Strategies and challenges for the next generation of therapeutic antibodies

A combination of multiple LC-MS approaches for the comprehensive characterization of cysteine-linked ADCs

Antibody-drug conjugates (ADCs) represent the forefront of the next generation of biopharmaceuticals. An ADC typically comprises an antibody covalently linked to a cytotoxic drug via a linker, resulting in a highly heterogeneous product. This study focuses on the analysis of a custom-made cysteine-linked ADC. Initially, we developed a LC-MS-based characterization workflow using brentuximab vedotin (Adcetris®), encompassing native intact MS, analysis of reduced chains and subunits under denaturing condition, peptide mapping and online strong cation exchange chromatography coupled with UV and mass spectrometry detection (SCX-UV-MS) applied for brentuximab vedotin first time reported. Subsequently, we applied this in-depth characterization workflow to a custom-made cysteine-linked ADC. The measured drug-to-antibody ratio(DAR) of this ADC is 6.9, further analysis shown that there is a small amount of unexpected over-conjugation. Over-conjugation sites were successfully identified using multiple UHPLC-MS based characterization techniques. Also, one competitively cysteine-conjugated impurity was observed in native intact MS results, by combing native intact MS, reduced chains, subunit analysis and peptide mapping results, the impurity conjugation sites were also identified. Since this molecule is at early development stage, this provides important information for conjugation process improvement and link-drug material purification. SCX-UV-MS approach can separate the custom-made cysteine-linked ADC carrying different payloads and reduce the complexity of the spectra. The integrated approach underscores the significance of combining the SCX-UV-MS online coupling technique with other characterization methods to elucidate the heterogeneity of cysteine-linked ADCs.

Engineered polymeric excipients for enhancing the stability of protein biologics: Poly(N-isopropylacrylamide)-poly(ethylene glycol) (PNIPAM-PEG) block copolymers

Protein therapeutics, particularly antibodies, depend on maintaining their native structures for optimal function. Hydrophobic interfaces, such as the air-water interface, can trigger protein aggregation and denaturation. While completely avoiding such interfacial exposures during manufacturing and storage is impractical, minimizing them is crucial for enhancing protein drug stability and extending shelf life. In the biologics industry, surfactants like polysorbates are commonly used as additives (excipients) to mitigate these undesirable interfacial exposures. However, polysorbates, the most prevalent choice, have recognized limitations in terms of polydispersity, purity, and stability, prompting the exploration of alternative excipients. The present study identifies poly(N-isopropylacrylamide)-poly(ethylene glycol) (PNIPAM-PEG) block copolymers as a promising alternative to polysorbates. Due to its stronger affinity for the air-water interface, PNIPAM-PEG significantly outperforms polysorbates in enhancing protein stability. This claim is supported by results from multiple tests. Accelerated dynamic light scattering (DLS) experiments demonstrate PNIPAM-PEG's exceptional efficacy in preserving IgG stability against surface-induced aggregation, surpassing conventional polysorbate excipients (Tween 80 and Tween 20) under high-temperature conditions. Additionally, circular dichroism (CD) spectroscopy results reveal conformational alterations associated with aggregation, with PNIPAM-PEG consistently demonstrates a greater protective effect by mitigating negative shifts at λ ≅ 220 nm, indicative of changes in secondary structure. Overall, this study positions PNIPAM-PEG as a promising excipient for antibody therapeutics, facilitating the development of more stable and effective biopharmaceuticals.

Monoclonal antibody biosimilars for cancer treatment

Monoclonal antibodies are important cancer medicines. The European Medicines Agency (EMA) approved 48 and the Food and Drug Administration (FDA) 56 anticancer monoclonal antibody-based therapies. Their high prices burden healthcare systems and hamper global drug access. Biosimilars could retain costs and expand the availability of monoclonal antibodies. In Europe, five rituximab biosimilars, six trastuzumab biosimilars, and eight bevacizumab biosimilars are available as anti-cancer drugs. To gain insight into the biosimilar landscape for cancer treatment, we performed a literature search and analysis. In this review, we summarize cancer monoclonal antibodies' properties crucial for the desired pharmacology and point out sources of variability. The analytical assessment of all EMA-approved bevacizumab biosimilars is highlighted to illustrate this variability. The global landscape of investigational and approved biosimilars is mapped, and the challenges for access to cancer biosimilars are identified.

Panda-UV Unlocks Deeper Protein Characterization with Internal Fragments in Ultraviolet Photodissociation Mass Spectrometry

Ultraviolet photodissociation (UVPD) mass spectrometry unlocks insights into the protein structure and sequence through fragmentation patterns. While N- and C-terminal fragments are traditionally relied upon, this work highlights the critical role of internal fragments in achieving near-complete sequencing of protein. Previous limitations of internal fragment utilization, owing to their abundance and potential for random matching, are addressed here with the development of Panda-UV, a novel software tool combining spectral calibration, and Pearson correlation coefficient scoring for confident fragment assignment. Panda-UV showcases its power through comprehensive benchmarks on three model proteins. The inclusion of internal fragments boosts identified fragment numbers by 26% and enhances average protein sequence coverage to a remarkable 93% for intact proteins, unlocking the hidden region of the largest protein carbonic anhydrase II in model proteins. Notably, an average of 65% of internal fragments can be identified in multiple replicates, demonstrating the high confidence of the fragments Panda-UV provided. Finally, the sequence coverages of mAb subunits can be increased up to 86% and the complementary determining regions (CDRs) are nearly completely sequenced in a single experiment. The source codes of Panda-UV are available at https://github.com/PHOENIXcenter/Panda-UV.

AttABseq: an attention-based deep learning prediction method for antigen-antibody binding affinity changes based on protein sequences

The optimization of therapeutic antibodies through traditional techniques, such as candidate screening via hybridoma or phage display, is resource-intensive and time-consuming. In recent years, computational and artificial intelligence-based methods have been actively developed to accelerate and improve the development of therapeutic antibodies. In this study, we developed an end-to-end sequence-based deep learning model, termed AttABseq, for the predictions of the antigen-antibody binding affinity changes connected with antibody mutations. AttABseq is a highly efficient and generic attention-based model by utilizing diverse antigen-antibody complex sequences as the input to predict the binding affinity changes of residue mutations. The assessment on the three benchmark datasets illustrates that AttABseq is 120% more accurate than other sequence-based models in terms of the Pearson correlation coefficient between the predicted and experimental binding affinity changes. Moreover, AttABseq also either outperforms or competes favorably with the structure-based approaches. Furthermore, AttABseq consistently demonstrates robust predictive capabilities across a diverse array of conditions, underscoring its remarkable capacity for generalization across a wide spectrum of antigen-antibody complexes. It imposes no constraints on the quantity of altered residues, rendering it particularly applicable in scenarios where crystallographic structures remain unavailable. The attention-based interpretability analysis indicates that the causal effects of point mutations on antibody-antigen binding affinity changes can be visualized at the residue level, which might assist automated antibody sequence optimization. We believe that AttABseq provides a fiercely competitive answer to therapeutic antibody optimization.

