A phase I, randomized, observer-blinded, single and multiple ascending-dose study to investigate the safety, pharmacokinetics, and immunogenicity of BITS7201A, a bispecific antibody targeting IL-13 and IL-17, in healthy volunteers

Design of orthogonal constant domain interfaces to aid proper heavy/light chain pairing of bispecific antibodies

The correct pairing of cognate heavy and light chains is critical to the efficient manufacturing of IgG-like bispecific antibodies (bsAbs) from a single host cell. We present a general solution for the elimination of heavy chain (HC):light chain (LC) mispairs in bsAbs with κ LCs via the use of two orthogonal constant domain (CH1:Cκ ) interfaces comprising computationally designed amino acid substitutions. Substitutions were designed by Rosetta to introduce novel hydrogen bond (H-bond) networks at the CH1:Cκ interface, followed by Rosetta energy calculations to identify designs with enhanced pairing specificity and interface stability. Our final design, featuring a total of 11 amino acid substitutions across two Fab constant regions, was tested on a set of six IgG-like bsAbs featuring a diverse set of unmodified human antibody variable domains. Purity assessments showed near-complete elimination of LC mispairs, including in cases with high baseline mispairing with wild-type constant domains. The engineered bsAbs broadly recapitulated the antigen-binding and biophysical developability properties of their monospecific counterparts and no adverse immunogenicity signal was identified by an in vitro assay. Fab crystal structures containing engineered constant domain interfaces revealed no major perturbations relative to the wild-type coordinates and validated the presence of the designed hydrogen bond interactions. Our work enables the facile assembly of independently discovered IgG-like bispecific antibodies in a single-cell host and demonstrates a streamlined and generalizable computational and experimental workflow for redesigning conserved protein:protein interfaces.

CONSORT-DEFINE explanation and elaboration: recommendations for enhancing reporting quality and impact of early phase dose-finding clinical trials

Early phase dose-finding (EPDF) trials are key in the development of novel therapies, with their findings directly informing subsequent clinical development phases and providing valuable insights for reverse translation. Comprehensive and transparent reporting of these studies is critical for their accurate and critical interpretation, which may improve and expedite therapeutic development. However, quality of reporting of design characteristics and results from EPDF trials is often variable and incomplete. The international consensus-based CONSORT-DEFINE (Consolidated Standards for Reporting Trials Dose-finding Extension) statement, an extension of the CONSORT statement for randomised trials, was developed to improve the reporting of EPDF trials. The CONSORT-DEFINE statement introduced 21 new items and modified 19 existing CONSORT items.This CONSORT-DEFINE Explanation and Elaboration (E&E) document provides important information to enhance understanding and facilitate the implementation of the CONSORT-DEFINE checklist. For each new or modified checklist item, we provide a detailed description and its rationale with supporting evidence, and present examples from EPDF trial reports published in peer-reviewed scientific journals. When reporting the results of EPDF trials, authors are encouraged to consult the CONSORT-DEFINE E&E document, together with the CONSORT and CONSORT-DEFINE statement papers, and adhere to their recommendations. Widespread adoption of the CONSORT-DEFINE statement is likely to enhance the reporting quality of EPDF trials, thus facilitating the peer review of such studies and their appraisal by researchers, regulators, ethics committee members, and funders.

Funding

This work is a further extension of the CONSORT-DEFINE study, which was funded by the UK Medical Research Council (MRC)-National Institute for Health and Care Research (NIHR) Methodology Research Programme (MR/T044934/1). The Clinical Trials and Statistics Unit at The Institute of Cancer Research (ICR-CTSU) receives programmatic infrastructure funding from Cancer Research UK (C1491/A25351; CTUQQR-Dec 22/100 004), which has contributed to accelerating the advancement and successful completion of this work.

2023 White Paper on Recent Issues in Bioanalysis: ISR for ADA Assays, the Rise of dPCR vs qPCR, International Reference Standards for Vaccine Assays, Anti-AAV TAb Post-Dose Assessment, NanoString Validation, ELISpot as Gold Standard (Part 3 - Recommendations on Gene Therapy, Cell Therapy, Vaccines Immunogenicity & Technologies; Biotherapeutics Immunogenicity & Risk Assessment; ADA/NAb Assay/Reporting Harmonization)

The 17th Workshop on Recent Issues in Bioanalysis (17th WRIB) took place in Orlando, FL, USA on June 19-23, 2023. Over 1000 professionals representing pharma/biotech companies, CROs, and multiple regulatory agencies convened to actively discuss the most current topics of interest in bioanalysis. The 17th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week to allow an exhaustive and thorough coverage of all major issues in bioanalysis of biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on "EU IVDR 2017/746 Implementation and impact for the Global Biomarker Community: How to Comply with these NEW Regulations" and on "US FDA/OSIS Remote Regulatory Assessments (RRAs)" were the special features of the 17th edition. As in previous years, WRIB continued to gather a wide diversity of international, industry opinion leaders and regulatory authority experts working on both small and large molecules as well as gene, cell therapies and vaccines to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance, and achieving scientific excellence on bioanalytical issues. This 2023 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2023 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations on Gene Therapy, Cell therapy, Vaccines and Biotherapeutics Immunogenicity. Part 1A (Mass Spectrometry Assays and Regulated Bioanalysis/BMV), P1B (Regulatory Inputs) and Part 2 (Biomarkers, IVD/CDx, LBA and Cell-Based Assays) are published in volume 16 of Bioanalysis, issues 8 and 9 (2024), respectively.

