Mepolizumab and Benralizumab in Severe Eosinophilic Asthma: Preliminary Results of a Proteomic Study.

Benralizumab and mepolizumab are new therapies for severe eosinophilic asthma. They are both humanized IgG antibodies, targeting the IL-5 receptor and IL-5, respectively, suppressing the corresponding pathways. No specific biomarkers have been proposed to evaluate treatment response to benralizumab or mepolizumab. The aim of this proteomic study was to compare serum protein profiles of patients with severe eosinophilic asthma before and after anti-IL5 or anti-IL5R therapies. Proteomic analysis highlighted 22 differently abundant spots. Among the proteins identified, CAYP1, A1AT and A2M expression was significantly modified in both groups of patients after therapies while ceruloplasmin showed a significant modification in the group of benralizumab treatment. These differentially expressed proteins could be potential biomarkers of response to mepolizumab and benralizumab treatments and need further evaluation.

Pediatric use of omalizumab for allergic asthma.

INTRODUCTION: Severe pediatric asthma is associated with significant morbidity as well as with a high economic burden. It represents a heterogeneous disease with multiple clinical phenotypes. Currently, physicians are facing the challenge to provide a 'personalized medicine approach', which is tailored to the diverse pathomechanisms underlying clinical presentations. Three main endotypes of airway inflammation have been described in children with severe asthma. While neutrophilic and paucigranulocytic inflammatory patterns are quite uncommon in childhood, type Th2 inflammation asthma with elevated IgE is the most prevalent in pediatric asthma. Considering the pivotal role of IgE in type Th2 inflammation asthma, the blockade of IgE using anti-IgE therapy represents a potent therapeutic option for severe pediatric asthma in children. AREAS COVERED: This review aims to focus on the role of omalizumab as a treatment option in pediatric patients (aged six years and above) with severe allergic asthma. EXPERT OPINION: The clinical efficacy and safety of omalizumab for the treatment of pediatric asthma is well documented in clinical trials and observational studies. Further studies are still required to characterize the potential benefit of anti-IgE therapy in airway remodeling, identify additional biomarkers of clinical response and address current unmet needs, including the limit on omalizumab use in children younger than six years.

Development and validation of a new IgE-Tolerant ELISA method for quantifying serum concentration of omalizumab.

BACKGROUND: Omalizumab is effectively used in asthma therapy, but ELISA methods used for omalizumab determination in blood from asthma patients may be interfered by the pre-existing IgE. OBJECTIVE: To reduce the effect of pre-existing IgE on the omalizumab determination, the authors proposed a novel ELISA that can eliminate pre-existing IgE with by acid dissociation. METHOD: The method was developed by dissociating the IgE-omalizumab complex with glacial acetic acid, and bio-IgE was added to bind the free omalizumab in serum, then bio-IgE-complex was captured by the immobilized streptavidin and detected by HRP-conjugated mouse anti-human IgG. Then a full validation of standard curve fitness, precision, accuracy, dilutional linearity, specificity, selectivity, stability, hook effect, and parallelism was performed. At last, the method was used in two studies in compliance with Good Laboratory Practice. RESULTS: Correlation coefficient R2 obtained from each calibration curve was 0.999 or 1.000 in the detection range of 0.1 µg/mL to 12.8 µg/mL. Results of precision, accuracy, dilutional linearity, specificity, selectivity, stability, hook effect, and parallelism were acceptable according to the ICH guideline M10. The method was successfully used in omalizumab determination in serum from 20 monkeys treated with 150 mg/kg omalizumab. CONCLUSIONS: In conclusion, by dissociating IgE-omalizumab complex, the authors proposed for the first time a new validated IgE-tolerant ELISA assay to determine omalizumab concentration in serum samples.

Hypersensitivity and adverse reactions to biologics for asthma and allergic diseases.

