Omalizumab, a novel anti-IgE therapy in allergic disorders

Bidirectional Transport of IgE by CD23 in the Inner Ear of Patients with Meniere's Disease

Meniere's disease (MD) is a disorder of the inner ear characterized by episodes of spontaneous vertigo, fluctuating hearing loss, and tinnitus. Recent studies have demonstrated that IgE may play a role in the pathogenesis of MD. Patients with MD (n = 103), acoustic neuroma (n = 5), and healthy subjects (n = 72) were recruited into the study. Serum from the participants was analyzed for IgE and type 2-related cytokines. IgE and CD23 expression levels in vestibular end organs of patients, C57BL/6 mice, or mouse HEI-OC1 cells were analyzed. Finally, the role of CD23 in IgE transcytosis was assessed using HEI-OC1 cells. Serum IgE was elevated in patients with MD and positively correlated with clinical symptoms. IL-4, IL-5, IL-10, IL-13, and CD23 levels were increased in patients with MD compared with the control group. In the transcytosis assay, mouse IgE was found to be bidirectionally transported across the HEI-OC1 cell monolayer. Additionally, CD23 downregulation using a small interfering RNA approach significantly reduced the efficiency of IgE transcytosis, suggesting that IgE is transported by CD23. Furthermore, exposure to IL-4 increased CD23 expression and enhanced IgE transcytosis in the HEI-OC1 cells and primary vestibular end organs. Our study indicated that IgE may play a role in the pathophysiology of MD. In addition, CD23-mediated IgE transcytosis in the hair cells may play a critical role in initiating inflammation in the inner ear. Thus, reducing the level of IgE may be a potentially effective approach for MD treatment.

Nanobodies-Useful Tools for Allergy Treatment?

In the last decade single domain antibodies (nanobodies, VHH) qualified through their unique characteristics have emerged as accepted and even advantageous alternative to conventional antibodies and have shown great potential as diagnostic and therapeutic tools. Currently nanobodies find their main medical application area in the fields of oncology and neurodegenerative diseases. According to late-breaking information, nanobodies specific for coronavirus spikes have been generated these days to test their suitability as useful therapeutics for future outbreaks. Their superior properties such as chemical stability, high affinity to a broad spectrum of epitopes, low immunogenicity, ease of their generation, selection and production proved nanobodies also to be remarkable to investigate their efficacy for passive treatment of type I allergy, an exaggerated immune reaction to foreign antigens with increasing global prevalence.

Effect of monoclonal antibody drug therapy on mucosal biomarkers in airway disease: A systematic review

BACKGROUND

Monoclonal antibody therapies have a growing role in treating refractory airway disease.

OBJECTIVE

The review aimed to summarize the response of respiratory mucosa to monoclonal antibody treatments in inflammatory airway conditions.

DESIGN

We conducted a systematic review including risk of bias assessment.

DATA SOURCES

MEDLINE, EMBASE and PubMed from 1 January 2000 to 16 November 2019 were searched.

ELIGIBILITY CRITERIA

Eligible studies assessed the immunological and histological response of airway mucosa to monoclonal antibody therapy compared with baseline or a comparison group in patients with respiratory diseases (asthma, chronic rhinosinusitis and allergic rhinitis). Any prospective interventional studies, including randomized controlled trials (RCTs) and single-arm trials, were eligible.

RESULTS

There were 4195 articles screened, and full-text analysis produced n = 11 studies with extractable data. Nine were RCTs, and two were single-arm trials. These studies focused on asthma (n = 9 articles), chronic rhinosinusitis (n = 1) and allergic rhinitis (n = 1). Five monoclonal antibody drugs were assessed (omalizumab, mepolizumab, dupilumab, benralizumab and tralokinumab). Risk of bias was low (n = 6) or unclear (n = 3) in the RCTs and moderate in the single-arm trials. Omalizumab reduced the mucosal concentration of its target, IgE. Dupilumab reduced the concentration of one of its targets, IL-13, but not IL-4. Omalizumab, mepolizumab and benralizumab reduced tissue eosinophil cell density. Dupilumab decreased mucosal eosinophil granule proteins. Tralokinumab did not affect airway mucosa.

