[Quality Evaluation of Therapeutic Antibodies by Multi-attribute Method]

In the development of therapeutic monoclonal antibodies (mAbs), it is essential to characterize the modifications causing structural heterogeneity because certain modifications are associated with safety and efficacy. However, the rapid structural analysis of mAbs remains challenging due to their structural complexity. The multi-attribute method (MAM) is a structural analytical method based on peptide mapping using LC/MS, and has drawn attention as a new quality control method for therapeutic mAbs instead of conventional structural heterogeneity analyses using several chromatographic techniques. Peptide mapping, which is regarded as an identification test method, is used to confirm that the amino acid sequence corresponds to that deduced from the gene sequence for the desired product. In contrast, MAM is used for simultaneously monitoring the modification rates of individual amino acid residues of therapeutic mAbs, indicating that MAM is used as quantitative test rather than identification test. In this review, we summarized the typical structural heterogeneities of mAbs and the general scheme of MAM. We also introduced our optimized sample preparation method for MAM, and examples of simultaneous monitoring of several modifications including deamidation, oxidation, N-terminal pyroglutamination, C-terminal clipping and glycosylation by our MAM system.

Advanced strategies in glycosylation prediction and control during biopharmaceutical development: Avenues toward Industry 4.0

Glycosylation has been shown to define the safety and efficacy of biopharmaceuticals, thus classified as a critical quality attribute. However, controlling glycan heterogeneity has always been a major challenge owing to the multi-variate factors that govern the glycosylation process. Conventional approaches for controlling glycosylation such as gene editing and metabolic control have succeeded in obtaining desired glycan profiles in accordance with the Quality by Design paradigm. Nonetheless, the development of smart algorithms and omics-enabled complete cell characterization have made it possible to predict glycan profiles beforehand, and manipulate process variables accordingly. This review thus discusses the various approaches available for control and prediction of glycosylation in biopharmaceuticals. Further, the futuristic goal of integrating such technologies is discussed in order to attain an automated and digitized continuous bioprocess for control of glycosylation. Given, control of a process as complex as glycosylation requires intense monitoring intervention, we examine the current technologies that enable automation. Finally, we discuss the challenges and the technological gap that currently limits incorporation of an automated process in routine bio-manufacturing, with a glimpse into the economic bearing. This article is protected by copyright. All rights reserved.

Development of a multi faceted platform containing a tetrazine, fluorophore and chelator: synthesis, characterization, radiolabeling, and immuno-SPECT imaging

BACKGROUND

Combining optical (fluorescence) imaging with nuclear imaging has the potential to offer a powerful tool in personal health care, where nuclear imaging offers in vivo functional whole-body visualization, and the fluorescence modality may be used for image-guided tumor resection. Varying chemical strategies have been exploited to fuse both modalities into one molecular entity. When radiometals are employed in nuclear imaging, a chelator is typically inserted into the molecule to facilitate radiolabeling; the availability of the chelator further expands the potential use of these platforms for targeted radionuclide therapy if a therapeutic radiometal is employed. Herein, a novel mixed modality scaffold which contains a tetrazine (Tz)--for biomolecule conjugation, fluorophore-for optical imaging, and chelator-for radiometal incorporation, in one construct is presented. The novel platform was characterized for its fluorescence properties, radiolabeled with single-photon emission computed tomography (SPECT) isotope indium-111 (¹¹¹In³⁺) and therapeutic alpha emitter actinium-225 (²²⁵Ac³⁺). Both radiolabels were conjugated in vitro to trans-cyclooctene (TCO)-modified trastuzumab; biodistribution and immuno-SPECT imaging of the former conjugate was assessed.

RESULTS

Key to the success of the platform synthesis was incorporation of a 4,4'-dicyano-BODIPY fluorophore. The route gives access to an advanced intermediate where final chelator-incorporated compounds can be easily accessed in one step prior to radiolabeling or biomolecule conjugation. The DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) conjugate was prepared, displayed good fluorescence properties, and was successfully radiolabeled with ¹¹¹In & ²²⁵Ac in high radiochemical yield. Both complexes were then separately conjugated in vitro to TCO modified trastuzumab through an inverse electron demand Diels-Alder (IEDDA) reaction with the Tz. Pilot small animal in vivo immuno-SPECT imaging with [¹¹¹In]In-DO3A-BODIPY-Tz-TCO-trastuzumab was also conducted and exhibited high tumor uptake (21.2 ± 5.6%ID/g 6 days post-injection) with low uptake in non-target tissues.

CONCLUSIONS

The novel platform shows promise as a multi-modal probe for theranostic applications. In particular, access to an advanced synthetic intermediate where tailored chelators can be incorporated in the last step of synthesis expands the potential use of the scaffold to other radiometals. Future studies including validation of ex vivo fluorescence imaging and exploiting the pre-targeting approach available through the IEDDA reaction are warranted.

Integrated Process Analytical Platform for Automated Monitoring of Monoclonal Antibody N-Linked Glycosylation

The biopharmaceutical industry is transitioning toward the adoption of continuous biomanufacturing practices that are often more flexible and efficient than traditional batch processes. Federal regulatory agencies are further urging the use of advanced process analytical technology (PAT) to analyze the design space to increase the process knowledge and enable high-quality biologic production. Post-translational modifications of proteins, such as N-linked glycosylation, are often critical quality attributes that affect biologics' safety and efficacy, requiring close monitoring during manufacturing. Here, we developed an online sequential-injection-based PAT system, called N-GLYcanyzer, which can rapidly monitor mAb glycosylation during upstream biomanufacturing. The key innovation includes the design of an integrated mAb sampling and fully automated sample derivation system for antibody titer and glycoform analysis within 3 h. The N-GLYcanyzer process includes mAb capture, deglycosylation, released glycan labeling with fluorescent dyes, and labeled glycan enrichment for direct injection/analysis on an integrated high-performance liquid chromatography system. Different fluorescent tags and reductants were tested to maximize glycan labeling efficiency under aqueous conditions, while porous graphitized carbon (PGC) was used for optimizing glycan recovery and enrichment. We found that 2-aminobenzamide labeling of glycans with 2-picoline borane as a reducing agent, using the N-GLYcanyzer workflow, shows higher glycan labeling efficiency under aqueous conditions, leading upward to a 5-fold increase in fluorescent product intensity. Finally, we showcase how the N-GLYcanyzer platform can be implemented at-/online in an upstream bioreactor for automated and near-real-time glycosylation monitoring of a Trastuzumab biosimilar produced by Chinese hamster ovary cells.

Coupling CRISPR interference with FACS enrichment: New approach in glycoengineering of CHO cell lines for therapeutic glycoprotein production

Difficulties in obtaining and maintaining the desired level of the critical quality attributes (CQAs) of therapeutic proteins as well as the pace of the development are major challenges of current biopharmaceutical development. Therapeutic proteins, both innovative and biosimilars, are mostly glycosylated. Glycans directly influence the stability, potency, plasma half-life, immunogenicity, and effector functions of the therapeutic. Hence, glycosylation is widely recognized as a process-dependent CQA of therapeutic glycoproteins. Due to the typically high heterogeneity of glycoforms attached to the proteins, control of glycosylation represents one of the most challenging aspects of biopharmaceutical development. Here, we explored a new glycoengineering approach in therapeutic glycoproteins development, which enabled us to achieve the targeted glycoprofile of the Fc-fusion protein in a fast manner. Coupling CRISPRi technology with lectin-FACS sorting enabled downregulation of the endogenous gene involved in fucosylation and further enrichment of CHO cells producing Fc-fusion proteins with reduced fucosylation levels. Enrichment of cells with targeted glycoprofile can lead to time-optimized clone screening and speed up cell line development. Moreover, the presented approach allows isolation of clones with varying levels of fucosylation, which makes it applicable to a broad range of glycoproteins differing in target fucosylation level. This article is protected by copyright. All rights reserved.

