sFOLFOXIRI in Advanced Gastroesophageal Cancer, (SAGE)

This study (SAGE) is testing whether a modified, more intense chemotherapy regimen called sFOLFOXIRI — and possibly adding an immunotherapy drug — can improve outcomes for patients with advanced stomach or esophageal cancer. **You may be eligible if...** - You are 18 or older with confirmed metastatic or unresectable stomach, esophageal, or gastroesophageal junction adenocarcinoma - Your cancer is HER2-negative - You have not received prior chemotherapy for this cancer in the metastatic setting - Your blood counts, kidney, and liver function are adequate **You may NOT be eligible if...** - You have untreated brain metastases - You have significant nerve damage (peripheral neuropathy grade 2 or worse) - You have an active autoimmune disease requiring immunosuppression (if receiving immunotherapy) - You have had a serious infection or recent major surgery - You are allergic to any of the study drugs Talk to your doctor to see if this trial is right for you.