T-helper cells and their cytokines in pathogenesis and treatment of asthma

Prosperous advances in understanding the cellular and molecular mechanisms of chronic inflammation and airway remodeling in asthma have been made over the past several decades. Asthma is a chronic inflammatory disease of the airways characterized by reversible airway obstruction that is self-resolving or remits with treatment. Around half of asthma patients are "Type-2-high" asthma with overexpression of type 2 inflammatory pathways and elevated type 2 cytokines. When stimulated by allergens, airway epithelial cells secrete IL-25, IL-33, and TSLP to derive a Th2 immune response. First ILC2 followed by Th2 cells produces a series of cytokines such as IL-4, IL-5, and IL-13. TFH cells control IgE synthesis by secreting IL-4 to allergen-specific B cells. IL-5 promotes eosinophil inflammation, while IL-13 and IL-4 are involved in goblet cell metaplasia and bronchial hyperresponsiveness. Currently, "Type-2 low" asthma is defined as asthma with low levels of T2 biomarkers due to the lack of reliable biomarkers, which is associated with other Th cells. Th1 and Th17 are capable of producing cytokines that recruit neutrophils, such as IFN-γ and IL-17, to participate in the development of "Type-2-low" asthma. Precision medicine targeting Th cells and related cytokines is essential in the management of asthma aiming at the more appropriate patient selection and better treatment response. In this review, we sort out the pathogenesis of Th cells in asthma and summarize the therapeutic approaches involved as well as potential research directions.

Astegolimab or Efmarodocokin Alfa in Patients With Severe COVID-19 Pneumonia: A Randomized, Phase 2 Trial

OBJECTIVES

Severe cases of COVID-19 pneumonia can lead to acute respiratory distress syndrome (ARDS). Release of interleukin (IL)-33, an epithelial-derived alarmin, and IL-33/ST2 pathway activation are linked with ARDS development in other viral infections. IL-22, a cytokine that modulates innate immunity through multiple regenerative and protective mechanisms in lung epithelial cells, is reduced in patients with ARDS. This study aimed to evaluate safety and efficacy of astegolimab, a human immunoglobulin G2 monoclonal antibody that selectively inhibits the IL-33 receptor, ST2, or efmarodocokin alfa, a human IL-22 fusion protein that activates IL-22 signaling, for treatment of severe COVID-19 pneumonia.

DESIGN

Phase 2, double-blind, placebo-controlled study (COVID-astegolimab-IL).

SETTING

Hospitals.

PATIENTS

Hospitalized adults with severe COVID-19 pneumonia.

INTERVENTIONS

Patients were randomized to receive IV astegolimab, efmarodocokin alfa, or placebo, plus standard of care. The primary endpoint was time to recovery, defined as time to a score of 1 or 2 on a 7-category ordinal scale by day 28.

MEASUREMENTS AND MAIN RESULTS

The study randomized 396 patients. Median time to recovery was 11 days (hazard ratio [HR], 1.01 d; p = 0.93) and 10 days (HR, 1.15 d; p = 0.38) for astegolimab and efmarodocokin alfa, respectively, versus 10 days for placebo. Key secondary endpoints (improved recovery, mortality, or prevention of worsening) showed no treatment benefits. No new safety signals were observed and adverse events were similar across treatment arms. Biomarkers demonstrated that both drugs were pharmacologically active.

CONCLUSIONS

Treatment with astegolimab or efmarodocokin alfa did not improve time to recovery in patients with severe COVID-19 pneumonia.

Monoclonal antibodies in the management of asthma: Dead ends, current status and future perspectives

Patients with moderate-to-severe asthma may now be treated using a variety of monoclonal antibodies that target key inflammatory cytokines involved in disease pathogenesis. Existing clinical data on anti-IgE, anti-IL-5 and other immunological pathways indicate these therapies to offer reduced exacerbation rates, improved lung function, greater asthma control and better quality of life. However, as several patients still do not achieve satisfactory clinical response with the antibodies available, many more biologics, aiming different immunological pathways, are under evaluation. This review summarizes recent data on existing and potential monoclonal antibodies in asthma. Recent advances have resulted in the registration of a new antibody targeting TSLP (tezepelumab), with others being under development. Some of the researched monoclonal antibodies (e.g. anti-IL-13 tralokinumab and lebrikizumab or anti-IL-17A secukinumab) have shown optimistic results in preliminary research; however, these have been discontinued in asthma clinical research. In addition, as available monoclonal antibody treatments have shown little benefit among patients with T₂-low asthma, research continues in this area, with several antibodies in development. This article summarizes the available pre-clinical and clinical data on new and emerging drugs for treating severe asthma, discusses discontinued treatments and outlines future directions in this area.

