antibody therapeutics Archives - The Antibody Society

Most read from mAbs

November 21, 2018 by Janice Reichert

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 downloaded by following the links below.

Issue 10.8 (November/December 2018)

Rapid, automated characterization of disulfide bond scrambling and IgG2 isoform determination. In this new report, Resemann et al. discuss a rapid LC-MALDI-TOF/TOF workflow that can both identify the IgG2 disulfide linkages and provide a semi-quantitative assessment of the distribution of the disulfide isoforms. They established signature disulfide-bonded IgG2 hinge peptides that correspond to the A, A/B, and B disulfide isoforms, and can be applied to the fast classification of IgG2 isoforms in heterogeneous mixtures.

Charge variant native mass spectrometry benefits mass precision and dynamic range of monoclonal antibody intact mass analysis. Bailey et al. describe charge variant native mass spectrometry (CVMS), an integrated native ion exchange mass spectrometry-based charge variant analytical approach that delivers detailed molecular information in a single, semi-automated analysis. They used pure volatile salt mobile phases over a pH gradient that effectively separated variants based on minimal differences in isoelectric point. Characterization of variants such as deamidation, which are traditionally unattainable by intact mass due to their minimal molecular weight differences, were measured unambiguously by mass and retention time to allow confident MS1 identification. The authors demonstrated that efficient chromatographic separation allows introduction of the purified forms of the charge variant isoforms into the Orbitrap mass spectrometer. Based on their results, they conclude that the CVMS method allows confident assignment of intact monoclonal antibody isoforms of similar mass and relative abundance measurements across three orders of magnitude dynamic range.

A systematic approach for analysis and characterization of mispairing in bispecific antibodies with asymmetric architecture. In this new report, Wang et al. discuss a systematic approach for analysis and characterization of mispairing in asymmetric bispecific antibodies. This approach consists of three orthogonal components, the first of which is a liquid chromatography (LC)-mass spectrometry (MS)–based method to measure the mass of intact antibodies. This method is used for fast analysis of mispairing and requires minimal method development, which makes it an ideal choice for early-stage development. The second component is a hydrophobic interaction chromatography (HIC)–based mispairing method that is suitable for lot release testing. The HIC method is robust and quality control friendly, and offers great linearity, precision, and accuracy. The third component is a two-dimensional LC-MS method for on-line chromatographic peak identification, which not only expedites this task but also reduces the risk of undesirable modifications during conventional fraction collection. These three methods dovetail to form the foundation of a complementary toolbox for analysis and characterization of mispairing in asymmetric bispecific antibodies and provide guidance and support for process development throughout the drug development life cycle.

Characterization and analysis of scFv-IgG bispecific antibody size variants. Cao et al. report size variants that were observed for an appended scFv-IgG bispecific antibody. Structural characterization studies showed that the size variants resulted from the engineered disulfide bond on the scFv, whereby the engineered disulfide was found to be either open or unable to form an intrachain disulfide bond due to cysteinylation or glutathionylation of the cysteines. Furthermore, the scFv engineered cysteines also formed intermolecular disulfide bonds, leading to the formation of highly stable dimers and aggregates. Because both the monomer variants and dimers showed lower bioactivity, they were considered to be product-related impurities that must be monitored and controlled. To this end, the authors developed and optimized a robust, precise, and accurate high-resolution size-exclusion chromatographic method, using a statistical design-of-experiments methodology.

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Winners of the Antibody Engineering & Therapeutics Student/Postdoc Poster Competition

November 18, 2018 by The Antibody Society

Congratulations to our winners!

To recognize the research activities of promising student and postdoctoral attendees of Antibody Engineering & Therapeutics, The Antibody Society sponsors a competition for our student/postdoc members who submit posters for display at the meeting. Our judges select the best work based on originality, relevance and perceived impact on the field of antibody R&D.

This year, our judges selected 3 student/postdocs winners who receive: 1) a complimentary registration to attend the conference and pre-conference sessions; 2) an opportunity to give a short oral presentation of their work in one of the conference sessions; and 3) support for travel expenses.

The winners of the contest are:

Madeleine Jennewein (Ph.D. candidate, Harvard University). Poster title: Trans-placental antibody transfer selects for highly functional antibodies

Junpeng Qi (Postdoctoral Associate, The Scripps Research Institute. Poster title: Potent and selective antitumor activity of a T cell-engaging bispecific antibody targeting a membrane-proximal epitope of ROR1

Pietro Sormanni (Borysiewicz Biomedical Sciences Fellow (postdoctoral), University of Cambridge). Poster title: Third generation antibody discovery: In silico rational design

Antibody Engineering & Therapeutics, the annual meeting of The Antibody Society, is managed by KNect365. The meeting will be held December 10-13, 2018 in San Diego, CA. Society members receive a 15% discount on the registration fee. Contact us at membership@antibodysociety.org for the code.

