Comparison of efficacy and safety of first-line immunotherapy combined with chemotherapy in extensive-stage small cell lung cancer, a retrospective study.

Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis, in combination with platinum-based chemotherapy, have become the standard first-line treatment for extensive-stage small cell lung cancer (ES-SCLC). Among these agents, serplulimab is a PD-1 inhibitor, while adebrelimab, durvalumab, and atezolizumab are PD-L1 inhibitors, all of which have been integrated into clinical practice based on emerging evidence. However, the comparative efficacy of these combined therapies remains unclear. This study aims to compare the efficacy of Serplulimab, Adebrelimab, Durvalumab, and Atezolizumab when combined with chemotherapy, providing real-world data on their clinical benefits in ES-SCLC. This retrospective study included 322 patients diagnosed with extensive-stage small-cell lung cancer (ES-SCLC) who received first-line treatment with platinum-based chemotherapy combined with a PD-1 or PD-L1 immune checkpoint inhibitor between March 2019 and December 2023. The primary endpoints were overall survival (OS)and progression-free survival (PFS). A total of 322 patients with extensive-stage small-cell lung cancer (ES-SCLC) were enrolled in this study. All patients received chemotherapy in combination with one of the following PD-L1 inhibitors: Adebrelimab (n = 71), Serplulimab (n = 80), Durvalumab (n = 93), or Atezolizumab (n = 78).The median PFS was 7.63 months (95% CI 6.57–8.77) for Atezolizumab, 6.9 months (95% CI 5.67–8.57) for Serplulimab, 7.43 months (95% CI 6.3–9.43) for Durvalumab, and 7.4 months (95% CI 6.3–9.43) for Adebrelimab. No significant differences in PFS were observed between Serplulimab and the other PD-L1 inhibitors, with p values of 0.96 for Adebrelimab, 0.8 for Atezolizumab, and 0.44 for Durvalumab.The median OS was 17.2 months (95% CI 13.3–27.7) for Atezolizumab, 15.0 months (95% CI 12.8–NA) for Serplulimab, 17.6 months (95% CI 16.2–26.6) for Durvalumab, and 23.2 months (95% CI 23.1–NA) for Adebrelimab. No significant differences in OS were observed between Serplulimab and either Durvalumab (p = 0.23) or Atezolizumab (p = 0.61). However, Adebrelimab was associated with a significantly longer OS compared to Serplulimab (p = 0.029). Multivariate Cox regression analysis revealed that liver metastasis was an independent adverse prognostic factor for both PFS and OS. The combination of chemotherapy with PD-1 and PD-L1 inhibitors, including Serplulimab, Adebrelimab, Durvalumab, and Atezolizumab, demonstrates comparable efficacy regarding PFS. However, Adebrelimab provides a significantly better long-term survival benefit, indicating its potential as a superior treatment option for extensive-stage small cell lung cancer (ES-SCLC).