What is known and objective: Immune checkpoint inhibitors (ICIs) have been approved for treating small-cell lung cancer (SCLC). However, the efficacy and safety profile of ICIs for relapsed SCLC remains under investigation. In this study, we assessed the efficacy and safety of ICIs in the treatment of relapsed SCLC patients.
Methods: The databases, including Pubmed, Embase, and the Cochrane library, were systematically searched to retrieve potential eligible studies from the establishment of the database to May 2021. The primary outcomes were survival, treatment responses, and safety. Randomized controlled trials and real-world studies that met the inclusion criteria were included. The RevMan 5.4 and R software were used for meta-analysis.
Results and discussion: A total of eight articles involving 653 patients was included. Meta-analyses results showed that the overall response rate (objective response rate [ORR]) of the ICIs group was 0.12 (95% confidence interval [CI]: 0.07-0.18). The median overall survival was 7.97 (95% CI: 5.94-9.47) months, while the progression-free survival was 1.70 (95% CI: 1.40-2.28) months. Although chemotherapy showed a favourable ORR (odds ratio [OR] = 0.74; 95% CI: 0.39-1.41; p = 0.36) and a significantly better disease control rate (OR = 0.28; 95% CI: 0.11-0.70; p = 0.007), patients treated with ICIs had a reduced risk of mortality (hazard ratio = 0.87; 95% CI: 0.73-1.03; p = 0.10). With regards to adverse events (AEs), the rates of any AEs and ≥grade 3 AEs were 0.56 (95% CI: 0.52-0.60) and 0.13 (95%CI: 0.06-0.20), respectively.
What is new and conclusion: For relapsed SCLC patients, the administration of ICIs resulted in a similar survival outcome and acceptable safety compared with chemotherapy. Further studies are needed to explore potential biomarkers for relapsed SCLC patients who may benefit from immunotherapy.
Keywords: immune checkpoint inhibitor; meta-analysis; relapsed; small-cell lung cancer; survival.
© 2021 John Wiley & Sons Ltd.