PD-1 inhibitors + trastuzumab

PD-1 inhibitors + trastuzumab is a **combination therapy** used primarily in the treatment of HER2-positive cancers, most notably advanced and metastatic gastric cancer and breast cancer. This regimen combines **PD-1 inhibitors** (such as pembrolizumab, nivolumab, sintilimab, tislelizumab, toripalimab, or camrelizumab) with **trastuzumab**, a monoclonal antibody targeting HER2. PD-1 inhibitors are immune checkpoint inhibitors that block the PD-1 receptor on T cells, thereby enhancing immune responses against tumor cells by preventing immune evasion[2][4][6]. Trastuzumab targets and inhibits the human epidermal growth factor receptor 2 (HER2) on tumor cells, disrupting downstream signaling for cell growth and survival. The combination has shown improved efficacy over trastuzumab and chemotherapy alone, especially in HER2-positive gastric cancer, by modulating the tumor microenvironment, enhancing T cell activity, and overcoming trastuzumab resistance[1][3][5][7]. Combination therapy is typically administered intravenously, with specific regimens depending on the PD-1 inhibitor used. The combination is under advanced clinical investigation and is not a single manufactured product but rather a regimen involving approved monoclonal antibodies.