Definition

A human immunoglobulin G1 (IgG1) monoclonal antibody targeting Fc gamma receptor IIB (FcgRIIB; CD32B), with potential immunomodulatory- and antineoplastic-enhancing activities. Upon administration, anti-CD32B monoclonal antibody BI-1607 selectively targets and binds to CD32B, an inhibitory Fc gamma receptor (FcgR) protein expressed on immune cells, including macrophages. This prevents both the binding of human epidermal growth factor receptor 2 (HER2; ErbB2; HER-2)-targeting monoclonal antibodies to CD32B, and CD32B-mediated inhibition of the activation of macrophages. By blocking CD32B, BI-1607 may enhance the activity of anti-HER2 monoclonal antibodies. CD32B, an inhibitory member of the FcgR family, is implicated in immune cell desensitization and tumor cell resistance.