Designing antibodies as therapeutics

Antibody therapeutics are a large and rapidly expanding drug class providing major health benefits. We provide a snapshot of current antibody therapeutics including their formats, common targets, therapeutic areas, and routes of administration. Our focus is on selected emerging directions in antibody design where progress may provide a broad benefit. These topics include enhancing antibodies for cancer, antibody delivery to organs such as the brain, gastrointestinal tract, and lungs, plus antibody developability challenges including immunogenicity risk assessment and mitigation and subcutaneous delivery. Machine learning has the potential, albeit as yet largely unrealized, for a transformative future impact on antibody discovery and engineering.

Adipose Tissue Inflammation and Pulmonary Dysfunction in Obesity

Obesity is a chronic disease caused by an excess of adipose tissue that may impair health by altering the functionality of various organs, including the lungs. Excessive deposition of fat in the abdominal area can lead to abnormal positioning of the diaphragm and consequent reduction in lung volume, leading to a heightened demand for ventilation and increased exposure to respiratory diseases, such as chronic obstructive pulmonary disease, asthma, and obstructive sleep apnoea. In addition to mechanical ventilatory constraints, excess fat and ectopic deposition in visceral depots can lead to adipose tissue dysfunction, which promotes metabolic disorders. An altered adipokine-secretion profile from dysfunctional adipose tissue in morbid obesity fosters systemic, low-grade inflammation, impairing pulmonary immune response and promoting airway hyperresponsiveness. A potential target of these adipokines could be the NLRP3 inflammasome, a critical component of the innate immune system, the harmful pro-inflammatory effect of which affects both adipose and lung tissue in obesity. In this review, we will investigate the crosstalk between adipose tissue and the lung in obesity, highlighting the main inflammatory mediators and novel therapeutic targets in preventing pulmonary dysfunction.

Neutrophils and Asthma

Although eosinophilic inflammation is characteristic of asthma pathogenesis, neutrophilic inflammation is also marked, and eosinophils and neutrophils can coexist in some cases. Based on the proportion of sputum cell differentiation, asthma is classified into eosinophilic asthma, neutrophilic asthma, neutrophilic and eosinophilic asthma, and paucigranulocytic asthma. Classification by bronchoalveolar lavage is also performed. Eosinophilic asthma accounts for most severe asthma cases, but neutrophilic asthma or a mixture of the two types can also present a severe phenotype. Biomarkers for the diagnosis of neutrophilic asthma include sputum neutrophils, blood neutrophils, chitinase-3-like protein, and hydrogen sulfide in sputum and serum. Thymic stromal lymphoprotein (TSLP)/T-helper 17 pathways, bacterial colonization/microbiome, neutrophil extracellular traps, and activation of nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 pathways are involved in the pathophysiology of neutrophilic asthma and coexistence of obesity, gastroesophageal reflux disease, and habitual cigarette smoking have been associated with its pathogenesis. Thus, targeting neutrophilic asthma is important. Smoking cessation, neutrophil-targeting treatments, and biologics have been tested as treatments for severe asthma, but most clinical studies have not focused on neutrophilic asthma. Phosphodiesterase inhibitors, anti-TSLP antibodies, azithromycin, and anti-cholinergic agents are promising drugs for neutrophilic asthma. However, clinical research targeting neutrophilic inflammation is required to elucidate the optimal treatment.

Novel potential treatable traits in asthma: Where is the research taking us?

Asthma is a complex, heterogeneous disease in which the underlying mechanisms are not fully understood. Patients are often grouped into phenotypes (based on clinical, biologic, and physiologic characteristics) and endotypes (based on distinct genetic or molecular mechanisms). Recently, patients with asthma have been broadly split into 2 phenotypes based on their levels of type 2 inflammation: type 2 and non-type 2 asthma. However, this approach is likely oversimplified, and our understanding of the non-type 2 mechanisms in asthma remains extremely limited. A better understanding of asthma phenotypes and endotypes may assist in development of drugs for new therapeutic targets in asthma. One approach is to identify "treatable traits," which are specific patient characteristics related to phenotypes and endotypes that can be targeted by therapies. This review will focus on emerging treatable traits in asthma and aim to describe novel patient subgroups and endotypes that may represent the next step in the search for new therapeutic approaches.

