Clinical impact of first-line PD-1 or PD-L1 inhibitors combined with chemotherapy in extensive-stage small cell lung cancer patients: A real-world multicenter propensity score-matched study

Objectives: Our research aimed to evaluate the effectiveness of first-line immune checkpoint inhibitors (ICIs) with etoposide and platinum (EP) for extensive-stage small cell lung cancer (ES-SCLC) and identify prognostic factors, as real-world outcomes and the inconsistency of PD-1 and PD-L1 inhibitors are uncertain.Methods: We selected ES-SCLC patients in three centers and conducted a propensity score-matched analysis. The Kaplan-Meier method and Cox proportional hazards regression were conducted to compare the survival outcomes. We also performed univariate and multivariate Cox regression analyses to investigate predictors.Results: Among 236 patients included, 83 pairs of cases were matched. The EP plus ICIs cohort had a longer median overall survival (OS) (17.3 months) than the EP cohort (13.4 months) (hazard ratio [HR], 0.61 [0.45, 0.83]; p = 0.001). The median progression-free survival (PFS) was also longer in the EP plus ICIs cohort (8.3 months) than in the EP cohort (5.9 months) (HR, 0.44 [0.32, 0.60]; p < 0.001). The EP plus ICIs group had a higher objective response rate (ORR) (EP: 62.3%, EP + ICIs: 84.3%, p < 0.001). Multivariate analysis presented that liver metastases (HR, 2.08; p = 0.018) and lymphocyte-monocyte ratio (LMR) (HR, 0.54; p = 0.049) were independent prognostic factors for OS, and performance status (PS) (HR, 2.11; p = 0.015), liver metastases (HR, 2.64; p = 0.002), and neutrophil-lymphocyte ratio (NLR) (HR, 0.45; p = 0.028) were for PFS in patients with chemo-immunotherapy.Conclusion: Our real-world data demonstrated that ICIs with chemotherapy as the first-line setting for ES-SCLC are effective and safe. PS, liver metastases, and inflammatory markers could serve as valuable risk factors.