Mapping and characterization of the epitope(s) of Sch 55700, a humanized mAb, that inhibits human IL-5

Biologics and airway remodeling in severe asthma

Asthma is a chronic inflammatory airway disease resulting in airflow obstruction, which in part can become irreversible to conventional therapies, defining the concept of airway remodeling. The introduction of biologics in severe asthma has led in some patients to the complete normalization of previously considered irreversible airflow obstruction. This highlights the need to distinguish a "fixed" airflow obstruction due to structural changes unresponsive to current therapies, from a "reversible" one as demonstrated by lung function normalization during biological therapies not previously obtained even with high-dose systemic glucocorticoids. The mechanisms by which exposure to environmental factors initiates the inflammatory responses that trigger airway remodeling are still incompletely understood. Alarmins represent epithelial-derived cytokines that initiate immunologic events leading to inflammatory airway remodeling. Biological therapies can improve airflow obstruction by addressing these airway inflammatory changes. In addition, biologics might prevent and possibly even revert "fixed" remodeling due to structural changes. Hence, it appears clinically important to separate the therapeutic effects (early and late) of biologics as a new paradigm to evaluate the effects of these drugs and future treatments on airway remodeling in severe asthma.

Airway autoimmunity, asthma exacerbations, and response to biologics

Biologic therapies in asthma are indicated in severe disease, and they are directed against specific inflammatory modulators that contribute to pathogenesis and severity. Currently approved biologics target T2 cytokines (IgE, IL-5, IL-4/IL-13, and TLSP) and have demonstrated efficacy in clinical outcomes such as exacerbation rate and oral corticosteroid dose reductions, blood and airway eosinophil depletion, and lung function improvement. However, a proportion of these patients may show inadequate responses to biologics, with either initial lack of improvement or clinical and functional worsening after an optimal initial response. Exacerbations while on a biologic may be due to several reasons, including imprecise identification of the dominant effector pathway contributing to severity, additional inflammatory pathways that are not targeted by the biologic, inaccuracies of the biomarker used to guide therapy, inadequate dosing schedules, intercurrent airway infections, anti-drug neutralizing antibodies, and a novel phenomenon of autoimmune responses in the airways interfering with the effectiveness of the monoclonal antibodies. This review, illustrated using case scenarios, describes the underpinnings of airway autoimmune responses in driving exacerbations while patients are being treated with biologics, device a strategy to evaluate such exacerbations, an algorithm to switch between biologics, and perhaps to consider two biologics concurrently.

Pharmacological approaches to target type 2 cytokines in asthma

Asthma is the most common chronic lung disease, affecting more than 250 million people worldwide. The heterogeneity of asthma phenotypes represents a challenge for adequate assessment and treatment of the disease. However, approximately 50% of asthma patients present with chronic type 2 inflammation initiated by alarmins, such as IL-33 and thymic stromal lymphopoietin (TSLP), and driven by the T_H2 interleukins IL-4, IL-5 and IL-13. These cytokines have therefore become important therapeutic targets in asthma. Here, we discuss current knowledge on the structure and functions of these cytokines in asthma. We review preclinical and clinical data obtained with monoclonal antibodies (mAbs) targeting these cytokines or their receptors, as well as novel strategies under development, including bispecific mAbs, designed ankyrin repeat proteins (DARPins), small molecule inhibitors and vaccines targeting type 2 cytokines.

Emerging Evidence for Pleiotropism of Eosinophils

Eosinophils are complex granulocytes with the capacity to react upon diverse stimuli due to their numerous and variable surface receptors, which allows them to respond in very different manners. Traditionally believed to be only part of parasitic and allergic/asthmatic immune responses, as scientific studies arise, the paradigm about these cells is continuously changing, adding layers of complexity to their roles in homeostasis and disease. Developing principally in the bone marrow by the action of IL-5 and granulocyte macrophage colony-stimulating factor GM-CSF, eosinophils migrate from the blood to very different organs, performing multiple functions in tissue homeostasis as in the gastrointestinal tract, thymus, uterus, mammary glands, liver, and skeletal muscle. In organs such as the lungs and gastrointestinal tract, eosinophils are able to act as immune regulatory cells and also to perform direct actions against parasites, and bacteria, where novel mechanisms of immune defense as extracellular DNA traps are key factors. Besides, eosinophils, are of importance in an effective response against viral pathogens by their nuclease enzymatic activity and have been lately described as involved in severe acute respiratory syndrome coronavirus SARS-CoV-2 immunity. The pleiotropic role of eosinophils is sustained because eosinophils can be also detrimental to human physiology, for example, in diseases like allergies, asthma, and eosinophilic esophagitis, where exosomes can be significant pathophysiologic units. These eosinophilic pathologies, require specific treatments by eosinophils control, such as new monoclonal antibodies like mepolizumab, reslizumab, and benralizumab. In this review, we describe the roles of eosinophils as effectors and regulatory cells and their involvement in pathological disorders and treatment.

Eosinophil Knockout Humans: Uncovering the Role of Eosinophils Through Eosinophil-Directed Biological Therapies

The enigmatic eosinophil has emerged as an exciting component of the immune system, involved in a plethora of homeostatic and inflammatory responses. Substantial progress has been achieved through experimental systems manipulating eosinophils in vivo, initially in mice and more recently in humans. Researchers using eosinophil knockout mice have identified a contributory role for eosinophils in basal and inflammatory processes and protective immunity. Primarily fueled by the purported proinflammatory role of eosinophils in eosinophil-associated diseases, a series of anti-eosinophil therapeutics have emerged as a new class of drugs. These agents, which dramatically deplete eosinophils, provide a valuable opportunity to characterize the consequences of eosinophil knockout humans. Herein, we comparatively describe mouse and human eosinophil knockouts. We put forth the view that human eosinophils negatively contribute to a variety of diseases and, unlike mouse eosinophils, do not yet have an identified role in physiological health; thus, clarifying all roles of eosinophils remains an ongoing pursuit.

