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At the AIRR C IV meeting in Genoa, the Communications Sub-committee was ratified. Its current members are Jean-Philippe Bürckert (BISC Global, Inc., USA, Co-Leader), Victor Greiff (Univ of Oslo, Norway, Co-Leader), Jamie Scott (Simon Fraser Univ, CA), Susanna Marquez (Yale, USA), and Pam Borghardt (SFU, CA).
The Sub-committee’s mission statement can be found here: https://www.antibodysociety.org/the-airr-community/airr-subcomittees/communications-sub-committee/.
The Antibody Society is pleased to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue.
All the articles are open access; PDFs can be freely downloaded by following the links below.
In this review, Darowski et al. summarize emerging approaches that aim to further evolve CAR-T cell therapy based on combinations of so-called universal or modular CAR-(modCAR-)T cells, and their respective adaptor molecules (CAR-adaptors), which mediate the crosslinking between target and effector cells. The activity of such modCAR-T cells is entirely dependent on binding of the respective CAR-adaptor to both a tumor antigen and to the CAR-expressing T cell. Contrary to conventional CAR-T cells, where the immunological synapse is established by direct interaction of CAR and membrane-bound target, modCAR-T cells provide a highly flexible and customizable development of the CAR-T cell concept and offer an additional possibility to control T cell activity.
Using a sequence-based discovery platform, Trinklein et al. identified new anti-CD3 antibodies from humanized rats that bind to multiple epitopes and elicit varying levels of T-cell activation. In T-BsAb format, 12 different anti-CD3 arms induce equivalent levels of tumor cell lysis by primary T-cells, but potency varies by a thousand-fold. The lead CD3-targeting arm stimulates very low levels of cytokine release, but drives robust tumor antigen-specific killing in vitro and in a mouse xenograft model. This new CD3-targeting antibody underpins a next-generation T-BsAb platform in which potent cytotoxicity is uncoupled from high levels of cytokine release, which may lead to a wider therapeutic window in the clinic.
In this study by Gjetting et al., the Symplex antibody discovery platform was adapted to chicken immunoglobulin genes and combined with high-throughput humanization of antibody frameworks by “mass complementarity-determining region grafting”. Wild type chickens were immunized with an immune checkpoint inhibitor programmed cell death 1 (PD1) antigen, and a repertoire of 144 antibodies was generated. The PD1 antibody repertoire was successfully humanized, and the authors found that most humanized antibodies retained affinity largely similar to that of the parental chicken antibodies. The lead antibody Sym021 blocked PD-L1 and PD-L2 ligand binding, resulting in elevated T-cell cytokine production in vitro. Detailed epitope mapping showed that the epitope recognized by Sym021 was unique compared to the clinically approved PD1 antibodies pembrolizumab and nivolumab. Moreover, Sym021 bound human PD1 with a stronger affinity (30 pM) compared to nivolumab and pembrolizumab, while also cross-reacting with cynomolgus and mouse PD1. This enabled direct testing of Sym021 in the syngeneic mouse in vivo cancer models and evaluation of preclinical toxicology in cynomolgus monkeys. Preclinical in vivo evaluation in various murine and human tumor models demonstrated a pronounced anti-tumor effect of Sym021, supporting its current evaluation in a Phase 1 clinical trial.
At the Genoa AIRR Community Meeting IV, the official logo of the AIRR Community was ratified. AIRR-C members were able to vote between 3 different variations of the logo.
We thank Fran Breden for her outstanding help with the logo design.
The Antibody Society is pleased and proud to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue. All the articles are open access; PDFs can be freely downloaded by following the links below.
Antibodies to watch in 2019.
For the past 10 years, the annual ‘Antibodies to watch’ articles have provided updates on key events in the late-stage development of antibody therapeutics, such as first regulatory review or approval, that occurred in the year before publication or were anticipated to occur during the year of publication. To commemorate the 10th anniversary of the article series and to celebrate the 2018 Nobel Prizes in Chemistry and in Physiology or Medicine, which were given for work that is highly relevant to antibody therapeutics research and development, Kaplon and Reichert expanded the scope of the data presented to include an overview of all commercial clinical development of antibody therapeutics and approval success rates for this class of molecules. The data indicate that:
1) antibody therapeutics are entering clinical study, and being approved, in record numbers;
2) the commercial pipeline is robust, with over 570 antibody therapeutics at various clinical phases, including 62 in late-stage clinical studies; and
3) Phase 1 to approval success rates are favorable, ranging from 17–25%, depending on the therapeutic area (cancer vs. non-cancer).
Ion channels as therapeutic antibody targets.
In this review, Hutchings et al evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. They also discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.
Influence of N-glycosylation on effector functions and thermal stability of glycoengineered IgG1 monoclonal antibody with homogeneous glycoforms.
