Background: DuoBody (R)-CD3xCD20 (GEN3013) is a full-length human IgG1 bispecific antibody (bsAb) recognizing CD3 and CD20, generated by controlled Fab-arm exchange. Its Fc domain was silenced by... Show moreBackground: DuoBody (R)-CD3xCD20 (GEN3013) is a full-length human IgG1 bispecific antibody (bsAb) recognizing CD3 and CD20, generated by controlled Fab-arm exchange. Its Fc domain was silenced by introduction of mutations L234F L235E D265A.Methods: T-cell activation and T-cell-mediated cytotoxicity were measured by flow cytometry following co-culture with tumour cells. Anti-tumour activity of DuoBody-CD3xCD20 was assessed in humanized mouse models in vivo. Non-clinical safety studies were performed in cynomolgus monkeys.Findings: DuoBody-CD3xCD20 induced highly potent T-cell activation and T-cell-mediated cytotoxicity towards malignant B cells in vitro. Comparison of DuoBody-CD3xCD20 to CD3 bsAb targeting alternative B-cell antigens, or to CD3xCD20 bsAb generated using alternative CD20 Ab, emphasized its exceptional potency. In vitro comparison with other CD3xCD20 bsAb in clinical development showed that DuoBody-CD3xCD20 was significantly more potent than three other bsAb with single CD3 and CD20 binding regions and equally potent as a bsAb with a single CD3 and two CD20 binding regions. DuoBody-CD3xCD20 showed promising anti-tumour activity in vivo, also in the presence of excess levels of a CD20 Ab that competes for binding. In cynomolgus monkeys, DuoBody-CD3xCD20 demonstrated profound and long-lasting B-cell depletion from peripheral blood and lymphoid organs, which was comparable after subcutaneous and intravenous administration. Peak plasma levels of DuoBody-CD3xCD20 were lower and delayed after subcutaneous administration, which was associated with a reduction in plasma cytokine levels compared to intravenous administration, while bioavailability was comparable.Interpretation: Based on these preclinical studies, a clinical trial was initiated to assess the clinical safety of subcutaneous DuoBody-CD3xCD20 in patients with B-cell malignancies. (C) 2020 The Authors. Published by Elsevier B.V. Show less
Benonisson, H.; Altintas, I.; Sluijter, M.; Verploegen, S.; Labrijn, A.F.; Schuurhuis, D.H.; ... ; Hall, T. van 2019
Immune responsiveness is carefully regulated. Cells of the immune system have to respond adequately to invading micro-organisms and possibly to transformed cells, but tolerance for the own body... Show moreImmune responsiveness is carefully regulated. Cells of the immune system have to respond adequately to invading micro-organisms and possibly to transformed cells, but tolerance for the own body constituents needs to be preserved. Dendritic cells (DC) comprise a family of professional antigen presenting cells (APC) that play a central role in the regulation of the immune response. Immature DC, located in the periphery, can efficiently take up Ag, but lack the co-stimulatory signals for effective T-cell activation. Upon maturation, DC migrate to secondary lymphoid organs and increase the expression of co-stimulatory molecules and MHC molecules. Mature DC are very efficient in priming na____ve T-cells. In contrast to their T-cell priming capacity, DC in peripheral tissues constitutively process and present Ag in the absence of pathogen-related or endogenous inflammatory stimuli, and make a major contribution to peripheral tolerance by inducing unresponsiveness or deletion of specific T-cells. The central role of DC in controlling immunity makes these cells attractive tools for many clinical situations that involve T-cells: induction of tolerance in case of transplantation, allergy and autoimmune disease and induction of efficient T-cell responsiveness in case of infection and tumors. Many tumor components do not elicit Ag-specific T-cell responses in patients, which may be due to the absence of functional DC in tumors or the secretion of factors by tumor cells that reduce DC development and function. Application of tumor Ag to DC ex vivo and reinfusion of these DC leads to induction of specific immunity. In animals this strategy can lead to protection against tumors and even a reduction in size of established tumors. At present similar studies are carried out in patients. The research described in this thesis focuses on the requirements for induction of efficient cytotoxic T lymphocyte (CTL)- responses and tumor immunity by DC. Different modes of Ag presentation were studied for the induction of CTL-responses and tumor protection. Show less