Monoclonal Antibodies and Airway Diseases

Monoclonal antibodies, biologics, are a relatively new treatment option for severe chronic airway diseases, asthma, allergic rhinitis, and chronic rhinosinusitis (CRS). In this review, we focus on the physiological and pathomechanisms of monoclonal antibodies, and we present recent study results regarding their use as a therapeutic option against severe airway diseases. Airway mucosa acts as a relative barrier, modulating antigenic stimulation and responding to environmental pathogen exposure with a specific, self-limited response. In severe asthma and/or CRS, genome-environmental interactions lead to dysbiosis, aggravated inflammation, and disease. In healthy conditions, single or combined type 1, 2, and 3 immunological response pathways are invoked, generating cytokine, chemokine, innate cellular and T helper (Th) responses to eliminate viruses, helminths, and extracellular bacteria/fungi, correspondingly. Although the pathomechanisms are not fully known, the majority of severe airway diseases are related to type 2 high inflammation. Type 2 cytokines interleukins (IL) 4, 5, and 13, are orchestrated by innate lymphoid cell (ILC) and Th subsets leading to eosinophilia, immunoglobulin E (IgE) responses, and permanently impaired airway damage. Monoclonal antibodies can bind or block key parts of these inflammatory pathways, resulting in less inflammation and improved disease control.

Mabs for treating asthma: omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab

The introduction of biologics for the treatment of patients with refractory asthma represented a marked therapeutic advance. For more than 10 y, the only biologic available has been the monoclonal anti-IgE antibody omalizumab, reserved for patients with asthma caused by perennial allergen. In recent years, other biologics have been licensed for the treatment of severe eosinophilic asthma. They include monoclonal antibodies that target the Th2-pathway cytokines, such as IL-5 (mepolizumab and reslizumab) or its receptor (benralizumab) and the IL-4 and IL-13 receptor (dupilumab). The effectiveness of these biologics was demonstrated in several placebo controlled trials, the main outcomes being the significant reduction of the rate of asthma exacerbation and the improvement of respiratory function in actively treated patients. Based on the further understanding of the pathogenesis of asthma, new cytokines network and new targets are emerging, such as thymic stromal lymphopoietin, which can activate Th2 cells, innate lymphoid cells, or both, or prostaglandin D2 (PGD2), to develop additional biologics.

Interleukin-5 in the Pathophysiology of Severe Asthma

Interleukin-5 (IL-5) exerts a central pathogenic role in differentiation, recruitment, survival, and degranulation of eosinophils. Indeed, during the last years, significant advances have been made in our understanding of the cellular and molecular mechanisms underlying the powerful actions of IL-5 finalized to the induction, maintenance, and amplification of eosinophilic inflammation. Therefore, IL-5 is a suitable target for add-on biological therapies based on either IL-5 inhibition (mepolizumab, reslizumab) or blockade of its receptor (benralizumab). These modern treatments can result in being definitely beneficial for patients with severe type 2 (T2)-high eosinophilic asthma, refractory to conventional anti-inflammatory drugs such as inhaled and even systemic corticosteroids.

A Review of Respiratory Biologic Agents in Severe Asthma

Asthma is a common but complex chronic inflammatory heterogeneous lung disease, punctuated by the pathophysiological phenomenon of airway narrowing, coupled with symptoms of wheezing and coughing. The mechanism behind these symptoms is due to migration of eosinophils, mast cells, and CD4 T-helper cells into the submucosa of the airway, leading to hyperresponsiveness to common allergens, microorganisms, oxidants, pollutants, and consequently, airway remodeling. There is evidence that this migration is mediated by inflammatory cytokines derived from T-helper 2 (Th2) cells and type 2 innate lymphoid cells (ILC2), such as interleukins 4, 5, and 13. These cytokines lead to an increase in immunoglobulin E (IgE) production. Additionally, thymic stromal lymphopoietin (TSLP) released from airway epithelium can activate Th2 cells, innate lymphoid cells, or both. All have proven significant in the promotion of chronic airway inflammation and remodeling. In the past, most treatment strategies for this condition focused on two drug classes: β2 agonists (both short- and long-acting), and inhaled corticosteroids. Other treatments have included maintenance drugs, such as leukotriene receptor antagonists, long-acting anticholinergic agents, and theophylline. None of these, however, directly impact the interleukin or IgE pathways in a meaningful manner. Clinical trials of novel agents impacting these pathways have demonstrated efficacy and improved outcomes in asthma exacerbations, control, and forced expiratory volume in 1 second (FEV₁) in patients with severe asthma. Future treatments in asthma will focus on drugs that target these aforementioned cytokines.

Active vaccination against interleukin-5 as long-term treatment for insect-bite hypersensitivity in horses

Background

Insect‐bite hypersensitivity (IBH) in horses is a chronic allergic dermatitis caused by insect bites. Horses suffer from pruritic skin lesions, caused by type‐I/type‐IV allergic reactions accompanied by prominent eosinophil infiltration into the skin. Interleukin‐5 (IL‐5) is the key cytokine for eosinophils and we have previously shown that targeting IL‐5 by vaccination reduces disease symptoms in horses.

