Managing unwanted immunogenicity of biologicals

Computation-Guided Rational Design of Cysteine-Less Protein Variants in Engineered hCGL

The engineered human cystathionine-γ-lyase (hCGL) resulting in enhanced activity toward both cysteine and cystine unveils a potential robust antitumor activity. However, the presence of cysteine residues has the potential to induce oligomerization or incorrect disulfide bonding, which may decrease the bioavailability of biopharmaceuticals. Through a meticulous design process targeting the cysteine residues within engineered hCGL, a set of potential beneficial mutants were obtained by virtual screening employing Rosetta and ABACUS. Experimental measurements have revealed that most of the mutants showed increased activity toward both substrates l-Cys and CSSC. Furthermore, mutants C109V and C229D demonstrated Tm value increases of 8.2 and 1.8 °C, respectively. After an 80 min incubation at 60 °C, mutant C229D still maintained high residual activity. Unexpectedly, mutant C109V, displaying activity approximately 2-fold higher than the activity of wild type (WT) for both substrates, showed disappointing instability in plasma, which suggests that computational design still requires further consideration. Analysis of their structure and molecular dynamics (MD) simulation revealed the impact of hydrophobic interaction, hydrogen bonds, and near-attack conformation (NAC) stability on activity and stability. This study acquired information about mutants that exhibit enhanced activity or thermal resistance and serve as valuable guidance for subsequent specific cysteine modifications.

Assessing MAPPs assay as a tool to predict the immunogenicity potential of protein therapeutics

MHC-II-associated peptide proteomics (MAPPs) is a mass spectrometry-based (MS) method to identify naturally presented MHC-II-associated peptides that could elicit CD4+T cell activation. MAPPs assay is considered one of the assays that better characterize the safety of biotherapeutics by driving the selection of the best candidates concerning their immunogenicity risk. However, there is little knowledge about the impact of bead material on the recovery of MHC-II MS-eluted ligands in MAPPs assays. Here, we firstly describe a robust MAPPs protocol by implementing streptavidin magnetic beads for the isolation of these peptides instead of commonly used NHS-activated beads. Moreover, we assessed the impact of the cell medium used for cell cultures on the morphology and recovery of the in vitro-generated APCs, and its potential implications in the amount of MHC-II isolated peptides. We also described an example of a MAPPs assay application to investigate drug-induced immunogenicity of two bispecific antibodies and compared them with monospecific trastuzumab IgG1 control. This work highlighted the importance of MAPPs in the preclinical in vitro strategy to mitigate the immunogenicity risk of biotherapeutics.

Preclinical risk assessment strategy to mitigate the T-cell dependent immunogenicity of protein biotherapeutics: State of the art, challenges and future perspectives

Protein therapeutics hold a prominent role and have brought significant diversity in efficacious medicinal products. Not just monoclonal antibodies and different antibody formats (pegylated antigen-binding fragments, bispecifics, antibody-drug conjugates, single chain variable fragments, nanobodies, dia-, tria- and tetrabodies), but also purified blood products, growth factors, recombinant cytokines, enzyme replacement factors, fusion proteins are all good instances of therapeutic proteins that have been developed in the past decades and approved for their value in oncology, immune-oncology, and autoimmune diseases discovery programs. Although there was an ingrained belief that fully humanized proteins were expected to have limited immunogenicity, adverse effects associated with immune responses to biological therapies raised some concern in biotech companies. Consequently, drug developers are designing strategies to assess potential immune responses to protein therapeutics during both the preclinical and clinical phases of development. Despite the many factors that can contribute to protein immunogenicity, T cell- (thymus-) dependent (Td) immunogenicity seems to play a crucial role in the development of anti-drug antibodies (ADAs) to biologics. A broad range of methodologies to predict and rationally assess Td immune responses to protein drugs has been developed. This review aims to briefly summarize the preclinical immunogenicity risk assessment strategy to mitigate the risk of potential immunogenic candidates coming towards clinical phases, discussing the advantages and limitations of these technologies, and suggesting a rational approach for assessing and mitigating Td immunogenicity.

Fundamental concepts of protein therapeutics and spacing in oncology: an updated comprehensive review

Current treatment regimens in cancer cases cause significant side effects and cannot effectively eradicate the advanced disease. Hence, much effort has been expended over the past years to understand how cancer grows and responds to therapies. Meanwhile, proteins as a type of biopolymers have been under commercial development for over three decades and have been proven to improve the healthcare system as effective medicines for treating many types of progressive disease, such as cancer. Following approving the first recombinant protein therapeutics by FDA (Humulin), there have been a revolution for drawing attention toward protein-based therapeutics (PTs). Since then, the ability to tailor proteins with ideal pharmacokinetics has provided the pharmaceutical industry with an important noble path to discuss the clinical potential of proteins in oncology research. Unlike traditional chemotherapy molecules, PTs actively target cancerous cells by binding to their surface receptors and the other biomarkers particularly associated with tumorous or healthy tissue. This review analyzes the potential and limitations of protein therapeutics (PTs) in the treatment of cancer as well as highlighting the evolving strategies by addressing all possible factors, including pharmacology profile and targeted therapy approaches. This review provides a comprehensive overview of the current state of PTs in oncology, including their pharmacology profile, targeted therapy approaches, and prospects. The reviewed data show that several current and future challenges remain to make PTs a promising and effective anticancer drug, such as safety, immunogenicity, protein stability/degradation, and protein-adjuvant interactions.