Introduction: The development of new biologic agents has provided definite therapeutic advances but, like with any new medications, safety remains a concern.Areas covered: Using PubMed, we reviewed the literature on the adverse effects (AE) to five biologics approved for asthma and/or allergic diseases: one anti-IgE (omalizumab), three anti-IL5 (mepolizumab, reslizumab, benralizumab), and one anti-IL4 (dupilumab).Expert opinion: Biologic agents approved for asthma and allergic diseases are generally safe. Most common AE are benign and tolerated, though long-term safety is lacking for most of them. A slightly increased risk of anaphylaxis to omalizumab and reslizumab required the inclusion of a black box warning, informing the patient, the need for post-injection observation period, and the provision of epinephrine autoinjectors for self-administration when needed. Hypersensitivity reactions, mainly urticaria and very rarely serum sickness have occurred.

Regulatory T Cells in Severe Persistent Asthma in the Era of Monoclonal Antibodies Target Therapies.

Asthma is an immunoinflammatory disease characterized by bronchial hyper-reactivity to different external stimuli. New monoclonal target treatments have been developed, but few studies have investigated the role of regulatory T cells in severe asthma and the modulatory effect of biological therapy on regulatory T cell functions. Their dysfunction may contribute to the development and exacerbation of asthma. Here we review the recent literature on the potential immunological role of regulatory T cells in the pathogenesis of severe asthma. The analysis of the role of regulatory T cells was performed in terms of functions and their possible interactions with mechanisms of action of the novel treatment for severe asthma. In an era of biological therapies for severe asthma, little data is available on the potential effects of what could be a new therapy: monoclonal antibody targeting of regulatory T cell numbers and functions.

Mangiferin suppresses allergic asthma symptoms by decreased Th9 and Th17 responses and increased Treg response.

Mangiferin is the major bioactive ingredient in the leaves of Mangifera indica L., Aqueous extract of such leaves have been traditionally used as an indigenous remedy for respiratory diseases including cough and asthma in Traditional Chinese Medicine. Mangiferin was shown to exert its anti-asthmatic effect by modulating Th1/Th2 cytokines imbalance via STAT6 signaling pathway. However, compelling evidence indicated that subtypes of T helpers and regulatory T cells other than Th1/Th2 were also involved in the pathogenesis of asthma. In current study, we investigated the effects of mangiferin on the differentiation and function of Th9, Th17 and Treg cells in a chicken egg ovalbumin (OVA)-induced asthmatic mouse model. Mangiferin significantly attenuated the symptoms of asthma attacks, reduced the total number of leukocytes, EOS and goblet cells infiltration in lung. Simultaneously, treatment with mangiferin remarkably decreased the proportion of Th9 and Th17 cells; reduced the levels of IL-9, IL-17A; inhibited the expression of PU.1 and RORγt in lung. However, the proportion of Treg cells, the expression of IL-10, TGF-ß1 and Foxp3 were increased by mangiferin. Our data suggest that mangiferin exerted anti-asthmatic effect through decreasing Th9 and Th17 responses and increasing Treg response in OVA-induced asthmatic mouse model.

Important roles of CD32 in promoting suppression of IL-4 induced immune responses by a novel anti-IL-4Rα therapeutic antibody.

Asthma is characterized by airway hyperresponsiveness and inflammation, as well as underlying structural changes to the airways. Interleukin-4 (IL-4) is a key T-helper type 2 (Th2) cytokine that plays important roles in the pathogenesis of atopic and eosinophilic asthma. We developed a novel humanized anti-IL-4Rα antibody that can potently inhibit IL-4/IL-13-mediated TF-1 cell proliferation. Using monocytes isolated from human peripheral blood mononuclear cells (PBMCs), we revealed a critical role of CD32 in modulating the immune responses of monocytes in response to blockade of IL-4Rα signaling pathway. We, therefore, devised a new strategy to increase the efficacy of the anti-IL-4Rα monoclonal antibody for the treatment of asthma and other atopic diseases by co-engaging CD32 and IL-4Rα on monocytic cells by choosing IgG classes or Fc mutations with higher affinities for CD32. The antibody with selectively enhanced affinity for CD32A displayed superior suppression of IL-4-induced monocytes' activities, including the down-regulation of CD23 expression. Intriguingly, further analysis demonstrated that both CD32A and CD32B contributed to the enhancement of antibody-mediated suppression of CD23 expression from monocytes in response to blockade of IL-4Rα signaling. Furthermore, inhibition of IgE secretion from human PBMC by the antibody variants further suggests that the complex allergic inflammation mediated by IL-4/IL-4Rα signaling might result from a global network where multiple cell types that express multiple FcγRs are all involved, of which CD32, especially CD32A, is a key mediator. In this respect, our study provides new insights into designing therapeutic antibodies for targeting Th2 cytokine-mediated allergic pathogenesis.

