Collectively, in line with the in vitro results, HLX22 in combination with HLX02 strongly enhanced antitumor activity either in human gastric CDX or in PDX tumor models with 3 + HER2 expression, suggesting that HLX22 and HLX02 combination regimen had the potential to change the paradigm for treatment of HER2-positive gastric cancer. Here, ERBB2 is linked to gastric cancer.