Study to Evaluate the Efficacy and Safety of Andecaliximab Combined With Nivolumab Versus Nivolumab Alone in Adults With Unresectable or Recurrent Gastric or Gastroesophageal Junction Adenocarcinoma

Key Inclusion Criteria

• Histologically confirmed inoperable locally advanced or metastatic adenocarcinoma of the stomach or GEJ which have progressed on at least 1 prior systemic therapy or line of treatment for unresectable/metastatic disease
• Eastern Cooperative Oncology Group (ECOG) performance score of ≤ 1
• Measurable disease according to Response Criteria in Solid Tumors (RECIST) v1.1
• Tumor sites that can be accessed for repeat biopsies
• Archival tumor tissue, preferably obtained from the most recent available biopsy; there must be adequate tissue for a Cochran-Mantel Haenszel (CMH) test stratified by programmed death ligand 1 (PD-L1) stratification test, as assessed by central pathologist
• Individuals not receiving anticoagulant medication must have an international normalized ratio (INR) ≤ 1.5 and activated partial thromboplastin (aPTT) ≤ 1.5 x upper limit of normal (ULN)
• Required baseline laboratory data as outlined in protocol

Key Exclusion Criteria

• Individuals who have received only neoadjuvant or adjuvant therapy for gastric adenocarcinoma
• Radiotherapy within 28 days of randomization
• Uncontrolled intercurrent illness as outlined in protocol
• History of a concurrent or second malignancy except for those outlined in protocol
• Major surgery, within 28 days of first dose of study drug
• Known positive status for human immunodeficiency virus (HIV)
• Known acute or chronic-active infection with hepatitis B virus (HBV) or hepatitis C virus (HCV)
• Chronic daily treatment with oral corticosteroids (dose of > 10 mg/day prednisone equivalent) or other immunosuppressive medications within 14 days of randomization
• Known or suspected central nervous system metastases
• Documented myocardial infarction or unstable/uncontrolled cardiac disease within 6 months of randomization
• Serious systemic fungal, bacterial, viral, or other infection that is not controlled or requires intravenous antibiotics
• Current or history of pneumonitis or interstitial lung disease
• Active known or suspected autoimmune disease with exceptions noted in protocol.
• History of bone marrow, stem cell, or allogenic organ transplantation

NOTE: Other protocol defined Inclusion/ Exclusion criteria may apply.