Evolving strategies and application of proteins and peptide therapeutics in cancer treatment

Several proteins and peptides have therapeutic potential and can be used for cancer therapy. By binding to cell surface receptors and other indicators uniquely linked with or overexpressed on tumors compared to healthy tissue, protein biologics enhance the active targeting of cancer cells, as opposed to the passive targeting of cells by conventional small-molecule chemotherapeutics. This study focuses on peptide medications that exist to slow or stop tumor growth and the spread of cancer, demonstrating the therapeutic potential of peptides in cancer treatment. As an alternative to standard chemotherapy, peptides that selectively kill cancer cells while sparing healthy tissue are developing. A mountain of clinical evidence supports the efficacy of peptide-based cancer vaccines. Since a single treatment technique may not be sufficient to produce favourable results in the fight against cancer, combination therapy is emerging as an effective option to generate synergistic benefits. One example of this new area is the use of anticancer peptides in combination with nonpeptidic cytotoxic drugs or the combination of immunotherapy with conventional therapies like radiation and chemotherapy. This review focuses on the different natural and synthetic peptides obtained and researched. Discoveries, manufacture, and modifications of peptide drugs, as well as their contemporary applications, are summarized in this review. We also discuss the benefits and difficulties of potential advances in therapeutic peptides.

mRNA delivery in cancer immunotherapy

Messenger RNA (mRNA) has drawn much attention in the medical field. Through various treatment approaches including protein replacement therapies, gene editing, and cell engineering, mRNA is becoming a potential therapeutic strategy for cancers. However, delivery of mRNA into targeted organs and cells can be challenging due to the unstable nature of its naked form and the low cellular uptake. Therefore, in addition to mRNA modification, efforts have been devoted to developing nanoparticles for mRNA delivery. In this review, we introduce four categories of nanoparticle platform systems: lipid, polymer, lipid-polymer hybrid, and protein/peptide-mediated nanoparticles, together with their roles in facilitating mRNA-based cancer immunotherapies. We also highlight promising treatment regimens and their clinical translation.

Immunogenicity of Monoclonal Antibodies and the Potential Use of HLA Haplotypes to Predict Vulnerable Patients

The use of monoclonal antibodies (mAbs) in the clinic has successfully expanded to treatment of cancer, viral infections, inflammations, and other indications. However, some of the classes of mAbs that are used in the clinic show the formation of anti-drug antibodies (ADAs) leading to loss of efficacy. This review describes ADA formation for the various mAbs, and its clinical effect. Lastly, this review considers the use of HLA-haplotypes as biomarkers to predict vulnerability of patients sensitive to formation of ADAs.

The Potential of Exosomes in Allergy Immunotherapy

Allergic diseases represent a global health and economic burden of increasing significance. The lack of disease-modifying therapies besides specific allergen immunotherapy (AIT) which is not available for all types of allergies, necessitates the study of novel therapeutic approaches. Exosomes are small endosome-derived vesicles delivering cargo between cells and thus allowing inter-cellular communication. Since immune cells make use of exosomes to boost, deviate, or suppress immune responses, exosomes are intriguing candidates for immunotherapy. Here, we review the role of exosomes in allergic sensitization and inflammation, and we discuss the mechanisms by which exosomes could potentially be used in immunotherapeutic approaches for the treatment of allergic diseases. We propose the following approaches: (a) Mast cell-derived exosomes expressing IgE receptor FcεRI could absorb IgE and down-regulate systemic IgE levels. (b) Tolerogenic exosomes could suppress allergic immune responses via induction of regulatory T cells. (c) Exosomes could promote TH1-like responses towards an allergen. (d) Exosomes could modulate IgE-facilitated antigen presentation.

Were magnetic materials useful in cancer therapy?

Cancer is one of the major challenges fronting the biomedical basic researches in our time. The study and development of effective therapeutic strategies for cancer therapy are vital. Among the many probable core constituents of nanoparticles, magnetite-based nanoparticles have been widely studied for cancer therapy owing to their inherent magnetic features, multifunctional design, biodegradable and biocompatible properties. Magnetic nanoparticles have been also designed for utilizing as contrast enhancer agents for magnetic resonance imaging, drug delivery systems, and most recently as a therapeutic element in inducing cellular death in tumor ablation therapies. This review aimed to provide an overview of the various applications of magnetic nanoparticles and recent achievements in developing these advanced materials for cancer therapy.

Structural and biochemical insights into a hyperthermostable urate oxidase from Thermobispora bispora for hyperuricemia and gout therapy

Microbial urate oxidase has emerged as a potential source of therapeutic properties for hyperuricemia in arthritic gout and renal disease. The thermostability and long-term thermal tolerance of the enzyme need to be established to prolong its therapeutic effects. Here, we present the biochemical and structural aspects of a hyperthermostable urate oxidase (TbUox) from the thermophilic microorganism Thermobispora bispora. Enzymatic characterization of TbUox revealed that it was active over a wide range of temperatures, from 30 to 70 °C, with optimal activity at 65 °C and pH 8.0, which suggests its applicability under physiological conditions. Moreover, TbUox exhibits high thermostability from 10 to 65 °C, with Tm of 70.3 °C and near-neutral pH stability from pH 7.0 to 8.0 and high thermal tolerance. The crystal structures of TbUox revealed a distinct feature of the C-terminal loop extensions that may help with protein stability via inter-subunit interactions. In addition, the high thermal tolerance of TbUox may be contributed by the extensive inter-subunit contacts via salt bridges, hydrogen bonds, and hydrophobic interactions. The findings in this study provide a molecular basis for the thermophilic TbUox urate oxidase for application in hyperuricemia and gout therapy.

