Programmed cell death ligand 1 (PD-L1) inhibitors versus programmed cell death 1 (PD-1) inhibitors for the first-line therapy of extensive-stage small cell lung cancer: a propensity score-matched study.

Background: The clinical efficacy and safety differences between PD-L1 inhibitors and PD-1 inhibitors remain controversial for ES-SCLC. We conduct the retrospective study and propensity score-matched analysis to explore the potential differences between them.

Methods: This retrospective study analyzed 736 ES-SCLC patients from three centers treated with EP plus either a PD-L1 or PD-1 inhibitor. According to PD-L1 or PD-1 inhibitors, they were divided into two groups. Propensity score matching (PSM, 1:1) was performed to balance the baseline characteristics of the two groups. The primary endpoints were OS and PFS.

Results: As a result, 485 patients received PD-L1 inhibitors plus EP and 251 received PD-1 inhibitors plus EP. Before PSM, the PD-1 inhibitor group showed a significantly longer PFS (8.26 vs. 7.44 months; HR 1.252, p = 0.007), but no significant OS difference (20.30 vs. 18.85 months; p = 0.337). After PSM, both median OS (22.43 vs. 20.69 months) and PFS (8.23 months for both) were comparable, with no statistical differences (OS: HR 0.938, p = 0.613; PFS: HR 1.008, p = 0.940). Safety profiles were similar between groups.

Conclusions: In conclusion, the overall efficacy and safety profile were similar between PD-L1 inhibitors and PD-1 inhibitors for the first-line treatment of ES-SCLC.