Phase II Study of Trastuzumab Rezetecan Combined With Retlirafusp Alfa With or Without CAPOX as Perioperative Therapy for Resectable Locally Advanced Gastric/Gastroesophageal Junction Adenocarcinoma

Summary

This two-stage, multicenter, randomized open-label phase II trial enrolls untreated resectable stage II-III gastric/gastroesophageal junction adenocarcinoma patients with any HER2 expression. Stage 1 is a safety lead-in cohort of 6 patients receiving Trastuzumab Rezetecan(SHR-A1811)+Retlirafusp alfa(SHR-1701) plus CAPOX to assess dose-limiting toxicity (DLT) within 21 days after initial dosing. If safety risk is acceptable, stage 2 will randomize 74 eligible patients 1:1 into two parallel cohorts stratified by HER2 status. Cohort1 receives perioperative Trastuzumab Rezetecan(SHR-A1811)+Retlirafusp alfa(SHR-1701)+CAPOX; Cohort2 receives dual targeted-immunotherapy without chemotherapy (Trastuzumab Rezetecan+Retlirafusp alfa). All patients undergo D2 radical gastrectomy after neoadjuvant therapy, followed by adjuvant treatment and Retlirafusp alfa(SHR-1701) maintenance up to maximum 17 total cycles. The primary endpoint is pCR rate evaluated by CAP pathological criteria. Secondary endpoints include R0 resection rate, EFS, DFS, OS and perioperative/surgical/systemic safety profiles. Biomarker exploratory analysis will be performed to evaluate the correlation between PD-L1, MSI, TMB and clinical efficacy.

Timeline

Start

2026-09-30

Primary completion

2029-04-30

Completion

2031-09-30

Drugs

Indications