Balancing the Affinity and Tumor Cell Binding of a Two-in-One Antibody Simultaneously Targeting EGFR and PD-L1

The optimization of the affinity of monoclonal antibodies is crucial for the development of drug candidates, as it can impact the efficacy of the drug and, thus, the dose and dosing regimen, limit adverse effects, and reduce therapy costs. Here, we present the affinity maturation of an EGFR×PD-L1 Two-in-One antibody for EGFR binding utilizing site-directed mutagenesis and yeast surface display. The isolated antibody variants target EGFR with a 60-fold-improved affinity due to the replacement of a single amino acid in the CDR3 region of the light chain. The binding properties of the Two-in-One variants were confirmed using various methods, including BLI measurements, real-time antigen binding measurements on surfaces with a mixture of both recombinant proteins and cellular binding experiments using flow cytometry as well as real-time interaction cytometry. An AlphaFold-based model predicted that the amino acid exchange of tyrosine to glutamic acid enables the formation of a salt bridge to an arginine at EGFR position 165. This easily adaptable approach provides a strategy for the affinity maturation of bispecific antibodies with respect to the binding of one of the two antigens.

Progress in novel delivery technologies to improve efficacy of therapeutic antibodies

Monoclonal antibody-based therapeutics have achieved remarkable success in treating a wide range of human diseases. However, conventional systemic delivery methods have limitations in insufficient target tissue permeability, high costs, repeated administrations, etc. Novel technologies have been developed to address these limitations and further enhance antibody therapy. Local antibody delivery via respiratory tract, gastrointestinal tract, eye and blood-brain barrier have shown promising results in increasing local concentrations and overcoming barriers. Nucleic acid-encoded antibodies expressed from plasmid DNA, viral vectors or mRNA delivery platforms also offer advantages over recombinant proteins such as sustained expression, rapid onset, and lower costs. This review summarizes recent advances in antibody delivery methods and highlights innovative technologies that have potential to expand therapeutic applications of antibodies.

A human anti-matriptase-2 antibody limits iron overload, α-globin aggregates, and splenomegaly in β-thalassemic mice

ABSTRACT

Iron plays a major role in the deterioration of β-thalassemia. Indeed, the high levels of transferrin saturation and iron delivered to erythroid progenitors are associated with production of α-globin precipitates that negatively affect erythropoiesis. Matriptase-2/TMPRSS6, a membrane-bound serine protease expressed in hepatocytes, negatively modulates hepcidin production and thus is a key target to prevent iron overload in β-thalassemia. To address safety concerns raised by the suppression of Tmprss6 by antisense oligonucleotides or small interfering RNA, we tested a fully human anti-matriptase-2 antibody, RLYB331, which blocks the protease activity of matriptase-2. When administered weekly to Hbbth3/+ mice, RLYB331 induced hepcidin expression, reduced iron loading, prevented the formation of toxic α-chain/heme aggregates, reduced ros oxygen species formation, and improved reticulocytosis and splenomegaly. To increase the effectiveness of RLYB331 in β-thalassemia treatment even further, we administered RLYB331 in combination with RAP-536L, a ligand-trapping protein that contains the extracellular domain of activin receptor type IIB and alleviates anemia by promoting differentiation of late-stage erythroid precursors. RAP-536L alone did not prevent iron overload but significantly reduced apoptosis in the erythroid populations of the bone marrow, normalized red blood cell counts, and improved hemoglobin and hematocrit levels. Interestingly, the association of RLYB331 with RAP-536L entirely reversed the β-thalassemia phenotype in Hbbth3/+ mice and simultaneously corrected iron overload, ineffective erythropoiesis, splenomegaly, and hematological parameters, suggesting that a multifunctional molecule consisting of the fusion of RLYB331 with luspatercept (human version of RAP-536L) would allow administration of a single medication addressing simultaneously the different pathophysiological aspects of β-thalassemia.

Generation and characterization of nanobodies targeting human pepsinogens

Human pepsinogens (mainly pepsinogen I and pepsinogen II) are the major inactive precursor forms of the digestive enzyme pepsin which play a crucial role in protein digestion. The levels and ratios of human pepsinogens have demonstrated potential as diagnostic biomarkers for gastrointestinal diseases, particularly gastric cancer. Nanobodies are promising tools for the treatment and diagnosis of diseases, owing to their unique recognition properties. In this study, recombinant human pepsinogens proteins were expressed and purified as immunized antigens. We constructed a VHH phage library and identified several nanobodies via phage display bio-panning. We determined the binding potency and cross-reactivity of these nanobodies. Our study provides technical support for developing immunodiagnostic reagents targeting human pepsinogens.

Insights into the history and tendency of glycosylation and digestive system tumor: A bibliometric-based visual analysis

BACKGROUND

Glycosylation, a commonly occurring post-translational modification, is highly expressed in several tumors, specifically in those of the digestive system, and plays a role in various cellular pathophysiological mechanisms. Although the importance and detection methods of glycosylation in digestive system tumors have garnered increasing attention in recent years, bibliometric analysis of this field remains scarce. The present study aims to identify the developmental trends and research hotspots of glycosylation in digestive system tumors.

AIM

To find and identify the developmental trends and research hotspots of glycosylation in digestive system tumors.

METHODS

We obtained relevant literature from the Web of Science Core Collection and employed VOSviewer 1.6.19 and CiteSpace (version 6.1.R6) to perform bibliometric analysis.

RESULTS

A total of 2042 documents spanning from 1978 to the present were analyzed, with the research process divided into three phases: the period of obscurity (1978-1990), continuous development period (1991-2006), and the rapid outbreak period (2007-2023). These documents were authored by researchers from 66 countries or regions, with the United States and China leading in terms of publication output. Reis Celso A had the highest number of publications, while Pinho SS was the most cited author. Co-occurrence analysis revealed the most popular keywords in this field are glycosylation, expression, cancer, colorectal cancer, and pancreatic cancer. Furthermore, the Journal of Proteome Research was the most prolific journal in terms of publications, while the Journal of Biological Chemistry had the most citations.

CONCLUSION

The bibliometric analysis shows current research focus is primarily on basic research in this field. However, future research should aim to utilize glycosylation as a target for treating tumor patients.

Polymer-mediated nanoformulations: a promising strategy for cancer immunotherapy

Engineering polymer-based nano-systems have attracted many researchers owing to their unique qualities like shape, size, porosity, mechanical strength, biocompatibility, and biodegradability. Both natural and synthetic polymers can be tuned to get desired surface chemistry and functionalization to improve the efficacy of cancer therapy by promoting targeted delivery to the tumor site. Recent advancements in cancer immunoediting have been able to manage both primary tumor and metastatic lesions via activation of the immune system. The combinations of nano-biotechnology and immunotherapeutic agents have provided positive outcomes by enhancing the host immune response in cancer therapy. The nanoparticles have been functionalized using antibodies, targeted antigens, small molecule ligands, and other novel agents that can interact with biological systems at nanoscale levels. Several polymers, such as polyethylene glycol (PEG), poly(lactic-co-glycolic acid) (PLGA), poly(ε-caprolactone) (PCL), and chitosan, have been approved by the Food and Drug Administration for clinical use in biomedicine. The polymeric nanoformulations such as polymers-antibody/antigen conjugates and polymeric drug conjugates are currently being explored as nanomedicines that can target cancer cells directly or target immune cells to promote anti-cancer immunotherapy. In this review, we focus on scientific developments and advancements on engineered polymeric nano-systems in conjugation with immunotherapeutic agents targeting the tumor microenvironment to improve their efficacy and the safety for better clinical outcomes.

