This study is testing a new treatment combination for HER2-positive gastric (stomach) or gastroesophageal junction (where the esophagus meets the stomach) cancer that has spread or cannot be removed by surgery. You might be eligible if you have this type of cancer and haven't received prior treatment for it. The study is comparing HLX22, a monoclonal antibody (a type of targeted therapy), given with trastuzumab and chemotherapy (oxaliplatin and capecitabine), against a placebo (an inactive substance) combined with trastuzumab and chemotherapy. Researchers want to see if adding HLX22 helps patients live longer without their cancer getting worse (Progression-Free Survival) and how long they live overall (Overall Survival), with results measured for up to 5 years. The study is currently recruiting participants.

Study design

This is a double-blind, randomized study, meaning neither you nor your doctors will know if you are receiving HLX22 or the placebo. About 550 participants will be randomly assigned to one of two treatment groups.

What's involved

You would receive the study drug combination every three weeks until your cancer worsens, you experience severe side effects, or you choose to stop participating.

Compensation

Not stated in the trial record.

Follow-up

Researchers will follow your progress for up to 5 years to assess how long you live without your cancer worsening and your overall survival.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.