TIME-of-day immunotherapy was associated with longer survival in patients receiving ICIs for advanced solid tumors.
Time-Of-Day Immunotherapy Shows Survival Signal
Time-of-day immunotherapy may represent a modifiable factor in cancer care, with earlier immune checkpoint inhibitor administration linked to improved overall survival and progression-free survival in a systematic review and meta-analysis of 29 studies involving 6,129 patients with advanced solid tumors.
The analysis included 1 randomized clinical trial in non-small cell lung cancer, 1 prospective cohort study in head and neck squamous cell carcinoma, and 27 retrospective cohort studies across cancer types including melanoma, gastric cancer, renal cell carcinoma, esophageal cancer, small cell lung cancer, urothelial carcinoma, biliary tract cancer, hepatocellular carcinoma, and other tumors.
Earlier ICI administration was associated with improved overall survival, with a pooled hazard ratio of 0.60, and improved progression-free survival, with a pooled hazard ratio of 0.62. The findings suggest that the timing of immunotherapy delivery could have clinical relevance, although prospective validation remains needed before standardized scheduling strategies can be adopted.
Strongest Findings Seen Across Several Tumor Types
Survival benefits were most consistent in non-small cell lung cancer, gastric cancer, renal cell carcinoma, small cell lung cancer, and biliary tract cancer, where both overall survival and progression-free survival improved with earlier administration.
For non-small cell lung cancer, early administration was associated with better overall survival and progression-free survival, and this signal was supported by randomized clinical trial evidence. Retrospective data also suggested benefit in gastric, renal cell, small cell lung, and biliary tract cancers.
Findings were less consistent for other tumors. No overall survival difference was identified for head and neck squamous cell carcinoma or esophageal cancer, while melanoma showed improved overall survival but not progression-free survival. Urothelial carcinoma findings approached but did not clearly meet conventional significance thresholds.
Circadian Biology May Help Explain The Association
The findings build on the concept of chronotherapy, which aims to align treatment delivery with circadian rhythms. Circadian biology regulates immune function, and immune cells involved in antitumor activity can fluctuate across the day. These rhythms may influence cytokine production, phagocytosis, dendritic cell activity, CD8-positive T-cell responses, and immune checkpoint expression within the tumor microenvironment.
However, clinical implementation remains premature. Most included studies were retrospective, and definitions of “early” versus “late” administration varied, ranging from simple clock-time cutoffs to infusion-proportion approaches. Overall analyses also showed substantial heterogeneity, likely reflecting variation in tumor type, ICI regimen, concomitant therapies, and patient scheduling patterns.
No consistent association was observed between time-of-day immunotherapy and adverse event incidence or severity, but safety reporting was too inconsistent for pooled analysis. Future multicenter randomized trials should establish standardized timing definitions, evaluate chronotype-guided scheduling, and clarify whether timing has causal effects on survival.
Reference
Inoue S et al. Time-of-Day Immunotherapy Administration and Outcomes in Advanced Cancers: A Systematic Review and Meta-Analysis. JAMA Network Open. 2026;9(5):e2610815.
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