 0.677), suggesting no significant difference in efficacy between the two groups. Furthermore, a significantly longer median PFS was observed in patients with stage III disease compared to those with stage IV disease (20.4 vs. 11.9 months, P = 0.009). The median OS for all patients was 29.7 months (95% CI: 29.7-NR), with a 12-month OS rate of 90.1% (95% CI: 84.7%-95.9%). The updated findings confirm sustained antitumor activity, as evidenced by an objective response rate of 66.7% (95% CI: 57.9%-74.6%) and a disease control rate of 95.5% (95% CI: 90.4%-98.3%). Adverse events (AEs) of any grade occurred in 48 patients (36.4%), most of whom had hematological disorders. Immune-related AEs (irAEs) were reported in 35 patients (26.5%), including 9 (6.8%) who experienced grade ≥3 irAEs. Conclusions: Updated results from the ASTRUM-004R study show that first-line serplulimab platinum-based therapy provides a significant survival benefit with a manageable safety profile in locally advanced or metastatic sqNSCLC, consistent with findings from the ASTRUM-004 trial. The long-term survival benefit warrants further validation with extended follow-up.