Relationship between immune-related adverse events and treatment effectiveness in extensive disease small cell lung cancer

Abstract

Background: This study aimed to assess the relationship between immune response adverse events (irAEs) and treatment efficacy in patients with extensive disease small cell lung cancer (ED-SCLC). Methods: We retrospectively evaluated the clinical effects in 40 ED-SCLC patients who had received immune-checkpoint inhibitors (ICIs), platinum agents, and etoposide between September 2019 and September 2021. We identified and compared patients belonging to two groups: irAE and non-irAE. Results: Fifteen patients experienced irAEs, and 25 did not. The median progression-free survival in patients with irAE was longer than that in patients without irAE (12.6 months [95% CI: 6.3–19.3 months] vs. 7.2 months [95% CI: 5.8–7.9 months], p = 0.0108). However, the median overall survival (OS) was similar between irAE and non-irAE groups (27.6 months [95% CI: 15.4–NA] vs. 24.9 months [95% CI: 13.7–NA], p = 0.268). Seven (46.7%) in the irAE group and 20 (80%) in the non-irAE group received sequential therapy. The median OS was prolonged in patients who received first- and second-line therapy than in those who received first-line therapy alone (27.6 months [95% CI: 19.2–NA] vs. 6.6 months [95% CI: 0.3–NA], p = 0.053). Grade ≧ 3 irAEs occurred in five (12.5%) patients. Among them, grade 5 irAEs were observed in two patients, including exacerbation of polymyositis and pulmonary arterial embolism. Conclusion: In this study, the development of irAEs did not affect OS in patients with ED-SCLC who received platinum-based agents, etoposide, or ICI therapy. We determined that managing irAEs and administering first- and second-line therapies could contribute to prolonged OS.