CD20 as target for immunotherapy

Most lymphomas and leukemias are neo¬plasms of B cells. Due to the many different B cell development stages from which these neoplasms arise, the resulting diseases are quite heterogeneous, which amongst other things is manifested in different tumor growth location, proliferation potential and surface antigen repertoire. Neverthe¬less, some population characteristics are found in almost all B cell malignancies as the cell-of-origin is identical. One of these is the cell surface antigen CD20. Originally used as a marker to distinguishing B cells from other lymphocytes, it quickly became a target for immunotherapy. Immuno-therapy is a treatment that makes use of immune system components to fight cancer, in this case by the injection of a monoclonal antibody specifically targeting one protein: CD20. The addition of CD20-targeting an¬tibodies to an anti-tumor treatment allows your immune system to recognize CD20-ex¬pressing B cells (diseased and healthy), and dispose of them. Overall, after several decades of research and therapeutic experience with antibodies targeting CD20, new functional discoveries as well as therapeutic advances are still being made, and CD20 therefore remains a highly attractive and fruitful target for the therapy of B cell malignancies as well as certain B-cell mediated autoimmune diseases.LUMC / Geneeskund

Response to Comment on "Type I CD20 Antibodies Recruit the B Cell Receptor for Complement-Dependent Lysis of Malignant B Cells"

Transplantation and autoimmunit

Loss of CD20 and bound CD20 antibody from opsonized B cells occurs more rapidly because of trogocytosis mediated by Fc receptor-expressing effector cells than direct internalization by the B cells

We previously reported that 1 h after infusion of CD20 mAb rituximab in patients with chronic lymphocytic leukemia (CLL), > 80% of CD20 was removed from circulating B cells, and we replicated this finding, based on in vitro models. This reaction occurs via an endocytic process called shaving/trogocytosis, mediated by Fc gamma R on acceptor cells including monocytes/macrophages, which remove and internalize rituximab-CD20 immune complexes from B cells. Beers et al. reported that CD20 mAb-induced antigenic modulation occurs as a result of internalization of B cell-bound mAb-CD20 complexes by the B cells themselves, with internalization of similar to 40% observed after 2 h at 37 degrees C. These findings raise fundamental questions regarding the relative importance of shaving versus internalization in promoting CD20 loss and have substantial implications for the design of mAb-based cancer therapies. Therefore, we performed direct comparisons, based on flow cytometry, to determine the relative rates and extent of shaving versus internalization. B cells, from cell lines, from patients with CLL, and from normal donors, were opsonized with CD20 mAbs rituximab or ofatumumab and incubated for varying times and then reacted with acceptor THP-1 monocytes to promote shaving. We find that shaving induces considerably greater loss of CD20 and bound mAb from opsonized B cells in much shorter time periods (75-90% i

Cognition and health-related quality of life in a well-defined subgroup of patients with partial epilepsy

To investigate the extent and nature of the objective and subjective cognitive deficits and health-related quality of life (HRQOL) in adult outpatients with relatively well-controlled partial epilepsy without symptomatic aetiology, who were on carbamazepine (CBZ) monotherapy. Furthermore, we studied the influence of the epilepsy history and medication on various cognitive functions and the HRQOL. 56 outpatients (29 male, 27 female, mean age 41.3 years) with partial epilepsy were compared with 56 age-, gender-, and education-matched healthy controls. Patients were tested on attention, memory, speed of information processing, and executive functioning. Questionnaires aimed at measuring self-perceived cognitive functioning (CFQ) and HRQOL (SF-36) were administered. Mann Whitney-U tests were used to compare the two groups. Linear regression analysis was performed to identify the epilepsy and medication-related factors that are associated with cognitive functioning and HRQOL. Patients scored lower on measures of attention (P = 0.03), learning (P = 0.02) and speed of information processing (P = 0.00). Mental aspects of HRQOL such as fatigue were lower (P = 0.00), whereas physical functioning was unaffected. These patients also expressed reductions in mental functioning as indicated by a low self-perceived cognitive functioning (P = 0.01). Age at onset, duration of epilepsy, seizure type, seizure frequency, localisation, years on CBZ, and CBZ dosage were not related to cognitive functioning or HRQOL. Patients with partial epilepsy, even when able to maintain regular jobs, have impaired cognition and HRQOL that cannot be attributed to their epilepsy history or CBZ dosage or years of CBZ intake. Therefore, physicians should be more aware of their cognition and HRQOL, in addition to the antiepileptic drug regime

DuoBody-CD3xCD20 induces potent T-cell-mediated killing of malignant B cells in preclinical models and provides opportunities for subcutaneous dosing

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 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.Transplantation and autoimmunit

Duobody-CD3xCD20 Shows Unique and Potent Preclinical Anti-Tumor Activity in Vitro and In Vivo, and Is Being Evaluated Clinically in Patients with B-Cell Malignancies

Transplantation and autoimmunit