CONCLUSIONS

Knowledge of the expected biological response of monoclonal antibody therapy on biomarkers in disease tissue provides an important supplement to data about clinical outcomes. An understanding of the biological effect is essential to identify likely responders, reasons for treatment failure and necessary adjustments to monoclonal antibody treatment. Further investigation into the effect of monoclonal antibody therapy on disease mucosa and more precise endotyping are required to move closer to achieving personalized medicine.

Generation of IgE-specific cytotoxic T lymphocytes as a novel immunotherapeutic approach for the treatment of allergic asthma

INTRODUCTION

Overproduction of immunoglobulin E (IgE) by a subset of B cells plays a key role in the pathogenesis of allergic asthma. Anti-IgE monoclonal antibodies have been successfully used to treat the disease, but long-term application is required.

METHODS

For this study, cytotoxic T lymphocytes (CTLs) against IgE-producing B cells were generated ex vivo by stimulating naive CD8 T cells with IgE-derived peptides presented by Drosophila-derived artificial antigen-presenting cells. Based on the treatment of allergic asthma in mice, the inhibitive effect of this CTL on IgE responses and airway inflammation was determined with the enzyme-linked immunosorbent assay and histochemical method.

RESULTS

The IgE-specific CTLs effectively lysed target cells in vitro, while the adoptively transferred CTLs specifically inhibited IgE responses and airway inflammation in an asthmatic mouse model. The effect of IgE-specific CTLs is MHC (major histocompatibility complex) Class I-restricted and requires the expression of perforin.

CONCLUSION

IgE-specific CTLs generated ex vivo may provide a novel treatment for allergic asthma and lead to a new therapy for other immunological disorders.

Short- and long-term real-world effectiveness of omalizumab in severe allergic asthma: systematic review of 42 studies published 2008-2018

INTRODUCTION

Omalizumab is a recombinant monoclonal anti-IgE antibody approved in the US as add-on treatment in moderate-to-severe allergic asthma (in severe allergic asthma [SAA] in Europe). A 2016 review of 24 real-world effectiveness studies in SAA published between 2008-2015 concluded that omalizumab was associated with significant improvements in objective and subjective outcomes with benefits extending beyond 2 years. Several new real-world studies have been published since, bringing the total to 42 studies. Areas covered: This systematic review of 42 studies published since 2008 updates and extends the 2016 review on the real-word evidence on omalizumab in SAA. It offers greater granularity as to time windows within which outcomes are reported and includes studies extending well beyond 4 years post omalizumab initiation. Expert commentary: This review firmly establishes the short-term effectiveness of omalizumab in adolescent and adult patients with SAA at 1 year, and provides strong evidence of long-term effectiveness up to 4 years and emergent evidence of effectiveness beyond 4 years. In the aggregate, these 42 studies underscore the long-term effectiveness of omalizumab in terms of: reducing exacerbations and symptoms, achieving asthma control, improving lung function, enhancing quality of life, decreasing emergency department visits and hospitalizations, and promoting concomitant medication-sparing.

Improvement in the quality of life of patients with chronic spontaneous urticaria treated with omalizumab in real life

OBJECTIVE

Evaluation of the impact on the quality of life (QOL) relating to health in patients with chronic urticaria (CSU) treated with omalizumab.

METHOD

Longitudinal descriptive observational study of quality of life based on18 patients with chronic urticaria ≥12 years treated with omalizumab. Changes in QOL examined at 1 month (T1), at 6 months (T6) and 12 months (T12), by: Visual Analogical Scale (UAS), specific urticaria QOL questionnaire (CU-Q2oL), general health questionnaire (SF-36) and activity of urticaria questionnaire (Score UAS7).

RESULTS

The most disabling symptoms for patients were: pruritus (61.1%); decrease in health and physical activity (55.5%), wheals, swelling and nervousness (50%); depression and shame of marks (38.89%); side effects to drugs (33.33%); sleepiness and tiredness (27.78%); work (22.22%); "choosing clothes and pain" 16.67% and social relations (11.11%). Statistically significant differences were observed in T1, T6 and T12. In T1, UAS -4.72 (p=.001); CU-Q2oL -16.38 (p<.001); SF-36 15.44 (p=.006); UAS7 wheals -7.27 (p=.001), UAS7 pruritus -8.72 (p=.003). In T6, UAS -4.26 (p=.001); CU-Q2oL -18.94 (p<.001); SF-36 15.41 (p<.001); UAS7 wheals -7.41 (p=.001), UAS7 pruritus -7.11 (p=.001). In T12 UAS -9.61 (p=.004); CU-Q2oL -21.38 (p=.01); SF-36 17.53 (p=.04); UAS7 wheals -8.23 (p=.004), UAS7 pruritus -10.69 (p=.004).

