tislelizumab + zanidatamab

Tislelizumab + zanidatamab is an investigational combination therapy consisting of two monoclonal antibodies: tislelizumab, a humanized IgG4 anti-programmed death-1 (PD-1) immune checkpoint inhibitor, and zanidatamab, a bispecific antibody targeting two distinct extracellular domains of the human epidermal growth factor receptor 2 (HER2). Tislelizumab blocks PD-1 to enhance T-cell mediated antitumor immunity, while zanidatamab binds HER2 with biparatopic binding for dual signal blockade, increased receptor internalization and downregulation, and potent effector function. This combination is being studied primarily as first-line treatment for advanced or metastatic HER2-positive gastroesophageal adenocarcinoma in combination with chemotherapy. Early-phase studies have shown promising antitumor activity and manageable safety profiles[1][3][6].