Thermostable and Long-Circulating Albumin-Conjugated Arthrobacter globiformis Urate Oxidase

Urate oxidase derived from Aspergillus flavus has been investigated as a treatment for tumor lysis syndrome, hyperuricemia, and gout. However, its long-term use is limited owing to potential immunogenicity, low thermostability, and short circulation time in vivo. Recently, urate oxidase isolated from Arthrobacter globiformis (AgUox) has been reported to be thermostable and less immunogenic than the Aspergillus-derived urate oxidase. Conjugation of human serum albumin (HSA) to therapeutic proteins has become a promising strategy to prolong circulation time in vivo. To develop a thermostable and long-circulating urate oxidase, we investigated the site-specific conjugation of HSA to AgUox based on site-specific incorporation of a clickable non-natural amino acid (frTet) and an inverse electron demand Diels-Alder reaction. We selected 14 sites for frTet incorporation using the ROSETTA design, a computational stability prediction program, among which AgUox containing frTet at position 196 (Ag12) exhibited enzymatic activity and thermostability comparable to those of wild-type AgUox. Furthermore, Ag12 exhibited a high HSA conjugation yield without compromising the enzymatic activity, generating well-defined HSA-conjugated AgUox (Ag12-HSA). In mice, the serum half-life of Ag12-HSA was approximately 29 h, which was roughly 17-fold longer than that of wild-type AgUox. Altogether, this novel formulated AgUox may hold enhanced therapeutic efficacy for several diseases.

Pharmaceutical strategies to extend pulmonary exposure of inhaled medicines

Pulmonary administration route has been extensively exploited for the treatment of local lung diseases such as asthma, chronic obstructive pulmonary diseases and respiratory infections, and systemic diseases such as diabetes. Most inhaled medicines could be cleared rapidly from the lungs and their therapeutic effects are transit. The inhaled medicines with extended pulmonary exposure may not only improve the patient compliance by reducing the frequency of drug administration, but also enhance the clinical benefits to the patients with improved therapeutic outcomes. This article systematically reviews the physical and chemical strategies to extend the pulmonary exposure of the inhaled medicines. It starts with an introduction of various physiological and pathophysiological barriers for designing inhaled medicines with extended lung exposure, which is followed by recent advances in various strategies to overcome these barriers. Finally, the applications of the inhaled medicines with extended lung exposure for the treatment of various diseases and the safety concerns associated to various strategies to extend the pulmonary exposure of the inhaled medicines are summarized.

Allometric scaling of therapeutic monoclonal antibodies in preclinical and clinical settings

Constant technological advancement enabled the production of therapeutic monoclonal antibodies (mAbs) and will continue to contribute to their rapid expansion. Compared to small-molecule drugs, mAbs have favorable characteristics, but also more complex pharmacokinetics (PK), e.g., target-mediated nonlinear elimination and recycling by neonatal Fc-receptor. This review briefly discusses mAb biology, similarities and differences in PK processes across species and within human, and provides a detailed overview of allometric scaling approaches for translating mAb PK from preclinical species to human and extrapolating from adults to children. The approaches described here will remain vital in mAb drug development, although more data are needed, for example, from very young patients and mAbs with nonlinear PK, to allow for more confident conclusions and contribute to further growth of this field. Improving mAb PK predictions will facilitate better planning of (pediatric) clinical studies and enable progression toward the ultimate goal of expediting drug development.

Assessment of immunogenicity from galcanezumab phase 3 trials in patients with episodic or chronic migraine

BACKGROUND

This analysis characterizes the immunogenicity profile of galcanezumab, a humanized monoclonal antibody that selectively binds calcitonin gene-related peptide and inhibits its activity, in phase 3 migraine trials.

METHODS

Immunogenicity data were analyzed from baseline and double-blind, placebo-controlled phases of the 3-month chronic migraine study REGAIN, the 6-month episodic migraine studies EVOLVE-1 and EVOLVE-2, and from baseline and open-label phases of the 12-month chronic and episodic migraine Study CGAJ. The incidence of baseline antidrug antibodies, treatment-emergent antidrug antibodies, neutralizing antidrug antibodies, and the effect of antidrug antibody titer on pharmacokinetics and pharmacodynamics were assessed. The relationship between antidrug antibody status and efficacy was explored using average change in monthly migraine headache days. Safety analyses assessed the potential relationship between treatment-emergent antidrug antibodies and hypersensitivity events or adverse events related to injection sites.

FINDINGS

Across studies, 5.9-11.2% of patients had baseline antidrug antibodies. The incidence of treatment-emergent antidrug antibodies was 2.6-12.4% in the galcanezumab group and 0.5-1.7% in the placebo group. The majority of treatment-emergent antidrug antibodies were detected approximately 3-6 months after first study drug dose. Overall, the observed antidrug antibody titer did not impact galcanezumab concentrations, calcitonin gene-related peptide concentrations, or galcanezumab efficacy. There was no evidence that hypersensitivity events or adverse events related to injection sites were mediated by treatment-emergent antidrug antibodies.

INTERPRETATION

These data showed that immunogenicity did not impact galcanezumab concentrations, calcitonin gene-related peptide concentrations, or the efficacy and hypersensitivity profile of galcanezumab in patients with migraine.

Home storage of biological medications administered to patients with rheumatic diseases

Background

The inadequate storage of biopharmaceuticals may result in an ineffective therapeutic response since poor conservation can lead to the emergence of protein aggregates and cause immunogenicity in patients, which can increase the risk of adverse events by inducing the production of anti-drug antibodies. This can also lead to significant economic losses for public health, given the high cost of these medicines. The aim of this study was to verify whether the home storage of biopharmaceuticals dispensed by the Unified Public System was in accordance with the manufacturers’ specified standards and whether external variables interfered with the correct home storage.