Objective

Here, we analyzed the potential for long‐term therapy by assessing a second follow‐up year of the previously published study.

Methods

The vaccine consisted of equine IL‐5 (eIL‐5) covalently linked to a cucumber mosaic virus‐like particle (VLP) containing a universal T cell epitope (CuMV_TT) using a semi‐crossover design to follow vaccinated horses during a second treatment season. Thirty Icelandic horses were immunized with 300 μg of eIL‐5‐CuMV_TT without adjuvant.

Results

The vaccine was well tolerated and did not reveal any safety concerns throughout the study. Upon vaccination, all horses developed reversible anti‐eIL‐5 auto‐antibody titers. The mean course of eosinophil levels was reduced compared to placebo treatment leading to significant reduction of clinical lesion scores. Horses in their second vaccination year showed a more pronounced improvement of disease symptoms when compared to first treatment year, most likely due to more stable antibody titers induced by a single booster injection. Hence, responses could be maintained over two seasons and the horses remained protected against disease symptoms.

Conclusion

Yearly vaccination against IL‐5 may be a long‐term solution for the treatment of IBH and other eosinophil‐mediated diseases in horses and other species including humans.

Pharmacokinetics and pharmacodynamics of monoclonal antibodies for asthma treatment

INTRODUCTION

Asthma is a chronic inflammatory airway disease. It occurs in a 'severe' form in about 8-10% of asthmatic patients. In the last decade, the development of biological drugs (e.g. monoclonal antibodies) allowed to efficiently approach severe asthma. The current therapeutic targets available are mainly those related to TH2 inflammation. Areas covered: The main pharmacokinetic and pharmacodynamic characteristics of the monoclonal antibodies against IL-5, IL-5Ra, IL4-IL13, and IgE, that are currently marketed or understood for severe asthma are discussed in this paper. Expert opinion: The currently available biological drugs represent an excellent therapeutic add-on to traditional drugs, especially in replacing systemic corticosteroid therapies. The different pharmacokinetic and pharmacodynamic characteristics of the drugs, despite sometime sharing the same target, would allow a better personalization of the therapy, tailoring the treatment to the characteristics of the patient.

Impact of reslizumab on outcomes of severe asthmatic patients: current perspectives

Approximately 5%–10% of asthmatics suffer from severe asthma. New biological treatments represent a great opportunity to reduce asthma burden and to improve asthma patients’ lives. Reslizumab will soon be available in several European countries. This anti-IL-5 IgG4/κ monoclonal antibody, administered intravenously at a dose of 3 mg/kg over 20–50 minutes every 4 weeks, has been shown to be safe and effective in patients with 400 eosinophils/μL or more in their peripheral blood. The clinical effects in reducing asthma exacerbations and in improving the quality of life and lung function are clear, but further research is needed to determine the best biological compound for a specific cluster of patients. Research data have shown that in patients who were expressing other clinical features of eosinophilic inflammation over asthma (rhinosinusitis and nasal polyposis), the clinical benefit of reslizumab was greater. Furthermore, it has also been observed that in patients with unsatisfactory response to mepolizumab, reslizumab is able to significantly improve the clinical and biological parameters. The aim of personalized medicine is to provide the right drug to the right patient at the right dose at the right moment. The biological treatments that were developed to modify specific pathological pathways not only provide us with the tools for the management of asthma patients but also clarify the biological mechanisms involved in its pathogenesis.

Biologic agents for severe asthma patients: clinical perspectives and implications

Asthma is a chronic inflammatory multifactorial disorder of the airways characterized by the involvement of immune cells and mediators in its onset and maintenance. Traditional therapeutic strategies have been unsatisfactory in controlling the underlying pathology, especially in the more severe states. Hence in the last couple of decades, new biological approaches targeting molecular mediators have been developed. In this narrative review we examine biological agents currently available for the management of severe asthma, focusing our attention on their clinical application, pros and cons, and in particular on gaps regarding the use of these agents. The most well-known and used biologic agent in clinical practice is omalizumab, though there is emerging evidence for mepolizumab too. The future of these biological therapies is to broaden our knowledge of their practical use and ascertain predictive biomarkers, or define an algorithm, useful in the optimal application of these 'biological weapons'.

Pharmacokinetic/pharmacodynamic profile of reslizumab in asthma

INTRODUCTION

Allergic asthma is a Th2-driven inflammatory process characterized by the infiltration of eosinophils into the airways. IL-5 is a key trigger for eosinophil expansion and release from the bone marrow and plays a crucial role in the entire life span of eosinophils from differentiation to maturation and survival. IL-5 can be considered among the most obvious targets to selectively inhibit eosinophilic airway inflammation. Areas covered: The preclinical and clinical development of reslizumab, a humanized mAb against IL-5 that has been developed to block IL-5 bioactivity and reduce biologically available IL-5, are described with a particular focus on its pharmacodynamics (PK)/pharmacokinetic (PD) profile. Expert opinion: Although pivotal trials have documented that reslizumab can be recommended as add-on therapy for the treatment of patients with severe eosinophilic asthma, there is still important information that is lacking and some PK and PD properties of reslizumab are still not fully understood.

