Puerto Blest

Researchers are evaluating HLX22 combined with trastuzumab and chemotherapy as a first-line treatment for patients with HER2-positive locally advanced or metastatic adenocarcinoma of the gastric or gastroesophageal junction. This phase 3, randomized, double-blind study compares this combination against trastuzumab plus chemotherapy with or without pembrolizumab. The trial aims to assess the efficacy and safety of adding HLX22 in this patient population. Participants will be randomly assigned in a 11 ratio to either the experimental group receiving HLX22 15 mgkg plus trastuzumab and chemotherapy XELOX with or without a placebo for pembrolizumab every three weeks, or the control group receiving placebo for HLX22 plus trastuzumab and chemotherapy XELOX with or without pembrolizumab also every three weeks. Treatment continues until clinical benefit is lost, intolerable side effects occur, death, withdrawal, or other protocol-specified reasons. Throughout the study, participants will have their disease progression monitored by an independent radiology review committee using RECIST v1.1 criteria for up to five years, along with overall survival and response rates. Safety will be regularly assessed by tracking adverse events. The study includes multiple assessments to evaluate treatment effects, and participants will be followed for long-term outcomes during the trial period.