At data cut-off (Oct. 29, 2021), 45 pts were enrolled and treated with KN026; 39 were eligible for response evaluation (25 pts in Cohort 1 and 14 pts in Cohort 2). In Cohort 1, ORR was 56% (95%CI 35%-76%) with 14 PR; the median DoR was 9.7 months (mo) (95%CI 4.2-not evaluable (NE)). At a median follow-up of 14.7 mo (95%CI 9.4-16.5), the median PFS was 8.3 mo (95%CI 4.2-11.4), and median OS was 16.3 mo (95% CI 11.0- NE). In Cohort 2, ORR was 14% (95%CI 2%-43%), with median DoR being 6.2 mo (95%CI 3.2-NE). At a median follow-up of 27.5 mo (95%CI 4.1-NE), the median PFS was 1.4 mo (95%CI 1.4-4.1), and median OS was 9.6 mo (95% CI 3.5-14.9). KN026 monotherapy yielded promising efficacy with mild to moderate toxicities in pts with previously treated, advanced GC/GEJC.