DuoHexaBody-CD37\xae, a novel biparatopic CD37 antibody with enhanced Fc-mediated hexamerization as a potential therapy for B-cell malignancies

Simone C Oostindie,Tuna Mutis,Paul W H I Parren,Margaret A Lindorfer,Laurens P Kil,Hendrik J Rademaker,Janine Schuurman,Martine E D Chamuleau,Jeroen H N Van Den Brakel,Ronald P Taylor,Marije B Overdijk,Juliette Van Den Noort,Berris Van Kessel,Frank J Beurskens,Kristin Strumane,Hilma J Van Der Horst,Esther C W Breij,Edward N Van Den Brink

doi:10.1038/s41408-020-0292-7

Abstract

Tetraspanin CD37 has recently received renewed interest as a therapeutic target for B-cell malignancies. Although complement-dependent cytotoxicity (CDC) is a powerful Fc-mediated effector function for killing hematological cancer cells, CD37-specific antibodies are generally poor inducers of CDC. To enhance CDC, the E430G mutation was introduced into humanized CD37 monoclonal IgG1 antibodies to drive more efficient IgG hexamer formation through intermolecular Fc-Fc interactions after cell surface antigen binding. DuoHexaBody-CD37, a bispecific CD37 antibody with the E430G hexamerization-enhancing mutation targeting two non-overlapping epitopes on CD37 (biparatopic), demonstrated potent and superior CDC activity compared to other CD37 antibody variants evaluated, in particular ex vivo in patient-derived chronic lymphocytic leukemia cells. The superior CDC potency was attributed to enhanced IgG hexamerization mediated by the E430G mutation in combination with dual epitope targeting. The mechanism of action of DuoHexaBody-CD37 was shown to be multifaceted, as it was additionally capable of inducing efficient antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis in vitro. Finally, potent anti-tumor activity in vivo was observed in cell line- and patient-derived xenograft models from different B-cell malignancy subtypes. These encouraging preclinical results suggest that DuoHexaBody-CD37 (GEN3009) may serve as a potential therapeutic antibody for the treatment of human B-cell malignancies.

Highlights

B-cell malignancies comprise a heterogeneous group of lymphoproliferative disorders including non-Hodgkin lymphomas (NHL) and chronic lymphocytic leukemia (CLL)
Similar to CD20, CD37 is highly expressed on tumor B cells across all major NHL and CLL subtypes
DuoHexaBody-CD37 exhibits highly potent complement-dependent cytotoxicity (CDC) activity in vitro and ex vivo, which was superior to the parental WT or hexamerization-enhanced CD37 mAbs and to the combinations thereof

Summary

Introduction

B-cell malignancies comprise a heterogeneous group of lymphoproliferative disorders including non-Hodgkin lymphomas (NHL) and chronic lymphocytic leukemia (CLL). CD37 is signaling-competent as it contains intracellular functional ITIM-like and ITAM-like motifs that play a role in pro-survival and pro-apoptotic signaling via the PI3K/AKT pathway. It controls IL-6 receptor signaling through interaction with SOCS312,13. CD37 is highly expressed on malignant B cells in a variety of B-cell lymphomas and leukemias, including NHL and CLL14,15. Multiple CD37targeting agents have shown preclinical or clinical efficacy[5,6,7], including antibody drug conjugates[16,17], a small modular immuno-pharmaceutical protein (SMIP)[18], an antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC) capacity[19], a radiolabeled antibody[20] and chimeric antigen receptor (CAR) T cells[21]. CD37 antibody-based therapeutics currently in (pre-)clinical development are poor inducers of complement-dependent cytotoxicity (CDC)[5,6,7], another powerful Fc-mediated effector mechanism for killing hematological cancer cells[22,23]

Methods

Results

Conclusion