Efficacy of an Inhaled IL-13 Antibody Fragment in a Model of Chronic Asthma.

RATIONALE: IL-13 is an important cytokine implicated in the pathogenesis of allergic asthma and is an attractive target for an inhaled therapeutic. OBJECTIVE: To investigate the efficacy of CDP7766, a nebulized inhaled anti-IL-13 monoclonal antibody Fab fragment, in a model of allergic asthma in cynomolgus macaques naturally sensitized to Ascaris suum. METHODS: CDP7766 was nebulized using a vibrating-membrane nebulizer on the basis of eFlow technology. The aerosol generated was analyzed to determine the particle size profile and the biophysical and functional properties of CDP7766. Nebulized CDP7766 (0.1-60 mg/animal, once daily for 5 d) was delivered via the inhaled route. MEASUREMENTS AND MAIN RESULTS: The investigational eFlow nebulizer used in this study generated a respirable aerosol of CDP7766 with no evidence of degradation, loss of potency, aggregation, or formation of particulates. Inhaled CDP7766 was well tolerated in the model (no adverse effects related to local irritation) and significantly inhibited BAL allergen-induced cytokine and chemokine upregulation (60 mg vs. vehicle: eotaxin-3, P < 0.0008; MIP [macrophage inflammatory protein]-1ß, IL-8, IFN-γ, P ≤ 0.01). CDP7766 significantly inhibited the increase in pulmonary resistance stimulated by inhaled allergen, measured 15 minutes and 24 hours after allergen challenge. CONCLUSION: Inhaled CDP7766 potently inhibited the function of IL-13 generated during the airway response to inhaled allergen in cynomolgus macaques, demonstrating the potential of inhaled anti-IL-13 therapeutics for the treatment of allergic asthma.

Selection of a Ligand-Binding Neutralizing Antibody Assay for Benralizumab: Comparison with an Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) Cell-Based Assay.

Assessment of anti-drug antibodies (ADAs) for neutralizing activity is important for the clinical development of biopharmaceuticals. Two types of neutralizing antibody (NAb) assays (competitive ligand-binding assay [CLBA] and cell-based assay [CBA]) are commonly used to characterize neutralizing activities. To support the clinical development of benralizumab, a humanized, anti-interleukin-5 receptor α, anti-eosinophil monoclonal antibody, we developed and validated a CLBA and a CBA. The CLBA and CBA were compared for sensitivity, drug tolerance, and precision to detect NAbs in serum samples from clinical trials. The CLBA was more sensitive (27.1 and 37.5 ng/mL) than the CBA (1.02 and 1.10 µg/mL) in detecting NAbs to benralizumab for the polyclonal and monoclonal ADA controls, respectively. With the same polyclonal ADA control, the CLBA detected 250 ng/mL of ADA in the presence of 100 ng/mL of benralizumab, whereas the CBA detected 1.25 µg/mL of ADA in the presence of 780 ng/mL of benralizumab. In 195 ADA-positive samples from 5 studies, 63.59% (124/195) and 16.9% (33/195) were positive for NAb as measured by the CLBA and the CBA, respectively. ADA titers were strongly correlated (Pearson's correlation coefficient r = 0.91; n = 195) with CLBA titers. Moreover, the CLBA titer correlated with CBA percentage inhibition in the CBA-positive samples (Spearman's coefficient r = 0.50; n = 33). Our data demonstrated advantages of the CLBA in various aspects and supported the choice of the CLBA as a NAb assay for the phase III trials.

Targeted anti-IL-13 therapies in asthma: current data and future perspectives.