Methods

This was a prospective observational study. Patients with a confirmed diagnosis of rheumatoid arthritis, ankylosing spondylitis or psoriatic arthritis who were using a biologic exclusively dispensed by Unified Public System were included. Storage temperature was measured by digital thermometer inserted into the refrigerator of the participant’s home. Fisher’s exact test was performed to cross-reference the temperature data and the qualitative variables obtained using an epidemiologic questionnaire. Mean, minimum, maximum values and standard deviation were described in the quantitative data. Mann-Whitney non-parametric test was performed to the association between temperature excursion and the number of people in the house.

Results

A total of 81 participants were included and 67 (82.71%) did not maintain home storage correctly. The maximum temperature observed among all patients was 15.5 °C, the minimum was − 4.4 °C and the average was 5.6 °C (standard deviation 2.8); 10 (12.3%) had at least one negative temperature measured. The average time for participants who had an inadequate temperature record was 8 h and 31 min. Nine participants (90%) who stored the medication into the shelf/drawer below the freezer had a temperature excursion (p = 0.011). Most of the participants (88.5%) who stored their biopharmaceutical near the back side, close to the wall of the refrigerator had a negative temperature record (p < 0.001).

Conclusion

Most of the study participants (82.71%) did not maintain adequate home storage conditions for their biopharmaceutical. Intrinsic factors of household refrigerators may be involved in temperature deviations.

The Giants (biologicals) against the Pigmies (small molecules), pros and cons of two different approaches to the disease modifying treatment in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease that, if untreated, can lead to disability and reduce the life expectancy of affected patients. Over the last two decades the improvement of knowledge of the pathogenetic mechanisms leading to the development of the disease has profoundly changed the treatment strategies of RA through the development of biotechnological drugs (bDMARDs) directed towards specific pro-inflammatory targets involved in the RA network. To date, the therapeutic armamentarium for RA includes ten bDMARDs able to produce the depletion B-cells, the blockade of three different pro-inflammatory cytokines (tumour necrosis factor alpha, interleukin-6 and interleukin-1), or the inhibition of T-cell co-stimulation. The introduction of these new compounds has dramatically improved outcomes in the short and long term, although still a significant proportion of patients are unable to reach or maintain the treatment target over time. The identification of the fundamental role of Janus kinases in the process of transduction of the inflammatory signal within the immune cells has recently provided the opportunity to use the new pharmacological class of small molecules for the therapy of RA, further increasing the number of treatment options. In this review the PROS and CONS of these two drug classes will be discussed, trying to provide the evidence currently available to make the right choice based on the analysis of the efficacy and safety profile of the different drugs on the market and close to marketing.

Structure-based design of a hyperthermostable AgUricase for hyperuricemia and gout therapy

Arthrobacter globiformis Uricase (AgUricase) is a homotetrameric uricase with the potential for therapeutic use in treating hyperuricemia-related diseases. To achieve sufficient therapeutic effects, it is essential for this enzyme to have high thermostability and long half-life in physiological condition. To improve the thermostability of this enzyme, we introduced a series of cysteine pair mutations into the AgUricase subunits based on its structural model and studied the thermostability of the mutant enzymes with introduced disulfide bridges. Two intersubunit cysteine pair mutations, K12C-E286C and S296C-S296C, were found to markedly increase the melting temperatures of the corresponding mutant enzymes compared with WT AgUricase. The crystal structure of the K12C-E286C mutant at 1.99 Å resolution confirmed the formation of a distinct disulfide bond between the two subunits in the dimer. Structural analysis and biochemical data revealed that the C-terminal loop of AgUricase was flexible, and its interaction with neighboring subunits was required for the stability of the enzyme. We introduced an additional intersubunit K244C-C302 disulfide bond based on the crystal structure of the K12C-E286C mutant and confirmed that this additional disulfide bond further stabilized the flexible C-terminal loop and improved the thermostability of the enzyme. Disulfide cross-linking also protected AgUricase from protease digestion. Our studies suggest that the introduction of disulfide bonds into proteins is a potential strategy for enhancing the thermostability of multimeric proteins for medical applications.

Evaluating a Multiscale Mechanistic Model of the Immune System to Predict Human Immunogenicity for a Biotherapeutic in Phase 1

A mechanistic model of the immune response was evaluated for its ability to predict anti-drug antibody (ADA) and their impact on pharmacokinetics (PK) and pharmacodynamics (PD) for a biotherapeutic in a phase 1 clinical trial. Observed ADA incidence ranged from 33 to 67% after single doses and 27-50% after multiple doses. The model captured the single dose incidence well; however, there was overprediction after multiple dosing. The model was updated to include a T-regulatory (Treg) cell mediated tolerance, which reduced the overprediction (relative decrease in predicted incidence rate of 21.5-59.3% across multidose panels) without compromising the single dose predictions (relative decrease in predicted incidence rate of 0.6-13%). The Treg-adjusted model predicted no ADA impact on PK or PD, consistent with the observed data. A prospective phase 2 trial was simulated, including co-medication effects in the form of corticosteroid-induced immunosuppression. Predicted ADA incidences were 0-10%, depending on co-medication dosage. This work demonstrates the utility in applying an integrated, iterative modeling approach to predict ADA during different stages of clinical development.

Nonclinical immunogenicity risk assessment of therapeutic proteins

Therapeutic protein drugs have significantly improved the management of many severe and chronic diseases. However, their development and optimal clinical application are complicated by the induction of unwanted immune responses. Therapeutic protein-induced antidrug antibodies can alter drug pharmacokinetics and pharmacodynamics leading to impaired efficacy and occasionally serious safety issues. There has been a growing interest over the past decade in developing methods to assess the risk of unwanted immunogenicity during preclinical drug development, with the aim to mitigate the risk during the molecular design phase, clinical development and when products reach the market. Here, we discuss approaches to therapeutic protein immunogenicity risk assessment, with attention to assays and in vivo models used to mitigate this risk.