Sialylation as an Important Regulator of Antibody Function

Antibodies play a critical role in linking the adaptive immune response to the innate immune system. In humans, antibodies are categorized into five classes, IgG, IgM, IgA, IgE, and IgD, based on constant region sequence, structure, and tropism. In serum, IgG is the most abundant antibody, comprising 75% of antibodies in circulation, followed by IgA at 15%, IgM at 10%, and IgD and IgE are the least abundant. All human antibody classes are post-translationally modified by sugars. The resulting glycans take on many divergent structures and can be attached in an N-linked or O-linked manner, and are distinct by antibody class, and by position on each antibody. Many of these glycan structures on antibodies are capped by sialic acid. It is well established that the composition of the N-linked glycans on IgG exert a profound influence on its effector functions. However, recent studies have described the influence of glycans, particularly sialic acid for other antibody classes. Here, we discuss the role of glycosylation, with a focus on terminal sialylation, in the biology and function across all antibody classes. Sialylation has been shown to influence not only IgG, but IgE, IgM, and IgA biology, making it an important and unappreciated regulator of antibody function.

Strategies for Glycoengineering Therapeutic Proteins

Almost all therapeutic proteins are glycosylated, with the carbohydrate component playing a long-established, substantial role in the safety and pharmacokinetic properties of this dominant category of drugs. In the past few years and moving forward, glycosylation is increasingly being implicated in the pharmacodynamics and therapeutic efficacy of therapeutic proteins. This article provides illustrative examples of drugs that have already been improved through glycoengineering including cytokines exemplified by erythropoietin (EPO), enzymes (ectonucleotide pyrophosphatase 1, ENPP1), and IgG antibodies (e.g., afucosylated Gazyva^®, Poteligeo^®, Fasenra™, and Uplizna^®). In the future, the deliberate modification of therapeutic protein glycosylation will become more prevalent as glycoengineering strategies, including sophisticated computer-aided tools for “building in” glycans sites, acceptance of a broad range of production systems with various glycosylation capabilities, and supplementation methods for introducing non-natural metabolites into glycosylation pathways further develop and become more accessible.

Therapeutic antibody glycosylation impacts antigen recognition and immunogenicity

In this study we show that glycosylation is relevant for immune recognition of therapeutic antibodies, and that defined glycan structures can modulate immunogenicity. Concerns regarding immunogenicity arise from the high heterogeneity in glycosylation that is difficult to control and can deviate from human glycosylation if produced in non-human cell lines. While non-human glycosylation is thought to cause hypersensitivity reactions and immunogenicity, less is known about effects of Fc-associated glycan structures on immune cell responses. We postulated that glycosylation influences antigen recognition and subsequently humoral responses to therapeutic antibodies by modulating 1) recognition and uptake by dendritic cells (DCs), and 2) antigen routing, processing and presentation. Here, we compared different glycosylation variants of the antibody rituximab (RTX) in in vitro assays using human DCs and T cells as well as in in vivo studies. We found that human DCs bind and internalize unmodified RTX stronger compared to its aglycosylated form suggesting that glycosylation mediates uptake after recognition by glycan-specific receptors. Furthermore, we show that DC-uptake of RTX increases or decreases if glycosylation is selectively modified to recognize activating (by mannosylation) or inhibitory lectin receptors (by sialylation). Moreover, glycosylation seems to influence antigen presentation by DCs because specific glycovariants tend to induce either stronger or weaker T cell activation. Finally, we demonstrate that antibody glycosylation impacts anti-drug antibody (ADA) responses to RTX in vivo. Hence, defined glycan structures can modulate immune recognition and alter ADA responses. Glyco-engineering may help to decrease clinical immunogenicity and ADA-associated adverse events such as hypersensitivity reactions.

Strategies and Considerations for Improving Recombinant Antibody Production and Quality in Chinese Hamster Ovary Cells

Recombinant antibodies are rapidly developing therapeutic agents; approximately 40 novel antibody molecules enter clinical trials each year, most of which are produced from Chinese hamster ovary (CHO) cells. However, one of the major bottlenecks restricting the development of antibody drugs is how to perform high-level expression and production of recombinant antibodies. The high-efficiency expression and quality of recombinant antibodies in CHO cells is determined by multiple factors. This review provides a comprehensive overview of several state-of-the-art approaches, such as optimization of gene sequence of antibody, construction and optimization of high-efficiency expression vector, using antibody expression system, transformation of host cell lines, and glycosylation modification. Finally, the authors discuss the potential of large-scale production of recombinant antibodies and development of culture processes for biopharmaceutical manufacturing in the future.

Detailed Analytical Characterization of a Bispecific IgG1 CrossMab Antibody of the Knob-into-Hole Format Applying Various Stress Conditions Revealed Pronounced Stability

In recent years, a variety of new antibody formats have been developed. One of these formats allows the binding of one type of antibody to two different epitopes. This can for example be achieved by introduction of the "knob-into-hole" format and a combined CrossMab approach. Due to their complexity, these bispecific antibodies are expected to result in an enhanced variety of different degradation products. Reports on the stability of these molecules are still largely lacking. To address this, a panel of stress conditions, including elevated temperature, pH, oxidizing agents, and forced glycation via glucose incubation, to identify and functionally evaluate critical quality attributes in the complementary-determining and conserved regions of a bispecific antibody was applied in this study. The exertion of various stress conditions combined with an assessment by size exclusion chromatography, ion exchange chromatography, LC-MS/MS peptide mapping, and functional evaluation by cell-based assays was adequate to identify chemical modification sites and assess the stability and integrity, as well as the functionality of a bispecific antibody. Stress conditions induced size variants and post-translational modifications, such as isomerization, deamidation, and oxidation, albeit to a modest extent. Of note, all the observed stress conditions largely maintained functionality. In summary, this study revealed the pronounced stability of IgG1 "knob-into-hole" bispecific CrossMab antibodies compared to already marketed antibody products.

Non-targeted characterization of attributes affecting antibody-FcγRIIIa V158 (CD16a) binding via online affinity chromatography-mass spectrometry

Antibodies facilitate targeted cell killing by engaging with immune cells such as natural killer cells through weak binding interactions with Fcγ receptors on the cell surface. Here, we evaluate the binding affinity of the receptor FcγRIIIa V158 (CD16a) for several therapeutic antibody classes, isoforms, and Fc-fusion proteins using an immobilized receptor affinity liquid chromatography (LC) approach coupled with online mass spectrometry (MS) detection. Aglycosylated FcγRIIIa was used in the affinity chromatography and compared with published affinities using glycosylated receptors. Affinity LC-MS differentiated the IgG1 antibodies primarily according to their Fc glycosylation patterns, with highly galactosylated species having greater affinity for the immobilized receptors and thus eluting later from the column (M5< G0F < G0 afucosylated ≅ G1F < G2F). Sialylated species bound weaker to their asialylated counterparts as reported previously. High mannose glycoforms bound weaker than G0F, contrary to previously published studies using glycosylated receptors. Also, increased receptor binding affinity associated with afucosylated antibodies was not observed with the aglycosylated FcγRIIIa. This apparent difference from previous findings highlighted the importance of the glycans on the receptors for mediating stronger binding interactions. Characterization of temperature-stressed samples by LC-MS peptide mapping revealed over 200 chemical and post-translational modifications, but only the Fc glycans, deamidation of EU N325, and an unknown modification to either proline or cysteine residues of the hinge region were found to have a statistically significant impact on binding.

Abbreviations: Antibody-dependent cell-mediated cytotoxicity (ADCC), chimeric antigen receptor (CAR), Chinese hamster ovary (CHO), dithiothreitol (DTT), electrospray ionization (ESI), hydrogen-deuterium exchange (HDX), filter aided-sample preparation (FASP), Fcγ receptor (FcγR), fragment crystallizable (Fc), high-pressure liquid chromatography (HPLC), immunoglobulin G (IgG), liquid chromatography (LC), monoclonal antibody (mAb), mass spectrometry (MS), natural killer (NK), N-glycolylneuraminic acid (NGNA), N-acetylneuraminic acid (NANA), principal component analysis (PCA), surface plasmon resonance (SPR), trifluoroacetic acid (TFA), and extracted mass chromatogram (XMC).