INTRODUCTION: The identification of patients with severe asthma who will benefit from a personalized management approach remains an unmet need. Interleukin-13 (IL-13) is a cytokine possessing a significant role in asthma pathogenesis and progression of disease. Humanised monoclonal antibodies against IL-13 and IL-13 and IL-4 receptors are mainly proposed as add-on therapy in patients with TH2-high inflammation with uncontrolled asthma despite maximum therapy. AREAS COVERED: The role of IL-13 in airway inflammation in severe asthma, the targeted anti-IL-13 therapies and biomarkers that predict response to anti-IL-13 treatment are discussed. EXPERT OPINION: New effective individualized therapies in severe asthma are urgently needed to block specific inflammatory pathways using monoclonal antibodies. Studies on anti-IL-13 therapies showed that asthmatic patients could benefit from this novel targeted therapy as far as lung function and exacerbation rate are concerned. TH2-high and especially periostin-high groups of asthmatics with moderate-to-severe uncontrolled asthma seem to compose the group that could benefit from anti-IL-13 therapy. Targeting IL-13 alone may not be sufficient to achieve asthma control. Inhibition of IL-13 and IL-4 with mabs may be more encouraging and patients will probably have additional benefits from these therapeutic interventions because of IL-13/IL-4 overlapping actions in asthma pathophysiology.

Severe eosinophilic asthma: from the pathogenic role of interleukin-5 to the therapeutic action of mepolizumab.

Mepolizumab is an anti-interleukin-5 (IL-5) humanized monoclonal antibody that has been recently approved as an add-on biological treatment for severe eosinophilic asthma, by both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Moreover, mepolizumab is also currently included within the step 5 of the Global Initiative for Asthma guidelines, as an add-on therapy for severe uncontrolled asthma. The relevant therapeutic benefits detectable in patients with refractory eosinophilic asthma receiving mepolizumab depend on the pivotal pathogenic role played by IL-5 in these subjects. Indeed, IL-5 is the key cytokine responsible for maturation, activation, proliferation, and survival of eosinophils. Therefore, IL-5 represents a strategic molecular target for anti-eosinophilic treatments. By selectively inhibiting the biological actions of IL-5, mepolizumab provides a valuable therapeutic option for patients with severe eosinophilic asthma, refractory to standard treatments including inhaled and even systemic corticosteroids. In particular, the very important advantages linked to the use of mepolizumab in these difficult-to-treat asthmatic individuals have been well documented by several different trials performed worldwide.

Blomia tropicalis allergen 5 (Blo t 5) T-cell epitopes and their ability to suppress the allergic immune response.

Blomia tropicalis is the major asthma allergen in the tropics comparable to Dermatophagoides pteronyssinus. However, little is known about the B. tropicalis epitopes recognized by T cells. Our aim was to identify the T-cell epitopes in the major B. tropicalis allergen, Blo t 5, and investigate the potential of the corresponding peptides to inhibit the allergic inflammatory lung response. C57BL/6 mice were immunized with plasmid DNA encoding Blo t 5 and T-cell epitopes identified using the interferon-γ ELISPOT assay with 15-mer overlapping peptides. C57BL/6 mice were sensitized with bone-marrow-derived dendritic cells (BMDC) pulsed with Blo t 5 allergen followed by intranasal Blo t 5 challenge. Two H-2b restricted epitopes (Bt576-90 and Bt5106-115 ) were recognized by CD4 T cells specific for Blo t 5, but no CD8 epitopes were identified. In mice sensitized with Blo t 5-pulsed BMDC and challenged with intranasal Blo t 5 Bt576-90 and Bt5106-115 , peptide-specific CD4 T cells were found to secrete the T helper type 2 cytokines interleukin-5 and interleukin-13. Intradermal administration of synthetic peptides encoding the identified T-cell epitopes suppressed allergic airway inflammation to further allergen challenges. Hence, we have identified novel CD4 T-cell epitopes specific for Blo t 5 and demonstrated that these peptides could be employed therapeutically to suppress the T-cell response in a murine model of allergic airway inflammation.

Extracorporeal IgE Immunoadsorption in Allergic Asthma: Safety and Efficacy.

