4010Background: Chemotherapy-refractory GC is a uniformly fatal illness and an unmet therapeutic need. Nivo is a fully human anti-PD-1 monoclonal antibody with a manageable safety profile and efficacy in solid tumors. We report results of a completed A/M GC cohort of CheckMate-032 study evaluating nivo monotherapy and nivo with ipi in pts with solid tumors. Methods: Pts with A/M, histologically confirmed GC, esophageal (EC), or gastroesophageal junction cancer (GEC), irrespective of PD-L1 status, who had progressed on chemotherapy, were treated with nivo 3 mg/kg Q2W (N3), nivo 1 mg/kg + ipi 3 mg/kg (N1+I3), or nivo 3 mg/kg + ipi 1 mg/kg (N3+I1) Q3W x 4 cycles, followed by nivo 3 mg/kg Q2W until confirmed disease progression or intolerable toxicity. Primary endpoint was ORR; other endpoints included safety, OS, and biomarker status. Results: 160 pts with A/M GC were treated with N3 (n = 59), N1+I3 (n = 49), or N3+I1 (n = 52). Baseline characteristics were comparable across cohorts; the majority of pts had ...