IgG1 conformational behavior: elucidation of the N-glycosylation role via molecular dynamics

Currently, monoclonal antibodies (mAbs) are the most used biopharmaceuticals for human therapy. One of the key aspects in their development is the control of effector functions mediated by the interaction between fragment crystallizable (Fc) and Fcγ receptors, which is a secondary mechanism of the action of biotherapeutics. N-glycosylation at the Fc portion can regulate these mechanisms, and much experimental evidence suggests that modifications of glycosidic chains can affect antibody binding to FcγRIIIa, consequently impacting the immune response. In this work, we try to elucidate via in silico procedures the structural role exhibited by glycans, particularly fucose, in mAb conformational freedom that can potentially affect the receptor recognition. By using adalimumab, a marketed IgG1, as a general template, after rebuilding its three-dimensional (3D) structure through homology modeling approaches, we carried out molecular dynamics simulations of three differently glycosylated species: aglycosylated, afucosylated, and fucosylated antibody. Trajectory analysis showed different dynamical behaviors and pointed out that sugars can influence the overall 3D structure of the antibody. As a result, we propose a putative structural mechanism by which the presence of fucose introduces conformational constraints in the whole antibody and not only in the Fc domain, preventing a conformation suitable for the interaction with the receptor. As secondary evidence, we observed a high flexibility of the antibodies that is translated into an asymmetric behavior of Fab portions shown by all the simulated biopolymers, making the dynamical asymmetry a new, to our knowledge, molecular aspect that may be further investigated. In conclusion, these findings can help understand the contribution of sugars on the structural architecture of mAbs, paving the way to novel strategies of pharmaceutical development.

N-glycosylation structure - function characterization of omalizumab, an anti-asthma biotherapeutic product

Omalizumab, a glycoprotein based biotherapeutics, is one of the most frequently used targeted antibody biopharmaceutical to reduce asthma exacerbations, improve lung function and reduce oral corticosteroid use. The effector function and clearance time of such glycoprotein drugs is affected by their N-glycosylation, that defines the required administration frequency to improve the quality of life in appropriately selected patients. Therefore, the glycosylation of biologics is an important critical quality attribute (CQA). The profile of asparagine linked carbohydrates is greatly dependent on the manufacturing process. Even a small deviation may have a major effect on the structure and therefore the function of the biotherapeutic product. For this reason, comprehensive N-glycosylation analysis is of high importance during production and release. Capillary electrophoresis (CE) is one of the frequently used tools to characterize protein therapeutics and utilized by the biopharmaceutical industry for protein and glycan level analysis, which are key parts both for drug development and quality control. To reveal important structure - function relationships, characterization of omalizumab is presented using capillary SDS gel electrophoresis with UV detection at the protein level and capillary gel electrophoresis with laser induced fluorescent detection at the N-linked carbohydrate level. This latter technique was also used for oligosaccharide sequencing for glycan structure validation. The results suggested no ADCC function - structure relationship due to the mostly core fucosylated biantennary glycans found. However, the presence of the high mannose structures probably affects the clearance rate of the drug.

IgG N-glycans

Glycosylation, one of the most common post-translational modifications in mammalian cells, impacts many biological processes such as cell adhesion, proliferation and differentiation. As the most abundant glycoprotein in human serum, immunoglobulin G (IgG) plays a vital role in immune response and protection. There is a growing body of evidence suggests that IgG structure and function are modulated by attached glycans, especially N-glycans, and aberrant glycosylation is associated with disease states. In this chapter, we review IgG glycan repertoire and function, strategies for profiling IgG N-glycome and recent studies. Mass spectrometry (MS) based techniques are the most powerful tools for profiling IgG glycome. IgG glycans can be divided into high-mannose, biantennary complex and hybrid types, modified with mannosylation, core-fucosylation, galactosylation, bisecting GlcNAcylation, or sialylation. Glycosylation of IgG affects antibody half-life and their affinity and avidity for antigens, regulates crystallizable fragment (Fc) structure and Fcγ receptor signaling, as well as antibody effector function. Because of their critical roles, IgG N-glycans appear to be promising biomarkers for various disease states. Specific IgG glycosylation can convert a pro-inflammatory response to an anti-inflammatory activity. Accordingly, IgG glycoengineering provides a powerful approach to potentially develop effective drugs and treat disease. Based on the understanding of the functional role of IgG glycans, the development of vaccines with enhanced capacity and long-term protection are possible in the near future.

Glycoproteomic Characterization of FUT8 Knock-Out CHO Cells Reveals Roles of FUT8 in the Glycosylation

The α1,6-fucosyltransferase (encoded by FUT8 gene) is the key enzyme transferring fucose to the innermost GlcNAc residue on an N-glycan through an α-1,6 linkage in the mammalian cells. The presence of core fucose on antibody Fc region can inhibit antibody-dependent cellular cytotoxicity (ADCC) and reduce antibody therapeutic efficiency in vivo. Chinese hamster ovary (CHO) cells are the predominant production platform in biopharmaceutical manufacturing. Therefore, the generation of FUT8 knock-out (FUT8KO) CHO cell line is favorable and can be applied to produce completely non-fucosylated antibodies. The characterization of monoclonal antibodies as well as host cell glycoprotein impurities are required for quality control purposes under regulation rules. To understand the role of FUT8 in the glycosylation of CHO cells, we generated a FUT8 knock-out CHO cell line and performed a large-scale glycoproteomics to characterize the FUT8KO and wild-type (WT) CHO cells. The glycopeptides were enriched by hydrophilic chromatography and fractionated 25 fractions by bRPLC followed by analysis using high-resolution liquid chromatography mass spectrometry (LC-MS). A total of 7,127 unique N-linked glycosite-containing intact glycopeptides (IGPs), 928 glycosites, and 442 glycoproteins were identified from FUT8KO and WT CHO cells. Moreover, 28.62% in 442 identified glycoproteins and 26.69% in 928 identified glycosites were significantly changed in the FUT8KO CHO compared to wild-type CHO cells. The relative abundance of all the three N-glycan types (high-mannose, hybrid, and complex) was determined in FUT8KO comparing to wild-type CHO cells. Furthermore, a decrease in fucosylation content was observed in FUT8KO cells, in which core-fucosylated glycans almost disappeared as an effect of FUT8 gene knockout. Meantime, a total of 51 glycosylation-related enzymes were also quantified in these two cell types and 16 of them were significantly altered in the FUT8KO cells, in which sialyltransferases and glucosyltransferases were sharply decreased. These glycoproteomic results revealed that the knock-out of FUT8 not only influenced the core-fucosylation of proteins but also altered other glycosylation synthesis processes and changed the relative abundance of protein glycosylation.

Outcome of Reverse Switching From CT-P13 to Originator Infliximab in Patients With Inflammatory Bowel Disease

BACKGROUND

Patients suffering from inflammatory bowel diseases (IBD) and treated with originator infliximab are increasingly being switched to biosimilars. Some patients, however, are "reverse switched" to treatment with the originator. Here we assess the prevalence of reverse switching, including its indication and outcomes.

METHODS

In this retrospective multicenter cohort study, data on patients with IBD from 9 hospitals in the Netherlands were collected. All adult patients with IBD were included if they previously had been switched from originator infliximab to the biosimilar CT-P13 and had a follow-up time of at least 52 weeks after the initial switch. The reasons for reverse switching were categorized into worsening gastrointestinal symptoms, adverse effects, or loss of response to CT-P13. Drug persistence was analyzed through survival analyses.

RESULTS

A total of 758 patients with IBD were identified. Reverse switching was observed in 75 patients (9.9%). Patients with reverse switching were predominantly female (70.7%). Gastrointestinal symptoms (25.5%) and dermatological symptoms (21.8%) were the most commonly reported reasons for reverse switching. In 9 patients (12.0%), loss of response to CT-P13 was the reason for reverse switching. Improvement of reported symptoms was seen in 73.3% of patients after reverse switching and 7 out of 9 patients (77.8%) with loss of response regained response. Infliximab persistence was equal between patients who were reverse-switched and those who were maintained on CT-P13.