AbImmPred: An immunogenicity prediction method for therapeutic antibodies using AntiBERTy-based sequence features

Due to the unnecessary immune responses induced by therapeutic antibodies in clinical applications, immunogenicity is an important factor to be considered in the development of antibody therapeutics. To a certain extent, there is a lag in using wet-lab experiments to test the immunogenicity in the development process of antibody therapeutics. Developing a computational method to predict the immunogenicity at once the antibody sequence is designed, is of great significance for the screening in the early stage and reducing the risk of antibody therapeutics development. In this study, a computational immunogenicity prediction method was proposed on the basis of AntiBERTy-based features of amino sequences in the antibody variable region. The AntiBERTy-based sequence features were first calculated using the AntiBERTy pre-trained model. Principal component analysis (PCA) was then applied to reduce the extracted feature to two dimensions to obtain the final features. AutoGluon was then used to train multiple machine learning models and the best one, the weighted ensemble model, was obtained through 5-fold cross-validation on the collected data. The data contains 199 commercial therapeutic antibodies, of which 177 samples were used for model training and 5-fold cross-validation, and the remaining 22 samples were used as an independent test dataset to evaluate the performance of the constructed model and compare it with other prediction methods. Test results show that the proposed method outperforms the comparison method with 0.7273 accuracy on the independent test dataset, which is 9.09% higher than the comparison method. The corresponding web server is available through the official website of GenScript Co., Ltd., https://www.genscript.com/tools/antibody-immunogenicity.

Enhancing affinity purification of monoclonal antibodies from human serum for subsequent CZE-MS analysis

Due to the separation technique employed, capillary electrophoresis coupled to mass spectrometry (CE-MS) analysis performances are significantly influenced by the chemical composition and the complexity of the sample. In various applications, that impact has prevented the use of CE-MS for the characterization and quantification of proteins in biological samples. Here we present the development and evaluation and a sample preparation procedure, based on affinity purification, for the specific extraction of the monoclonal antibody (mAbs) infliximab from human serum in order to perform subsequent proteolytic digestion and CE-MS/MS analysis. Three distinctive sample preparation strategies were envisaged. In each case, the different steps composing the protocol were thoroughly optimized and evaluated in order to provide a sample preparation addressing the important complexity of serums samples while providing an optimal compatibility with CE-MS/MS analysis. The different sample preparation strategies were assessed concerning the possibility to achieve an appropriate absolute quantification of the mAbs using CE-MS/MS for samples mimicking patient serum samples. Also, the possibility to perform the characterization of several types of post-translational modifications (PTMs) was evaluated. The sample preparation protocols allowed the quantification of the mAbs in serums samples for concentration as low as 0.2 µg·mL-1 (2.03 nM) using CE-MS/MS analysis, also the possibility to characterize and estimate the modification level of PTMs hotspots in a consistent manner. Results allowed to attribute the effect on the electrophoretic separation of the different steps composing sample preparation. Finally, they demonstrated that sample preparation for CE-MS/MS analysis could benefit greatly for the extended applicability of this type of analysis for complex biological matrices.

Internal Fragments Enhance Middle-Down Mass Spectrometry Structural Characterization of Monoclonal Antibodies and Antibody-Drug Conjugates

Monoclonal antibodies (mAbs) and antibody-drug conjugates (ADCs) are important large biotherapeutics (∼150 kDa) and high structural complexity that require extensive sequence and structure characterization. Middle-down mass spectrometry (MD-MS) is an emerging technique that sequences and maps subunits larger than those released by trypsinolysis. It avoids potentially introducing artifactual modifications that may occur in bottom-up MS while achieving higher sequence coverage compared to top-down MS. However, returning complete sequence information by MD-MS is still challenging. Here, we show that assigning internal fragments in direct infusion MD-MS of a mAb and an ADC substantially improves their structural characterization. For MD-MS of the reduced NIST mAb, including internal fragments recovers nearly 100% of the sequence by accessing the middle sequence region that is inaccessible by terminal fragments. The identification of important glycosylations can also be improved after the inclusion of internal fragments. For the reduced lysine-linked IgG1-DM1 ADC, we show that considering internal fragments increases the DM1 conjugation sites coverage to 80%, comparable to the reported 83% coverage achieved by peptide mapping on the same ADC (Luo et al. Anal. Chem. 2016, 88, 695-702). This study expands our work on the application of internal fragment assignments in top-down MS of mAbs and ADCs and can be extended to other heterogeneous therapeutic molecules such as multispecifics and fusion proteins for more widespread applications.

OX40L-expressing M1-like macrophage exosomes for cancer immunotherapy

With only limited clinical patient benefit, focusing on new immune checkpoint pathways could be an important complement to current immune checkpoint drugs. In addition, not only does T cell-mediated adaptive immunity play an important role, but also macrophage-mediated innate immunity, due to its abundant presence in solid tumors. Here, we developed an engineered M1-like macrophage exosome, OX40L M1-exos. OX40L M1-exos can activate the adaptive immunity by activating the OX40/OX40L pathway and can reprogram M2-like tumor-associated macrophages into M1-like macrophages, thereby restoring and enhancing macrophage-mediated innate immunity. Our OX40L M1-exos achieved an effective synergistic effect of innate and adaptive immunity and achieved a potent therapeutic effect in a mouse breast cancer model, effectively inhibiting tumor growth and metastasis. These results suggest that OX40L M1-exos are an attractive therapeutic strategy and may be an important complement to current cancer immunotherapies.

Protein therapeutics as an emerging strategy to deal with skin cancer: A short review

Cancer has turned into a global menace with an exponential increase in the rate of death every year. Amongst all forms of cancers, skin cancer is the one becoming more common day by day because of the increased exposure to ultraviolet rays, chemicals, pollutants, etc. Skin cancer is of three types namely basal cell, squamous cell and melanoma which is one of the most aggressive forms of cancer with a low survival rate and easy relapse. Melanoma is also notorious for being multi-drug resistant which accounts for its low survival rates in it. Many kinds of therapeutics are been practiced in the contemporary world, but among them, protein therapeutics is been emerging as a promising field with multiple molecular pathway targets that have revolutionized the science of oncology. Proteins acts as small-molecule targets for cancer cells by binding to the cell surface receptors. Proteins including bromodomain and extra-terminal domain (BET) and some toxin proteins are been tried on for dealing with melanoma targeting the major pathways including MAPK, NF-κB and PI3K/AKT. The protein therapeutics also targets the tumour microenvironment including myofibrils, lymphatic vessels etc., thus inducing tumour cell death. In the review, several kinds of proteins and their function toward cell death will be highlighted in the context of skin cancer. In addition to this, the review will look into the inhibition of the function of other inflammatory pathways by inflammasomes and cytokines, both of which have a role in preventing cancer.

Benchmark Glycan Profile of Therapeutic Monoclonal Antibodies Produced by Mammalian Cell Expression Systems

PURPOSE

This study aims to establish a benchmark glycan profile for commercial therapeutic monoclonal antibodies (mAbs) approved by the US Food and Drug Administration (FDA).

METHODS

We conducted a rigorous comparison of glycosylation data from the regulatory submissions for FDA-approved therapeutic antibodies up to May 2023. This analysis includes over 150 mAbs produced by various mammalian cell expression systems.

RESULTS

The study identified nine prevalent glycan epitopes across all FDA-approved monoclonal antibodies produced by different expression systems. These epitopes include terminal N-acetylglucosamine, core fucose, terminal galactose, high mannose, α-galactose, terminal α2,3-linked N-acetylneuraminic acid, terminal α2,6-linked N-glycolylneuraminic acid, triantennary structure, and bisecting N-acetylglucosamine, thus establishing a benchmark glycan profile.