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Most read from mAbs issue 10.7

October 9, 2018 by Janice Reichert

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 downloaded by following the links below.

MAbs Issue 10.7 (October 2018)

Platform development for expression and purification of stable isotope labeled monoclonal antibodies in Escherichia coli. In this report, Reddy et al. present the expression and purification of a stable isotope labeled mAb from a genetically engineered E. coli strain capable of forming disulfide bonds in its cytoplasm. Using 2D NMR spectral fingerprinting, they show that the unlabeled mAb and the mAb singly or triply labeled with 13C, 15N, 2H are well folded, with only minor structural differences relative to the mammalian cell-produced mAb that are attributed to the lack of glycosylation in the Fc domain.

Massive parallel screening of phage libraries for the generation of repertoires of human immunomodulatory monoclonal antibodies. Sasso et al discuss a novel approach for the generation of several novel human immunomodulatory antibodies capable of binding their targets in their native conformation and useful for therapeutic applications. They performed a massive parallel screening of phage libraries by using activated human lymphocytes to generate large collections of scFvs against 10 immune checkpoints: LAG-3, PD-L1, PD-1, TIM3, BTLA, TIGIT, OX40, 4-1BB, CD27 and ICOS. By next-generation sequencing and bioinformatics analysis, they ranked individual scFvs in each collection and identified those with the highest level of enrichment. Human IgGs from three of these collections (i.e., PD-1, PD-L1 and LAG-3) were generated and shown to have comparable or better binding affinity and biological activity than clinically validated mAbs. The repertoires generated in this work represent a convenient source of agonistic or antagonistic antibodies against the ‘Checkpoint Immunome’ for preclinical screening and clinical implementation of optimized treatments.

High-throughput screening of antibody variants for chemical stability: identification of deamidation-resistant mutants. In this report, DiCara et al describe a high-throughput method for antibody stability screening during the early stages of antibody discovery and highlight the value of broad searches of antibody sequence space. They developed a high-throughput assay to characterize asparagine deamidation and used it to identify a mutation that unexpectedly stabilizes a critical asparagine. Ninety antibody variants were incubated under thermal stress in order to induce deamidation and screened for both affinity and total binding capacity. Surprisingly, a mutation five residues downstream from the unstable asparagine greatly reduced deamidation.

Extending human IgG half-life using structure-guided design. Booth et al. report on the development of a structure- and network-based framework to interrogate the engagement of IgG with multiple Fc receptors (FcRn, C1q, TRIM21, FcγRI, FcγRIIa/b, FcγRIIIa) simultaneously. They identified features that govern Fc-FcRn interactions and identified multiple distinct pathways for enhancing FcRn binding in a pH-specific manner. Network analysis provided a novel lens to study the allosteric impact of half-life-enhancing Fc mutations on FcγR engagement, which occurs distal to the FcRn binding site. Applying these principles, they engineered a panel of unique Fc variants that enhance FcRn binding while maintaining robust biophysical properties and wild type-like binding to activating receptors.

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We encourage you to join the Society to take advantage of the substantial benefits of membership, including discounts on fees for selected KNect365, CHI, and Hanson Wade meetings, discounted subscriptions to Society-affiliated journals PEDS and mAbs (special subscription rate of US $84 online only access for Antibody Society members) and access to information in the Members Only section of the website. In particular, we encourage members to take advantage of the discount on registration for Antibody Engineering & Therapeutics, which is the annual meeting of The Antibody Society traditionally held in San Diego in December. Membership is free for students, post-docs and employees of our corporate sponsors!

First approval for cemiplimab-rwlc

September 28, 2018 by Janice Reichert

On September 28, 2018, the U.S. Food and Drug Administration (FDA) approved cemiplimab-rwlc (Libtayo) for the treatment of patients with metastatic cutaneous squamous cell carcinoma (CSCC) or locally advanced CSCC who are not candidates for curative surgery or curative radiation. Cemiplimab-rwlc is the third antibody therapeutic targeting PD1 to be granted an FDA approval, but it is the first drug to be approved in the US specifically for advanced CSCC.

FDA’s approval of Libtayo was based on a combined analysis of data from an open-label, multi-center, non-randomized Phase 2 trial known as EMPOWER-CSCC-1 (Study 1540) and two advanced CSCC expansion cohorts from a multi-center, open-label, non-randomized Phase 1 trial (Study 1423). A total of 108 patients (75 with metastatic disease and 33 with locally-advanced disease) were included in the efficacy evaluation. The confirmed objective response rate for all patients treated with Libtayo was 47%. FDA granted cemiplimab Breakthrough Therapy Designation status for advanced CSCC in 2017, and the drug’s marketing application was granted a priority review.