Development of a robust reporter gene based assay for the bioactivity determination of IL-5-targeted therapeutic antibodies

Eosinophilic asthma is characterized by the eosinophilic inflammation with the allergen independent activation of Th2 lymphocytes. Since IL-5 plays an important role in the maturation, survival and migration of eosinophils, hence the pathogenesis of eosinophilic asthma, biotherapeutics targeting IL-5/IL-5Rα have been developed and/or marketed, including Mepolizumab, Reslizumab, and Benralizumab. Accurate determination of bioactivity is crucial for the safety and efficacy of therapeutic antibodies. The current mode of action (MOA) based method used in the quality control and stability tests for anti-IL-5 mAbs is anti-proliferation assay, which is tedious with long duration and high variation. We describe here the development and validation of a reporter gene assay (RGA), based on an IL-5-dependent TF-1 cell line variant we established that stably expresses the luciferase reporter under the control of STAT5 response elements. After careful optimization, we demonstrate the excellent specificity, precision, accuracy and linearity of the established RGA. Our study also proves that the assay is superior on precision, sensitivity and assay simplicity to the anti-proliferation assay. The established RGA is also applicable to another anti-IL-5Rα mAb. These results show for the first time that this novel RGA, based on the IL-5-IL-5R-STAT5 pathway, can be a valuable supplement to the anti-proliferation assay and employed in the bioactivity determination of anti-IL-5/anti-IL-5Rα biotherapeutics.

Reslizumab in the treatment of inadequately controlled asthma in adults and adolescents with elevated blood eosinophils: clinical trial evidence and future prospects

Eosinophils have long been implicated as playing a central role in the pathophysiology of asthma in many patients, and eosinophilic asthma is now recognized as an important asthma endotype. Eosinophil differentiation, maturation, migration, and survival are primarily under the control of interleukin-5 (IL-5). Reslizumab is a humanized monoclonal (immunoglobulin G4/κ) antibody that binds with high affinity to circulating human IL-5 and downregulates the IL-5 signaling pathway, potentially disrupting the maturation and survival of eosinophils. In 2016, an intravenous formulation of reslizumab was approved in the USA, Canada, and Europe as add-on maintenance treatment for patients aged ⩾18 years with severe asthma and with an eosinophilic phenotype. The efficacy of reslizumab as add-on intravenous therapy has been reported in several phase III studies in patients with inadequately controlled moderate-to-severe asthma and elevated blood eosinophil counts (⩾400 cells/µl). Compared with placebo, reslizumab was associated with significant improvements in clinical exacerbation rate, forced expiratory volume in 1 s, asthma symptoms and quality of life, and significant reductions in blood eosinophil counts. Reslizumab also demonstrated a favorable tolerability profile similar to that of placebo, with reported adverse events being mostly mild to moderate in severity. Ongoing studies are focusing on the evaluation of a subcutaneous formulation of reslizumab in patients with asthma and elevated eosinophil levels. This review discusses the preclinical and clinical trial data available on reslizumab, potential opportunities for predicting an early response to reslizumab, and future directions in the field of anti-IL-5 antibody therapy.

Reslizumab in Eosinophilic Asthma: A Review

Reslizumab (Cinqaero^®; Cinqair^®) is a humanized monoclonal antibody against interleukin-5 (IL-5), a cytokine mediator of eosinophilic airway inflammation. Reslizumab is indicated as an add-on treatment for severe eosinophilic asthma in adults, on the basis of data from the BREATH phase III clinical trial programme. In three double-blind BREATH studies of up to 52 weeks' duration, adding intravenous reslizumab (3 mg/kg, once every 4 weeks) to the current asthma therapy of patients (aged 12-75 years) with eosinophilic asthma inadequately controlled with inhaled corticosteroids resulted in significant reductions in clinical asthma exacerbation frequency and significant improvements in lung function, asthma control and health-related quality of life relative to adding placebo. Pooled data from the two trials of 52 weeks' duration indicated similar benefits with reslizumab across various patient subgroups, including patients with severe eosinophilic asthma. Reslizumab was generally well tolerated, with very few recipients experiencing severe or serious treatment-related adverse events. Moreover, in an open-label extension study, continued use of reslizumab for up to 2 years was associated with durable lung function benefit, without any new tolerability concerns. Thus, intravenous reslizumab extends the valuable add-on treatment options for adults with severe eosinophilic asthma inadequately controlled with standard therapies.

Reslizumab and Eosinophilic Asthma: One Step Closer to Precision Medicine?

Human eosinophils represent approximately 1% of peripheral blood leukocytes. However, these cells have the propensity to leave the blood stream and migrate into inflamed tissues. Eosinophilic inflammation is present in a significant proportion of patients with severe asthma. Asthma is a chronic inflammatory disorder that affects more than 315 million people worldwide, with 10% having severe uncontrolled disease. Although the majority of patients can be efficiently treated, severe asthmatics continue to be uncontrolled and are at risk of exacerbations and even death. Interleukin-5 (IL-5) plays a fundamental role in eosinophil differentiation, maturation, activation and inhibition of apoptosis. Therefore, targeting IL-5 is an appealing approach to the treatment of patients with severe eosinophilic asthma. Reslizumab, a humanized anti-IL-5 monoclonal antibody, binds with high affinity to amino acids 89–92 of IL-5 that are critical for binding to IL-5 receptor α. Two phase III studies have demonstrated that reslizumab administration in adult patients with severe asthma and eosinophilia (≥400 cells/μL) improved lung function, asthma control, and symptoms. Thus, the use of blood eosinophils as a baseline biomarker could help to select patients with severe uncontrolled asthma who are likely to achieve benefits in asthma control with reslizumab. In conclusion, targeted therapy with reslizumab represents one step closer to precision medicine in patients with severe eosinophilic asthma.