CONCLUSIONS

The findings of this study have significant implications for therapeutic antibody development, quality control, and regulatory compliance. The benchmark glycan profile enables the assessment of glycosylation consistency and comparability across a diverse range of antibody products, ensuring improved product quality within the biopharmaceutical industry.

Sample transformation in online separations: how chemical conversion advances analytical technology

While the advent of modern analytical technology has allowed scientists to determine the complexity of mixtures, it also spurred the demand to understand these sophisticated mixtures better. Chemical transformation can be used to provide insights into properties of complex samples such as degradation pathways or molecular heterogeneity that are otherwise unaccessible. In this article, we explore how sample transformation is exploited across different application fields to empower analytical methods. Transformation mechanisms include molecular-weight reduction, controlled degradation, and derivatization. Both offline and online transformation methods have been explored. The covered studies show that sample transformation facilitates faster reactions (e.g. several hours to minutes), reduces sample complexity, unlocks new sample dimensions (e.g. functional groups), provides correlations between multiple sample dimensions, and improves detectability. The article highlights the state-of-the-art and future prospects, focusing in particular on the characterization of protein and nucleic-acid therapeutics, nanoparticles, synthetic polymers, and small molecules.

Isolation and characterization of a novel single-chain variable fragment (scFv) against Lymphocyte function-associated antigen-1 (LFA-1) using phage display method

Lymphocyte function-associated antigene-1 (LFA-1) is a well-described integrin found on lymphocytes and other leukocytes, which is known to be overexpressed in leukemias and lymphomas. This receptor plays a significant role in immune responses such as T-cell activation, leukocyte cell-cell interactions, and trafficking of leukocyte populations. Subsequently, binders of LFA-1 emerge as potential candidates for cancer and autoimmune therapy. This study used the phage display technique to construct and characterize a high-affinity single-chain fragment variable (scFv) antibody against LFA-1. After expression, purification, dialysis, and concentration of the recombinant LFA-1 protein, four female BALB/c mice were immunized, splenocyte's mRNA was extracted, and cDNA was synthesized. A scFv library was constructed by linking the amplified VH/Vκ fragments through a 72-bp linker using SOEing PCR. Next, the scFv gene fragments were cloned into the pComb-3XSS phagemid vector; thus, the phage library was developed. The selection process involved three rounds of phage-bio-panning, polyclonal, and monoclonal phage ELISA. AF17 was chosen and characterized among the positive clones through SDS-PAGE, Western blotting, indirect ELISA, and in-silico analyses. The results of the study showed the successful construction of a high-affinity scFv library against LFA-1. The accuracy of the AF17 production and its ability to bind to the LFA-1 were confirmed through SDS-PAGE, Western blot, and ELISA. This study highlights the potential application of the high-affinity AF17 against LFA-1 for targeting T lymphocytes for therapeutic purposes.

Bispecific antibodies revolutionizing breast cancer treatment: a comprehensive overview

Breast cancer (BCa) is known as a complex and prevalent disease requiring the development of novel anticancer therapeutic approaches. Bispecific antibodies (BsAbs) have emerged as a favorable strategy for BCa treatment due to their unique ability to target two different antigens simultaneously. By targeting tumor-associated antigens (TAAs) on cancer cells, engaging immune effector cells, or blocking critical signaling pathways, BsAbs offer enhanced tumor specificity and immune system involvement, improving anti-cancer activity. Preclinical and clinical studies have demonstrated the potential of BsAbs in BCa. For example, BsAbs targeting human epidermal growth factor receptor 2 (HER2) have shown the ability to redirect immune cells to HER2-positive BCa cells, resulting in effective tumor cell killing. Moreover, targeting the PD-1/PD-L1 pathway by BsAbs has demonstrated promising outcomes in overcoming immunosuppression and enhancing immune-mediated tumor clearance. Combining BsAbs with existing therapeutic approaches, such as chemotherapy, targeted therapies, or immune checkpoint inhibitors (ICIs), has also revealed synergistic effects in preclinical models and early clinical trials, emphasizing the usefulness and potential of BsAbs in BCa treatment. This review summarizes the latest evidence about BsAbs in treating BCa and the challenges and opportunities of their use in BCa.

An off-the-shelf small extracellular vesicle nanomedicine for tumor targeting therapy

Small extracellular vesicles (sEVs) have shown excellent prospects as drug delivery systems for cancer therapy. However, the inherent non-targeting and short blood circulation characteristics severely restrict their practical applications as a delivery system. In addition, post-encapsulating drugs into sEVs also remains challenging. Here, we constructed an engineered cell line that secreted multifunctional sEVs (termed NBsEV204) with 7D12 (an anti-EGFR nanobody) and hCD47 decorations on their surface, as well as high levels of miR-204-5p encapsulation. NBsEV204 exhibited extended blood circulation and improved macrophage-mediated phagocytosis of tumor cells by blocking CD47 signaling. Importantly, NBsEV204 specifically targeted EGFR+ tumor cells and showed robust tumor-suppressive effects both in vitro and in vivo. Overall, this study provides a convenient and feasible method to produce off-the-shelf anticancer sEV nanomedicine, which exhibits tremendous potential for clinical translation.

Recent advances in structural mass spectrometry methods in the context of biosimilarity assessment: from sequence heterogeneities to higher order structures

Biotherapeutics and their biosimilar versions have been flourishing in the biopharmaceutical market for several years. Structural and functional characterization is needed to achieve analytical biosimilarity through the assessment of critical quality attributes as required by regulatory authorities. The role of analytical strategies, particularly mass spectrometry-based methods, is pivotal to gathering valuable information for the in-depth characterization of biotherapeutics and biosimilarity assessment. Structural mass spectrometry methods (native MS, HDX-MS, top-down MS, etc.) provide information ranging from primary sequence assessment to higher order structure evaluation. This review focuses on recent developments and applications in structural mass spectrometry for biotherapeutic and biosimilar characterization.

Bispecific Antibody Detection Using Antigen-Conjugated Synthetic Nucleic Acid Strands

We report here the development of two different sensing strategies based on the use of antigen-conjugated nucleic acid strands for the detection of a bispecific antibody against the tumor-related proteins Mucin1 and epidermal growth factor receptor. Both approaches work well in serum samples (nanomolar sensitivity), show high specificity against the two monospecific antibodies, and are rapid. The results presented here demonstrate the versatility of DNA-based platforms for the detection of bispecific antibodies and could represent a versatile alternative to other more reagent-intensive and time-consuming analytical approaches.

Modulating antibody effector functions by Fc glycoengineering

Antibody based drugs, including IgG monoclonal antibodies, are an expanding class of therapeutics widely employed to treat cancer, autoimmune and infectious diseases. IgG antibodies have a conserved N-glycosylation site at Asn297 that bears complex type N-glycans which, along with other less conserved N- and O-glycosylation sites, fine-tune effector functions, complement activation, and half-life of antibodies. Fucosylation, galactosylation, sialylation, bisection and mannosylation all generate glycoforms that interact in a specific manner with different cellular antibody receptors and are linked to a distinct functional profile. Antibodies, including those employed in clinical settings, are generated with a mixture of glycoforms attached to them, which has an impact on their efficacy, stability and effector functions. It is therefore of great interest to produce antibodies containing only tailored glycoforms with specific effects associated with them. To this end, several antibody engineering strategies have been developed, including the usage of engineered mammalian cell lines, in vitro and in vivo glycoengineering.