The Antibody Society maintains a comprehensive table of approved mAb therapeutics and those in regulatory review in the EU or US. As of Sep 28, a total of 11 antibody therapeutics had been granted first approvals in either the US or EU in 2018, and marketing applications for another 5 that have not yet been approved in either the EU or US are undergoing review in these regions. Please log in to access the table in either PDF or Excel formats, located in the Members Only section.

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Most read from mAbs issue 10.6

September 24, 2018 by Janice Reichert

Issue 10.6 (Aug/Sep 2018)

Antigen recognition by single-domain antibodies: structural latitudes and constraints. In this new review, Henry and MacKenzie comprehensively surveyed the evidence in support of the hypothesis that sdAbs may adopt paratope structures that predispose them to preferential recognition of recessed protein epitopes, but poor or non-recognition of protuberant epitopes and small molecules. They found some support for a global structural difference in the paratope shapes of sdAbs compared with those of conventional antibodies. Comparison of X-ray crystal structures of sdAbs and conventional antibodies in complex with cognate antigens showed that sdAbs and conventional antibodies bury similar solvent-exposed surface areas on proteins and form similar types of non-covalent interactions, although these are more concentrated in the compact sdAb paratope. Thus, the authors conclude that sdAbs likely have privileged access to distinct antigenic regions on proteins, but only owing to their small molecular size and not to general differences in molecular recognition mechanism. The evidence surrounding the purported inability of sdAbs to bind small molecules was less clear. The available data provide a structural framework for understanding the evolutionary emergence and function of autonomous heavy chain-only antibodies.

Biosimilars in oncology and inflammatory diseases: current and future considerations for clinicians in Latin America. Scheinberg et al. review the use of biosimilars in Latin America, which is complicated by the presence of “non-comparable biotherapeutics” (also known as “intended copies”) that have not been rigorously compared with the originator product. The authors discuss the current situation and the considerations for clinicians in Latin American countries, focusing on monoclonal antibody biosimilars relevant to oncology, rheumatology, gastroenterology, and dermatology.

Homology modeling and structure-based design improve hydrophobic interaction chromatography behavior of integrin binding antibodies. In this new report, Jetha et al. optimized a candidate integrin α11-binding mAb for developability using molecular modeling, rational design, and hydrophobic interaction chromatography (HIC). A homology model of the parental mAb Fv region was built, and this revealed hydrophobic patches on the surface of the complementarity-determining region loops. A series of 97 variants of the residues primarily responsible for the hydrophobic patches were expressed and their HIC retention times (RT) were measured. As intended, many of the computationally designed variants reduced the HIC RT compared to the parental mAb, and mutating residues that contributed most to hydrophobic patches had the greatest effect on HIC RT. A retrospective analysis was then performed where 3-dimentional protein property descriptors were evaluated for their ability to predict HIC RT using the current series of mAbs. The same descriptors were used to train a simple multi-parameter protein quantitative structure-property relationship model on this data, producing an improved correlation. This analysis was extended to recently published HIC data for 137 clinical mAb candidates as well as 31 adnectin variants, and the authors found that the surface area of hydrophobic patches averaged over a molecular dynamics sample consistently correlated to the experimental data across a diverse set of biotherapeutics.

Heterologous recombinant expression of non-originator NISTmAb. Kashi et al. describe the development and initial expression of an intended copy of the NISTmAb using three non-originator murine cell lines. The authors found that, without optimization and in culture flasks, all three cell lines produce approximately 100 mg mAb per liter of culture. SDS-PAGE, SEC, NMR spectroscopy, intact MS, and SPR were used to demonstrate that the products of all three cell lines embody quality attributes with a sufficient degree of sameness to the NISTmAb Reference Material 8671 to warrant further bioreactor studies, process improvements and optimization. The implications of the work with regard to pre-competitive innovation to support process design and feedback control, comparability and biosimilarity assessments, and process analytical technologies are discussed.

Like this post but not a member?

We encourage you to join the Society to take advantage of the substantial benefits of membership, including discounts on fees for selected KNect365, CHI, and Hanson Wade meetings, discounted subscriptions to Society-affiliated journals PEDS and mAbs (special subscription rate of US $84 online only access for Antibody Society members) and access to information in the Members Only section of the website. In particular, we encourage members to take advantage of the discount on registration for Antibody Engineering & Therapeutics, which is the annual meeting of The Antibody Society traditionally held in San Diego in December. Membership is free for students, post-docs and employees of our corporate sponsors!