REGN5678-PSMA-hIgG4-S228P

REGN5678 is a human IgG4-based, first-in-class costimulatory bsAb designed to target prostate tumors by bridging prostate specific membrane antigen expressing tumor cells with the costimulatory receptor, CD28, on T cells, and providing amplified T-cell receptor-CD3 complex-mediated T-cell activation within the tumor through the activation of CD28 signaling. At the tumor site, REGN5678 may synergize with PD-1 inhibitors, similar to cemiplimab. In mouse models, REGN5678 in combination with PD-1 antibody has improved anti-tumor activity compared with either therapy alone. By engaging previously activated T-cells that express CD28, REGN5678 may exhibit less toxicity than CD3 directed bi-specifics.