Recent applications of quantitative mass spectrometry in biopharmaceutical process development and manufacturing

Biopharmaceutical products have seen rapid growth over the past few decades and continue to dominate the global pharmaceutical market. Aligning with the quality by design (QbD) framework and realization, recent advances in liquid chromatography-mass spectrometry (LC-MS) instrumentation and related techniques have enhanced biopharmaceutical characterization capabilities and have supported an increased development of biopharmaceutical products. Beyond its routine qualitative characterization, the quantitative feature of LC-MS has unique applications in biopharmaceutical process development and manufacturing. This review describes the recent applications and implications of the advancement of quantitative MS methods in biopharmaceutical process development, and characterization of biopharmaceutical product, product-related variants, and process-related impurities. We also provide insights on the emerging applications of quantitative MS in the lifecycle of biopharmaceutical product development including quality control in the Good Manufacturing Practice (GMP) environment and process analytical technology (PAT) practices during process development and manufacturing. Through collaboration with instrument and software vendors and regulatory agencies, we envision broader adoption of phase-appropriate quantitative MS-based methods for the analysis of biopharmaceutical products, which in turn has the potential to enable manufacture of higher quality products for patients.

A prospective, randomized, double-blind, placebo-controlled multisite, parallel-group field study in dogs with osteoarthritis conducted in the United States of America evaluating bedinvetmab, a canine anti-nerve growth factor monoclonal antibody

OBJECTIVE

Bedinvetmab, a fully canine anti-nerve growth factor monoclonal antibody, was evaluated in dogs for control of osteoarthritis-related pain in a study conducted to support registration in the USA.

STUDY DESIGN

Randomized, double-blind, placebo-controlled, multicenter, parallel-group study.

ANIMALS

General practice client-owned dogs with osteoarthritis (n = 272).

METHODS

Dogs were block randomized 1:1 to placebo (saline, n = 137) or bedinvetmab (n = 135; 0.5-1.0 mg kg-1) administered subcutaneously, once monthly. The primary end point, day 28 Canine Brief Pain Inventory (CBPI) treatment success (TS), required pain severity score (PSS; 0-10) decrease ≥1 and pain interference score (PIS; 0-10) decrease ≥ 2. CBPI TS rates [and number needed to treat (NNT)], change in scores [and standardized effect size (ES)], change in quality of life (QoL) and bedinvetmab half-life were calculated.

RESULTS

Significant (p < 0.05) improvement with bedinvetmab over placebo occurred (days 28, 42, 56, 84) for CBPI TS. Of cases evaluable for day 28 CBPI TS (placebo, n = 131; bedinvetmab, n = 128), success rates were 36.6% and 47.4%, respectively (p = 0.0410) (NNT, 9.3; PSS and PIS ES, 0.3). CBPI TS increased after the second dose in both groups, plateaued for bedinvetmab at day 42 and decreased for placebo beginning day 84. Day 84 NNT (4.3), PSS (0.4) and PIS (0.5) showed continued improvement with monthly dosing. After the first dose, mean (± standard deviation) bedinvetmab half-life was 19.1 (8.3) days. Adverse events were similar between groups and not considered treatment-related. There was a significant effect of bedinvetmab versus placebo on all CBPI components (PIS, PSS, QoL).

CONCLUSIONS AND CLINICAL RELEVANCE

These results corroborated those previously reported and provide further support of safety and effectiveness of bedinvetmab (0.5-1.0 mg kg-1) administered subcutaneously at monthly intervals to dogs for control of osteoarthritis-related pain.

Physicochemical and Functional Similarity Assessment Between Proposed Bevacizumab Biosimilar BAT1706 and Reference Bevacizumab

BACKGROUND

BAT1706 is a proposed biosimilar of bevacizumab, a vascular endothelial growth factor A (VEGF-A)-targeting biologic used to treat several different cancers, including metastatic colorectal cancer. A comprehensive physicochemical and functional similarity assessment is a key component of demonstrating biosimilarity between a reference biologic and a proposed biosimilar. Here we report the physicochemical and functional similarity of BAT1706 and reference bevacizumab sourced from both the United States (US-bevacizumab) and the European Union (EU-bevacizumab).

METHOD

A large range of product attributes, including primary and higher order structure, post-translational modifications, purity, stability, and potency, were characterized for BAT1706 and EU/US-bevacizumab using sensitive state-of-the-art analytical techniques. Up to 18 lots of US- and 29 lots of EU-bevacizumab, and 10 unique drug substance lots of BAT1706, were assessed.

RESULT

BAT1706 was shown to have an identical amino acid sequence and an indistinguishable higher-order structure compared with EU/US-bevacizumab. BAT1706 and EU/US-bevacizumab also exhibited similar post-translational modifications, glycan profiles, and charge variants. Potency, assessed using a wide range of bioassays, was also shown to be comparable between BAT1706 and EU/US-bevacizumab, with statistical equivalence demonstrated for VEGF-A binding and neutralizing activity.

CONCLUSION

Overall, this extensive comparability exercise demonstrated BAT1706 to match EU/US-bevacizumab in terms of all physicochemical and functional attributes assessed.

Antibody-drug conjugates: the paradigm shifts in the targeted cancer therapy

Cancer is one of the deadliest diseases, causing million of deaths each year globally. Conventional anti-cancer therapies are non-targeted and have systemic toxicities limiting their versatile applications in many cancers. So, there is an unmet need for more specific therapeutic options that will be effective as well as free from toxicities. Antibody-drug conjugates (ADCs) are suitable alternatives with the right potential and improved therapeutic index for cancer therapy. The ADCs are highly precise new class of biopharmaceutical products that covalently linked a monoclonal antibody (mAb) (binds explicitly to a tumor-associated surface antigen) with a customized cytotoxic drug (kills cancer cells) and tied via a chemical linker (releases the drug). Due to its precise design, it brings about the target cell killing sparing the normal counterpart and free from the toxicities of conventional chemotherapy. It has never been so easy to develop potential ADCs for successful therapeutic usage. With relentless efforts, it took almost a century for scientists to advance the formula and design ADCs for its current clinical applications. Until now, several ADCs have passed successfully through preclinical and clinical trials and because of proven efficacy, a few are approved by the FDA to treat various cancer types. Even though ADCs posed some shortcomings like adverse effects and resistance at various stages of development, with continuous efforts most of these limitations are addressed and overcome to improve their efficacy. In this review, the basics of ADCs, physical and chemical properties, the evolution of design, limitations, and future potentials are discussed.

Engineering strategies of Anti-HIV antibody therapeutics in clinical development

PURPOSE OF REVIEW

Anti-human immunodeficiency virus (HIV) antibody-based therapeutics offer an alternative treatment option to current antiretroviral drugs. This review aims to provide an overview of the Fc- and Fab-engineering strategies that have been developed to optimize broadly neutralizing antibodies and discuss recent findings from preclinical and clinical studies.

RECENT FINDINGS

Multispecific antibodies, including bispecific and trispecific antibodies, DART molecules, and BiTEs, as well as Fc-optimized antibodies, have emerged as promising therapeutic candidates for the treatment of HIV. These engineered antibodies engage multiple epitopes on the HIV envelope protein and human receptors, resulting in increased potency and breadth of activity. Additionally, Fc-enhanced antibodies have demonstrated extended half-life and improved effector function.

SUMMARY

The development of Fc and Fab-engineered antibodies for the treatment of HIV continues to show promising progress. These novel therapies have the potential to overcome the limitations of current antiretroviral pharmacologic agents by more effectively suppressing viral load and targeting latent reservoirs in individuals living with HIV. Further studies are needed to fully understand the safety and efficacy of these therapies, but the growing body of evidence supports their potential as a new class of therapeutics for the treatment of HIV.

