DV Combined With Cadonilimab in Subjects With HER2-expressing Gastric Cancer and Gastroesophageal Junction Adenocarcinoma After Progression on First-line Therapy

This study is testing a combination of two drugs — an antibody-drug conjugate (DV) and an immunotherapy drug (Cadonilimab) — in people with advanced stomach or gastroesophageal junction cancer that has stopped responding to first-line treatment and has a protein called HER2 on the tumor. **You may be eligible if...** - You are between 18 and 75 years old - You have locally advanced or metastatic stomach or gastroesophageal junction cancer confirmed by biopsy - Your cancer has the HER2 protein present (even at low levels) - Your cancer stopped working or you could not tolerate your first standard treatment - Your heart, liver, kidneys, and blood counts are functioning adequately - You are willing to use contraception during and for 6 months after treatment **You may NOT be eligible if...** - Your cancer has spread to the brain or the lining of the brain - You have previously received an antibody-drug conjugate treatment - You have had a major infection, heart attack, stroke, or blood clot in the past 6 months - You are pregnant or breastfeeding - You have active hepatitis B, C, or HIV - You have an autoimmune disease requiring ongoing systemic treatment Talk to your doctor to see if this trial is right for you.