Bispecific antibodies targeting tumor-associated antigens and neutralizing complement regulators increase the efficacy of antibody-based immunotherapy in mice

Abstract

The efficacy of antibody-based immunotherapy is due to the activation of apoptosis, the engagement of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity (CDC). We developed a novel strategy to enhance CDC using bispecific antibodies (bsAbs) that neutralize the C-regulators CD55 and CD59 to enhance C-mediated functions. Two bsAbs (MB20/55 and MB20/59) were designed to recognize CD20 on one side. The other side neutralizes CD55 or CD59. Analysis of CDC revealed that bsAbs could kill 4-25 times more cells than anti-CD20 recombinant antibody in cell lines or cells isolated from patients with chronic lymphocytic leukemia. The pharmacokinetics of the bsAbs was evaluated in a human-SCID model of Burkitt lymphoma. The distribution profile of bsAbs mimics the data obtained by studying the pharmacokinetics of anti-CD20 antibodies, showing a peak in the tumor mass 3-4 days after injection. The treatment with bsAbs completely prevented the development of human/SCID lymphoma. The tumor growth was blocked by the activation of the C cascade and by the recruitment of macrophages, polymorphonuclear and natural killer cells. This strategy can easily be applied to the other anti-tumor C-fixing antibodies currently used in the clinic or tested in preclinical studies using the same vector with the appropriate modifications.

The dual role of complement in cancer and its implication in anti-tumor therapy

“…This approach is aiming at combining the tissue-specificity of an anti-tumor mAb together with the CDC effects of an anti-CRP mAb. Such antibodies against Crry, CD59 and CD55 have shown promising results (118,(128)(129)(130)(131).…”

Critical Role and Therapeutic Control of the Lectin Pathway of Complement Activation in an Abortion-Prone Mouse Mating

“…This recombinant Ab was previously found to prevent C5 activation in several animal models developed in mice (17,18) and rats (16,(19)(20)(21)). An essentially similar procedure was followed for the production of a recombinant Ab to human CD20 reported in a previous publication (22) and used in this study as an unrelated Ab.…”

Complement in therapy and disease

“…Remarkably, ofatumumab allows for much lower CD20 expression levels and the presence of much higher levels of (negative) complement regulatory proteins in complement-mediated cell killing than rituximab (Barth et al, 2012;Teeling et al, 2004;van Meerten et al, 2010). Based on these latter findings, antibody constructs targeting both CD20 and CD55 or CD59 were developed, which showed increased killing in pre-clinical studies compared to targeting CD20 alone (Macor et al, 2014(Macor et al, , 2007Ziller et al, 2005).…”