Role of Th17 Cytokines in Airway Remodeling in Asthma and Therapy Perspectives

Airway remodeling is a frequent pathological feature of severe asthma leading to permanent airway obstruction in up to 50% of cases and to respiratory disability. Although structural changes related to airway remodeling are well-characterized, immunological processes triggering and maintaining this phenomenon are still poorly understood. As a consequence, no biotherapy targeting cytokines are currently efficient to treat airway remodeling and only bronchial thermoplasty may have an effect on bronchial nerves and smooth muscles with uncertain clinical relevance. Th17 cytokines, including interleukin (IL)-17 and IL-22, play a role in neutrophilic inflammation in severe asthma and may be involved in airway remodeling. Indeed, IL-17 is increased in sputum from severe asthmatic patients, induces the expression of "profibrotic" cytokines by epithelial, endothelial cells and fibroblasts, and provokes human airway smooth muscle cell migration in in vitro studies. IL-22 is also increased in asthmatic samples, promotes myofibroblast differentiation, epithelial-mesenchymal transition and proliferation and migration of smooth muscle cells in vitro. Accordingly, we also found high levels of IL-17 and IL-22 in a mouse model of dog-allergen induced asthma characterized by a strong airway remodeling. Clinical trials found no effect of therapy targeting IL-17 in an unselected population of asthmatic patients but showed a potential benefit in a sub-population of patients exhibiting a high level of airway reversibility, suggesting a potential role on airway remodeling. Anti-IL-22 therapies have not been evaluated in asthma yet but were demonstrated efficient in severe atopic dermatitis including an effect on skin remodeling. In this review, we will address the role of Th17 cytokines in airway remodeling through data from in vitro, in vivo and translational studies, and examine the potential place of Th17-targeting therapies in the treatment of asthma with airway remodeling.

Novel regulators of airway epithelial barrier function during inflammation: potential targets for drug repurposing

INTRODUCTION

Endogenous inflammatory signaling molecules resulting from deregulated immune responses, can impair airway epithelial barrier function and predispose individuals with airway inflammatory diseases to exacerbations and lung infections. Targeting the specific endogenous factors disrupting the airway barrier therefore has the potential to prevent disease exacerbations without affecting the protective immune responses.

AREAS COVERED

Here, we review the endogenous factors and specific mechanisms disrupting airway epithelial barrier during inflammation and reflect on whether these factors can be specifically targeted by repurposed existing drugs. Literature search was conducted using PubMed, drug database of US FDA and European Medicines Agency until and including September 2021.

EXPERT OPINION

IL-4 and IL-13 signaling are the major pathways disrupting the airway epithelial barrier during airway inflammation. However, blocking IL-4/IL-13 signaling may adversely affect protective immune responses and increase susceptibility of host to infections. An alternate approach to modulate airway epithelial barrier function involves targeting specific downstream component of IL-4/IL-13 signaling or different inflammatory mediators responsible for regulation of airway epithelial barrier. Airway epithelium-targeted therapy using inhibitors of HDAC, HSP90, MIF, mTOR, IL-17A and VEGF may be a potential strategy to prevent airway epithelial barrier dysfunction in airway inflammatory diseases.

Full-length recombinant antibodies from Escherichia coli: production, characterization, effector function (Fc) engineering, and clinical evaluation

