A Real-World Study of the Efficacy of Immune-Checkpoint Inhibitors for Extensive-Stage Small Cell Lung Cancer

Abstract

<h3>Purpose/Objective(s)</h3> We carried out this retrospective real-world study to explore the efficacy of immune checkpoint inhibitors (ICIs) in patients with extensive-stage small cell lung cancer (ESSCLC). <h3>Materials/Methods</h3> Clinical data of 221 ES-SCLC patients treated with PD-1 or PD-L1 inhibitors were retrospectively collected during February 2017 to June 2020. The primary end points were overall survival (OS) and progression-free survival (PFS), while the secondary endpoints included objective response rate and adverse events. <h3>Results</h3> The mOS of the ICIs plus anti-VEGF/VEGFR agent group has not reached and the mPFS was 8.10 months. The mOS of patients received ICIs plus chemotherapy was 19.73 months and the mPFS was 8.28 months. No significant differences were observed in OS (P = 0.498) or PFS (P = 0.521) between these two groups. And no significant differences were observed between patients received PD-1 inhibitors or PD-L1 inhibitors in OS (p = 0.198; mOS 19.07 months vs undefined) and PFS (p = 0.251; mPFS 8.27 months vs 7.95 months). Additionally, a longer PFS of PD-1 inhibitors was observed in the first-line treatment of ES-SCLC patients (P=0.041), but no significant difference was showed in the second-line or later treatment between PD-1 and PD-L1 inhibitors. In the subgroup analysis, a better OS of PD-L1 inhibitors for ES-SCLC patients without osseous metastases was observed (P=0.044). PD-1 and PD-L1 inhibitors also revealed comparable efficacy for ES-SCLC patients with brain metastases, with no significant differences in OS (p=0.309) and PFS (p=0.157). <h3>Conclusion</h3> PD-1/PD-L1 inhibitors combined with chemotherapy or anti-VEGF/VEGFR agent showed a similar efficacy. PD-1 versus PD-L1 inhibitors provided a comparable survival benefit in the second-line or later treatment, as well as patients with brain metastases, and a longer PFS was observed in ES-SCLC patients treated with PD-1 inhibitors as the first-line treatment.