Fc region of trastuzumab (Trastuzumab Fc)

The Fc region of trastuzumab is the fragment crystallizable domain of the humanized IgG1 monoclonal antibody trastuzumab. It is not a standalone therapeutic target but a critical functional component of the drug that mediates immune effector functions. While the Fab region of trastuzumab binds to the HER2 receptor on tumor cells, the Fc region interacts with Fc gamma receptors (FcγRs) on immune cells, such as natural killer (NK) cells and macrophages, to trigger antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). It also binds to the neonatal Fc receptor (FcRn), which protects the antibody from lysosomal degradation and extends its circulation time. Engineering of this region, as seen in margetuximab, is a key strategy to enhance the immune-mediated anti-tumor activity of HER2-targeted therapies by optimizing affinity for activating versus inhibitory Fc receptors.

Other names

Trastuzumab Fc domainFragment crystallizable region of trastuzumabIgG1 Fc region of trastuzumab

The Fc region of trastuzumab binds to Fc gamma receptors (FcγRs) on immune effector cells to induce ADCC and ADCP, and to the neonatal Fc receptor (FcRn) to regulate its serum half-life.