1D09C3

1D09C3 is a fully human monoclonal IgG4-type antibody that targets the human leukocyte antigen-DR (HLA-DR), a component of the major histocompatibility complex (MHC) class II molecule, which is primarily expressed on blood cells and certain tumor cells. Developed for the treatment of lymphoid cancers, including B-cell and T-cell lymphomas as well as chronic lymphocytic leukemia, 1D09C3 binds to MHC class II-positive tumor cells and induces programmed cell death (apoptosis) through activation of reactive oxygen species (ROS), c-Jun-NH2-kinase (JNK) signaling, mitochondrial membrane depolarization, and release of apoptosis-inducing factor from mitochondria. This mechanism does not require a functioning immune system for its cytotoxic effect. In clinical studies, 1D09C3 demonstrated dose-dependent reduction in peripheral blood B cells and monocytes in patients with relapsed or refractory B cell malignancies. The drug was granted orphan drug designation by the European Commission for chronic lymphocytic leukemia but development has been discontinued[1][3][4][5][6][7].