CONCLUSIONS

Reverse switching occurred in 9.9% of patients, predominantly for biosimilar-attributed adverse effects. Switching back to originator infliximab seems effective in patients who experience adverse effects, worsening gastrointestinal symptoms, or loss of response after switching from originator infliximab to CT-P13.

Desalting Paper Spay Mass Spectrometry (DPS-MS) for Rapid Detection of Glycans and Glycoconjugates

The detection of glycans and glycoconjugates has gained increasing attention in biological fields. Traditional mass spectrometry (MS)-based methods for glycoconjugate analysis are challenged with poor intensity when dealing with complex biological samples. We developed a desalting paper spray mass spectrometry (DPS-MS) strategy to overcome the issue of signal suppression of carbohydrates in salted buffer. Glycans and glycoconjugates (i.e., glycopeptides, nucleotide sugars, etc.) in non-volatile buffer (e.g., Tris buffer) can be loaded on the paper substrate from which buffers can be removed by washing with ACN/H₂O (90/10 v/v) solution. Glycans or glycoconjugates can then be eluted and spray ionized by adding ACN/H₂O/formic acid (FA) (10/90/1 v/v/v) solvent and applying a high voltage (HV) to the paper substrate. This work also showed that DPS-MS is applicable for direct detection of intact glycopeptides and nucleotide sugars as well as determination of glycosylation profiling of antibody, such as NIST monoclonal antibody IgG (NISTmAb). NISTmAb was deglycosylated with PNGase F to release N-linked oligosaccharides. Twenty-six N-linked oligosaccharides were detected by DPS-MS within a 5-minute timeframe without the need for further enrichment or derivatization. This work demonstrates that DPS-MS allows fast and sensitive detection of glycans/oligosaccharides and glycosylated species in complex matrices and has great potential in bioanalysis.

Implementation of in vitro glycoengineering of monoclonal antibodies into downstream processing of industrial production

In vitro glycoengineering using exoenzymes for specific modification is recognized as appropriate method to tailor sugar moieties of glycan structures during the recombinant production of monoclonal antibodies (mAbs). This report describes enhanced in vitro glycoengineering approaches using β1,4-galactosyltransferase and α2,6-sialyltransferase to improve the efficiency of galactosylation and sialylation with the aim to implement in vitro glycoengineering into common mAb purification processes. Feasibility studies tested the potential of different in vitro glycoengineering protocols (2-step vs. 1-step) to facilitate the overall procedure. Scalability of the reactions was demonstrated for mAb amounts ranging from 1 mg to 1 g. Additionally, the reactions of β1,4-galactosyltransferase and α2,6-sialyltransferase were shown to work on column during affinity chromatography using Protein A or KappaSelect, the latter providing more efficient galactosylation and sialylation of IgG1 and IgG4 mAbs. Performing in vitro glycoengineering on column enabled the use of cell culture harvest which yielded results comparable to that of purified bulk. Based thereon, an optimized 2-step mixed mode approach was found most appropriate to integrate in vitro glycoengineering of the IgG1 mAb into the overall manufacturing process. Using harvest for on-column reaction of β1,4-galactosyltransferase combined with in-solution reaction of α2,6-sialyltransferase, this approach yielded 100 percent biantennary galactosylation and 61 percent biantennary sialylation. Moreover, the enzymes applied in in vitro glycoengineering could be separated, recycled, and reused in further reactions to improve economic efficiency. Overall, the study provides a toolbox for in vitro glycoengineering and presents an optimized easy-to-handle workflow to implement this method into the downstream processing of industrial mAb production.

Protein engineering of a stable and potent anti-inflammatory IL-37-Fc fusion with enhanced therapeutic potential

Harnessing the immunomodulatory activity of cytokines is a focus of therapies targeting inflammatory disease. The interleukin (IL)-1 superfamily contains pro-inflammatory and anti-inflammatory members that help orchestrate the immune response in adaptive and innate immunity. Of these molecules, IL-37 has robust anti-inflammatory activity across a range of disease models through inhibition of pro-inflammatory signaling cascades downstream of tumor necrosis factor, IL-1, and toll-like receptor pathways. We find that IL-37 is unstable with a poor pharmacokinetic and manufacturing profile. Here, we present the engineering of IL-37 from an unstable cytokine into an anti-inflammatory molecule with an excellent therapeutic likeness. We overcame these shortcomings through site-directed mutagenesis, the addition of a non-native disulfide bond, and the engineering of IL-37 as an Fc-fusion protein. Our results provide a platform for preclinical testing of IL-37 Fc-fusion proteins. The engineering approaches undertaken herein will apply to the conversion of similar potent yet short-acting cytokines into therapeutics.

Activity of CcpA-Regulated GH18 Family Glycosyl Hydrolases That Contributes to Nutrient Acquisition and Fitness in Enterococcus faecalis

The ability of Enterococcus faecalis to colonize host anatomical sites is dependent on its adaptive response to host conditions. Three glycosyl hydrolase gene clusters, each belonging to glycosyl hydrolase family 18 (GH18) (ef0114, ef0361, and ef2863), in E. faecalis were previously found to be upregulated under glucose-limiting conditions. The GH18 catalytic domain is present in proteins that are classified as either chitinases or β-1,4 endo-β-N-acetylglucosaminidases (ENGases) based on their β-1,4 endo-N-acetyl-β-d-glucosaminidase activity, and ENGase activity is commonly associated with cleaving N-linked glycoprotein, an abundant glycan structure on host epithelial surfaces. Here, we show that all three hydrolases are negatively regulated by the transcriptional regulator carbon catabolite protein A (CcpA). Additionally, we demonstrate that a constitutively active CcpA variant represses the expression of CcpA-regulated genes irrespective of glucose availability. Previous studies showed that the GH18 catalytic domains of EndoE (EF0114) and EfEndo18A (EF2863) were capable of deglycosylating RNase B, a model high-mannose-type glycoprotein. However, it remained uncertain which glycosidase is primarily responsible for the deglycosylation of high-mannose-type glycoproteins. In this study, we show by mutation analysis as well as a dose-dependent analysis of recombinant protein expression that EfEndo18A is primarily responsible for deglycosylating high-mannose glycoproteins and that the glycans removed by EfEndo18A support growth under nutrient-limiting conditions in vitro. In contrast, IgG is representative of a complex-type glycoprotein, and we demonstrate that the GH18 domain of EndoE is primarily responsible for the removal of this glycan decoration. Finally, our data highlight the combined contribution of glycosidases to the virulence of E. faecalis in vivo.

The impact of CGRPergic monoclonal antibodies on prophylactic antimigraine therapy and potential adverse events

Migraine is a prevalent medical condition and the second most disabling neurological disorder. Regarding its pathophysiology, calcitonin gene-related peptide (CGRP) plays a key role, and, consequently, specific antimigraine pharmacotherapy has been designed to target this system. Hence, apart from the gepants, the recently developed monoclonal antibodies (mAbs) are a novel approach to treat this disorder. In this review we consider the current knowledge on the mechanisms of action, specificity, safety, and efficacy of the above mAbs as prophylactic antimigraine agents, and examine the possible adverse events that these agents may trigger. Antimigraine mAbs act as direct scavengers of CGRP (galcanezumab, fremanezumab, and eptinezumab) or against the CGRP receptor (erenumab). Due to their long half-lives, these molecules have revolutionized the prophylactic treatment of this neurovascular disorder. Moreover, because of their physicochemical properties, these agents are hepato-friendly and do not cross the blood-brain barrier (highlighting the relevance of peripheral mechanisms in migraine). Nevertheless, apart from potential cardiovascular side effects, the interaction with AMY₁ receptors and immunogenicity induced by autoantibodies against mAbs could be a concern for the safety of long-term treatment with these molecules.

