BSI-111

BSI-111 is a fully human monoclonal antibody that acts as a highly selective agonist of CD16a (low affinity immunoglobulin gamma Fc region receptor III-A). It was developed by Biosion for oncology indications, specifically as an anti-CD16a monoclonal antibody with the goal of building a natural killer (NK) cell engager platform. BSI-111 binds specifically to CD16a without recognizing the closely related CD16b, and it demonstrates high affinity for both allelic variants of CD16A (158F and 158V). The antibody shows cross-reactivity to cynomolgus monkey CD16a, can significantly activate NFAT signaling in cell-based reporter assays, and strongly activates primary NK cells. Its Fc region has been engineered for potentially longer half-life and silenced Fc-effector function. The drug is currently in preclinical development for cancer therapy[1][3][4][5].