Systematic review and meta-analysis of impact of time-of-day immunotherapy administration and outcomes in advanced cancers

Circadian rhythms affect immunity, which could affect the effectivenss of immune checkpoint inhibitors (ICIs). Systematic review and meta-analysis of published studies evaluated the association between time of day of ICI administration and oncologic outcomes in patients with advanced solid tumors. In the literature up to February 2026, the authors identified 29 eligible studies with 6129 patients: one randomized trial (210 patients), one prospective cohort study (62 patients), and 27 retrospective cohort studies (5857 patients). Earlier time-of-day ICI administration was associated with increased overall survival (HR 0.60; 95% CI 0.51-0.70) and progression-free survival (0.62; 0.54-0.71). Subset analyses by cancer type confirmed significantly increased OS and PFS in NSCLC, gastric cancer, renal cell carcinoma, small cell lung cancer, and biliary tract cancer. The authors conclude that early immunotherapy administration was associated with improved survival, a finding that warrants prospective evaluation.