Background: NIVO + chemo demonstrated clinically meaningful improvement in overall survival (OS) and an acceptable safety profile vs chemo in previously untreated Chinese pts from CheckMate 649, consistent with the overall study population with advanced GC/GEJC/EAC. 1L NIVO + chemo is approved for advanced GC/GEJC/EAC in multiple countries, including China. We report 4-yr results of NIVO + chemo vs chemo in Chinese pts from CheckMate 649. Methods: Adults with previously untreated, unresectable advanced or metastatic, non-HER2+ GC/GEJC/EAC were enrolled regardless of programmed death ligand 1 (PD-L1) expression. Randomized pts received NIVO (360 mg Q3W or 240 mg Q2W) + chemo (XELOX Q3W or FOLFOX Q2W), NIVO + ipilimumab, or chemo. Dual primary endpoints for NIVO + chemo vs chemo were OS and progression-free survival (PFS) by blinded independent central review (BICR) in pts with PD-L1 combined positive score (CPS) ≥ 5. Results: 208 Chinese pts were randomized to NIVO + chemo or chemo. At 49-month (mo) minimum follow-up, NIVO + chemo continued to demonstrate OS and PFS benefit vs chemo in pts with PD-L1 CPS ≥ 5 and in all randomized pts (Table). The 4-yr OS rate was 25% with NIVO + chemo vs 11% with chemo in pts with PD-L1 CPS ≥ 5 and 21% vs 9% in all randomized pts. Objective response rate (ORR; 95% CI) per BICR in pts with PD-L1 CPS ≥ 5 who had measurable lesions at baseline was 68% (56–79) with NIVO + chemo vs 48% (36–60) with chemo; corresponding ORR in all randomized pts was 66% (55–76) and 45% (35–56). Responses were more durable with NIVO + chemo vs chemo both in pts with PD-L1 CPS ≥ 5 (median duration of response [mDOR; 95% CI] 12.5 mo [7.2–23.4] vs 6.9 mo [3.9–8.5]) and in all randomized pts (mDOR [95% CI] 12.5 mo [7.2–17.7] vs 5.6 mo [4.4–8.3]). No new safety signals were identified (Table). Conclusions: After 4 yrs of follow-up, NIVO + chemo continued to demonstrate clinically meaningful survival benefit and more durable responses vs chemo in Chinese pts, with an acceptable safety profile. These results are consistent with previous reports and with the overall study population with advanced GC/GEJC/EAC and further support NIVO + chemo as a standard 1L treatment option for Chinese pts. Clinical trial information: NCT02872116.

^aPer BICR. TRAE, treatment-related adverse event.