131P The efficacy and safety of cadonilimab with or without trastuzumab in combination with SOX as first-line (1L) treatment for advanced gastric (G) or gastroesophageal Junction adenocarcinoma (GEJA)

PD-1 inhibitors plus chemotherapy was approved as standard 1L treatment for advanced HER2-negative G/GEJA, but its outcomes remain poor in patients (pts) with low PD-L1 expression. For advanced HER2-positive G/GEJA, integrating immunotherapy with trastuzumab and chemotherapy has shown a significant improvement in progression-free survival (PFS) and overall survival (OS). Cadonilimab, a PD-1/CTLA-4 bispecific antibody, has demonstrated its efficacy and safety in previously untreated advanced G/GEJA pts, even those with PD-L1 CPS<5 in a phase III study.