Abstract 1539P
Background
Immunotherapy combined with trastuzumab, and chemotherapy have been recommended by the clinical guidelines of many countries as the first-line treatment for advanced HER2-positive G/GEJ adnocarcinoma. Combining chemotherapy with tislizumab and trastuzumab in the neoadjuvant/adjuvant setting may benefit patients with locally advanced, resectable HER2-positive GC/GEJC.
Methods
This study is a multicentre, single-arm, open-label phase II study. Patients with histologically confirmed cT2-4NxM0 or cTxN+M0, (TNM 8th edition), resectable GC/GEJC are eligible for this study. Neoadjuvant therapy will be administered for four cycles. The patients will receive tislelizumab and trastuzumab for 1 cycle (Q3W), followed by tislelizumab and trastuzumab combined with DOS (Docetaxel + Oxaliplatin + S-1) for 3 cycles (Q3W). Surgery is planned 4-6 weeks after preoperative treatment. Patients will receive adjuvant therapy starting within 4–6 weeks after surgery for 9 cycles. The primary endpoint was pathological complete response rate (pCR). Secondary endpoints included R0 resection rate, 1-year and 2-year event-free survival (EFS), overall survival (OS) and safety.
Results
From September 13, 2021, to May 05, 2023, 18 patients were enrolled, and the median follow up time was 9.2 months (0.1-20.0).11 patients completed surgery, and 5 patients were undergoing neoadjuvant therapy, 2 patients required organ preservation therapy. R0 resection rate was 100%, 6 patients (54.5%) achieved pCR, and 7 patients (63.6%) achieved MPR. Postoperative pathology showed that T stage decreased in 9 cases after neoadjuvant therapy, with a decrease rate of 81.8%. Median OS and EFS have not been reached. The most common AEs (grade ≥3) were anaemia in 1 (5.6%) and neutropenia in 1 case (5.6%). The immune-related adverse events were all grade 1. No treatment related deaths were reported.
Conclusions
According to the preliminary results, tislelizumab combined with trastuzumab and standard chemotherapy in the perioperative period of HER2-positive GC / EGJ have a good clinical benefit trend and controllable security.
Clinical trial identification
NCT04819971.
Editorial acknowledgement
Legal entity responsible for the study
The First Affiliated Hospital of Zhengzhou University.
Funding
BeiGene (Beijing) Co., Ltd.
Disclosure
All authors have declared no conflicts of interest.
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