Immunogenicity of immunomodulatory, antibody-based, oncology therapeutics

The increasing use of multiple immunomodulatory (IMD) agents for cancer therapies (e.g. antibodies targeting immune checkpoints, bispecific antibodies, and chimeric antigen receptor [CAR]-T cells), is raising questions on their potential immunogenicity and effects on treatment. In this review, we outline the mechanisms of action (MOA) of approved, antibody-based IMD agents, potentially related to their immunogenicity, and discuss the reported incidence of anti-drug antibodies (ADA) as well as their clinical relevance in patients with cancer. In addition, we discuss the impact of the administration route and potential strategies to reduce the incidence of ADA and manage treated patients. Analysis of published reports indicated that the risk of immunogenicity did not appear to correlate with the MOA of anti-programmed death 1 (PD-1)/PD-ligand 1 monoclonal antibodies nor to substantially affect treatment with most of these agents in the majority of patients evaluated to date. Treatment with B-cell depleting agents appears associated with a low risk of immunogenicity. No significant difference in ADA incidence was found between the intravenous and subcutaneous administration routes for a panel of non-oncology IMD antibodies. Additionally, while the data suggest a higher likelihood of immunogenicity for antibodies with T-cell or antigen-presenting cell (APC) targets versus B-cell targets, it is possible to have targets expressed on APCs or T cells and still have a low incidence of immunogenicity.

Production and Characterization of Recombinant Wild Type Uricase from Indonesian Coelacanth (L. menadoensis) and Improvement of Its Thermostability by In Silico Rational Design and Disulphide Bridges Engineering

The ideal therapeutic uricase (UOX) is expected to have the following properties; high expression level, high activity, high thermostability, high solubility and low immunogenicity. The latter property is believed to depend largely on sequence identity to the deduced human UOX (dH-UOX). Herein, we explored L. menadoensis uricase (LM-UOX) and found that it has 65% sequence identity to dH-UOX, 68% to the therapeutic chimeric porcine-baboon UOX (PBC) and 70% to the resurrected ancient mammal UOX. To study its biochemical properties, recombinant LM-UOX was produced in E. coli and purified to more than 95% homogeneity. The enzyme had specific activity up to 10.45 unit/mg, which was about 2-fold higher than that of the PBC. One-litre culture yielded purified protein up to 132 mg. Based on homology modelling, we successfully engineered I27C/N289C mutant, which was proven to contain inter-subunit disulphide bridges. The mutant had similar specific activity and production yield to that of wild type (WT) but its thermostability was dramatically improved. Up on storage at −20 °C and 4 °C, the mutant retained ~100% activity for at least 60 days. By keeping at 37 °C, the mutant retained ~100% activity for 15 days, which was 120-fold longer than that of the wild type. Thus, the I27C/N289C mutant has potential to be developed for treatment of hyperuricemia.

Evaluation of a 3D Human Artificial Lymph Node as Test Model for the Assessment of Immunogenicity of Protein Aggregates

The immunogenicity of protein aggregates has been investigated in numerous studies. Nevertheless, it is still unknown which kind of protein aggregates enhance immunogenicity the most. The ability of the currently used in vitro and in vivo systems regarding their predictability of immunogenicity in humans is often questionable, and results are partially contradictive. In this study, we used a 2D in vitro assay and a complex 3D human artificial lymph node model to predict the immunogenicity of protein aggregates of bevacizumab and adalimumab. The monoclonal antibodies were exposed to different stress conditions such as light, heat, and mechanical stress to trigger the formation of protein aggregates and particles, and samples were analyzed thoroughly. Cells and culture supernatants were harvested and analyzed for dendritic cell marker and cytokines. Our study in the artificial lymph node model revealed that bevacizumab after exposure to heat triggered a TH1- and proinflammatory immune response, whereas no trend of immune responses was seen for adalimumab after exposure to different stress conditions. The human artificial lymph node model represents a new test model for testing the immunogenicity of protein aggregates combining the relevance of a 3D human system with the rather easy handling of an in vitro setup.

Nomenclature of humanized mAbs: Early concepts, current challenges and future perspectives

Nomenclature of monoclonal antibodies traditionally followed a strict scheme indicating target and species information. Because of the rapid advances in this field, emphasized by approval of four humanized and six human antibodies in 2017, the International Nonproprietary Name of new antibodies was updated profoundly by removing the species substem completely. In this review we give an overview about what developments led to the preference of the scientific community towards human-like antibodies. We summarize the major updates in naming schemes that tried to classify antibodies according to their humanization technique or to the final primary sequence and how this led to the erroneous perception to indicate expected immunogenicity. Following the new 2017 nomenclature update, there will not be any information available about the species origin in the names of new antibodies, which emphasizes the need for providing additional supplemental information to the scientific community and develop tools to accurately estimate and control the safety of new monoclonal antibody molecules.

Peptide-nanoparticle conjugates: a next generation of diagnostic and therapeutic platforms?

Peptide-nanoparticle conjugates (PNCs) have recently emerged as a versatile tool for biomedical applications. Synergism between the two promising classes of materials allows enhanced control over their biological behaviors, overcoming intrinsic limitations of the individual materials. Over the past decades, a myriad of PNCs has been developed for various applications, such as drug delivery, inhibition of pathogenic biomolecular interactions, molecular imaging, and liquid biopsy. This paper provides a comprehensive overview of existing technologies that have been recently developed in the broad field of PNCs, offering a guideline especially for investigators who are new to this field.