CONCLUSIONS

There was a very good response in T1, which was maintained in T6 and T12. Patients with chronic urticaria treated with omalizumab presented good results with a reduction of CUE activity and improvement of their QOL.

'Real-life' effectiveness studies of omalizumab in adult patients with severe allergic asthma: systematic review

We reviewed 24 'real-life' effectiveness studies of omalizumab in the treatment of severe allergic asthma that included 4117 unique patients from 32 countries with significant heterogeneity in patients, clinicians and settings. The evidence underscores the short- and long-term benefit of anti-IgE therapy in terms of the following: improving lung function; achieving asthma control and reducing symptomatology, severe exacerbations and associated work/school days lost; reducing healthcare resource utilizations, in particular hospitalizations, hospital lengths of stay and accident specialist or emergency department visits; reducing or discontinuing other asthma medications; and improving quality of life - thus confirming, complementing and extending evidence from randomized trials. Thus, omalizumab therapy is associated with signal improvements across the full objective and subjective burden of illness chain of severe allergic asthma. Benefits of omalizumab may extend up to 2-4 years, and the majority of omalizumab-treated patients may benefit for many years. Omalizumab has positive short- and long-term safety profiles similar to what is known from randomized clinical trials. Initiated patients should be monitored for treatment response at 16 weeks. Those showing positive response at that time are highly likely to show sustained treatment response and benefit in terms of clinical, quality of life and health resource utilization outcomes.

Asthma: a simple concept but in reality a complex disease

BACKGROUND

Asthma is a disorder of the conducting airways that contract too easily and too much to cause variable airflow obstruction with symptoms of wheeze, cough, chest tightness and shortness of breath. Based on this knowledge, initial treatments were directed to dilating the contracted airways with anticholinergic and adrenergic drugs. The recognition that allergic-type inflammation underlay the hyperresponsive airways in asthma led to the introduction of anti-inflammatory drugs such as sodium cromoglicate and corticosteroids. Over the 2 decades that followed, these drugs have been progressively improved by increasing their therapeutic index and duration of action.

METHODS

A review of the recent literature indicates that since the 1980s, the explosive increase in knowledge of the cell and mediator mechanisms of asthma has only led to modest improvements in therapy including the introduction of leukotriene modifiers and a blocking monoclonal antibody against IgE. Indeed, biologics targeting allergic cytokines and effector cells have on the whole proven disappointing despite initial promise being shown in animal models.

RESULTS

Part of the difficulty lies in the oversimplified concept that asthma is only driven by allergic processes when in reality there are many environmental causes and triggers and the view that it is a homogeneous disorder only varying in severity.

CONCLUSIONS

The more recent views that asthma is a complex disorder made up of different subtypes with differing causes, treatment responses and natural histories creates a new opportunity for stratified medicine in which therapies acting upstream selectively target specific disease subtypes identified by specific diagnostic biomarkers.

