Histological or cytological confirmed gastric, gastroesophageal junction or esophageal adenocarcinoma.
Evidence of locally advanced or metastatic disease.
Eastern Cooperative Oncology Group performance status (ECOG) 0-1
No prior systemic therapy for advanced or metastatic disease.
Adequate hepatic, liver, and renal function
HER-2 negative status based on local testing
PD-L1 positive status based on local testing
You may not be if
Participants with known active CNS metastases, including leptomeningeal, brainstem, meningeal, or spinal cord metastases or compression
Clinically significant risk of hemorrhage or fistula
Major surgery or severe trauma within 4 weeks prior to the first dose, or planned major surgery during the study
History of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation.
Any Grade ≥3 bleeding/hemorrhage events within 28 days of Cycle 1 Day 1, or prior history of clinically significant bleeding events
Clinically significant cardiovascular disease, or other comorbidities, within 6 months prior to first dose
Participants with active autoimmune diseases requiring systemic treatment within the past 2 years
Evidence of non-infectious or drug-induced interstitial lung disease (ILD) pneumonitis
Clareo Health | Symbiotic-GI-16: A Study to Learn About the Study Medicine Called PF-08634404 in Combination With Chemotherapy in Gastroesophageal Cancer
