Estancia La Pampa

Researchers are evaluating the safety and effectiveness of HLX22 combined with trastuzumab and chemotherapy as the first treatment for patients with HER2-positive locally advanced or metastatic adenocarcinoma of the gastric or gastroesophageal junction. This phase 2, double-blind, randomized, and multiregional study compares this combination against trastuzumab and chemotherapy with or without pembrolizumab. The study aims to measure how well the treatments work in controlling the disease and improving survival for up to five years. Participants will be randomly assigned to one of two groups. One group receives HLX22 at 15 mg/kg every three weeks along with trastuzumab, chemotherapy (XELOX regimen), and possibly a placebo for pembrolizumab. The other group receives a placebo for HLX22 plus trastuzumab, chemotherapy (XELOX), and possibly pembrolizumab every three weeks. Treatment continues until the disease worsens, unacceptable side effects occur, withdrawal of consent, or other protocol-specified reasons. Throughout the study, participants will undergo regular assessments including tumor scans reviewed by an independent committee to evaluate progression-free survival and overall survival over up to five years. Other evaluations include safety monitoring and organ function tests. The study tracks how long patients live without disease progression and overall survival, aiming to better understand the benefits and risks of HLX22 combined with current standard treatments.