Severe asthma and the omalizumab option

Atopic diseases and asthma are increasing at a remarkable rate on a global scale. It is now well recognized that asthma is a chronic inflammatory disease of the airways. The inflammatory process in many patients is driven by an immunoglobulin E (IgE)-dependent process. Mast cell activation and release of mediators, in response to allergen and IgE, results in a cascade response, culminating in B lymphocyte, T lymphocyte, eosinophil, fibroblast, smooth muscle cell and endothelial activation. This complex cellular interaction, release of cytokines, chemokines and growth factors and inflammatory remodeling of the airways leads to chronic asthma. A subset of patients develops severe airway disease which can be extremely morbid and even fatal. While many treatments are available for asthma, it is still a chronic and incurable disease, characterized by exacerbation, hospitalizations and associated adverse effects of medications. Omalizumab is a new option for chronic asthma that acts by binding to and inhibiting the effects of IgE, thereby interfering with one aspect of the asthma cascade reviewed earlier. This is a humanized monoclonal antibody against IgE that has been shown to have many beneficial effects in asthma. Use of omalizumab may be influenced by the cost of the medication and some reported adverse effects including the rare possibility of anaphylaxis. When used in selected cases and carefully, omalizumab provides a very important tool in disease management. It has been shown to have additional effects in urticaria, angioedema, latex allergy and food allergy, but the data is limited and the indications far from clear. In addition to decreasing exacerbations, it has a steroid sparing role and hence may decrease adverse effects in some patients on high-dose glucocorticoids. Studies have shown improvement in quality of life measures in asthma following the administration of omalizumab, but the effects on pulmonary function are surprisingly small, suggesting a disconnect between pulmonary function, exacerbations and quality of life. Anaphylaxis may occur rarely with this agent and appropriate precautions have been recommended by the Food and Drug Administration (FDA). As currently practiced and as suggested by the new asthma guidelines, this biological agent is indicated in moderate or severe persistent allergic asthma (steps 5 and 6).

Emerging drugs for ocular allergy

Ocular allergy is a common condition that usually affects the conjunctiva of the eye and is, therefore, often referred to as allergic conjunctivitis. The severity of the disease can range from mild itching and redness, as seen in seasonal allergic conjunctivitis, to the more severe, sight-threatening forms such as vernal and atopic keratoconjunctivitis. The central mechanism in the pathogenesis of these diseases is IgE-mediated mast cell degranulation and activation of T lymphocytes, eosinophils and conjunctival structural cells. The pharmacotherapy of allergic conjunctivitis consists of several classes of drugs: antihistamines, mast cell stabilisers, dual-acting agents and corticosteroids. None of the available drugs completely abolishes the development of ocular allergy. For this reason, new topical antiallergic/anti-inflammatory agents are currently and continually under clinical trials. This review provides a background to ocular allergic diseases, the medical need for therapy and current and potential new treatments.

Immunomodulation in asthma: a distant dream or a close reality?

The search for new treatments of asthma or any other disease for that matter is an infinite exercise. The scope for discovering new forms of treatment has increased now more than ever due to a better understanding of the molecular pathogenesis of the disease. Regulation of biomolecular or immunological events could occur at numerous points in the disease pathogenesis. This review describes the strategies to regulate the inappropriate immune responses that are elicited after exposure to an allergen. One such successful therapy is treatment with omalizumab, the anti-IgE antibody. Other therapies include cytokine antagonists, transcription factor antagonists, immunostimulatory DNA therapy, cytokine therapy and anti-T cell strategies. All these agents have been shown to be promising and could serve as an alternative approach to the treatment of asthma and maybe other allergic diseases.

Convergent Recognition of the IgE Binding Site on the High-Affinity IgE Receptor

Two structurally distinct classes of peptides were recently identified by phage display that bind the high-affinity IgE receptor, FcepsilonRI, and block IgE binding and subsequent receptor activation. Both classes adopt highly stable structures in solution, one forming a beta hairpin, with the other forming a helical "zeta" structure. Despite these differences, the two classes bind competitively to the same site on the receptor. Structural analyses of both peptide-receptor complexes by NMR spectroscopy and/or X-ray crystallography reveal that the unrelated peptide scaffolds have nevertheless converged to present a similar three-dimensional surface to interact with FcepsilonRI and that their modes of interaction share a key feature of the IgE-FcepsilonRI complex, the proline/tryptophan sandwich.

