Neoadjuvant toripalimab plus CapeOX in locally advanced Epstein-Barr virus-associated gastric or gastroesophageal junction adenocarcinoma: a phase Ⅱ trial.

In this phase 2 trial (NCT04744649), 17 patients with locally advanced Epstein-Barr virus-associated gastric or gastroesophageal junction adenocarcinoma (cT2-4aN1-3M0) received four cycles neoadjuvant toripalimab plus capecitabine/oxaliplatin. The primary endpoint was major pathological response; secondary endpoints included pathological complete response, R0 resection, adverse events, event-free survival, overall survival, and tumor microenvironment. Paired pre-/post-treatment tissues were assessed by immunofluorescence. 16 patients underwent curative resection; 1 declined surgery. Major pathological response, pathological complete response, and ypN0 were 37.5% (6/16, 95% CI 0.15-0.65), 25.0% (4/16, 95% CI 0.07-0.52), and 81.3% (13/16, 95% CI 0.54-0.96), respectively. Major pathological response was more frequent in patients with programmed death ligand 1 ≥20 (57.1%, 95%CI 0.18-0.90). Major pathological response was associated with higher pretreatment CD8⁺ T-cell density. 35.3% reported grade 3-4 adverse events. These findings suggest that neoadjuvant immunochemotherapy demonstrated favorable efficacy with a manageable safety profile in Epstein-Barr virus-associated gastric or gastroesophageal junction adenocarcinoma.