Predictive Nature of High-Throughput Assays in ADC Formulation Screening

Utilization of high-throughput biophysical screening techniques during early screening studies is warranted due to the limited amount of material and large number of samples. But the predictability of the data to longer-term storage stability is critical as the high-throughput methods assist in defining the design space for the longer-term studies. In this study, the biophysical properties of two ADCs in 16 formulation conditions were evaluated using high-throughput techniques. Conformational stability and colloidal stability were evaluated by determining Tm values, kD, B22, and Tagg. In addition, the samples were placed on stability and the extent of aggregate formation over the 8-week interval was determined. The rank order of the 16 different formulations in the high-throughput assays was compared to the rank order observed during the stability studies to assess the predictive capabilities of the screening methods. It was demonstrated that similar rank orders can be expected between high-throughput physical stability indicating assays such as Tagg and B22 and traditional aggregation by SEC data, whereas conformational stability read-outs (Tm) are less predictive. In addition, the high-throughput assays appropriately identified the poor performing formulation conditions, which is ultimately what is desired of screening assays.

Added Value of Internal Fragments for Top-Down Mass Spectrometry of Intact Monoclonal Antibodies and Antibody-Drug Conjugates

Monoclonal antibodies (mAbs) and antibody-drug conjugates (ADCs) are two of the most important therapeutic drug classes that require extensive characterization, whereas their large size and structural complexity make them challenging to characterize and demand the use of advanced analytical methods. Top-down mass spectrometry (TD-MS) is an emerging technique that minimizes sample preparation and preserves endogenous post-translational modifications (PTMs); however, TD-MS of large proteins suffers from low fragmentation efficiency, limiting the sequence and structure information that can be obtained. Here, we show that including the assignment of internal fragments in native TD-MS of an intact mAb and an ADC can improve their molecular characterization. For the NIST mAb, internal fragments can access the sequence region constrained by disulfide bonds to increase the TD-MS sequence coverage to over 75%. Important PTM information, including intrachain disulfide connectivity and N-glycosylation sites, can be revealed after including internal fragments. For a heterogeneous lysine-linked ADC, we show that assigning internal fragments improves the identification of drug conjugation sites to achieve a coverage of 58% of all putative conjugation sites. This proof-of-principle study demonstrates the potential value of including internal fragments in native TD-MS of intact mAbs and ADCs, and this analytical strategy can be extended to bottom-up and middle-down MS approaches to achieve even more comprehensive characterization of important therapeutic molecules.

The Dawn of a New Era: Targeting the "Undruggables" with Antibody-Based Therapeutics

The high selectivity and affinity of antibodies toward their antigens have made them a highly valuable tool in disease therapy, diagnosis, and basic research. A plethora of chemical and genetic approaches have been devised to make antibodies accessible to more "undruggable" targets and equipped with new functions of illustrating or regulating biological processes more precisely. In this Review, in addition to introducing how naked antibodies and various antibody conjugates (such as antibody-drug conjugates, antibody-oligonucleotide conjugates, antibody-enzyme conjugates, etc.) work in therapeutic applications, special attention has been paid to how chemistry tools have helped to optimize the therapeutic outcome (i.e., with enhanced efficacy and reduced side effects) or facilitate the multifunctionalization of antibodies, with a focus on emerging fields such as targeted protein degradation, real-time live-cell imaging, catalytic labeling or decaging with spatiotemporal control as well as the engagement of antibodies inside cells. With advances in modern chemistry and biotechnology, well-designed antibodies and their derivatives via size miniaturization or multifunctionalization together with efficient delivery systems have emerged, which have gradually improved our understanding of important biological processes and paved the way to pursue novel targets for potential treatments of various diseases.

Automated optimisation of solubility and conformational stability of antibodies and proteins

Biologics, such as antibodies and enzymes, are crucial in research, biotechnology, diagnostics, and therapeutics. Often, biologics with suitable functionality are discovered, but their development is impeded by developability issues. Stability and solubility are key biophysical traits underpinning developability potential, as they determine aggregation, correlate with production yield and poly-specificity, and are essential to access parenteral and oral delivery. While advances for the optimisation of individual traits have been made, the co-optimization of multiple traits remains highly problematic and time-consuming, as mutations that improve one property often negatively impact others. In this work, we introduce a fully automated computational strategy for the simultaneous optimisation of conformational stability and solubility, which we experimentally validate on six antibodies, including two approved therapeutics. Our results on 42 designs demonstrate that the computational procedure is highly effective at improving developability potential, while not affecting antigen-binding. We make the method available as a webserver at www-cohsoftware.ch.cam.ac.uk.

Generation of a symmetrical trispecific NK cell engager based on a two-in-one antibody

To construct a trispecific IgG-like antibody at least three different binding moieties need to be combined, which results in a complex architecture and challenging production of these molecules. Here we report for the first time the construction of trispecific natural killer cell engagers based on a previously reported two-in-one antibody combined with a novel anti-CD16a common light chain module identified by yeast surface display (YSD) screening of chicken-derived immune libraries. The resulting antibodies simultaneously target epidermal growth factor receptor (EGFR), programmed death-ligand 1 (PD-L1) and CD16a with two Fab fragments, resulting in specific cellular binding properties on EGFR/PD-L1 double positive tumor cells and a potent ADCC effect. This study paves the way for further development of multispecific therapeutic antibodies derived from avian immunization with desired target combinations, valencies, molecular symmetries and architectures.

Analytical Performance Evaluation of Identity, Quality-Attribute Monitoring and new Peak Detection in a Platform Multi-Attribute Method Using Lys-C Digestion for Characterization and Quality Control of Therapeutic Monoclonal Antibodies

The use of multi-attribute method (MAM) for identity and purity testing of biopharmaceuticals offers the ability to complement and replace multiple conventional analytical technologies with a single mass spectrometry (MS) method. Phase-appropriate method validation is one major consideration for the implementation of MAM in a current Good Manufacturing Practice (cGMP) environment. We developed a MAM workflow for therapeutic monoclonal antibodies (mAbs) with optimized sample preparation using lysyl endopeptidase (Lys-C) digestion. In this study, we evaluated the assay performances of this platform MAM workflow for identity, product quality attributes (PQAs) monitoring and new peak detection (NPD) for single and coformulated mAbs. An IgG4 mAb-1 and its coformulations were used as model molecules in this study. The assay performance evaluation demonstrated the full potential of the platform MAM approach for its intended use for characterization and quality control of single mAb-1 and mAb-1 in its coformulations. To the best of our knowledge, this is the first performance evaluation of MAM for mAb identity, PQA monitoring, and new peak detection (NPD) in a single assay, featuring 1) the first performance evaluation of MAM for PQA monitoring using Lys-C digestion with a high-resolution MS, 2) a new approach for mAb identity testing capable of distinguishing single mAb from coformulations using MAM, and 3) the performance evaluation of NPD for MAM with Lys-C digestion. The developed platform MAM workflow and the MAM performance evaluation paved the way for its GMP qualification and enabled clinical release of mAb-1 in GMP environment with MAM.

Advances in antibody-based therapy in oncology

Monoclonal antibodies are a growing class of targeted cancer therapeutics, characterized by exquisite specificity, long serum half-life, high affinity and immune effector functions. In this review, we outline key advances in the field with a particular focus on recent and emerging classes of engineered antibody therapeutic candidates, discuss molecular structure and mechanisms of action and provide updates on clinical development and practice.

