O-006: Genomic Profiling of Diffuse Gastric Carcinoma (DGC)
Amanda Hemmerich, et al.

This study demonstrates an enrichment for ERBB2 pm in DGC, analogous to ILC of the breast, as well as possible enrichment in other kinase alterations, notably MET amps. Further genomic analysis including assessment of all CDH1 mutations for germline status will be performed. Relatedly, the female preponderance in DGC raises the concern for misdiagnosed ILC, and pathology review will be conducted to assess this possibility.

O-007: ZEBRA: An ACCRU/IRCI Multicenter Phase II Study of Pembrolizumab in Patients with Advanced Small Bowel Adenocarcinoma (SBA)
Katrina Pedersen, et al.

In the largest study of SBA to date, and the first using immunotherapy, Pembrolizumab did not achieve the goal ORR in pretreated advanced SBA pts; however, it may control disease in some MSS patients (1 PR, DCR 50%), though further study is needed to confirm this outcome. Efficacy in MSI-H is confirmed. Further predictive marker testing is underway.

O-008: Proof of Concept of the Abscopal Effect in MSS GI Cancers: A Phase 2 study of Ipilimumab and Nivolumab with radiation in metastatic pancreatic and colorectal adenocarcinoma
Aparna Parikh, et al.

Dual blockade of CTLA-4 and PD-1 with RT is feasible and demonstrates promising activity in patients with advanced MSS CRC and PDAC. Updated efficacy data and outcomes from correlative serial biopsies will be reported subsequently.