Changing Paradigms in the Treatment of Severe Asthma: The Role of Biologic Therapies

Cytokine antagonists are monoclonal antibodies that offer new treatment options for refractory asthma but will also increase complexity because they are effective only for patients with certain asthma subtypes that remain to be more clearly defined. The clinical and inflammatory heterogeneity within refractory asthma makes it difficult to manage the disease and to determine which, if any, biologic therapy is suitable for a specific patient. The purpose of this article is to provide a data-driven discussion to clarify the use of biologic therapies in patients with refractory asthma. We first discuss the epidemiology and pathophysiology of refractory asthma. We then interpret current evidence for biomarkers of eosinophilic or type 2-high asthma so that clinicians can determine potential treatments for patients based on knowledge of their effectiveness in specific asthma phenotypes. We then assess clinical data on the efficacy, safety, and mechanisms of action of approved and pipeline biologic therapies. We conclude by discussing the potential of phenotyping or endotyping refractory asthma and how biologic therapies can play a role in treating patients with refractory asthma.

Reslizumab in the management of poorly controlled asthma: the data so far

Interleukin-5, an important cytokine in the pathophysiology of asthma, participates in terminal maturation and increases chemotaxis, endothelial adhesion, and activation of eosinophils. Blockade of interleukin-5 activity with monoclonal antibodies have been successful in decreasing eosinophil counts. Reslizumab, a monoclonal antibody that targets interleukin-5, has been studied for the treatment of severe asthma. Several studies have shown that reslizumab can effectively treat severe asthma with an eosinophilic phenotype. Compared to placebo, patients treated with reslizumab had a reduction in the rates of asthma exacerbations and experienced improvement in FEV₁ and asthma control questionnaires scores as early as 4 weeks after the therapy was initiated. Reslizumab was not effective in various asthma outcomes in patients without eosinophilia. The adverse events reported were similar in both treatment and placebo groups. Patients should be observed immediately after treatment because anaphylaxis may occur rarely (0.3%) after exposure to reslizumab. Future surveillance studies are still needed to establish the risks of malignancy and safety during pregnancy.

The efficacy and safety of reslizumab for inadequately controlled asthma with elevated blood eosinophil counts: A systematic review and meta-analysis

CONTEXT

Reslizumab is a humanised anti-interleukin 5 monoclonal antibody that disrupts eosinophil maturation and promotes programmed cell death.

OBJECTIVE

We carried out a systematic review and meta-analysis to assess the efficacy and safety of the drug in patients with inadequately controlled, eosinophilic asthma.

DATA SOURCES

The search included the following databases: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register.

STUDY SELECTION

A literature review was performed to identify all published randomized double-blind, placebo-controlled trials of reslizumab for the treatment of inadequately controlled, eosinophilic asthma.

DATA EXTRACTION

Two reviewers independently extracted and verified pre-defined data fields.

RESULTS

Four publications including 5 RCTs that compared reslizumab with placebo. For the comparison of reslizumab with placebo, asthma exacerbation (odds ratio (OR) = 0.46, 95% confidence interval (CI) = 0.35 to 0.59, p <0.00001); a forced expiratory volume in 1 s (FEV1) (the standardized mean difference (SMD) = 0.16, 95%CI = 0.10 to 0.23, p <0.00001); Asthma Control Questionnaire (ACQ) score (the SMD = -0.26, 95%CI= -0.36 to -0.16, p <0.00001); blood eosinophil counts (the SMD = -475.62, 95%CI = -528.41 to -422.83, p <0.00001). Safety assessments included the proportion of individuals who withdrawn due to adverse event (AE) (OR = 0.60 95%CI = 0.38 to 1.17, p = 0.16) indicated that reslizumab was well tolerated.

LIMITATIONS

The article didn't research the safety, efficacy of reslizumab with longer term.

CONCLUSIONS

This meta-analysis indicates that reslizumab to be an effective and safe treatment for inadequately controlled, eosinophilic asthma.

Role of biologics in severe eosinophilic asthma - focus on reslizumab

Within the context of the heterogeneous phenotypic stratification of asthmatic population, many patients are characterized by moderate-to-severe eosinophilic asthma, not adequately controlled by relatively high dosages of inhaled and even oral corticosteroids. Therefore, these subjects can obtain significant therapeutic benefits by additional biologic treatments targeting interleukin-5 (IL-5), given the key pathogenic role played by this cytokine in maturation, activation, proliferation, and survival of eosinophils. In particular, reslizumab is a humanized anti-IL-5 monoclonal antibody that has been found to be an effective and safe add-on therapy, capable of decreasing asthma exacerbations and significantly improving disease control and lung function in patients experiencing persistent allergic or nonallergic eosinophilic asthma, despite the regular use of moderate-to-high doses of inhaled corticosteroids. These important therapeutic effects of reslizumab, demonstrated by several controlled clinical trials, have led to the recent approval by US Food and Drug Administration of its use, together with other antiasthma medications, for the maintenance treatment of patients suffering from severe uncontrolled asthma.

Efficacy and safety of reslizumab in patients with moderate to severe eosinophilic asthma

Reslizumab, a neutralizing anti-IL-5 monoclonal antibody, is a promising adjunctive treatment for severe eosinophilic asthma. Monthly intravenous 3.0 mg/kg reslizumab had resulted in improvements in lung function and asthma control. It is well tolerated and common adverse events include headache, nasopharyngitis and upper respiratory tract infection. Rebound eosinophilia after cessation of reslizumab and attenuation of the treatment response with repeated dosing had been reported. Stringent selection of patients with a high eosinophil burden, who are poorly controlled despite moderate to high doses of inhaled corticosteroid, confers the most significant treatment response. Future trials should compare the dose, delivery platform, frequency of dosing and study combinations with other biologics, which will affect its maximal clinical efficacy.

