This is a single-center, prospective, open-label, single-arm, phase Ib/II study evaluating the safety and efficacy of neoadjuvant propranolol combined with SOX chemotherapy and toripalimab in patients with resectable locally advanced gastric or gastroesophageal junction adenocarcinoma. A total of 49 participants will be enrolled. Stage 1 includes an initial safety lead-in of 12 participants, followed by efficacy evaluation using a Simon two-stage design. Participants will receive propranolol, toripalimab, oxaliplatin, and S-1 during the neoadjuvant period, followed by curative-intent surgery.
The primary efficacy endpoint is pathological complete response. Secondary endpoints include safety and tolerability, major pathological response, R0 resection rate, event-free survival, recurrence-free survival, and overall survival. Exploratory analyses will assess changes in adrenergic stress markers, heart rate variability, peripheral immune parameters, β-adrenergic receptor signaling, and the tumor immune microenvironment.