Anticalin® Proteins as Therapeutic Agents in Human Diseases

Anticalin proteins are an emerging class of clinical-stage biopharmaceuticals with high potential as an alternative to antibodies. Anticalin molecules are generated by combinatorial design from natural lipocalins, which are abundant plasma proteins in humans, and reveal a simple, compact fold dominated by a central β-barrel, supporting four structurally variable loops that form a binding site. Reshaping of this loop region results in Anticalin proteins that can recognize and tightly bind a wide range of medically relevant targets, from small molecules to peptides and proteins, as validated by X-ray structural analysis. Their robust format allows for modification in several ways, both as fusion proteins and by chemical conjugation, for example, to tune plasma half-life. Antagonistic Anticalin therapeutics have been developed for systemic administration (e.g., PRS-080: anti-hepcidin) or pulmonary delivery (e.g. PRS-060/AZD1402: anti-interleukin [IL]-4-Rα). Moreover, Anticalin proteins allow molecular formatting as bi- and even multispecific fusion proteins, especially in combination with antibodies that provide a second specificity. For example, PRS-343, which has recently entered clinical-stage development, combines an agonistic Anticalin targeting the costimulatory receptor 4-1BB with an antibody directed against the cancer antigen human epidermal growth factor receptor 2 (HER2), thus offering a novel treatment option in immuno-oncology.

Designing a mutant Candida uricase with improved polymerization state and enzymatic activity

As human uricase has been silenced during evolution, counterparts from other species become an alternative for the treatment of hyperuricemia. Candida uricase is a promising option among them, but its aggregation propensity remains a major obstacle to clinical use. In this study, we designed two mutations according to homology-modeled 3D structure of Candida uricase: Cys249Ser substitution and C-terminal Leu deletion. The wild-type uricase and three mutants containing either or both of the mutations were expressed in Escherichia coli BL21 and validated by mass spectrometry. Size-exclusion chromatography and electrophoresis analysis demonstrated that aggregation was induced by interchain disulfide bonds and could be significantly avoided by Cys249Ser substitution. In combination with Cys249Ser substitution, deletion of Leu increased the enzymatic activity by 8%. Taken together, mutant containing both mutations is chosen as our target protein which is comparatively more suitable for therapeutic use. In addition, homology-modeled 3D structure was proved to be an efficient approach for protein engineering.

Identifying the Epitope Regions of Therapeutic Antibodies Based on Structure Descriptors

Therapeutic antibodies are widely used for disease detection and specific treatments. However, as an exogenous protein, these antibodies can be detected by the human immune system and elicit a response that can lead to serious illnesses. Therapeutic antibodies can be engineered through antibody humanization, which aims to maintain the specificity and biological function of the original antibodies, and reduce immunogenicity. However, the antibody drug effect is synchronously reduced as more exogenous parts are replaced by human antibodies. Hence, a major challenge in this area is to precisely detect the epitope regions in immunogenic antibodies and guide point mutations of exogenous antibodies to balance both humanization level and drug effect. In this article, the latest dataset of immunoglobulin complexes was collected from protein data bank (PDB) to discover the spatial features of immunogenic antibody. Furthermore, a series of structure descriptors were generated to characterize and distinguish epitope residues from non-immunogenic regions. Finally, a computational model was established based on structure descriptors, and results indicated that this model has the potential to precisely predict the epitope regions of therapeutic antibodies. With rapid accumulation of immunoglobulin complexes, this methodology could be used to improve and guide future antibody humanization and potential clinical applications.

A study on the safety and efficacy of reveglucosidase alfa in patients with late-onset Pompe disease

BACKGROUND

Late-onset Pompe disease is a rare genetic neuromuscular disorder caused by lysosomal acid alpha-glucosidase (GAA) deficiency that ultimately results in mobility loss and respiratory failure. Current enzyme replacement therapy with recombinant human (rh)GAA has demonstrated efficacy in subjects with late-onset Pompe disease. However, long-term effects of rhGAA on pulmonary function have not been observed, likely related to inefficient delivery of rhGAA to skeletal muscle lysosomes and associated deficits in the central nervous system. To address this limitation, reveglucosidase alfa, a novel insulin-like growth factor 2 (IGF2)-tagged GAA analogue with improved lysosomal uptake, was developed. This study evaluated the pharmacokinetics, safety, and exploratory efficacy of reveglucosidase alfa in 22 subjects with late-onset Pompe disease who were previously untreated with rhGAA.

RESULTS

Reveglucosidase alfa plasma concentrations increased linearly with dose, and the elimination half-life was <1.2 h. Eighteen of 22 subjects completed 72 weeks of treatment. The most common adverse events were hypoglycemia (63%), dizziness, fall, headache, and nausea (55% for each). Serious adverse events included hypersensitivity (n = 1), symptomatic hypoglycemia (n = 2), presyncope (n = 1), and acute cardiac failure (n = 1). In the dose-escalation study, all treated subjects tested positive for anti-reveglucosidase alfa, anti-rhGAA, anti-IGF1, and anti-IGF2 antibodies at least once. Subjects receiving 20 mg/kg of reveglucosidase alfa demonstrated increases in predicted maximum inspiratory pressure (13.9%), predicted maximum expiratory pressure (8.0%), forced vital capacity (-0.4%), maximum voluntary ventilation (7.4 L/min), and mean absolute walking distance (22.3 m on the 6-min walk test) at 72 weeks.

CONCLUSIONS

Additional studies are needed to further assess the safety and efficacy of this approach. Improvements in respiratory muscle strength, lung function, and walking endurance in subjects with LOPD may make up for the risk of hypersensitivity reactions and hypoglycemia. Reveglucosidase alfa may provide a new treatment option for patients with late-onset Pompe disease.