Update on reslizumab for eosinophilic asthma

INTRODUCTION

Patients with severe eosinophilic asthma have an unmet need for novel and efficacious treatments. Reslizumab is one of the three monoclonal antibodies targeting the IL-5 pathway and has been found in Phase IIIb clinical trials to reduce asthma exacerbations, control asthma-related symptoms and improve pulmonary function in patients with eosinophilic asthma.

AREAS COVERED

In this article, we discuss the results of asthma clinical trials using reslizumab, beginning with a discussion of the relationship between eosinophils, IL-5 and asthma. We conducted PubMed searches using the terms 'reslizumab', 'anti-IL-5', 'eosinophilic asthma', 'IL-5 asthma'. We also searched ClinicalTrials.gov for 'reslizumab', 'reslizumab asthma', 'SCH 55700', 'SCH 55700 asthma', 'Cinquil' and 'Cinquil asthma'.

EXPERT OPINION

Reslizumab and other anti-IL-5 therapies have seen success in recent trials through more stringent study participant selection targeting eosinophilic inflammation. This selection can now be based on simple blood counts. These drugs have shown a very good safety profile, but long-term safety data are not yet available. Approval for these drugs is eagerly awaited by clinicians and patients alike.

Therapeutic strategies for harnessing human eosinophils in allergic inflammation, hypereosinophilic disorders, and cancer

The eosinophil is a multifunctional granulocyte best known for providing host defense against parasites. Paradoxically, eosinophils are also implicated in the pathogenesis of allergic inflammation, asthma, and hypereosinophilic syndromes. Emerging evidence also supports the potential for harnessing the cytotoxic power of eosinophils and redirecting it to kill solid tumors. Central to eosinophil physiology is interleukin-5 (IL-5) and its receptor (IL-5R) which is composed of a ligand-specific alpha chain (IL-5Rα) and the common beta chain (βc). Eosinophil activation can lead to their degranulation, resulting in rapid release of an arsenal of tissue-destructive proinflammatory mediators and cytotoxic proteins that can be both beneficial and detrimental to the host. This review discusses eosinophil immunobiology and therapeutic strategies for targeting of IL-5 and IL-5R, as well as the potential for harnessing eosinophil cytotoxicity as a tumoricide.

A review of treatment with mepolizumab, an anti-IL-5 mAb, in hypereosinophilic syndromes and asthma

The hypereosinophilic syndromes (HESs) are a heterogeneous group of diseases characterized by peripheral blood eosinophilia with end-organ damage and varying in severity from nonspecific symptoms to life-threatening. Treatment objectives are a safe reduction of blood and tissue eosinophil levels and prevention of eosinophil-mediated tissue damage. Current treatment of patients with HESs, who lack the FIP-1-like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) fusion gene, is mainly systemic corticosteroid therapy. Eosinophil development from hematopoietic progenitor cells is regulated by IL-5, which influences maturation, differentiation, mobilization, activation, and survival. Consequently, inhibiting IL-5 is a logical therapeutic objective for patients with HESs or selected patients with asthma. Mepolizumab is a fully humanized anti-IL-5 monoclonal IgG(1) antibody that binds to free IL-5 with high affinity and specificity to prevent IL-5 from associating with the IL-5 receptor complex alpha-chain on the surface of eosinophils. In clinical trials with patients with HESs, mepolizumab reduced blood eosinophil counts and the maintenance corticosteroid dose and had no major safety concerns. Mepolizumab reduced airway and blood eosinophils and prevented asthma exacerbations. Thus, mepolizumab may be effective for long-term treatment of patients with selected eosinophilic disorders.

[Anti-interleukin-5 therapy for eosinophilic diseases]

In a number of diseases with eosinophilia, elevated interleukin (IL)-5 levels are detected in the peripheral blood and/or tissues. IL-5 plays an important role in regulating the production, differentiation, recruitment, activation, and survival of eosinophils. Therefore, neutralizing IL-5 by blocking antibodies seems a promising approach in the treatment of eosinophilic diseases. Clinical trials have demonstrated that anti-IL-5 therapy results in a rapid decrease in peripheral blood eosinophil numbers. Moreover, improvement of symptoms in patients with lymphocytic variants of hypereosinophilic syndromes, in eosinophilic esophagitis and chronic rhinitis with nasal polyposis has been observed. In contrast, in patients with bronchial asthma or atopic eczema, anti-IL-5 therapy showed only moderate or no clinical effects. Future studies will have to identify those eosinophilic diseases in which anti-IL-5 antibodies are effective, perhaps with the help of newly developed biomarkers.

A critical appraisal of conventional and investigational drug therapy in patients with hypereosinophilic syndrome and clonal eosinophilia

Hypereosinophilic syndrome (HES) is a rare disorder characterized by persistent and marked eosinophilia, leading to end-organ damage. Over the last decade, great progress has been made in unraveling the molecular basis of HES that has resulted in the characterization of specific genetic alterations linked to clonal eosinophilia. The most frequently encountered genetic aberrancy is the cryptic FIP1-like 1/platelet-derived growth factor receptor alpha (FIP1L1-PDGFRA) fusion transcript, which results in an eosinophilic, myeloproliferative disorder. In addition, in a subset of patients with HES, a population of aberrant T cells that secretes interleukin-5 can be identified, indicating the existence of lymphocyte-mediated hypereosinophilia. These new insights have led to both a genetically based (re)classification of eosinophilic blood disorders and to effective therapies with targeted agents, such as small-molecule tyrosine kinase inhibitors (eg, imatinib, nilotinib, PKC412) and, more recently, monoclonal antibodies (eg, mepolizumab, alemtuzumab). These targeted therapies hold great promise for improving the clinical outcomes of patients with HES and clonal eosinophilia, and they have exhibited relatively safe toxicity profiles.

