Systematic review and meta-analysis of phase 3 studies of first-line chemo-immunotherapy in extensive-stage small cell lung cancer

PD-1 ior PD-L1nhibitors plus platinum-etoposide is standard first-line therapy for extensive-stage small cell lung cancer (ES-SCLC), but the consistency of benefit across trials and potential PD-1 versus PD-L1 class differences are debated. Systematic review and meta-analysis of phase 3 studies published through 11 February 2026 compared first-line platinum-etoposide with or without a PD-(L)1 inhibitor. Six trials (n=2,897) were included. In meta-analysis, addition of immunotherapy to chemotherapy improved overall survival (HR 0.74; 95% CI 0.67-0.81; I²=0%) as well as progression-free survival (0.68; 0.58-0.78; 65.5%) without statistically significant differences between efficacy of PD-1 and PD-L1 inhibitor classes. Grade ≥3 treatment-related adverse events were not increased by addition of immunotherapy, whereas immune-mediated adverse events were more frequent (RR 2.39; 95% CI 1.61-3.54) with substantial heterogeneity. Certainty was high for overall survival, low for progression-free survival, and moderate-to-very low for safety. The authors conclude that adding a PD-(L)1 inhibitor to first-line platinum-etoposide for ES-SCLC provides a consistent overall survival benefit.