TRIAL REGISTRATION

ISRCTN01435772 and ISRCTN01230801 , registered 27 October 2011.

Emerging Strategies for Developing Next-Generation Protein Therapeutics for Cancer Treatment

Protein-based therapeutics have been revolutionizing the oncology space since they first appeared in the clinic two decades ago. Unlike traditional small-molecule chemotherapeutics, protein biologics promote active targeting of cancer cells by binding to cell-surface receptors and other markers specifically associated with or overexpressed on tumors versus healthy tissue. While the first approved cancer biologics were monoclonal antibodies, the burgeoning field of protein engineering is spawning research on an expanded range of protein formats and modifications that allow tuning of properties such as target-binding affinity, serum half-life, stability, and immunogenicity. In this review we highlight some of these strategies and provide examples of modified and engineered proteins under development as preclinical and clinical-stage drug candidates for the treatment of cancer.

Antidrug Antibody Formation in Oncology: Clinical Relevance and Challenges

: In oncology, an increasing number of targeted anticancer agents and immunotherapies are of biological origin. These biological drugs may trigger immune responses that lead to the formation of antidrug antibodies (ADAs). ADAs are directed against immunogenic parts of the drug and may affect efficacy and safety. In other medical fields, such as rheumatology and hematology, the relevance of ADA formation is well established. However, the relevance of ADAs in oncology is just starting to be recognized, and literature on this topic is scarce. In an attempt to fill this gap in the literature, we provide an up-to-date status of ADA formation in oncology. In this focused review, data on ADAs was extracted from 81 clinical trials with biological anticancer agents. We found that most biological anticancer drugs in these trials are immunogenic and induce ADAs (63%). However, it is difficult to establish the clinical relevance of these ADAs. In order to determine this relevance, the possible effects of ADAs on pharmacokinetics, efficacy, and safety parameters need to be investigated. Our data show that this was done in fewer than 50% of the trials. In addition, we describe the incidence and consequences of ADAs for registered agents. We highlight the challenges in ADA detection and argue for the importance of validating, standardizing, and describing well the used assays. Finally, we discuss prevention strategies such as immunosuppression and regimen adaptations. We encourage the launch of clinical trials that explore these strategies in oncology.

IMPLICATIONS FOR PRACTICE

Because of the increasing use of biologicals in oncology, many patients are at risk of developing antidrug antibodies (ADAs) during therapy. Although clinical consequences are uncertain, ADAs may affect pharmacokinetics, patient safety, and treatment efficacy. ADA detection and reporting is currently highly inconsistent, which makes it difficult to evaluate the clinical consequences. Standardized reporting of ADA investigations in the context of the aforementioned parameters is critical to understanding the relevance of ADA formation for each drug. Furthermore, the development of trials that specifically aim to investigate clinical prevention strategies in oncology is needed.

Cellulose nanocrystals: a versatile nanoplatform for emerging biomedical applications

INTRODUCTION

Cellulose nanocrystals (CNCs) are bio-based nanomaterials typically derived from the acid hydrolysis of the most abundant natural polymer, cellulose. These nanomaterials have garnered significant interest due to their unique properties, such as uniform rod-like shape, high surface area, high strength, liquid crystalline behavior, tailored surface chemistry, biocompatibility, biodegradability, sustainability and non-toxic carbohydrate-based nature.

AREAS COVERED

The recent developments in the use of unmodified and modified CNCs as versatile nanoplatforms for emerging biomedical applications such as drug delivery systems, enzyme/protein immobilization scaffolds, bioimaging, biosensing and tissue engineering are highlighted. A brief discussion of the biological and toxicity properties of CNCs is also presented.

EXPERT OPINION

While a number of recent studies have indicated that CNCs are promising nanomaterials for biomedical applications, there is a substantial amount of work that still remains to be done before realizing the full therapeutic potential of CNCs. Major effort should be focused on detailed in vitro and in vivo studies of modified CNCs constructs in order to better understand the integration of CNCs in the biological systems.

Evaluation of Multiple Immunoassay Technology Platforms to Select the Anti-Drug Antibody Assay Exhibiting the Most Appropriate Drug and Target Tolerance

The aim of this study was, at the assay development stage and thus with an appropriate degree of rigor, to select the most appropriate technology platform and sample pretreatment procedure for a clinical ADA assay. Thus, ELISA, MSD, Gyrolab, and AlphaLISA immunoassay platforms were evaluated in association with target depletion and acid dissociation sample pretreatment steps. An acid dissociation step successfully improved the drug tolerance for all 4 technology platforms and the required drug tolerance was achieved with the Gyrolab and MSD platforms. The target tolerance was shown to be better for the ELISA format, where an acid dissociation treatment step alone was sufficient to achieve the desired target tolerance. However, inclusion of a target depletion step in conjunction with the acid treatment raised the target tolerance to the desired level for all of the technologies. A higher sensitivity was observed for the MSD and Gyrolab assays and the ELISA, MSD, and Gyrolab all displayed acceptable interdonor variability. This study highlights the usefulness of evaluating the performance of different assay platforms at an early stage in the assay development process to aid in the selection of the best fit-for-purpose technology platform and sample pretreatment steps.

Recent Advances in Application of Pharmacogenomics for Biotherapeutics

Biotherapeutics (BTs), one of the fastest growing classes of drug molecules, offer several advantages over the traditional small molecule pharmaceuticals because of their relatively high specificity, low off-target effects, and biocompatible metabolism, in addition to legal and logistic advantages. However, their clinical utility is limited, among other things, by their high immunogenic potential and/or variable therapeutic efficacy in different patient populations. Both of these issues, also commonly experienced with small molecule drugs, have been addressed effectively in a number of cases by the successful application of pharmacogenomic tools and approaches. In this introductory article of the special issue, we review the current state of application of pharmacogenomics to BTs and offer suggestions for further expansion of the field.

