Efficacy and Safety of First-Line Chemoimmunotherapy with Durvalumab or Atezolizumab in Extensive-Stage of Small-Cell Lung Cancer in Real World Practice

Abstract

: Background: Small-cell lung cancer (SCLC) is characterised by an aggressive clinical course and the early development of distant metastases. The introduction of immune checkpoint inhibitors to platinum-based chemotherapy has significantly improved survival outcomes. The aim of this study was to compare the efficacy and safety of two immunochemotherapy regimens with durvalumab and atezolizumab in patients with extensive-stage small-cell lung cancer (ES-SCLC) and different clinical characteristics. Methods: This retrospective study included 201 patients diagnosed with ES-SCLC, who received first-line treatment with either durvalumab (n = 104) or atezolizumab (n = 97) in combination with chemotherapy. Overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) were compared according to treatment regimen and clinical characteristics. The effectiveness of treatment was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Treatment-related adverse events (TRAEs) were evaluated using the Common Terminology Criteria for Adverse Events (CTCAE version 5.0). Results: Disease control rates were comparable between the durvalumab and atezolizumab groups, with similar ORR observed in both cohorts. The median PFS was 6.3 months in the durvalumab arm and 6.0 months in the atezolizumab arm (HR = 0.8053, 95% CI: 0.5851–1.1083, p = 0.1839). Median OS was 16.9 months among patients treated with durvalumab and 12.0 months among those treated with atezolizumab (HR = 0.703, 95% CI: 0.4829–1.0233, p = 0.0658). In the overall study population, the presence of liver metastases was associated with a significantly higher risk of disease progression (HR = 1.5643, 95% CI: 1.1102–2.2244, p = 0.0127) and death (HR = 2.0848, 95% CI: 1.3886–3.1292, p = 0.0004). Conclusions: The type of immune checkpoint inhibitor used in combination with chemotherapy did not significantly influence treatment outcomes. However, the presence of liver metastases emerged as a major adverse prognostic factor associated with shorter OS and PFS in patients with ES-SCLC treated with chemoimmunotherapy.