Glycosylation and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for approximately 18 million deaths in 2017. Coronary artery disease is the predominant cause of death from CVD, followed by stroke. Owing to recent technological advancements, glycans and glycosylation patterns of proteins have been investigated in association with CVD risk factors and clinical events. These studies have found significant associations of glycans as biomarkers of systemic inflammation and major CVD risk factors and events. While more limited, studies have also shown that glycans may be useful for monitoring response to anti-inflammatory therapies and may be responsive to changes in lifestyle, particularly in patients with chronic inflammatory diseases. Glycans capture summative risk information related to inflammatory, immune, and signaling pathways and are promising biomarkers for CVD risk prediction and therapeutic monitoring.

A Phase 1 first-in-human study of the safety, tolerability, and pharmacokinetics of the ROBO2 fusion protein PF-06730512 in healthy participants

Proteinuria associated with podocyte effacement is a hallmark of focal segmental glomerulosclerosis (FSGS). Preclinical studies implicated ROBO2/SLIT2 signaling in the regulation of podocyte adhesion, and inhibition of this pathway is a novel target to slow FSGS disease progression. This first-in-human dose-escalation study evaluated the safety, tolerability, pharmacokinetics, and immunogenicity of PF-06730512, an Fc fusion protein that targets the ROBO2/SLIT2 pathway, in healthy adults. In this Phase 1, double-blind, sponsor-open study, single ascending dose (SAD) cohorts were randomized to receive up to 1000 mg or placebo intravenously (IV); multiple ascending dose (MAD) cohorts were randomized to receive up to 400 mg subcutaneous (SC) doses, 1000 mg IV dose, or matching placebo. Safety evaluations were performed up to 71 (SAD) and 113 (MAD) days after dosing; blood samples were collected to measure serum PF-06730512 concentrations and antidrug antibodies (ADA) to PF-06730512. Seventy-nine participants (SAD, 47; MAD, 32) were enrolled. There were 108 mild (SAD, 46; MAD, 62) and 21 moderate (SAD, 13; MAD, 8) treatment-emergent adverse events (TEAEs); no deaths, treatment-related serious AEs, severe TEAEs, or infusion reactions were reported. PF-06730512 exposure generally increased in an approximately dose-proportional manner; mean t1/2 ranged from 12-15 days across 50-1000 mg doses. Immunogenicity incidence was low (SAD, 0 ADA+; MAD, 2 ADA+). In conclusion, single IV doses of PF-06730512 up to 1000 mg and multiple IV and SC dosing up to 1000 and 400 mg, respectively, were safe and well tolerated in healthy participants. Further trials in patients with FSGS are warranted. Clinical trial registration: Clinicaltrials.gov: NCT03146065.

Simultaneous monitoring of multiple attributes of pyrrolobenzodiazepine antibody-drug conjugates by size exclusion chromatography - high resolution mass spectrometry

Antibody-drug conjugates (ADCs) are an emerging class of oncology treatments combining the unique specificity of monoclonal antibodies with the highly cytotoxic properties of small molecule compounds. Pyrrolobenzodiazepines (PBDs) are highly potent agents capable of inhibiting cellular DNA replication which leads to apoptosis. To ensure efficacy and patient safety upon administration of such toxic and heterogeneous molecules, their structure and quality attributes must be closely monitored. Size exclusion chromatography (SEC) is a powerful, fast and robust tool for the separation of compounds varying in molecular weight. When using volatile components in the chromatographic mobile phase, SEC has also been shown to be amenable for interfacing to mass spectrometry, providing potential for reliable identification of protein isoforms across the size variants present. Here, we present a SEC-MS method developed for the characterisation of PBD-based ADCs on the intact molecular level. We demonstrate that information on ADC monomers such as the glycoform distribution and the average drug-antibody ratio (DAR) can be obtained in 15 minutes of analysis time. Qualitative and quantitative information on low and high molecular weight impurities such as aggregates and fragments, fundamental for critical quality attribute analysis of biopharmaceuticals, can be generated simultaneously. SEC-MS enables the characterisation of multiple product quality attributes of complex biotherapeutics at the same time.

A new approach for identifying positional isomers of glycans cleaved from monoclonal antibodies

Glycosylation patterns in monoclonal antibodies (mAbs) can vary significantly between different host cell types, and these differences may affect mAbs safety, efficacy, and immunogenicity. Recent studies have demonstrated that glycan isomers with the terminal galactose position on either the Man α1-3 arm or the Man α1-6 arm have an impact on the effector functions and dynamic structure of mAbs. The development of a robust method to distinguish positional isomers of glycans is thus critical to guarantee mAb quality. In this work, we apply high-resolution ion mobility combined with cryogenic infrared spectroscopy to distinguish isomeric glycans with different terminal galactose positions, using G1F as an example. Selective enzymatic synthesis of the G1(α1-6)F isomer allows us to assign the peaks in the arrival-time distributions and the infrared spectra to their respective isomeric forms. Moreover, we demonstrate the impact of the host cell line (CHO and HEK-293) on the IgG G1F gycan profile at the isomer level. This work illustrates the potential of our approach for glycan analysis of mAbs.

Physicochemical and functional characterization of trastuzumab-dkst, a trastuzumab biosimilar

Aims: Preclinical comparative similarity studies of trastuzumab-dkst, a Herceptin^® biosimilar, are reported. Materials & methods: Primary sequence and higher order structure and pharmacological mechanisms of action were compared using multiple techniques. Pharmacokinetics and repeat-dose toxicity were assessed in cynomolgus monkeys. Results: Primary structures were identical; secondary and tertiary structures were highly similar. Non-significant differences were observed for charge heterogeneity. Twelve of 13 glycan species were highly similar, with slightly higher total mannose levels in trastuzumab-dkst. FcγR and FcRn binding activity was highly similar. Each drug equally inhibited HER2⁺ cell proliferation, demonstrating equivalent relative potency in mediating HER2⁺ cell cytolysis by antibody-dependent cellular cytotoxicity. Pharmacokinetic and toxicological profiles in cynomolgus monkeys were similar. Conclusion: Trastuzumab-dkst, US-licensed trastuzumab and EU-approved trastuzumab demonstrate high structural and functional similarity.

Inflammation and tumor progression: signaling pathways and targeted intervention

Cancer development and its response to therapy are regulated by inflammation, which either promotes or suppresses tumor progression, potentially displaying opposing effects on therapeutic outcomes. Chronic inflammation facilitates tumor progression and treatment resistance, whereas induction of acute inflammatory reactions often stimulates the maturation of dendritic cells (DCs) and antigen presentation, leading to anti-tumor immune responses. In addition, multiple signaling pathways, such as nuclear factor kappa B (NF-kB), Janus kinase/signal transducers and activators of transcription (JAK-STAT), toll-like receptor (TLR) pathways, cGAS/STING, and mitogen-activated protein kinase (MAPK); inflammatory factors, including cytokines (e.g., interleukin (IL), interferon (IFN), and tumor necrosis factor (TNF)-α), chemokines (e.g., C-C motif chemokine ligands (CCLs) and C-X-C motif chemokine ligands (CXCLs)), growth factors (e.g., vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β), and inflammasome; as well as inflammatory metabolites including prostaglandins, leukotrienes, thromboxane, and specialized proresolving mediators (SPM), have been identified as pivotal regulators of the initiation and resolution of inflammation. Nowadays, local irradiation, recombinant cytokines, neutralizing antibodies, small-molecule inhibitors, DC vaccines, oncolytic viruses, TLR agonists, and SPM have been developed to specifically modulate inflammation in cancer therapy, with some of these factors already undergoing clinical trials. Herein, we discuss the initiation and resolution of inflammation, the crosstalk between tumor development and inflammatory processes. We also highlight potential targets for harnessing inflammation in the treatment of cancer.

An integrated modular framework for modeling the effect of ammonium on the sialylation process of monoclonal antibodies produced by CHO cells

BACKGROUND

Monoclonal antibodies (mABs) have emerged as one of the most important therapeutic recombinant proteins in the pharmaceutical industry. Their immunogenicity and therapeutic efficacy are influenced by post-translational modifications, specifically the glycosylation process. Bioprocess conditions can influence the intracellular process of glycosylation. Among all the process conditions that have been recognized to affect the mAB glycoforms, the detailed mechanism underlying how ammonium could perturb glycosylation remains to be fully understood. It was shown that ammonium induces heterogeneity in protein glycosylation by altering the sialic acid content of glycoproteins. Hence, understanding this mechanism would aid pharmaceutical manufacturers to ensure consistent protein glycosylation.