Although several antibody fragments and antibody fragment-fusion proteins produced in Escherichia coli (E. coli) are approved as therapeutics for various human diseases, a full-length monoclonal or a bispecific antibody produced in E. coli has not yet been approved. The past decade witnessed substantial progress in expression of full-length antibodies in the E. coli cytoplasm and periplasm, as well as in cell-free expression systems. The equivalency of E. coli-produced aglycosylated antibodies and their mammalian cell-produced counterparts, with respect to biochemical and biophysical properties, including antigen binding, in vitro and in vivo serum stability, pharmacokinetics, and in vivo serum half-life, has been demonstrated. Extensive engineering of the Fc domain of aglycosylated antibodies enables recruitment of various effector functions, despite the lack of N-linked glycans. This review summarizes recent research, preclinical advancements, and clinical development of E. coli-produced aglycosylated therapeutic antibodies as monoclonal, bispecific, and antibody-drug conjugates for use in autoimmune, oncology, and immuno-oncology areas.Abbreviations: ADA Anti-drug antibody; ADCC Antibody-dependent cellular cytotoxicity; ADCP Antibody-dependent cellular phagocytosis; ADC Antibody-drug conjugate; aFc Aglycosylated Fc; AMD Age-related macular degeneration aTTP Acquired thrombotic thrombocytopenic purpura; BCMA B-cell maturation antigen; BLA Biologics license application; BsAb Bispecific antibody; C1q Complement protein C1q; CDC Complement-dependent cytotoxicity; CDCC Complement-dependent cellular cytotoxicity; CDCP Complement-dependent cellular phagocytosis; CEX Cation exchange chromatography; CFPS Cell-free protein expression; CHO Chinese Hamster Ovary; CH1-3 Constant heavy chain 1-3; CL Constant light chain; DLBCL Diffuse large B-cell lymphoma; DAR Drug antibody ratio; DC Dendritic cell; dsFv Disulfide-stabilized Fv; EU European Union; EGFR Epidermal growth factor receptor; E. coli Escherichia coli; EpCAM Epithelial cell adhesion molecule; Fab Fragment antigen binding; FACS Fluorescence activated cell sorting; Fc Fragment crystallizable; FcRn Neonatal Fc receptor; FcɣRs Fc gamma receptors; FDA Food and Drug Administration; FL-IgG Full-length immunoglobulin; Fv Fragment variable; FolRαa Folate receptor alpha; gFc Glycosylated Fc; GM-CSF Granulocyte macrophage-colony stimulating factor; GPx7 Human peroxidase 7; HCL Hairy cell leukemia; HIV Human immunodeficiency virusl; HER2 Human epidermal growth factor receptor 2; HGF Hepatocyte growth factor; HIC Hydrophobic interaction chromatography; HLA Human leukocyte antigen; IBs Inclusion bodies; IgG1-4 Immunoglobulin 1-4; IP Intraperitoneal; ITC Isothermal titration calorimetry; ITP Immune thrombocytopenia; IV Intravenous; kDa Kilodalton; KiH Knob-into-Hole; mAb Monoclonal antibody; MAC Membrane-attack complex; mCRC Metastatic colorectal cancer; MM Multipl myeloma; MOA Mechanism of action; MS Mass spectrometry; MUC1 Mucin 1; MG Myasthenia gravis; NB Nanobody; NK Natural killer; nsAA Nonstandard amino acid; NSCLC Non-small cell lung cancer; P. aeruginosa Pseudomonas aeruginosa; PD-1 Programmed cell death 1; PD-L1 Programmed cell death-ligand 1; PDI Protein disulfide isomerase; PECS Periplasmic expression cytometric screening; PK Pharmacokinetics; P. pastoris Pichia pastoris; PTM Post-translational modification; Rg Radius of gyration; RA Rheumatoid arthritis; RT-PCR Reverse transcription polymerase chain reaction; SAXS Small angle X-ray scattering; scF Single chain Fv; SCLC Small cell lung cancer; SDS-PAGE Sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SEC Size exclusion chromatography; SEED Strand-exchange engineered domain; sRNA Small regulatory RNA; SRP Signal recognition particle; T1/2 Half-life; Tagg Aggregation temperature; TCR T cell receptor; TDB T cell-dependent bispecific; TF Tissue factor; TIR Translation initiation region; Tm Melting temperature; TNBC Triple-negative breast cancer; TNF Tumor necrosis factor; TPO Thrombopoietin; VEGF Vascular endothelial growth factor; vH Variable heavy chain; vL Variable light chain; vWF von Willebrand factor; WT Wild type.

Advances and Challenges of Antibody Therapeutics for Severe Bronchial Asthma

Asthma is a disease that consists of three main components: airway inflammation, airway hyperresponsiveness, and airway remodeling. Persistent airway inflammation leads to the destruction and degeneration of normal airway tissues, resulting in thickening of the airway wall, decreased reversibility, and increased airway hyperresponsiveness. The progression of irreversible airway narrowing and the associated increase in airway hyperresponsiveness are major factors in severe asthma. This has led to the identification of effective pharmacological targets and the recognition of several biomarkers that enable a more personalized approach to asthma. However, the efficacies of current antibody therapeutics and biomarkers are still unsatisfactory in clinical practice. The establishment of an ideal phenotype classification that will predict the response of antibody treatment is urgently needed. Here, we review recent advancements in antibody therapeutics and novel findings related to the disease process for severe asthma.

Development of Neutralizing Multimeric Nanobody Constructs Directed against IL-13: From Immunization to Lead Optimization

IL-13 is a pleiotropic cytokine mainly secreted by Th2 cells. It reacts with many different types of cells involved in allergy, inflammation, and fibrosis, e.g., mastocytes, B cells, and fibroblasts. The role of IL-13 in conditions involving one or several of these phenotypes has therefore been extensively investigated. The inhibition of this cytokine in animal models for various pathologies yielded highly promising results. However, most human trials relying on anti-IL-13 conventional mAbs have failed to achieve a significant improvement of the envisaged disorders. Where some studies might have suffered from several weaknesses, the strategies themselves, such as targeting only IL-13 using conventional mAbs or employing a systemic administration, could be questioned. Nanobodies are recombinant Ag-binding fragments derived from the variable part of H chain-only Abs occurring in Camelidae. Thanks to their single-domain structure, small size (≈15 kDa), good stability, and solubility, they can be engineered into multispecific constructs for combined therapies or for use in new strategies such as formulations for local administration, e.g., pulmonary administration. In this study, we describe the generation of 38 nanobodies that can be subdivided into five CDR3 families. Nine nanobodies were found to have a good affinity profile (K_D = 1-200 nM), but none were able to strongly inhibit IL-13 biological activity in vitro (IC₅₀ > 50 µM: HEK-Blue IL-13/IL-4 cells). Multimeric constructs were therefore designed from these inhibitors and resulted in an up to 36-fold improvement in affinity and up to 300-fold enhancement of the biological activity while conserving a high specificity toward IL-13.

