TEST:

MSI-IVD Kit

NO LIMIT (WJOG13320G/CA209-7W7) is a phase II trial of nivolumab plus low-dose ipilimumab (NIVO+IPI) for MSI-H advanced gastric or esophagogastric junction cancer (GC) in the first-line setting.1 Here, we investigated the relationship between the number of positive MSI markers and the efficacy of NIVO+IPI in NO LIMIT study. The number of MSI markers is not related to the efficacy of NIVO+IPI in NO LIMIT study. Further follow-up is needed to confirm the relationship between survival. 1.

We conducted a prospective observational study as screening for WJOG13320G, a single arm phase 2 trial of Nivolumab plus low dose Ipilimumab (jRCT2080225304), and to clarify the prevalence and clinicopathological features of chemotherapy-naïve MSI-H advanced G/GEJC. Conclusions The proportion of MSI-H in unresectable chemotherapy-naïve advanced G/GEJC was 5.6%. MSI-H G/GEJC was characterized by female, older age, lower stomach, no liver metastases, and HER2-negative.

Treatment-related death was not observed. Conclusions The chemo-free strategy with a combination of nivolumab and low-dose ipilimumab demonstrated high and robust efficacy with good tolerability in MSI-H GC patients.

Gene expression analysis in the PS-matched cohort suggested that recurrence was associated with the immunosuppressive microenvironment in MSI-H tumors but with expression of cancer/testis antigen genes in MSS tumors. Our data reveal a better adjusted survival for MSI-H versus MSS stage II GC treated with S-1 adjuvant therapy, and they suggest that mechanisms of recurrence differ between MSI-H and MSS tumors.

Notably, immune checkpoint inhibitors (ICIs) were administered to a greater proportion of patients with MSI-H/dMMR tumors (34.0%) than to patients with non–MSI-H/proficient MMR tumors (7.2%); most (77.8%) of the MSI-H/dMMR population received ICIs in the second-line or later setting. Table: 261MO Prevalence of MSI-H/dMMR across tumor types in the overall population and regional cohorts % (n/N) Overall population Asia-Pacific (Korea, Singapore, Taiwan) cohort (Ventana MMR RxDx Panel) Japan cohort (MSI-IVD Kit [FALCO]) Biliary tract 3.3 (7/209) 2.7 (3/111) 4.1 (4/98) Gastric 6.3 (18/285) 7.4 (14/189) 4.2 (4/96) Pancreatic 0.4 (2/486) N/A 0.4 (2/486) Cervical 2.6 (5/190) 4.0 (3/75) 1.7 (2/115) Endometrial 18.4 (52/282) 14.6 (19/130) 21.7 (33/152) Ovarian 4.2 (22/518) 4.9 (19/390) 2.3 (3/128) Conclusions The prevalence of MSI-H/dMMR across the 6 tumor types in this analysis of Asian patients was consistent with literature reports on non-Asian patients.