sotiburafusp alfa

A recombinant, humanized fusion protein composed of a monoclonal antibody directed against the immunosuppressive ligand programmed cell death-1 ligand 1 (PD-L1; cluster of differentiation 274; CD274) fused to vascular endothelial growth factor receptor 1 (VEGFR-1/FLT-1), with potential anti-angiogenesis, immune checkpoint inhibitory and antineoplastic activities. Upon administration of sotiburafusp alfa, the anti-PD-L1 antibody moiety specifically targets and binds to PD-L1 expressing cells in the tumor microenvironment (TME). In turn, VEGFR-1 moiety binds to pro-angiogenic vascular endothelial growth factors (VEGFs), thereby preventing VEGFs from binding to the endogenous receptors. Disruption of the binding of VEGFs to their cellular receptors may result in the inhibition of tumor angiogenesis and metastasis, and ultimately tumor regression. PD-L1, a transmembrane protein, is expressed on the surface of antigen presenting cells (APCs) and on many cancer cell types. PD-L1 binding to PD-1, a negative regulator of the immune system on activated T cells, limits the expansion and survival of CD8-positive T cells, suppresses the immune system and results in immune evasion.