An integrated approach for characterizing immunogenic responses toward a bispecific antibody

Bispecific antibodies (bsAbs) recognize and bind two different targets or two epitopes of the same antigen, making them an attractive diagnostic and treatment modality. Compared to the production of conventional bivalent monospecific antibodies, bsAbs require greater engineering and manufacturing. Therefore, bsAbs are more likely to differ from endogenous immunoglobulins and contain new epitopes that can increase immunogenic risk. Anti-A/B is a bsAb designed using a ‘knobs-into-holes’ (KIH) format. Anti-A/B exhibited an unexpectedly high immunogenicity in both preclinical and clinical studies, resulting in early termination of clinical development. Here, we used an integrated approach that combined in silico analysis, in vitro assays, and an in vivo study in non-human primates to characterize anti-A/B immunogenicity. Our findings indicated that the immunogenicity is associated with epitopes in the anti-B arm and not with mutations engineered through the KIH process. Our results showed the value of this integrated approach for performing immunogenicity risk assessment during clinical candidate selection to effectively mitigate risks during bsAb development.

Estimation of Clearance and Bioavailability of Therapeutic Monoclonal Antibodies from Only Subcutaneous Injection Data in Humans Based on Comprehensive Analysis of Clinical Data

Introduction

Theoretically, the separate estimation of clearance (CL) and bioavailability (F) requires both intravenous and extravascular injection data. This study investigated whether CL and subcutaneous F of therapeutic monoclonal antibodies (mAbs) in humans can be separately estimated from subcutaneous injection data only.

Methods

First, the geometric mean of linear pharmacokinetic parameters (CL, intercompartmental CL [Q], volume of distribution in the central compartment [V_c], and volume of distribution in the peripheral compartment [V_p]) after intravenous injection for mAbs in humans that have been reported in public data sources was estimated from 103 mAbs with linear pharmacokinetics and 44 mAbs with nonlinear pharmacokinetics. Next, we estimated the CL and F of 25 mAbs with linear pharmacokinetics from plasma/serum mAb concentration–time profiles after subcutaneous injection in humans by fixing the geometric mean of Q, V_c, and V_p based on the public data. Moreover, the plasma/serum concentration–time profile of 25 mAbs after intravenous injection was simulated using the estimated CL and the geometric mean of Q, V_c, and V_p.

Results

There were no significant differences in parameters among subclasses (immunoglobulin [Ig] G1, 2, and 4) or in linearity (derivation from linear and nonlinear pharmacokinetics). Using only subcutaneous injection data, we successfully estimated the CL of 23/25 mAbs (92%) and F of all 25 mAbs (100%) within 1.5-fold of the observed value. Moreover, overall, the simulated concentration–time profiles were largely consistent with observed data (90.8% within 1.5-fold of the observed values).

Conclusions

This approach does not require intravenous injection data to separately estimate CL and F after subcutaneous injection in humans and can therefore accelerate the clinical development of mAbs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-021-01023-z.

Key Features Defining the Disposition of Bispecific Antibodies and Their Efficacy In Vivo

Bispecific antibodies (BsAbs) are novel drugs, with only a few approved for clinical use. BsAbs are versatile molecules that come in many different forms and are designed and produced via genetic engineering. Although BsAbs share several pharmacokinetic (PK) and pharmacodynamic (PD) properties with monoclonal antibodies, they have their own unique characteristics based on their overall structure and specificities. BsAbs are generally more complex to investigate and develop than monoclonal antibodies, because they recognize at least 2 different antigens. Understanding their relative affinities to each target is crucial for determining their mechanism of action and efficacy. Moreover, the presence or absence of an Fc region determines, in part, their in vivo stability, distribution, and half-life. This study summarizes several PK and PD aspects that are specific for BsAbs and are important for the success of these new drugs. We emphasize previous PK/PD studies that have been fundamental for the correct prediction of appropriate dosages and schedules of these new drugs in clinical trials or for defining which drugs may take advantage of individualized and standardized drug monitoring for improved efficacy and safety.

