FcRn (FCGRT/B2M) Blocker

Neonatal Fc receptor for IgG (FcRn) is a heterodimeric protein consisting of the Fc Gamma Receptor and Transporter encoded by the FCGRT gene, associated with beta-2-Microglobulin (B2M) . FcRn binds to the Fc region of monomeric immunoglobulin G (IgG) . FcRn contributes to an effective humoral immunity by protecting IgGs from degradation, recycling them and extending their half-life in circulation. In addition to IgGs, it regulates the homeostasis of serum albumin. The loss of FcRn in tumor cells has been reported to play a role in cancer by increasing the breakdown of albumin to amino acids needed by tumor cells for proliferation.The function of FcRn can be exploited by engineering therapeutic antibodies to increase their binding to FcRn, thereby improving their half-life and therapeutic efficacy. For example, an antibody cocktail that contains Fc mutations and an extended half-life (Evusheld) is used to treat COVID-19. There are now several other drugs in clinical using similar strategies.