A Clinical Trial Evaluating TQB2102 for Injection in Combination With Behmosubaisumab/Payamprolizumab With or Without Chemotherapy in Unresectable Locally Advanced, Recurrent, or Metastatic Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Gastroesophageal Adenocarcinoma

TQB2102 for injection is a novel antibody-coupled drug (ADC) that enhances binding to tumor cell surface HER2 proteins by simultaneously targeting the two non-overlapping epitopes of the HER2 protein, Endothelial Cell Dysfunction 2 (ECD2) and Endothelial Cell Dysfunction 4 (ECD4), increasing HER2 internalization, and then down-regulating the tumor cell surface HER2 proteins more effectively, and doubly blocking the HER2 signaling, to achieve the effects of trastuzumab and Pertuzumab alone and in combination. This is a Phase II study to evaluate the efficacy and safety of TQB2102 for injection in combination with Benmelstobart Injection /Penpulimab Injection ± chemotherapy in patients with unresectable locally advanced, recurrent or metastatic HER2-positive gastroesophageal adenocarcinoma