Q1 · MEDICINE
Article
Author: Hötzel, Isidro ; Hristopoulos, Maria ; Sukumaran, Siddharth ; DiCara, Danielle ; Clark, Vanessa ; Ellerman, Diego ; Harris, Michael J ; Totpal, Klara ; Wu, Thomas D ; Lee, Genee Y ; Ye, Zhengmao ; Menzies, Sam A ; Danilenko, Dimitry ; Johnston, Jennifer ; Cook, Ryan ; Stagg, Nicola J ; Li, Ji ; Junttila, Teemu T ; Nakamura, Rin ; Luis, Elizabeth ; McCarty, Luke ; Sumiyoshi, Teiko ; James, John R ; Slaga, Dionysos
The anti-FcRH5/CD3 T cell-dependent bispecific antibody (TDB) targets the B cell lineage marker FcRH5 expressed in multiple myeloma (MM) tumor cells. We demonstrate that TDBs trigger T cell receptor activation by inducing target clustering and exclusion of CD45 phosphatase from the synapse. The dimensions of the target molecule play a key role in the efficiency of the synapse formation. The anti-FcRH5/CD3 TDB kills human plasma cells and patient-derived myeloma cells at picomolar concentrations and results in complete depletion of B cells and bone marrow plasma cells in cynomolgus monkeys. These data demonstrate the potential for the anti-FcRH5/CD3 TDB, alone or in combination with inhibition of PD-1/PD-L1 signaling, in the treatment of MM and other B cell malignancies.