BACKGROUND: Prevention of IgE-binding to cellular IgE-receptors by anti-IgE (Omalizumab) is clinically effective in allergic asthma, but limited by IgE threshold-levels. To overcome this limitation, we developed a single-use IgE immunoadsorber column (IgEnio). IgEnio is based on a recombinant, IgE-specific antibody fragment and can be used for the specific extracorporeal desorption of IgE. OBJECTIVE: To study safety and efficacy of IgEnio regarding the selective depletion of IgE in a randomized, open-label, controlled pilot trial in patients with allergic asthma and to investigate if IgEnio can bind IgE-Omalizumab immune complexes. METHODS: Fifteen subjects were enrolled and randomly assigned to the treatment group (n=10) or to the control group (n=5). Immunoadsorption was done by veno-venous approach, processing the twofold calculated plasma volume during each treatment. A minimum average IgE-depletion of 50% after the last cycle in the intention-to-treat population was defined as primary endpoint. Safety of the treatment was studied as secondary endpoint. In addition, possible changes in allergen-specific sensitivity were investigated, as well as clinical effects by peak flow measurement and symptom-recording. The depletion of IgE-Omalizumab immune complexes was studied in vitro. The study was registered at clinicaltrials.gov (NCT02096237) and conducted from December 2013 to July 2014. RESULTS: IgE immunoadsorption with IgEnio selectively depleted 86.2% (±5.1% SD) of IgE until the end of the last cycle (p<0.0001). Removal of pollen allergen-specific IgE was associated with a reduction of allergen-specific basophil-sensitivity and prevented increases of allergen-specific skin-sensitivity and clinical symptoms during pollen seasons. IgEnio also depleted IgE-Omalizumab immune complexes in vitro. The therapy under investigation was safe and well-tolerated. During a total of 81 aphereses, 2 severe adverse events (SAE) were recorded, one of which, an episode of acute dyspnea, possibly was related to the treatment and resolved after administration of antihistamines and corticosteroids. CONCLUSIONS: This pilot study indicates that IgE immunoadsorption with IgEnio may be used to treat patients with pollen-induced allergic asthma. Furthermore, the treatment could render allergic patients with highly elevated IgE-levels eligible for the administration of Omalizumab and facilitate the desorption of IgE-Omalizumab complexes. This study was funded by Fresenius Medical Care Deutschland GmbH, Bad Homburg, Germany.

The effect of inhaled inactived Mycobacterium phlei as a treatment for asthma.

Allergic asthma is a chronic airway disorder characterized by airway inflammation, mucus hypersecretion, and airway hyperresponsiveness (AHR). A murine model of asthma was used to examine the antiasthmatic effect of inhaled inactived Mycobacterium phlei (M. phlei). AHR, neutrophil levels, eosinophil levels and levels of interleukin (IL)­17 and IL­23 receptor (IL­23R) were monitored. The results demonstrated that inactivated M. phlei alleviates the IL­17+γδT cell­mediated immune response and attenuates airway inflammation and airway hyperresponsiveness in the asthmatic murine lung, partially through inhibiting the expression of IL­23R. In conclusion, inactivated M. phlei may be an effective antiasthmatic treatment, regulating IL­17­producing Î³Î´T (IL­17+γδT) cell­mediated airway inflammation and airway hyperresponsiveness to relieve the symptoms of mice with asthma.

The safety of monoclonal antibodies in asthma.

INTRODUCTION: In the last two decades the knowledge of the mechanisms of the inflammatory processes underlying asthma rapidly evolved, several key mediators (cytokines and receptors) were identified, and the laboratory techniques have allowed us to synthesize monoclonal antibodies highly specific for those target molecules. Nowadays, many biological agents are investigated in asthma (with anti IgE being the only commercially available). The clinical efficacy of some biologics was demonstrated in many cases, however, the safety issue has progressively emerged and has been recognized as a crucial aspect. AREAS COVERED: We summarized the currently available knowledge on the safety and side effects of biologics in asthma, as derived by reviews, meta analyses and clinical trials. PubMed was searched with the terms anti IL-x [AND] safety [OR] side effects, within the categories "clinical trial", meta-analysis" and "review". Case reports were excluded. The authors collegially selected the relevant entries to be included. EXPERT OPINION: Overall, the safety of most of the investigated agents seems to be satisfactory, a certain risk of side effects remains present, and is variable for the different molecules. Thus caution must be paid in evaluating the risk to benefit ratio. Specific biomarkers to predict the response to each biological are urgently needed to improve the safety profile.