HLX22 plus HLX02 and XELOX for first-line treatment of HER2-positive locally advanced or metastatic gastric/gastroesophageal junction cancer: A randomized, double-blind, multicenter phase 2 study.

• DOI: 10.1200/jco.2024.42.3_suppl.354
• Publication Date: 2024-01-22T21:12:58Z
• Authors: Jin Li; Yong Gao; Ning Li; Meng Qiu; Yan-Qiao Zhang; Mudan Yang; Linzhi Lu; Wei Li; Yuntao Ma; Xiaoming Hou; Guoping Sun; Mingquan Cai; Jingran Wang; Jianwei Lu; Diansheng Zhong; Futang Yang; Jing Li; Qingyu Wang; Jun Zhu
• Keywords: Clinical endpoint

354 Background: Gastric/gastroesophageal junction (G/GEJ) cancer represents a global healthcare challenge. With more than 1 million new cases estimated in 2020, it ranked fifth among all cancers. HER2 amplification or overexpression were reported around 20% of advanced G/GEJ cases. Despite the improved overall survival with trastuzumab plus chemotherapy, prognosis remains unsatisfactory, and thus effective treatments are needed. This study aimed to evaluate combination HLX22 (a novel anti-HER2 monoclonal antibody), HLX02 biosimilar), chemotherapy for patients first-line setting. Methods: The was unblinded 3 months after last patient enrolled. Patients locally metastatic HER2-positive had not received prior systemic antitumor therapy consisted 2 parts; current report will focus on part 1. In 1, randomized 1:1:1 receive 25 mg/kg + XELOX (group A), 15 B), placebo C) 3-week cycles. Primary endpoints PFS ORR assessed by IRRC per RECIST v1.1. Secondary included other efficacy measures safety. Results: As July 30, 2023 (data cutoff), 53 group A (n=18), B (n=17), C followed up median 14.3 months. 44 (83.0%) male. Main results presented Table. Tumor assessments Table performed IRRC. Treatment-related adverse events (TRAEs) occurred 18 (100.0%), 16 (94.1%), 17 (94.4%) respective groups. Serious TRAEs observed 5 (27.8%) A, (5.9%) B, (5.6%) C. Only grade TRAE. Conclusions: Adding response setting, manageable safety profile. Clinical trial information: NCT04908813 . [Table: see text]