Wednesday, November 19, 2025 Effects of serotonergic drugs on immune checkpoint inhibitor response: a pooled analysis of individual patient data from four Canadian Cancer Trials Group (CCTG) trials BR34, CO26, I226 and PA7Immune checkpoint inhibitors (ICIs) are used to treat various cancers. Serotonin receptors are expressed by immune cells. In preclinical models, serotonergic drugs affect T-cell cytokine production, proliferation and apoptosis. Interactions between clinical serotonergic drug use and dual ICI treatment remain unknown. Coschi CH, Ding K, Tu D, O’Callaghan C, Leighl NB, Vera-Badillo F, Juergens RA, Hao D, Seymour L, Renouf DJ, Chen E, Fung AS, Gaudreau P-O. Effects of serotonergic drugs on immune checkpoint inhibitor response: a pooled analysis of individual patient data from four Canadian Cancer Trials Group (CCTG) trials. Immunotherapy 17: 1085-1097. 2025. https://doi.org/10.1080/1750743X.2025.2578164