Immunogenicity to Biotherapeutics - The Role of Anti-drug Immune Complexes

Biological molecules are increasingly becoming a part of the therapeutics portfolio that has been either recently approved for marketing or those that are in the pipeline of several biotech and pharmaceutical companies. This is largely based on their ability to be highly specific relative to small molecules. However, by virtue of being a large protein, and having a complex structure with structural variability arising from production using recombinant gene technology in cell lines, such therapeutics run the risk of being recognized as foreign by a host immune system. In the context of immune-mediated adverse effects that have been documented to biological drugs thus far, including infusion reactions, and the evolving therapeutic platforms in the pipeline that engineer different functional modules in a biotherapeutic, it is critical to understand the interplay of the adaptive and innate immune responses, the pathophysiology of immunogenicity to biological drugs in instances where there have been immune-mediated adverse clinical sequelae and address technical approaches for their laboratory evaluation. The current paradigm in immunogenicity evaluation has a tiered approach to the detection and characterization of anti-drug antibodies (ADAs) elicited in vivo to a biotherapeutic; alongside with the structural, biophysical, and molecular information of the therapeutic, these analytical assessments form the core of the immunogenicity risk assessment. However, many of the immune-mediated adverse effects attributed to ADAs require the formation of a drug/ADA immune complex (IC) intermediate that can have a variety of downstream effects. This review will focus on the activation of potential immunopathological pathways arising as a consequence of circulating as well as cell surface bound drug bearing ICs, risk factors that are intrinsic either to the therapeutic molecule or to the host that might predispose to IC-mediated effects, and review the recent literature on prevalence and intensity of established examples of type II and III hypersensitivity reactions that follow the administration of a biotherapeutic. Additionally, we propose methods for the study of immune parameters specific to the biology of ICs that could be of use in conjunction with the detection of ADAs in circulation.

B cell epitopes on infliximab identified by oligopeptide microarray with unprocessed patient sera

Background

Autoimmune diseases like rheumatoid arthritis and inflammatory bowel disease are treated with TNF-alpha-blocking antibodies such as infliximab and adalimumab. A common side effect of therapeutic antibodies is the induction of anti-drug antibodies, which may reduce therapeutic efficacy.

Methods

In order to reveal immunogenic epitopes on infliximab which are responsible for the adverse effects, sera from patients treated with infliximab were screened by ELISA for anti-infliximab antibodies. Sera containing high levels of anti-drug-antibodies (>1.25 µg/ml) were analyzed in an oligopeptide microarray system containing immobilized 15-meric oligopeptides from the infliximab amino acid sequence. Immunogenic infliximab IgG-epitopes were identified by infrared fluorescence scanning and comparison of infliximab-treated patients versus untreated controls.

Results

Six relevant epitopes on infliximab were recognized by the majority of all patient sera: 4 in the variable and 2 in the constant region. Three of the epitopes in the variable region are located in the TNF-alpha binding region of infliximab. The fourth epitope of the variable part of infliximab is located close to the TNF-alpha binding region and contains an N-glycosylation sequon. The sera positive for anti-infliximab antibodies do not contain antibodies against adalimumab as determined by ELISA. Thus, there is no infliximab–adalimumab cross-reactivity as determined by these systems.

Conclusions

Our data shall contribute to a knowledge-based recommendation for a potentially necessary therapy switch from infliximab to another type of TNF-alpha-blocker. The characterization of immunogenic epitopes on therapeutic monoclonal antibodies using unprocessed patient sera shall lead to direct translational aspects for the development of less immunogenic therapeutic antibodies. Patients benefit from less adverse events and longer lasting drug effects.

A Neutralizing Antibody Assay Based on a Reporter of Antibody-Dependent Cell-Mediated Cytotoxicity

Benralizumab is a humanized anti-IL5 receptor α (IL5Rα) monoclonal antibody (mAb) with enhanced (afucosylation) antibody-dependent cell-mediated cytotoxicity (ADCC) function. An ADCC reporter cell-based neutralizing antibody (NAb) assay was developed and characterized to detect NAb against benralizumab in human serum to support the clinical development of benralizumab. The optimal ratio of target cells to effector cells was 3:1. Neither parental benralizumab (fucosylated) nor benralizumab Fab resulted in ADCC activity, confirming the requirement for ADCC activity in the NAb assay. The serum tolerance of the cells was determined to be 2.5%. The cut point derived from normal and asthma serum samples was comparable. The effective range of benralizumab was determined, and 35 ng/mL [80% maximal effective concentration (EC80)] was chosen as the standard concentration to run in the assessment of NAb. An affinity purified goat anti-benralizumab polyclonal idiotype antibody preparation was shown to have NAb since it inhibited ADCC activity in a dose-dependent fashion. The low endogenous concentrations of IL5 and soluble IL5 receptor (sIL5R) did not demonstrate to interfere with the assay. The estimated assay sensitivities at the cut point were 1.02 and 1.10 μg/mL as determined by the surrogate neutralizing goat polyclonal and mouse monoclonal anti-drug antibody (ADA) controls, respectively. The assay can detect NAb (at 2.5 μg/mL) in the presence of 0.78 μg/mL benralizumab. The assay was not susceptible to non-specific matrix effects. This study provides an approach and feasibility of developing an ADCC cell-based NAb assay to support biopharmaceuticals with an ADCC function.