B7-H3, also known as CD276, is a membrane protein belonging to the B7-CD28 family of immunomodulatory proteins that act as immune checkpoint molecules. B7-H3 is expressed at low levels in normal human tissues but is abnormally high in various tumors and cancers. It plays a critical role in tumor development, progression, and immune evasion, and its expression is associated with poor prognosis.
Due to its regulatory effect on the immune system and high expression in tumor cells, B7-H3 is a promising target for immunotherapy strategies. BCG001, an afucosylated monoclonal antibody developed in collaboration with Mabworks Biotech, has a higher affinity to tumor cells than enoblituzumab and shows more significant ADCC on tumor cells. The candidate molecule is more specific than enoblituzumab, as shown by negative B7-H3 cell line staining and membrane protein array analysis. It did not bind to any target other than B7-H3, indicating greater therapeutic efficacy and safety than enoblituzumab.