METHODS

Three different mechanisms have been proposed to explain how ammonium influences the sialylation process. In the first, the inhibition of CMP-sialic acid transporter, which transports CMP-sialic acid (sialylation substrate) into the Golgi, by an increase in UDP-GlcNAc content that is brought about by the augmented incorporation of ammonium into glucosamine formation. In the second, ammonia diffuses into the Golgi and raises its pH, thereby decreasing the sialyltransferase enzyme activity. In the third, the reduction of sialyltransferase enzyme expression level in the presence of ammonium. We employed these mechanisms in a novel integrated modular platform to link dynamic alteration in mAB sialylation process with extracellular ammonium concentration to elucidate how ammonium alters the sialic acid content of glycoproteins.

RESULTS

Our results show that the sialylation reaction rate is insensitive to the first mechanism. At low ammonium concentration, the second mechanism is the controlling mechanism in mAB sialylation and by increasing the ammonium level (< 8 mM) the third mechanism becomes the controlling mechanism. At higher ammonium concentrations (> 8 mM) the second mechanism becomes predominant again.

CONCLUSION

The presented model in this study provides a connection between extracellular ammonium and the monoclonal antibody sialylation process. This computational tool could help scientists to develop and formulate cell culture media. The model illustrated here can assist the researchers to select culture media that ensure consistent mAB sialylation.

In-House Packed Porous Graphitic Carbon Columns for Liquid Chromatography-Mass Spectrometry Analysis of N-Glycans

Protein glycosylation is a common post-translational modification that modulates biological processes such as the immune response and protein trafficking. Altered glycosylation profiles are associated with cancer and inflammatory diseases, as well as impacting the efficacy of therapeutic monoclonal antibodies. Consisting of oligosaccharides attached to asparagine residues, enzymatically released N-linked glycans are analytically challenging due to the diversity of isomeric structures that exist. A commonly used technique for quantitative N-glycan analysis is liquid chromatography-mass spectrometry (LC-MS), which performs glycan separation and characterization. Although many reversed and normal stationary phases have been utilized for the separation of N-glycans, porous graphitic carbon (PGC) chromatography has become desirable because of its higher resolving capability, but is difficult to implement in a robust and reproducible manner. Herein, we demonstrate the analytical properties of a 15 cm fused silica capillary (75 µm i.d., 360 µm o.d.) packed in-house with Hypercarb PGC (3 µm) coupled to an Agilent 6550 Q-TOF mass spectrometer for N-glycan analysis in positive ion mode. In repeatability and intermediate precision measurements conducted on released N-glycans from a glycoprotein standard mixture, the majority of N-glycans reported low coefficients of variation with respect to retention times (≤4.2%) and peak areas (≤14.4%). N-glycans released from complex samples were also examined by PGC LC-MS. A total of 120 N-glycan structural and compositional isomers were obtained from formalin-fixed paraffin-embedded ovarian cancer tissue sections. Finally, a comparison between early- and late-stage formalin-fixed paraffin-embedded ovarian cancer tissues revealed qualitative changes in the α2,3- and α2,6-sialic acid linkage of a fucosylated bi-antennary complex N-glycan. Although the α2,3-linkage was predominant in late-stage ovarian cancer, the alternate α2,6-linkage was more prevalent in early-stage ovarian cancer. This study establishes the utility of in-house packed PGC columns for the robust and reproducible LC-MS analysis of N-glycans.

PET imaging of immune checkpoint proteins in oncology

Despite the remarkable clinical successes of immune checkpoint inhibitors (ICIs) in various advanced cancers, response is still limited to a subset of patients that generally exhibit tumoral expression of immune checkpoint (IC) proteins. Development of biomarkers assessing the expression of such ICs is therefore a major challenge nowadays to refine patient selection and improve therapeutic benefits. Positron emission tomography (PET) imaging using IC-targeted radiolabeled monoclonal antibodies (immunoPET) provides a non-invasive and whole-body visualization of in vivo IC biodistribution. As such, PET imaging of ICs may serve as a robust biomarker to predict and monitor responses to ICIs, complementing the existing immunohistochemical techniques. Besides monoclonal antibodies, other PET radioligand formats, ranging from antibody-derived fragments to small proteins, have gained increasing interest owing to their faster pharmacokinetics and enhanced imaging characteristics. We provide an overview of the various strategies investigated so far for PET imaging of ICs in preclinical and clinical studies, emphasizing their benefits and limitations. Moreover, we discuss various parameters to consider for designing optimized and best-suited PET radioligands.

Bi/tri-specific antibodies (HN-Fc-CD16 and HN-Fc-IL-15-CD16) cross-linking natural killer (NK)-CD16 and Newcastle Disease Virus (NDV)-HN, enhanced NK activation for cancer immunotherapy

Cancer/tumor cells infected with the "avian paramyxovirus Newcastle Disease Virus (TC-NDV)" express the viral hemagglutinin-neuraminidase (HN) on the cell surface that is used as both the danger signal and anchor for bi/tri-specific antibodies (bs/tsAbs).We constructed a bs-Ab (HN-Fc-CD16) that bindsto HN and natural killer (NK)-CD16 receptor (FcgRIII)and a ts-Ab (HN-Fc-IL15-CD16) harbouring NK-activating cytokine "IL-15" within the bs-Ab.In silicoand computational predictions indicated proper exposure of both Abs in bs/tsAbs.Properbinding of thebi/tsAbstoHN on surface of TC-NDVandCD16⁺-cells was demonstrated by flow cytometry.The bi/tsAbstriggeredspecificcytotoxicity of NK cells againstTC-NDVand elicited substantial IFN-γproduction by activated NK cells(higher for ts-Ab) that sound promising for cancer immunotherapy purposes.

Modulation of high mannose levels in N-linked glycosylation through cell culture process conditions to increase antibody-dependent cell-mediated cytotoxicity activity for an antibody biosimilar

The regulatory approval of a biosimilar product is contingent on the favorable comparability of its safety and efficacy to that of the innovator product. As such, it is important to match the critical quality attributes of the biosimilar product to that of the innovator product. The N-glycosylation profile of a monoclonal antibody (mAb) can influence effector function activities such as antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity. In this study, we describe efforts to modulate the high-mannose (HM) levels of a biosimilar mAb produced in a Chinese hamster ovary cell fed-batch process. Because the HM level of the mAb was observed to impact ADCC activity, it was desirable to match it to the innovator mAb's levels. Several cell culture process related factors known to modulate the HM content of N-glycosylation were investigated, including osmolality, ammonium chloride (NH₄ Cl) addition, glutamine concentration, monensin addition, and the addition of alternate sugars and amino sugars to the feed medium. The process conditions evaluated varied in impact on HM levels, process performance and product quality. One condition, the addition of alternate sugars and amino sugars to feed medium, was identified as the preferred method for increasing HM levels with minimal disruptions to process performance or other product quality attributes. Interestingly, a secondary interaction between sugar and amino sugar supplemented feeds and osmolality was observed during process scale-up. These studies demonstrate sugar and amino sugar concentrations and osmolality are critical variables to evaluate to match HM content in biosimilar and their innovator mAbs.

Glycoengineering Chinese hamster ovary cells: a short history

Biotherapeutic glycoproteins have revolutionised the field of pharmaceuticals, with new discoveries and continuous improvements underpinning the rapid growth of this industry. N-glycosylation is a critical quality attribute of biotherapeutic glycoproteins that influences the efficacy, half-life and immunogenicity of these drugs. This review will focus on the advances and future directions of remodelling N-glycosylation in Chinese hamster ovary (CHO) cells, which are the workhorse of recombinant biotherapeutic production, with particular emphasis on antibody products, using strategies such as cell line and protein backbone engineering.

