Abstract 172P
Background
Based on two randomized phase III studies, IMPOWER133 and CASPIAN, immune checkpoint inhibitors combined with chemotherapy have shown improved clinical efficacy as first-line treatment for extensive-stage small cell lung cancer (ES-SCLC). This study will describe the real-world characteristics and outcomes of patients with ES-SCLC treated with standard chemotherapy with or without PD-L1 inhibitors.
Methods
Treatment-naïve ES-SCLC patients treated with standard platinum-based chemotherapy with or without PD-L1 inhibitors (atezolizumab and durvalumab) were enrolled from 12 sites in China between Jan 2019 and Dec 2021. Analyses of baseline characteristics, survival, treatment-related adverse effects (TRAEs), and subgroups were conducted. The primary end point was progression-free survival (PFS) and overall survival (OS).
Results
414 ES-SCLC patients were enrolled, of those 208 patients received durvalumab (66.3%) or atezolizumab (33.7%) combined with chemotherapy and 206 patients only received chemotherapy. In this study, 60.1% of patients had a history of smoking and 24.6% had brain metastases. Of 414 patients, 256 (61.8%) received six or more cycles of chemotherapy (median, 6) and 213 (61.8%) received radiotherapy to any site. Median PFS in PD-L1 inhibitors plus chemotherapy group or chemotherapy group was 7.2 months (95% CI 6.6–7.8) and 6.4 months (95% CI 5.8–7.0), respectively (P = 0.001), and HR for disease progression was 0.72 (95% CI 0.59–0.89; P = 0.002). The median OS was 20.6 months and 15.9 months, respectively (HR = 0.74, P = 0.020). TRAEs were similar in the two groups, with AE-related withdrawal rates from 1L therapy of 6.3% in the PD-L1 inhibitors plus chemotherapy group and 3.4% in the chemotherapy group, including one death from immune-related pneumonia in the former group.
Conclusions
In this real-world study, PD-L1 inhibitors combined with chemotherapy demonstrated good efficacy and tolerable safety profiles. The clinical characteristics and treatment patterns were markedly different from those in the two RCTs, including receipt of thoracic radiotherapy (tRT) or prophylactic cranial irradiation (PCI). The OS benefit and radiotherapy subgroup analysis of ES-SCLC patients need to be further followed up.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.