Evaluating the safety and efficacy of combination immune checkpoint inhibitors and chemotherapy treatment in extensive-stage small cell lung cancer

Abstract

Objective: This research effort was designed to retrospectively analyze the safety and efficacy of immune checkpoint inhibitors (ICIs) deployed in combination with chemotherapy in extensive-stage small cell lung cancer (ES-SCLC). Methods: ES-SCLC patients diagnosed at Guangzhou Chest Hospital from January 1, 2018, through June 30, 2022, were divided into two groups: an IEP group (administered ICIs with etoposide and platinum-based chemotherapy) and an EP group (chemotherapy only). Median overall survival (OS) and progression-free survival (PFS) served as the primary endpoints for analysis, while secondary endpoints that were assessed included objective response rate (ORR), 1- and 2-year OS, and safety. Subgroup analyses explored sites of metastatic progression and ICI types. Results: In total, 102 patients were enrolled, including 33 in the IEP group and 69 in the EP group. The median OS was significantly longer in the IEP group (14.3 vs. 10.8 months, P = 0.028), while the median PFS showed no significant difference (5.9 vs. 5.3 months, P = 0.746). In subgroup analyses, those patients with brain metastases were found to have derived benefit from IEP treatment (median OS 15.9 vs. 8.3 months, hazard ratio [HR], 0.266 [95% CI, 0.087 to 0.817], P = 0.014). The PFS of patients administered PD-L1 inhibitors was longer than that of those administered PD-1 inhibitors (median 7.0 vs. 3.5 months; HR, 0.342 [95% CI, 0.141 to 0.832], P = 0.014). The safety profile of the IEP regimen was favorable, although these patients were more likely to experience immune-related pneumonia (12.1% vs. 1.4%, P = 0.020). Subgroups analyses showed that patients with a history of smoking (HR = 0.54, 95% CI: 0.31–0.94) and brain metastases (HR = 0.27, 95% CI: 0.09–0.82) were more likely to benefit from IEP treatment. Conclusion: The combination of ICIs and chemotherapy can afford better survival outcomes for ES-SCLC patients, especially in individuals suffering from brain metastases, and they should thus be considered as promising first-line treatment options. However, careful management of immune-related adverse events is crucial.