4-(2,5-Dimethyl-1H-pyrrol-1-yl)-N-(2,5-dioxopyrrolidin-1-yl) benzamide improves monoclonal antibody production in a Chinese hamster ovary cell culture

There is a continuous demand to improve monoclonal antibody production for medication supply and medical cost reduction. For over 20 years, recombinant Chinese hamster ovary cells have been used as a host in monoclonal antibody production due to robustness, high productivity and ability to produce proteins with ideal glycans. Chemical compounds, such as dimethyl sulfoxide, lithium chloride, and butyric acid, have been shown to improve monoclonal antibody production in mammalian cell cultures. In this study, we aimed to discover new chemical compounds that can improve cell-specific antibody production in recombinant Chinese hamster ovary cells. Out of the 23,227 chemicals screened in this study, 4-(2,5-dimethyl-1H-pyrrol-1-yl)-N-(2,5-dioxopyrrolidin-1-yl) benzamide was found to increase monoclonal antibody production. The compound suppressed cell growth and increased both cell-specific glucose uptake rate and the amount of intracellular adenosine triphosphate during monoclonal antibody production. In addition, the compound also suppressed the galactosylation on a monoclonal antibody, which is a critical quality attribute of therapeutic monoclonal antibodies. Therefore, the compound might also be used to control the level of the galactosylation for the N-linked glycans. Further, the structure-activity relationship study revealed that 2,5-dimethylpyrrole was the most effective partial structure of 4-(2,5-dimethyl-1H-pyrrol-1-yl)-N-(2,5-dioxopyrrolidin-1-yl) benzamide on monoclonal antibody production. Further structural optimization of 2,5-dimethylpyrrole derivatives could lead to improved production and quality control of monoclonal antibodies.

Overview of Humira® Biosimilars: Current European Landscape and Future Implications

Humira® (adalimumab) by AbbVie has been the top-selling biologic drug product for the last few years - reaching nearly $20 billion in annual sales in 2018. Upon the October 2018 release of four adalimumab biosimilars into the European market, those sales began to shrink. By the end of 2019, the annual sales of Humira®, albeit still high, dipped closer to $19 billion as nearly 35% of European patients had been switched from Humira® to a biosimilar. Diminishing sales are expected to continue as the adoption of adalimumab biosimilars increases in Europe and Humira®'s patent protection is lost in the United States come 2023. In this review we discuss how impactful the availability of biosimilars has been to the European adalimumab market approximately two years after their release. We further analyze the marketed biosimilars with regards to differences in their formulation, delivery devices, biological activity, physicochemical properties, clinical trials data, and current financial foothold. More importantly, though, we highlight how "similar" these biosimilars are to Humira®. In doing so, we seek to educate the public on what they may be able to expect once adalimumab biosimilars enter the United States market in 2023.

Recent Advances in Radiometals for Combined Imaging and Therapy in Cancer

Nuclear medicine is defined as the use of radionuclides for diagnostic and therapeutic applications. The imaging modalities positron emission tomography (PET) and single-photon emission computed tomography (SPECT) are based on γ-emissions of specific energies. The therapeutic technologies are based on β^- -particle-, α-particle-, and Auger electron emitters. In oncology, PET and SPECT are used to detect cancer lesions, to determine dosimetry, and to monitor therapy effectiveness. In contrast, radiotherapy is designed to irreparably damage tumor cells in order to eradicate or control the disease's progression. Radiometals are being explored for the development of diagnostic and therapeutic radiopharmaceuticals. Strategies that combine both modalities (diagnostic and therapeutic), referred to as theranostics, are promising candidates for clinical applications. This review provides an overview of the basic concepts behind therapeutic and diagnostic radiopharmaceuticals and their significance in contemporary oncology. Select radiometals that significantly impact current and upcoming cancer treatment strategies are grouped as clinically suitable theranostics pairs. The most important physical and chemical properties are discussed. Standard production methods and current radionuclide availability are provided to indicate whether a cost-efficient use in a clinical routine is feasible. Recent preclinical and clinical developments and outline perspectives for the radiometals are highlighted in each section.

Similarity assessment by multivariate statistics method based on the distance between biosimilar and originator

The development of biosimilar products or follow-on biologics has been flourishing in recent years because of their lower price than the originators. In this study, a multivariate data analysis method based on JMP software was proposed to assess the glycosylation pattern similarity of antibody candidates from different conditions in optimization experiments with a reference. A specific distance was generated by this method and indicated the glycoform similarity between the biosimilar and the reference. This method can be applied to analyze the similarity of other physicochemical and functional characteristics between follow-on biologics and originators. Then, the design of experimental methods can be realized to optimize the conditions of cell culture to attain similar antibody candidates. A higher concentration of GlcNAc added to the basal media made the glycan of the antibody more similar to the glycan of the reference in this study.

High-level expression of human CH2 domain from the Fc region in Pichia pastoris and preparation of anti-CH2 antibodies

Pichia pastoris is a popular eukaryotic system employed for the fast, simple and inexpensive production of recombinant protein including biotherapeutics such as human albumin. The CH2 domain of human IgG is a promising scaffold for developing novel therapeutics. To accelerate the research of CH2 domain, we have established a procedure to highly express human CH2 domain (∼ 150 mg/L) as well as human Fc (∼ 30 mg/L) by yeast Pichia pastoris. The procedure yields, simultaneously, a major glycosylated (∼ 70%) and non-glycosylated (∼ 30%) fractions. That can be easily separated and with high purity. Although both forms of CH2 domain have essentially the same secondary structure, the presence of the short glycan increased the thermal stability of the CH2 domain by about 5 °C as determined from calorimetry. The purified glycosylated CH2 domain elicited polyclonal antibodies in mouse, recognizing not only the CH2 domain, but also recombinant human Fc and the commercial IgG1 antibody Rituxan. Protein A and Protein G binding to the kink region between CH2 domain and CH3 domain of human Fc are used to purify therapeutic proteins. Therefore, these antibodies are candidates to develop a novel affinity material to purify human antibodies using their CH2 domain.

Analytical comparability assessment on glycosylation of ziv-aflibercept and the biosimilar candidate

Ziv-aflibercept (aflibercept) is a recombinant fusion protein which combines the portions of human vascular endothelial growth factor receptors extracellular domains fused to the Fc portion of human IgG1. It is a highly sialylated glycoprotein with 5 N-glycosylation sites. In this study, a comprehensive strategy for comparability study of the complex glycosylation was developed between aflibercept and the biosimilar candidate including the investigations on N-glycosylation sites, site occupancy, site-specific glycoforms, released glycans and sialic acids. The results indicated that same N-glycosylation sites were identified, site occupancy were 100% except N₆₈ site, site-specific glycoforms and released glycans showed similar glycan species, contents of NANA were at a same level for two products. Minor differences were found between two products. The biosimilar candidate presented lower level of aglycosylation, lower level of glycans containing one terminal sialic acid, higher level of glycans containing two terminal sialic acids, higher level of G0F and Man5, lower level of G1F and G2F compared with aflibercept. However, further studies exhibited no differences were observed in the cell-based biological potency and Fc effector function. Moreover, the biosimilar candidate showed a similar pharmacokinetics curve and bioequivalence compared with aflibercept.

Development of a high cell density transient CHO platform yielding mAb titers greater than 2 g/L in only 7 days

We developed a simple transient Chinese Hamster Ovary expression platform. Titers for a random panel of 20 clinical monoclonal antibodies (mAbs) ranged from 0.6 to 2.7 g/L after 7 days. Two factors were the key in obtaining these high titers. First, we utilized an extremely high starting cell density (20 million cells/ml), and then arrested further cell growth by employing mild hypothermic conditions (32°C). Second, we performed a 6-variable Design of Experiments to find optimal concentrations of plasmid DNA (coding DNA), boost DNA (DNA encoding the XBP1S transcription factor), transfection reagent (polyethylenimine [PEI]), and nutrient feed amounts. High coding DNA concentrations (12.5 mg/L) were found to be optimal. We therefore diluted expensive coding DNA with inexpensive inert filler DNA (herring sperm DNA). Reducing the coding DNA concentration by 70% from 12.5 to 3.75 mg/L did not meaningfully reduce mAb titers. Titers for the same panel of 20 clinical mAbs ranged from 0.7 to 2.2 g/L after reducing the coding DNA concentration to 3.75 mg/L. Finally, we found that titer and product quality attributes were similar for a clinical mAb (rituximab) expressed at very different scales (volumes ranging from 3 ml to 2 L).

