A Trial of Adebrelimab Plus (SHR-A1811/SHR-A1904 With Chemotherapy) or SHR-8068 as Treatment for Gastric/GEJ Cancer

This study is testing several drug combinations for people with advanced stomach cancer or cancer at the junction of the stomach and esophagus, who have not received prior treatment. The combinations include immunotherapy (adebrelimab), antibody-drug therapies (SHR-A1811 or SHR-A1904), and chemotherapy. Researchers want to find the safest and most effective approach. **You may be eligible if...** - You have confirmed gastric or gastroesophageal junction adenocarcinoma (a type of stomach cancer) - You have not received any prior cancer treatment for this disease - You are 18-70 years old in good physical health (ECOG 0-1) - Your life expectancy is at least 6 months - Your blood counts, liver, and kidney function meet required levels - Tumor tissue is available for biomarker testing **You may NOT be eligible if...** - You have already received treatment for this cancer - You have active brain metastases - You have significant heart disease - You are pregnant or breastfeeding - You have an active autoimmune condition Talk to your doctor to see if this trial is right for you.