Clinical Outcomes of Immunosuppressant drugs in Patients Treated with Immune Checkpoint Inhibitors: A Systematic Review and Meta Analysis

Objectives: To systematically evaluate the impact of immunosuppressant drugs (ISDs) use on clinical outcomes in patients with cancer treated with Immune checkpoint inhibitors (ICIs). Methods: A systematic review and meta-analysis was conducted. Eligible studies reporting overall survival (OS) and/or progression-free survival (PFS), among adult cancer patients receiving ICIs stratified by the use of ISDs. Results: A total of 33 studies with 34,063 patients met the inclusion criteria. Pooled analyses showed significantly worse outcomes among patients receiving ISDs during ICI therapy, with poorer OS (HR = 1.31; 95% CI: 1.10–1.56; p = 0.003) and PFS (HR = 1.39; 95% CI: 1.10–1.76; p = 0.006) compared with those who did not receive ISDs with high heterogeneity of (I² ~80–85%). In subgroup analysis, patients with non–small-cell lung cancer exhibited significantly reduced OS associated with the use of ISDs. Conclusions: The results suggest an association between ISDs use and reduced OS and PFS in patients with cancer receiving ICI treatment. These findings highlight the need for precision-based immune-related adverse events (irAE) management strategies that balance toxicity control with preservation of therapeutic benefit.