NHDL, a recombinant VL/VH hybrid antibody control for IgG2/4 antibodies

The mechanism of action of recombinant IgG2/4 antibodies involves blocking of their target without the induction of effector functions. Examples are eculizumab (Soliris®), which is used clinically to block complement factor C5, as well as anti-human CD14 (r18D11) and anti-porcine CD14 (rMIL2) produced in our laboratory. So far, no proper IgG2/4 control antibody has been available for controlled validation of IgG2/4 antibody functions. Here, we describe the design of a recombinant control antibody (NHDL), which was generated by combining the variable light (V_L) and heavy (V_H) chains from two unrelated specificities. NHDL was readily expressed and purified as a stable IgG2/4 antibody, and showed no detectable specificity toward any putative antigen present in human or porcine blood. The approach of artificial V_L/V_H combination may be adopted for the design of other recombinant control antibodies.

Immunogenicity of biologic therapies for migraine: a review of current evidence

Background

Monoclonal antibodies (mAbs) targeting the calcitonin gene-related peptide (CGRP) pathway have been shown to be effective in migraine prevention. Eptinezumab, erenumab, fremanezumab, and galcanezumb have shown efficacy in clinical trials along with favorable safety and tolerability profiles. Although erenumab is a human mAb and the others have been humanized to varying degrees, they all have the capacity to provoke immune reactions. The present review article aims to discuss the current relationship between mAbs targeting the CGRP pathway (CGRP mAbs) and immunogenicity and their potential clinical implications.

Findings

The incidence of patients developing anti-drug antibodies (ADAs), their titer, and clinical significance are highly variable and depend on a variety of different drug and patient factors. Neutralizing ADAs (NAbs) bind to and inhibit or reduce the pharmacologic activity of the biologic drug molecule, whereas non-neutralizing antibodies (Non-NAbs) bind to the biologic drug molecule without affecting pharmacologic activity in an in vitro test, although pharmacokinetics and drug clearance may be affected. A direct comparison of immunogenicity data across clinical trials with different biologics is not possible due to a lack of standardized assays. Several phase 2, phase 3, and long-term studies evaluating CGRP mAbs for migraine prevention have reported immunogenicity data (5 studies each for eptinezumab, erenumab, fremanezumab, and galcanezumab). Across these studies, prevalence of ADAs varied, ranging from < 1% to ~ 18%. Neutralizing ADAs were slightly less common, with a prevalence ranging from 0 to 12%. Adverse events related to ADA formation were rare.

Conclusions

As more CGRP mAb studies are conducted and more long-term follow-up data become available, evidence is increasing that immunogenicity rates of biologic therapies for migraine are low, and adverse events related to ADAs are rare. Taken together, these results add to the growing body of evidence for the safety and tolerability of this class of migraine medications.

Causal link between immunoglobulin G glycosylation and cancer: A potential glycobiomarker for early tumor detection

Changes in immunoglobulin G (IgG) glycan structures are currently believed to closely related to the emergence of cancer. In this review, we summarize the current body of evidence suggesting that differences in serum IgG glycosylation patterns correspond to changes in multiple types of cancer. Modifications include IgG terminal N-link galactosylation, IgG core fucosylation, IgG terminal sialylation, and IgG terminal bisecting N-acetylglucosamine. IgG N-glycomic alterations represent promising novel biomarkers for non-invasive-cancer diagnosis, prognosis, and progression monitoring; they are characterized by high sensitivity and specificity, compensating for previously identified glycobiomarkers.

Immunoglobulin G Glycosylation in Diseases

Changes in immunoglobulin G (IgG) glycosylation pattern have been observed in a vast array of auto- and alloimmune, infectious, cardiometabolic, malignant, and other diseases. This chapter contains an updated catalog of over 140 studies within which IgG glycosylation analysis was performed in a disease setting. Since the composition of IgG glycans is known to modulate its effector functions, it is suggested that a changed IgG glycosylation pattern in patients might be involved in disease development and progression, representing a predisposition and/or a functional effector in disease pathology. In contrast to the glycopattern of bulk serum IgG, which likely relates to the systemic inflammatory background, the glycosylation profile of antigen-specific IgG probably plays a direct role in disease pathology in several infectious and allo- and autoimmune antibody-dependent diseases. Depending on the specifics of any given disease, IgG glycosylation read-out might therefore in the future be developed into a useful clinical biomarker or a supplementary to currently used biomarkers.

Importance and Monitoring of Therapeutic Immunoglobulin G Glycosylation

The complex diantennary-type oligosaccharides at Asn297 residues of the IgG heavy chains have a profound impact on the safety and efficacy of therapeutic IgG monoclonal antibodies (mAbs). Fc glycosylation of a mAb is an established critical quality attribute (CQA), and its oligosaccharide profile is required to be thoroughly characterized by state-of-the-art analytical methods. The Fc oligosaccharides are highly heterogeneous, and the differentially glycosylated species (glycoforms) of IgG express unique biological activities. Glycoengineering is a promising approach for the production of selected mAb glycoforms with improved effector functions, and non- and low-fucosylated mAbs exhibiting enhanced antibody-dependent cellular cytotoxicity activity have been approved or are under clinical evaluation for treatment of cancers, autoimmune/chronic inflammatory diseases, and infection. Recently, the chemoenzymatic glycoengineering method that allows for the transfer of structurally defined oligosaccharides to Asn-linked GlcNAc residues with glycosynthase has been developed for remodeling of IgG-Fc oligosaccharides with high efficiency and flexibility. Additionally, various glycoengineering methods have been developed that utilize the Fc oligosaccharides of IgG as reaction handles to conjugate cytotoxic agents by "click chemistry", providing new routes to the design of antibody-drug conjugates (ADCs) with tightly controlled drug-antibody ratios (DARs) and homogeneity. This review focuses on current understanding of the biological relevance of individual IgG glycoforms and advances in the development of next-generation antibody therapeutics with improved efficacy and safety through glycoengineering.

Glycosylation and Aging

Human lifespan has increased significantly in the last 200 years, emphasizing our need to age healthily. Insights into molecular mechanisms of aging might allow us to slow down its rate or even revert it. Similar to aging, glycosylation is regulated by an intricate interplay of genetic and environmental factors. The dynamics of glycopattern variation during aging has been mostly explored for plasma/serum and immunoglobulin G (IgG) N-glycome, as we describe thoroughly in this chapter. In addition, we discuss the potential functional role of agalactosylated IgG glycans in aging, through modulation of inflammation level, as proposed by the concept of inflammaging. We also comment on the potential to use the plasma/serum and IgG N-glycome as a biomarker of healthy aging and on the interventions that modulate the IgG glycopattern. Finally, we discuss the current knowledge about animal models for human plasma/serum and IgG glycosylation and mention other, less explored, instances of glycopattern changes during organismal aging and cellular senescence.

The therapeutic potential of sialylated Fc domains of human IgG

Pathogens frequently use multivalent binding to sialic acid to infect cells or to modulate immunity through interactions with human sialic acid-binding immunoglobulin-type lectins (Siglecs). Molecules that interfere with these interactions could be of interest as diagnostics, anti-infectives or as immune modulators. This review describes the development of molecular scaffolds based on the crystallizable fragment (Fc) region of immunoglobulin (Ig) G that deliver high-avidity binding to innate immune receptors, including sialic acid-dependent receptors. The ways in which the sialylated Fc may be engineered as immune modulators that mimic the anti-inflammatory properties of intravenous polyclonal Ig or as blockers of sialic-acid-dependent infectivity by viruses are also discussed.