Get what you want: Identifying antibodies against pre-defined epitopes on Frizzled receptors

In this issue of Structure, Ge et al. report an epitope-directed strategy to select antibodies specific for Frizzled subtypes. Structural and biochemical analyses provide mechanistic insights into the target binding of the isolated antibodies that could guide the design of reagents and therapeutics targeting distinct Frizzled receptors.

Modeling study of long-term stability of the monoclonal antibody infliximab and biosimilars using liquid-chromatography-tandem mass spectrometry and size-exclusion chromatography-multi-angle light scattering

Monoclonal antibodies (mAbs) represent a dynamic class of biopharmaceutical products, as evidenced by an increasing number of market authorizations for mAb innovator and biosimilar products. Stability studies are commonly performed during product development, for instance, to exclude unstable molecules, optimize the formulation or determine the storage limit. Such studies are time-consuming, especially for mAbs, because of their structural complexity which requires multiple analytical techniques to achieve a detailed characterization. We report the implementation of a novel methodology based on the accelerated stability assessment program (ASAP) in order to model the long-term stability of mAbs in relation to different structural aspects. Stability studies of innovator infliximab and two different biosimilars were performed using forced degradation conditions alongside in-use administration conditions in order to investigate their similarity regarding stability. Thus, characterization of post-translational modifications was achieved using liquid-chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the formation of aggregates and free chain fragments was characterized using size-exclusion chromatography-multi-angle light scattering (SEC-MALS-UV/RI) analysis. Consequently, ASAP models were investigated with regard to free chain fragmentation of mAbs concomitantly with N57 deamidation, located in the hypervariable region. Comparison of ASAP models and the long-term stability data from samples stored in intravenous bags demonstrated a relevant correlation, indicating the stability of the mAbs. The developed methodology highlighted the particularities of ASAP modeling for mAbs and demonstrated the possibility to independently consider the different types of degradation pathways in order to provide accurate and appropriate prediction of the long-term stability of this type of biomolecule.

Molecular Dynamics Simulation for Investigating Antigen-Antibody Interaction

Molecular dynamics (MD) simulation is a computational method which elucidates the protein dynamics. Following analyses characterize the dynamics and structural change as well as interaction energy. To characterize the protein structure effectively, the internal angular coordinates are often useful. Directional analysis provides the averages and variances of those coordinates in a mathematically rigorous way. Here, we describe not only a standard MD simulation procedure for the antigen-antibody system but also an umbrella sampling method following a multistep targeted MD simulation (US/mTMD), which is useful for evaluating the free energy profile along the antigen-antibody dissociation coordinate.

Applications of Synthetic Receptors in Bioanalysis and Drug Transport

Synthetic receptors are powerful tools for molecular recognition. They can bind to guests with high selectivity and affinity, and their structures are tunable and diversified. These features, plus the relatively low cost and high simplicity in synthesis and modification, support the feasibility of array-based molecular analysis with synthetic receptors for improved selectivity in the recognition of a wide range of targets. More attractively, host-guest interaction is reversible and guest displacement allows biocompatible and gentle release of the host-bound molecules, simplifying the stimulation designs needed to control analyte sensing, enrichment, and transportation. Here, we highlight a few recent advancements in using synthetic receptors for molecular analysis and manipulation, with the focus on macrocyclic receptors and their applications in displacement sensing, separation, imaging, and drug transport.

Prognostic effect of HER2 evolution from primary breast cancer to breast cancer metastases

Purpose

Therapeutic options for breast cancer (BC) treatment are constantly evolving. The Human Epidermal Growth Factor 2 (HER2)-low BC entity is a new subgroup, representing about 55% of all BC patients. New antibody–drug conjugates demonstrated promising results for this BC subgroup. Currently, there is limited information about the conversion of HER2 subtypes between primary tumor and recurrent disease.

Methods

This retrospective study included women with BC at the University Medical Centre Wuerzburg from 1998 to 2021. Data were retrieved from patients' records. HER2 evolution from primary diagnosis to the first relapse and the development of secondary metastases was investigated.

Results

In the HR-positive subgroup without HER2 overexpression, HER2-low expression in primary BC was 56.7 vs. 14.6% in the triple-negative subgroup (p < 0.000). In the cohort of the first relapse, HER2-low represented 64.1% of HR-positive vs. 48.2% of the triple-negative cohort (p = 0.03). In patients with secondary metastases, HER2-low was 75.6% vs. 50% in the triple negative subgroup (p = 0.10). The subgroup of HER2-positive breast cancer patients numerically increased in the course of disease; the HER2-negative overall cohort decreased. A loss of HER2 expression from primary BC to the first relapse correlated with a better OS (p = 0.018). No clinicopathological or therapeutic features could be identified as potential risk factors for HER2 conversion.

Conclusion

HER2 expression is rising during the progression of BC disease. In view of upcoming therapeutical options, the re-analysis of newly developed metastasis will become increasingly important.

Antibody-Drug Conjugates for the Treatment of HER2-Positive Breast Cancer

Human epidermal growth factor receptor 2 (HER2) receptor tyrosine kinase is overexpressed in 20-30% of breast cancers and is associated with poor prognosis and worse overall patient survival. Most women with HER2-positive breast cancer receive neoadjuvant chemotherapy plus HER2-targeted therapies. The development of HER2-directed therapeutics is an important advancement in targeting invasive breast cancer. Despite the efficacy of anti-HER2 monoclonal antibodies, they are still being combined with adjuvant chemotherapy to improve overall patient outcomes. Recently, significant progress has been made towards the development of a class of therapeutics known as antibody-drug conjugates (ADCs), which leverage the high specificity of HER2-targeted monoclonal antibodies with the potent cytotoxic effects of various small molecules, such as tubulin inhibitors and topoisomerase inhibitors. To date, two HER2-targeting ADCs have been approved by the FDA for the treatment of HER2-positive breast cancer: Ado-trastuzumab emtansine (T-DM1; Kadcyla^®) and fam-trastuzumab deruxtecan-nxki (T-Dxd; Enhertu^®). Kadcyla and Enhertu are approved for use as a second-line treatment after trastuzumab-taxane-based therapy in patients with HER2-positive breast cancer. The success of ADCs in the treatment of HER2-positive breast cancer provides novel therapeutic advancements in the management of the disease. In this review, we discuss the basic biology of HER2, its downstream signaling pathways, currently available anti-HER2 therapeutic modalities and their mechanisms of action, and the latest clinical and safety characteristics of ADCs used for the treatment of HER2-positive breast cancer.

