Petrelli et al. 2021 Immunotherapy 13: 621–631

This study is a meta-analysis of randomized controlled trials involving first-line studies in which immune checkpoint inhibitors were added to chemotherapy and were compared with chemotherapy alone. The primary end point was overall survival (OS). The analyses used random-effects models and the Grading of Recommendations Assessment, Development, and Evaluation system to rate the quality of the evidence. Nine articles were included for qualitative and quantitative synthesis. A meta-analysis of the nine randomized trials showed a significant benefit in terms of OS (hazard ratio: 0.75 [95% CI: 0.66–0.85]; p < 0.01). Only programmed death ligand-1 positive-high cancers derive a significant OS benefit. In this meta-analysis, there is moderate evidence that the addition of immune checkpoint inhibitors to chemothera…