Implications of preexisting asthma on COVID-19 pathogenesis

The coronavirus disease 2019 (COVID-19) pandemic spreading at an alarming rate has taken a heavy toll on the public healthcare systems and economies worldwide. An abnormal and overactivated inflammatory response is occasionally elicited by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and this hyperinflammation is associated with worse prognosis of COVID-19. Theoretically, one would expect patients with asthma to be at a greater risk of SARS-CoV-2 infection considering their increased susceptibility to common respiratory virus-associated exacerbations. Surprisingly, current data do not consistently suggest an increased prevalence of asthma among patients with COVID-19. Considering the high global prevalence of asthma, the characteristics of the disease and/or their conventional therapy might play a role in their potential defense against COVID-19. This may be attributed to the T helper type 2 immune response predominantly seen in patients with asthma. Likewise, asthma therapeutics, including corticosteroids and biologics, may in fact benefit the patients with asthma by alleviating the development of hyperinflammation. On the other hand, elevated IL-17 levels are characteristically seen in a subset of asthma patients with severe disease as well as in patients with COVID-19. Targeting the IL-17 pathway as a treatment strategy could plausibly alleviate acute respiratory distress syndrome (ARDS) in patients with COVID-19 and asthma demonstrating a predominant T helper type 17 response. A clinical trial including a drug targeting this pathway may thus, constitute a logical addition to the global pursuit for effective therapeutics against COVID-19. The complex interplay between the asthma endotypes and COVID-19 is not very well understood and will be discussed in this mini-review.

Immunogenicity risk assessment for biotherapeutics through in vitro detection of CD134 and CD137 on T helper cells

Biotherapeutics, which are biologic medications that are natural or bioengineered products of living cells, have revolutionized the treatment of many diseases. However, unwanted immune responses still present a major challenge to their widespread adoption. Many patients treated with biotherapeutics develop antigen-specific anti-drug antibodies (ADAs) that may reduce the efficacy of the therapy or cross-react with the endogenous counterpart of a protein therapeutic, or both. Here, we describe an in vitro method for assessing the immunogenic risk of a biotherapeutic. We found a correlation between clinical immunogenicity and the frequency with which a biotherapeutic stimulated an increase in CD134, CD137, or both cell surface markers on CD4+ T cells. Using high-throughput flow cytometry, we examined the effects of 14 biotherapeutics with diverse rates of clinical immunogenicity on peripheral blood mononuclear cells from 120 donors with diverse human leukocyte antigen class II-encoding alleles. Biotherapeutics with high rates of ADA development in the clinic had higher proportions of CD4+ T cells positive for CD134 or CD137 than biotherapeutics with low clinical immunogenicity. This method provides a rapid and simple preclinical test of the immunogenic potential of a new candidate biotherapeutic or biosimilar. Implementation of this approach during biotherapeutic research and development enables rapid elimination of candidates that are likely to cause ADA-related adverse events and detrimental consequences.

Prospects for severe asthma treatment

Biological drugs are approved to treat patients with severe uncontrolled asthma and are directed against mediators of type 2 immunity. These agents are effective in reducing the risk of exacerbation, maintaining asthma symptom control and reducing the need of systemic corticosteroids. Although biological drugs have revolutionized the management of the disease, to date there are no head-to-head studies across the current available molecules and there remains the need of specific biomarkers for the diagnosis, prognosis and response to treatment. Moreover, there is still an urgent need to identify further molecular targets to offer effective treatments for those patients who are not responsive to the currently available biological drugs, by moving upstream in the inflammatory cascade to inhibit multiple inflammatory pathways and/or identify effective nontype 2 immunity mechanisms.

Relationship between chemokines and T lymphocytes in the context of respiratory allergies (Review)

Allergic diseases have been classified in the last decades using various theories. The main classes of the newest classification in allergic respiratory diseases focus on the characterization of the endotype (which takes into account biomarkers related to determinant pathophysiological mechanisms) and of the phenotype (based on the description of the disease). Th2, Th1 and Th17 lymphocytes and the type of inflammatory response mediated by them represent the basis for Th2 and non-Th2 endotype classification. In addition, new lymphocytes were also used to characterize allergic diseases: Th9 lymphocytes, Th22 lymphocytes, T follicular helper cells (T_FH) lymphocytes and invariant natural killer T (iNKT) lymphocytes. In the last decade, a growing body of evidence focused on chemokines, chemoattractant cytokines, which seems to have an important contribution to the pathogenesis of this pathology. This review presents the interactions between chemokines and Th lymphocytes in the context of Th2/non-Th2 endotype classification of respiratory allergies.

The role of interleukin-17 in asthma: a protective response?