A Monoclonal Antibody to α1β1 Blocks Antigen-induced Airway Responses in Sheep

The integrin alpha1beta1 (very late antigen-1; CD49a/CD29) is a major adhesion receptor for collagen I, IV, and VI, and its induced expression on activated monocytes and lymphocytes plays a central role in their retention and activation at inflammatory sites in autoimmune pathologies. However, the role of alpha1beta1 in allergic settings has not been explored. In this study, we show that a single 45-mg dose of aerosolized monoclonal antibody AQC2 to the alpha1 chain of human and sheep very late antigen-1, given 30 minutes before challenge, blocks both the allergen-induced late response and the associated airway hyperresponsiveness, functional indicators of allergen-induced inflammation, in sheep. AQC2 does not affect the early response. Consistent with these effects, AQC2 tended to reduce the cell response associated with local antigen instillation. An isotype-matched control antibody had no protective effects. Two humanized versions of AQC2, a wild-type IgG1 and an aglycosyl form of the same monoclonal antibody, which has reduced Fc receptor-mediated effector functions, are equally effective in blocking the antigen-induced late response and airway hyperresponsiveness in the sheep model. These data suggest that mononuclear leukocyte adhesion-dependent pathologies contribute to allergic lung disease and provide proof-of-concept that antagonists of alpha1 integrins may be useful in preventing these events.

Pharmacology of airway inflammation in asthma and COPD

The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term treatment. Although inhaled glucocorticoids are highly effective in controlling airway inflammation in asthma, they are ineffective in the small group of patients with glucocorticoid-dependent and -resistant asthma. With very few exceptions, COPD is caused by tobacco smoking, and smoking cessation is the only truly effective treatment of COPD available. Current pharmacological treatment of COPD is unsatisfactory, as it does not significantly influence the severity of the disease or its natural course. Glucocorticoids are scarcely effective in COPD patients without concomitant asthma. Bronchodilators improves symptoms and quality of life, in COPD patients, but, with the exception of tiotropium, they do not significantly influence the natural course of the disease. Theophylline is the only drug which has been demonstrated to have a significant effect on airway inflammation in patients with COPD. Here we review the pharmacology of currently used antiinflammatory therapies for asthma and COPD and their proposed mechanisms of action. Recent understanding of disease mechanisms in severe steroid-dependent and -resistant asthma and in COPD, has lead to the development of novel compounds, which are in various stages of clinical development. We review the current status of some of these new potential drugs.

Ocular Allergic Disease: Mechanisms, Disease Sub-types, Treatment

Ocular allergy refers to a variety of hypersensitivity disorders that affect the lid, conjunctiva, and/or cornea. Its incidence is estimated at over 20% of the general population in the United States. This review will discuss the various forms of ocular allergy, their pathophysiology, clinical presentation, and treatment. New frontiers in mechanisms, therapy, and management in the office are emphasized throughout.

Peptide immunotherapy for allergic disease

The only disease-modifying treatment available for IgE-mediated disease is specific immunotherapy, but the retention of B cell epitopes in whole allergen preparations confers a risk of IgE-mediated systemic reactions to their administration. Compelling evidence for the central role of T cells in allergic disease suggests that IgE-binding epitopes could be removed from such therapy, improving safety without affecting efficacy. Short, allergen-derived peptides lack the conformational determinants required for IgE crosslinking and are, therefore, an attractive therapeutic possibility. However, human leukocyte antigen (HLA) polymorphism means that T cell peptide epitopes present a huge diversity, which makes the design of peptide-based vaccines problematic. Over the past 10 years, advances in our understanding of epitope selection and major histocompatibility complex (MHC)-peptide-T cell receptor interactions have taken this therapy forward to early clinical trials with human volunteers.

The role of anti-IgE therapies in the treatment of asthma

The prevalence of asthma, a chronic inflammatory disease often linked to allergy, is on the increase. The introduction of a blocking anti-IgE monoclonal antibody (omalizumab) as a new therapy has not only confirmed the pathogenic role of IgE in asthma but has also provided a novel therapy for a chronic severe disease where there are limited therapeutic options.

The structure of Fc receptor/Ig complexes: considerations on stoichiometry and potential inhibitors

Recently, Fc receptors for immunoglobulins moved further into the focus of pure and applied research as a role in the induction and development of autoimmune diseases and allergies is becoming more probable. Indeed by connecting the humoral with the cellular immune response FcRs possess an important role in the immune system in which the initial, crucial step is the binding of an immunoglobulin to the cell bound receptor. Thereafter a variety of effector functions depending on the cell and the receptor is triggered. This key event could recently be visualised with the solution of the crystal structure of a human Fc receptor in complex with its native ligand the Fc fragment of IgG1. In this paper the reasons for a 1:1 stoichiometry between Fc receptor and Fc Fragment and the medical applications of potential inhibitors of complex formation are highlighted.