Modulation of Ligand-Gated Glycine Receptors Via Functional Monoclonal Antibodies

Ion channels are targets of considerable therapeutic interest to address a wide variety of neurologic indications, including pain perception. Current pharmacological strategies have focused mostly on small molecule approaches that can be limited by selectivity requirements within members of a channel family or superfamily. Therapeutic antibodies have been proposed, designed, and characterized to alleviate this selectivity limitation; however, there are no Food and Drug Administration-approved therapeutic antibody-based drugs targeting ion channels on the market to date. Here, in an effort to identify novel classes of engineered ion channel modulators for potential neurologic therapeutic applications, we report the generation and characterization of six (EC₅₀ < 25nM) Cys-loop receptor family monoclonal antibodies with modulatory function against rat and human glycine receptor alpha 1 (GlyRα1) and/or GlyRα3. These antibodies have activating (i.e., positive modulator) or inhibiting (i.e., negative modulator) profiles. Moreover, GlyRα3 selectivity was successfully achieved for two of the three positive modulators identified. When dosed intravenously, the antibodies achieved sufficient brain exposure to cover their calculated in vitro EC₅₀ values. When compared head-to-head at identical exposures, the GlyRα3-selective antibody showed a more desirable safety profile over the nonselective antibody, thus demonstrating, for the first time, an advantage for GlyRα3-selectivity. Our data show that ligand-gated ion channels of the glycine receptor family within the central nervous system can be functionally modulated by engineered biologics in a dose-dependent manner and that, despite high protein homology between the alpha subunits, selectivity can be achieved within this receptor family, resulting in future therapeutic candidates with more desirable drug safety profiles. SIGNIFICANCE STATEMENT: This study presents immunization and multiplatform screening approaches to generate a diverse library of functional antibodies (agonist, potentiator, or inhibitory) raised against human glycine receptors (GlyRs). This study also demonstrates the feasibility of acquiring alpha subunit selectivity, a desirable therapeutic profile. When tested in vivo, these tool molecules demonstrated an increased safety profile in favor of GlyRα3-selectivity. These are the first reported functional GlyR antibodies that may open new avenues to treating central nervous system diseases with subunit selective biologics.

Discovery of Cyclic Peptide Inhibitors Targeting PD-L1 for Cancer Immunotherapy

Blockade of the interaction between programmed cell death ligand-1 (PD-L1) and its receptor PD-1 has shown great success in cancer immunotherapy. Peptides possess unique characteristics that give them significant advantages as immune checkpoint inhibitors. However, unfavorable physicochemical properties and proteolytic stability profiles limit the translation of bioactive peptides as therapeutic agents. Studies have revealed that cyclization improves the biological activity and stability of linear peptides. In this study, we report the use of macrocyclization scanning for the discovery of cyclic anti-PD-L1 peptides with improved bioactivity. The cyclic peptides demonstrated up to a 34-fold improvement in the PD-1/PD-L1 blocking activity and significant in vivo anti-tumor activity. Our results demonstrate that macrocyclization scanning is an effective way to improve the serum stability and bioactivity of the anti-PD-L1 linear peptide. This strategy can be employed in the optimization of other bioactive peptides, particularly those for protein-protein interaction modulation.

Chemistries and applications of DNA-natural product conjugate

Natural products and their derivatives have made great contributions to chemotherapy, especially for the treatment of tumors and infections. Despite the achievements, natural product-based small molecule drugs usually suffer from side effects, short circulation time, and solubility issue. To overcome these drawbacks, a common approach is to integrate another bio-functional motif into a natural product compound, enabling targeted or synergistic therapy. One of the most promising strategies is to form a DNA-natural product conjugate to improve therapeutic purposes. The incorporated DNA molecules can serve as an aptamer, a nucleic-acid-based congener of antibody, to specifically bind to the disease target of interest, or function as a gene therapy agent, such as immuno-adjuvant or antisense, to enable synergistic chemo-gene therapy. DNA-natural product conjugate can also be incorporated into other DNA nanostructures to improve the administration and delivery of drugs. This minireview aims to provide the chemistry community with a brief overview on this emerging topic of DNA-natural product conjugates for advanced therapeutics. The basic concepts to use the conjugation, the commonly used robust conjugation chemistries, as well as applications in targeted therapy and synergistic therapy of using DNA-natural product conjugates, are highlighted in this minireview. Future perspectives and challenges of this field are also discussed in the discussion and perspective section.

Virus-like particle vaccinology, from bench to bedside

Virus-like particles (VLPs) have become key tools in biology, medicine and even engineering. After their initial use to resolve viral structures at the atomic level, VLPs were rapidly harnessed to develop antiviral vaccines followed by their use as display platforms to generate any kind of vaccine. Most recently, VLPs have been employed as nanomachines to deliver pharmaceutically active products to specific sites and into specific cells in the body. Here, we focus on the use of VLPs for the development of vaccines with broad fields of indications ranging from classical vaccines against viruses to therapeutic vaccines against chronic inflammation, pain, allergy and cancer. In this review, we take a walk through time, starting with the latest developments in experimental preclinical VLP-based vaccines and ending with marketed vaccines, which earn billions of dollars every year, paving the way for the next wave of prophylactic and therapeutic vaccines already visible on the horizon.

KAI1/CD82 gene and autotaxin-lysophosphatidic acid axis in gastrointestinal cancers

The KAI1/CD82 gene inhibits the metastasis of most tumors and is remarkably correlated with tumor invasion and prognosis. Cell metabolism dysregulation is an important cause of tumor occurrence, development, and metastasis. As one of the important characteristics of tumors, cell metabolism dysregulation is attracting increasing research attention. Phospholipids are an indispensable substance in the metabolism in various tumor cells. Phospholipid metabolites have become important cell signaling molecules. The pathological role of lysophosphatidic acid (LPA) in tumors was identified in the early 1990s. Currently, LPA inhibitors have entered clinical trials but are not yet used in clinical treatment. Autotaxin (ATX) has lysophospholipase D (lysoPLD) activity and can regulate LPA levels in vivo. The LPA receptor family and ATX/lysoPLD are abnormally expressed in various gastrointestinal tumors. According to our recent pre-experimental results, KAI1/CD82 might inhibit the migration and metastasis of cancer cells by regulating the ATX-LPA axis. However, no relevant research has been reported. Clarifying the mechanism of ATX-LPA in the inhibition of cancer metastasis by KAI1/CD82 will provide an important theoretical basis for targeted cancer therapy. In this paper, the molecular compositions of the KAI1/CD82 gene and the ATX-LPA axis, their physiological functions in tumors, and their roles in gastrointestinal cancers and target therapy are reviewed.

Post-genomic platform for development of oligonucleotide vaccines against RNA viruses: diamond cuts diamond

The coronavirus pandemic has starkly demonstrated the need to create highly effective vaccines against various viral diseases. The emerging new platforms for vaccine creation (adenovirus vectors and mRNA vaccines) have shown their worth in the fight against the prevention of coronavirus infection. However, adenovirus vectors and mRNA vaccines have a serious disadvantage: as a rule, only the S protein of the coronavirus is presented as an antigen. This tactic for preventing infection allows the ever-mutating virus to escape quickly from the immunity protection provided by such vaccines. Today, viral genomic databases are well-developed, which makes it possible to create new vaccines on a fundamentally new post-genomic platform. In addition, the technology for the synthesis of nucleic acids is currently experiencing an upsurge in demand in various fields of molecular biology. The accumulated experience suggests that the unique genomic sequences of viruses can act as antigens that trigger powerful humoral and cellular immunity. To achieve this effect, the following conditions must be created: the structure of the nucleic acid must be single-stranded, have a permanent 3D nanostructure, and have a unique sequence absent in the vaccinated organism. Oligonucleotide vaccines are able to resist the rapidly changing genomic sequences of RNA viruses by using conserved regions of their genomes to generate a long-term immune response, acting according to the adage that a diamond cuts a diamond. In addition, oligonucleotide vaccines will not contribute to antibody-dependent enhanced infection, since the nucleic acid of the coronavirus is inside the viral particle. It is obvious that new epidemics and pandemics caused by RNA viruses will continue to arise periodically in the human population. The creation of new, safe, and effective platforms for the production of vaccines that can flexibly change and adapt to new subtypes of viruses is very urgent and at this moment should be considered as a strategically necessary task.