Anti-Interleukin-5 Antibody Therapy in Eosinophilic Diseases

Eosinophilia in atopic diseases and hypereosinophilic syndrome is often associated with a high expression of interleukin-5 (IL-5). IL-5 plays an important role in regulating the production, differentiation, recruitment, activation, and survival of eosinophils. Therefore, neutralizing IL-5 with an antibody is a promising therapeutic strategy in eosinophilic diseases. In patients with hypereosinophilic syndrome and eosinophilic esophagitis, anti-IL-5 antibody therapy resulted in an improvement of symptoms. In patients with bronchial asthma, no effect on the late phase reaction and on airway hyperresponsiveness has been observed. Moreover, patients with atopic dermatitis demonstrated only a moderate improvement of their skin lesions and pruritus. Anti-IL-5 therapy was followed by a rapid and sustained decrease of peripheral blood eosinophil numbers. The decrease of tissue eosinophils was, however, less dramatic. Investigating the effects of anti-IL-5 therapy will improve our understanding of the pathogenic roles of both IL-5 and eosinophils in eosinophilic inflammatory responses.

Traitement des hyperéosinophilies

Therapeutic management of blood hypereosinophilia depends on its underlying cause. The cause may be clearly established (parasitic infestation) or more hypothetical (systemic disease). Blood eosinophils often return to normal levels after treatment of either the cause or the associated eosinophilic disease. A targeted approach is more difficult when the cause is unknown (unexplained chronic hypereosinophilia). Various conventional treatments (corticosteroids, hydroxyurea, interferon) have been somewhat effective. The identification of new cellular and molecular markers with diagnostic and pathophysiologic significance makes more rational approaches possible.

Anti-interleukin-5 therapy for asthma and hypereosinophilic syndrome

Interleukin 5 (IL-5) is a key cytokine in the regulation of eosinophilia and eosinophil activation in humans. Monoclonal antibodies to anti-IL-5 have become available for use in clinical studies in humans. This article discusses the rationale for the use of anti-IL-5 therapy in asthma and hypereosinophilic syndrome and summarizes the available clinical data on the use of anti-IL-5 to treat these disorders.

A role for eosinophils in airway remodelling in asthma

Over the years, the role of the eosinophil in asthma and allergic processes has been disputed. Recent human experiments using a humanised monoclonal antibody to interleukin-5 (IL-5), and animal studies involving specific IL-5 gene deletion, indicates that eosinophils might control downstream repair and remodelling processes. Eosinophils are a rich source of fibrogenic factors, particularly transforming growth factor-beta (TGF-beta), the latent form of which is activated by epithelial-cell expression of the intergin alpha(v)beta(6). The emerging role for the eosinophil in airway remodelling might be important in future anti-asthma strategies. However, more effective eosinophil-depleting agents than anti-IL-5 are required before the definitive role of this cell type in asthma airway pathophysiology can be established.

Induction of lysosomal and plasma membrane-bound sialidases in human T-cells via T-cell receptor

Among the three isoenzymes of neuraminidase (Neu) or sialidase, Neu-1 has been suggested to be induced by cell activation and to be involved in IL (interleukin)-4 biosynthesis in murine T-cells. In the present study, we found that antigen-induced airway eosinophilia, a typical response dependent on Th2 (T-helper cell type 2) cytokines, as well as mRNA expression of Th2 cytokines, including IL-4, are suppressed in Neu-1-deficient mice, thereby demonstrating the in vivo role of murine Neu-1 in regulation of Th2 cytokines. To elucidate the roles of various sialidases in human T-cell activation, we investigated their tissue distribution, gene induction and function. Neu-1 is the predominant isoenzyme at the mRNA level in most tissues and cells in both mice and humans, including T-cells. T-cells also have significant levels of Neu-3 mRNAs, albeit much lower than those of Neu-1, whereas the levels of Neu-2 mRNAs are minimal. In human T-cells, both Neu-1 and Neu-3 mRNAs are significantly induced by T-cell-receptor stimulation, as is sialidase activity against 4-methylumbelliferyl- N -acetylneuramic acid (a substrate for both Neu-1 and Neu-3) and the ganglioside G(D1a) [NeuAcalpha2-3Galbeta1-3GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-4Glcbeta1-cer] (a substrate for Neu-3, but not for Neu-1). The expression of the two sialidase genes may be under differential regulation. Western blot analysis and enzymic comparison with recombinant sialidases have revealed that Neu-3 is induced as a major isoform in activated cells. The induction of Neu-1 and Neu-3 in T-cells is unique. In human monocytes and neutrophils stimulated with various agents, the only observation of sialidase induction has been by IL-1 in neutrophils. Functionally, a major difference has been observed in Jurkat T-cell lines over-expressing Neu-1- and Neu-3. Upon T-cell receptor stimulation, IL-2, interferon-gamma, IL-4 and IL-13 are induced in the Neu-1 line, whereas in the Neu-3 line the same cytokines are induced, with the exception of IL-4. Taken together, these results suggest an important immunoregulatory role for both Neu-1 and Neu-3 in humans.