The separation of various glycoforms to investigate the biological and functional relevance of glycosylation is a major challenge, and the individual contributions of each glycoform is usually not considered when evaluating mAbs with highly heterogeneous distributions. In this study, Wada et al used chemoenzymatic glycoengineering incorporating an endo-β-N-acetylglucosaminidase (ENGase) EndoS2 and its mutant with transglycosylation activity to generate mAb glycoforms with highly homogeneous and well-defined N-glycans to better understand and precisely evaluate the effect of each N-glycan structure on Fc effector functions and protein stability. They demonstrated that the core fucosylation, non-reducing terminal galactosylation, sialylation, and mannosylation of IgG1 mAb N-glycans impact not only on FcγRIIIa binding, antibody-dependent cell-mediated cytotoxicity, and C1q binding, but also FcRn binding, thermal stability and propensity for protein aggregation.
Co-engaging CD47 and CD19 with a bispecific antibody abrogates B-cell receptor/CD19 association leading to impaired B-cell proliferation.
In this report, Hatterer et al describes the generation of a CD47xCD19 bispecific antibody (biAb) to target and deplete B cells via multiple antibody-mediated mechanisms. Interestingly, the biAb, constructed of a CD19 binding arm and a CD47 binding arm, inhibited BCR-mediated B-cell proliferation with an effect even more potent than a CD19 monoclonal antibody (mAb). The inhibitory effect of the biAb was not attributable to CD47 binding because a monovalent or bivalent anti-CD47 mAb had no effect on B cell proliferation. Fluorescence resonance energy transfer analysis demonstrated that co-engaging CD19 and CD47 prevented CD19 clustering and its migration to BCR clusters, while only engaging CD19 (with a mAb) showed no impact on either CD19 clustering or migration. The lack of association between CD19 and the BCR resulted in decreased phosphorylation of CD19 upon BCR activation. Furthermore, the biAb differentially modulated BCR-induced gene expression compared to a CD19 mAb. Taken together, this unexpected role of CD47xCD19 co-ligation in inhibiting B cell proliferation illuminates a novel approach in which two B cell surface molecules can be tethered, to one another in order, which may provide a therapeutic benefit in settings of autoimmunity and B cell malignancies.
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The Antibody Society is pleased and proud to be affiliated with mAbs, a multi-disciplinary journal dedicated to advancing the art and science of antibody research and development. We hope you enjoy these summaries based on the abstracts of the most read papers published in a recent issue. All the articles are open access; PDFs can be freely downloaded by following the links below.
Evolution of a comprehensive, orthogonal approach to sequence variant analysis for biotherapeutics.
As discussed by Lin et al., a cross-functional team of Pfizer colleagues from the Analytical and Bioprocess Development departments worked closely together for over 6 years to formulate and communicate a practical, reliable sequence variant (SV) testing strategy with state-of-the-art techniques that did not necessitate more resources or lengthen project timelines. The final SV screening strategy relies on next-generation sequencing and amino acid analysis as frontline techniques to identify mammalian cell clones with genetic mutations and recognize cell culture process media/feed conditions that induce misincorporations, respectively. Once an industry-wide challenge, sequence variation is now routinely monitored and controlled at Pfizer (and other biopharmaceutical companies) through increased awareness, dedicated cross-line efforts, smart comprehensive strategies, and advances in instrumentation/software, resulting in even higher product quality standards for biopharmaceutical products.
The first World Health Organization International Standard for infliximab products: A step towards maintaining harmonized biological activity.
In this Brief Report, Metcalfe et al. present a collaborative study designed to assess the suitability of the first international standard (IS) for infliximab to serve as an IS for the in vitro biological activity of infliximab. The IS was developed by the UK’s National Institute for Biological Standards and Control (NIBSC). The study involved participants using in vitro cell-based bioassays (TNF neutralization, antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity) and binding assays. The results of this study showed that the candidate preparation, coded 16/170, is suitable as an IS for infliximab bioactivity. This infliximab IS from NIBSC, is intended to support in vitro bioassay calibration and validation by defining international units of bioactivity
Anti-PD1 ‘SHR-1210ʹ aberrantly targets pro-angiogenic receptors and this polyspecificity can be ablated by paratope refinement.
Finlay et al. report that the combination of receptor proteome screening and optimization of the antibody binding interface succeeded in generating novel, higher-potency, specificity-enhanced therapeutic IgGs from a single, clinically sub-optimal progenitor. They show that highly-specific off-target binding events might be an under-appreciated phenomenon in therapeutic antibody development, but that these unwanted properties can be fully ameliorated by paratope refinement.
Deamidation and isomerization liability analysis of 131 clinical-stage antibodies.
As discussed by Lu et al., knowledge of the chemical stability characteristics of clinical-stage therapeutic monoclonal antibodies (mAbs) is fragmented and lacks comprehensive comparative assessment. To address this knowledge gap, the authors produced 131 mAbs with amino acid sequences corresponding to the variable regions of clinical-stage mAbs, subjected these to low and high pH stresses and identified the resulting modifications at amino acid-level resolution via tryptic peptide mapping. Among this large set of mAbs, relatively high frequencies of asparagine deamidation events were observed in CDRs H2 and L1, while CDRs H3, H2 and L1 contained relatively high frequencies of instances of aspartate isomerization.
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