While there now exist effective treatments for type 2 high, eosinophilic asthma, there are no specific therapies for 40–50% of people with asthma with other phenotypes, which result from poorly understood underlying pathological mechanisms. One such pathology is neutrophilic inflammation, which has been associated with interleukin (IL)-17 family cytokines. Human genetic studies identified IL-17 polymorphisms associated with asthma; in murine models of allergic airways disease, IL-17A contributes to airway hyperresponsiveness, and in humans, elevated airway IL-17A levels are repeatedly observed in severe asthma. However, the directionality of this association is unknown, and the assumption that IL-17 cytokines drive disease pathology remains speculative. Here, we explore the evidence underlying the relationship between IL-17 and asthma, we review lessons learned from investigating IL-17 in other inflammatory diseases, and discuss the possibility that IL-17 may even be protective in asthma rather than pathogenic. We also critically examine the newly proposed paradigm of a reciprocal relationship between type 2 and type 17 airways inflammation. In summary, we suggest an association between IL-17 and asthma, but research is needed examining the diverse functions of these cytokines, their longitudinal stability, their response to clinical interventions, and for mechanistic studies determining whether they are protective or pathogenic.

IL-17 cytokines have been implicated in neutrophilic asthma by genetic, murine and human data. Here, previous studies are critiqued and the assumption their dominant role is pathogenic rather than protective of airway epithelial barrier integrity is challenged.http://bit.ly/3axB4Zs

Promises and challenges of biologics for severe asthma

Patients with severe asthma that remain uncontrolled incur significant medical burden and healthcare costs. Severe asthma is a heterogeneous airway disorder with complex pathophysiological mechanisms which can be broadly divided into type 2 (T2)-high and T2-low inflammatory pathways. Recent advances in asthma therapeutics with the advent of biologics have heralded an era of promising targeted therapy in this group of patients. The current available biologics, including anti-IgE mAb, anti-IL-5/IL-5R mAb and anti-IL-4Rα mAb, mainly target patients with an asthma endotype characterised by T2-high inflammation. While they have delivered positive outcomes in terms of reduction in exacerbations, improving lung function and quality of life, as well as reducing the dependence on oral corticosteroids, they have not functioned as the "panacea" as a significant proportion of patients do not respond completely to these targeted therapies. In addition, there is a lack of markers that can predict treatment response and clinicians are guided only by subjective asthma symptom scores. Suboptimal treatment response is common for individual patients. There has also been a dearth of effective targeted therapy for patients with T2-low asthma and treatment options remain limited for these patients. There is a pipeline of newer biologics targeting cytokines that operate at the interface between innate and adaptive immunity (e.g. IL-17A, thymic stromal lymphopoietin (TSLP), IL-25, IL-33, IL-32 and IL-36γ) with potential of modifying and reducing the severity of asthma. This commentary provides an overview of treatment with the current biologics and highlights the limitations, challenges and unmet needs in clinical management. We also summarise up-and-coming potential targets and therapeutic biologics for severe asthma.

Beyond type 2 cytokines in asthma - new insights from old clinical trials

Introduction: Human asthma is a heterogeneous disorder on molecular, pathological, and clinical levels. The paradigm of asthma as an allergic process driven by type 2 cytokines and mediators has led to targeted biologic therapies resulting in some clinical benefit in patient subsets. However, some patient subsets and clinical manifestations do not benefit from these interventions, thus redefining unmet needs. Clinical studies of type 2 directed therapies have identified new targets under investigation in clinical development; these include epithelial alarmins, non-type 2 cytokines, cytokine receptor signaling, mast cells and neuroinflammation.Areas covered: We consider lessons learned concerning asthma pathogenesis from observational studies and clinical trials of biologic agents that target type 2 mediators. We also provide a perspective on emerging therapeutic hypotheses to target processes independent of or orthogonal to type 2 inflammation in asthma.Expert opinion: Type 2 inflammation is continuous, not discrete, and is likely a modifier of underlying dysregulated airway physiology. Non-type 2 inflammatory mediators (e.g., IL17, IL6, IFNs), microbiome, alarmins (e.g., TSLP, IL33), mast cells and sensory neurons may represent orthogonal targets to type 2 mediators. There is a need to better match targets and outcome measures in biologically defined patient populations to appropriately test hypotheses in the clinic.

The emergence of new biologics for severe asthma

Patients with severe asthma experience severe symptoms and frequent exacerbations despite intensive treatment with inhaled and oral glucocorticoids. Biologics for severe asthma aim to reduce asthma-related and glucocorticoid-induced morbidity. Recently, new biologics targeting interleukin (IL)-5, IL-5 receptor and IL-4/IL-13, which are all cytokines involved in so-called type 2 airway inflammation, were approved for severe asthma. They show a reduction in exacerbation rate and an oral glucocorticoid-sparing effect. Studies with upstream biologics targeting alarmin cytokines such as thymic stromal lymphopoietin (TSLP) and IL-33 are underway, and newly designed bispecific antibodies targeting more than one pathway are in early phases of development. Such pathway-targeted add-on treatments will soon become standard of care for all patients with severe asthma.