Functional analysis of the interleukin-5 receptor antagonist peptide, AF18748

AF18748 is a dimeric peptide of 2 x 19 amino acids that specifically binds to the alpha-chain of the human IL-5 receptor (IL-5R), preventing binding of IL-5 and acting as a receptor antagonist. However, the peptide acts by inducing alpha-chain dimerization, and we therefore set out to investigate whether this peptide would have any residual agonist activity. AF18748 was unable to induce activation of a number of signal transduction pathways, but was able to specifically block IL-5-dependent signal transduction. The peptide was unable to support the survival and proliferation of the cytokine dependent cell line, Ba/F3-IL-5R, and was unable to prime the respiratory burst, or induce adhesion, migration or survival of primary human eosinophils. In each case the AF18748 functioned as an antagonist. These data suggest that AF18748 may be useful to specifically modulate eosinophil function in vivo.

Development and validation of a kinetic assay for analysis of anti-human interleukin-5 monoclonal antibody (SCH 55700) and human interleukin-5 interactions using surface plasmon resonance

A method to assess the kinetic interactions of a humanized anti-human interleukin-5 (IL-5) monoclonal antibody (SCH 55700) with native human IL-5 using surface plasmon resonance (SPR) has been developed and validated. Since there are no clearly defined validation requirements for a SPR-based binding kinetic assay, the validation strategy was based on the guidelines stipulated by the International Conference on Harmonization for Analytical Method Validation. Due to the uniqueness of the method, however, proper interpretation of the guidance was critical for establishing a validation plan. Validation was designed to assess repeatability, intermediate precision, specificity, linearity, and robustness which included analysis of baseline stability and reproducibility of ligand immobilization. Additionally, system suitability criteria were established to assure that the assay consistently performs as it was intended. The experimental artifacts that can complicate kinetic analysis using biosensor technology, such as heterogeneity of the ligand, mass transport, and nonspecific binding, were considered during the development of this assay. For each run, replicate concentrations of SCH 55700 were injected randomly over the immobilized surfaces to acquire association- and dissociation-phase data. The data were transformed and double referenced to remove systematic deviations seen in the binding responses. Association and dissociation rates were determined using a bivalent analyte model for curve fitting.

Biospecific interaction analysis: a tool for drug discovery and development

The recent development of surface plasmon resonance (SPR)-based biosensor technologies for biospecific interaction analysis (BIA) enables the monitoring of a variety of molecular reactions in real-time. The biomolecular interactions occur at the surface of a flow cell of a sensor chip between a ligand immobilized on the surface and an injected analyte. SPR-based BIA offers many advantages over most of the other methodologies available for the study of biomolecular interactions, including full automation, no requirement for labeling, and the availability of a large variety of activated sensor chips that allow immobilization of DNA, RNA, proteins, peptides and cells. The assay is rapid and requires only small quantitities of both ligand and analyte in order to obtain informative results. In addition, the sensor chip can be re-used many times, leading to low running costs. Aside from the analysis of all possible combinations of peptide, protein, DNA and RNA interactions, this technology can also be used for screening of monoclonal antibodies and epitope mapping, analysis of interactions between low molecular weight compounds and proteins or nucleic acids, interactions between cells and ligands, and real-time monitoring of gene expression. Applications of SPR-based BIA in medicine include the molecular diagnosis of viral infections and genetic diseases caused by point mutations. Future perspectives include the combinations of SPR-based BIA with mass spectrometry, the use of biosensors in proteomics, and the application of this technology to design and develop efficient drug delivery systems.

Progress in the use of biological assays during the development of biotechnology products

The complexity of the structure and function of many biotechnology derived products necessitates a wide range of analytical procedures to adequately characterize the product. In-depth characterization is required for the assessment of several criteria vital to the success of product development such as consistency, purity, stability, and potency. More recently, the concern over the immunogenicity of biologics has increased the need to develop assays to detect neutralizing anti-product antibodies. Although many physicochemical tests are available to characterize the structure of a protein and detect the presence of contaminants, they provide little, if any, information regarding biological potency or the neutralizing capacity of antibody responses in immunogenicity studies. There is a continual need to refine biological assays to increase their accuracy and reproducibility, in particular to replace in vivo bioassays with appropriate in vitro assays. There have also been several recent technological developments that could lead to more rapid and reproducible bioassays.

Th2 cytokines and asthma. The role of interleukin-5 in allergic eosinophilic disease

Interleukin-5 is produced by a number of cell types, and is responsible for the maturation and release of eosinophils in the bone marrow. In humans, interleukin-5 is a very selective cytokine as a result of the restricted expression of the interleukin-5 receptor on eosinophils and basophils. Eosinophils are a prominent feature in the pulmonary inflammation that is associated with allergic airway diseases, suggesting that inhibition of interleukin-5 is a viable treatment. The present review addresses the data that relate interleukin-5 to pulmonary inflammation and function in animal models, and the use of neutralizing anti-interleukin-5 monoclonal antibodies for the treatment of asthma in humans.

Survey of the 1999 surface plasmon resonance biosensor literature

The application of surface plasmon resonance biosensors in life sciences and pharmaceutical research continues to increase. This review provides a comprehensive list of the commercial 1999 SPR biosensor literature and highlights emerging applications that are of general interest to users of the technology. Given the variability in the quality of published biosensor data, we present some general guidelines to help increase confidence in the results reported from biosensor analyses.