Inflammatory stress determines the need for chemotherapy in patients with HER2-positive esophagogastric adenocarcinoma receiving targeted and immunotherapy.

Anti-PD-1, trastuzumab, and chemotherapy are used in the treatment of patients with advanced HER2-positive esophagogastric adenocarcinoma (EGA), but long-term survival remains limited. Herein, we report extended follow-up data from the INTEGA trial (NCT03409848), which investigated the efficacy of the anti-PD-1 nivolumab, trastuzumab, and FOLFOX chemotherapy (FOLFOX arm) in comparison to a chemotherapy-free regimen involving nivolumab, trastuzumab, and the anti-CTLA-4 ipilimumab (Ipi arm) in the first-line setting for advanced disease. The 12-month overall survival (OS) showed no statistical difference between the arms, with 57% OS (95% CI: 41%-71%) in the Ipi arm and 70% OS (95% CI: 54%-82%) in the FOLFOX arm. Crossing of the survival curves indicated a potential long-term benefit for some patients within the Ipi arm, but early progressors in the Ipi arm underlined the need for biomarker-guided strategies to optimize treatment selection. To this end, metabolomic and cytokine analysis demonstrated elevated levels of normetanephrine, cortisol, and interleukin 6 (IL-6) in immunotherapy-unresponsive patients in the Ipi arm, suggesting a role for systemic inflammatory stress in modulating antitumor immune responses. Patients with this signature also showed an increased neutrophil-to-lymphocyte ratio (NLR) that persisted in the Ipi arm, but not in the FOLFOX arm, and strongly correlated with survival. Furthermore, a low NLR characterized patients benefiting from immune- and targeted therapy without the need for additional chemotherapy. This data suggests that patient selection based on inflammatory stress-driven immune changes could help to customize first-line treatment in patients with advanced HER2-positive EGA to potentially improve long-term survival.