QL1706 Combined With SOX Used in Theperioperative Treatment

This is a single-center, single-arm clinical study to evaluate the efficacy and safety of QL1706 combined with SOX for the treatment of resectable locally advanced gastric or gastroesophageal junction adenocarcinoma. The study consists of the following two phases: Phase 1: The safety introduction phase of QL1706 combined with SOX, using a 3+3 design, enrolled about 6 to 12 patients with locally advanced gastric/gastroesophageal junction adenocarcinoma (primary clinical stage ≥T3 or N+, M0) and underwent 3-week DLT evaluation. Phase 2: This phase plans to enroll 42 to 45 patients, using investigator-evaluated pCR as the primary endpoint. QL1706 is administered by intravenous infusion of RP2D as defined in Part 1 starting from cycle 1. Preoperative QL1706 RP2D combined with SOX (3 cycles) → radical surgery (D2) → postoperative QL1706 RP2D combined with SOX (5 cycles) → postoperative maintenance of QL1706 RP2D (up to 1 year before and after surgery); neoadjuvant therapy Surgery should be performed within 3 to 6 weeks after the last dosing, with a minimum interval of 4 weeks after surgery and a maximum interval of 6 weeks recommended for postoperative adjuvant therapy.