Mepolizumab for severe refractory eosinophilic asthma: evidence to date and clinical potential

Severe asthma in children: An official statement from Saudi Pediatric Pulmonology Association

In Saudi Arabia, the prevalence of pediatric asthma ranges between 8% and 25%. However, there are no sufficient data regarding severe asthma in childhood in Saudi Arabia. Therefore, a task force has been formed by the Saudi Pediatric Pulmonology Association which is a subsidiary group of the Saudi Thoracic Society and consists of Saudi experts with well-respected academic and clinical backgrounds in the fields of pediatric asthma as well as other respiratory diseases to write a consensus on definitions, phenotypes, and pathophysiology, evaluation, and management. To achieve this, the subject was divided into various sections, each of which was assigned to at least 2 experts. Without a central literature review, the authors searched the literature using their own strategies. To reach an agreement, the entire panel reviewed and voted on proposed findings and recommendations.

The pharmacoeconomics of the state-of-the-art drug treatments for asthma: a systematic review

Asthma is a chronic disease characterized by significant morbidities and mortality, with a large impact on socio-economic resources and a considerable burden on health-care systems. In the standard care of asthma, inhaled corticosteroids (ICS) associated with long-acting β-adrenoceptor agonists (LABA) are a reliable and often cost-effective choice, especially if based on the single inhaler therapy (SIT) strategy; however, in a subset of patients it is not possible to reach an adequate asthma control. In these cases, it is possible to resort to other pharmacologic options, including corticosteroids (OCS) or biologics. Unfortunately, OCS are associated with important side effects, whilst monoclonal antibodies (mAbs) allow excellent results, even if far more expensive. Up to now, the economic impact of asthma has not been compared with equivalent indicators in several studies. In fact, a significant heterogeneity of the cost analysis is evident in literature, for which the assessment of the real cost-effectiveness of asthma therapies is remarkably complex. To maximize the cost-effectiveness of asthma strategies, especially of biologics, attention must be paid on phenotyping and identification of predictors of response. Several studies were included, involving comparative analysis of drug treatments for asthma, comparative analysis of the costs and consequences of therapies, measurement and evaluation of direct drug costs, and the reduction of health service use. The initial research identified 389 articles, classified by titles and abstracts. A total of 311 articles were excluded as irrelevant and 78 articles were selected. Pharmacoeconomic studies on asthma therapies often report conflicting data also due to heterogeneous indicators and different populations examined. A careful evaluation of the existing literature is extremely important, because the scenario is remarkably complex, with an attempt to homogenize and interpret available data. Based on these studies, the improvement of prescriptive appropriateness and the reduction of the use of healthcare resources thanks to controller medications and to innovative therapies such as biologics partially reduce the economic burden of these treatments. A multidisciplinary stakeholder approach can also be extremely helpful in deciding between the available options and thus optimizing healthcare resources.

Biologicals in the Treatment of Pediatric Atopic Diseases

The management of atopic diseases such as severe asthma, severe atopic dermatitis, and severe food allergy in childhood is challenging. In particular, there are safety concerns regarding the use of high-dose corticosteroids. The recent development of biologicals and their approval for the treatment of children offer a new, very promising, and more personalized therapy option. Omalizumab, mepolizumab, and dupilumab are currently approved as add-on treatments of severe asthma in children and have been shown to be effective in improvement of asthma control and reduction of exacerbations. Dupilumab is the only biological approved for the treatment of atopic dermatitis in adolescents so far. It has been demonstrated to significantly improve symptoms of atopic dermatitis.However, safety data for biologicals used in atopic diseases in children and adolescents are still very limited. Biologicals are generally considered to be safe in adults. These data are often extrapolated to children. Additionally, data for long-term use are lacking. Thus, the safety profiles of those biologicals cannot yet be conclusively assessed.

Response to mepolizumab treatment is sustained across 4-weekly dosing periods

Background

Mepolizumab (100 mg delivered s.c. every 4 weeks) is indicated for add-on maintenance treatment for patients with severe eosinophilic asthma. Mepolizumab has been shown to reduce exacerbations and the requirement for daily oral corticosteroids, and improve asthma control and symptoms. However, data on the durability of the response to mepolizumab during dosing periods are limited. The aim of this study was to investigate the efficacy profile in patients with severe eosinophilic asthma over the 4-weekly dosing period for various fixed mepolizumab doses.

Methods

This was a post hoc analysis of data from the phase IIb/III DREAM study. Patients ≥12 years of age with severe eosinophilic asthma were randomised (1:1:1:1) to receive intravenous mepolizumab 75 mg (equivalent to 100 mg s.c.), 250 mg, 750 mg or placebo, plus standard of care, every 4 weeks for 52 weeks. The number of exacerbations and eDiary data (peak expiratory flow, rescue medication use and symptom scores) from two periods in each 4-weekly dosing interval (days 1-14 and 15-28) over the 52-week treatment period were analysed.

Findings

eDiary data and the proportion of patients experiencing ≥1 exacerbation were similar during the first and second 2 weeks of a dosing period across all mepolizumab doses.

Interpretation

These results demonstrate that the response to mepolizumab is sustained over the 4-weekly dosing period with no differences across a 10-fold dose range and supports the use of the current mepolizumab dosing regimen in patients with severe eosinophilic asthma.

Effects of the Toll-like receptor 7 (TLR7) agonist, AZD8848, on allergen-induced responses in patients with mild asthma: a double-blind, randomised, parallel-group study

Background

Although allergic asthma is a complex area with many interacting factors involved, the ‘hygiene hypothesis’ proposes that a lack of exposure to infection during childhood may polarise the immune system towards allergen-reactive Th2-type responses in genetically susceptible individuals. Toll-like receptors (TLRs) play a key role within the innate immune system and TLR7 agonists have previously been shown to up-regulate Th1 responses and down-regulate Th2 responses to allergens in murine models of allergic or chronic asthma. This study aimed to examine the efficacy and safety of the novel TRL7 agonist AZD8848, which has been developed as an antedrug.

Methods

In this double-blind, randomised, parallel-group study, AZD8848 60 μg or placebo was administered intranasally once-weekly for 8 weeks in patients with mild-to-moderate allergic asthma (NCT00999466). Efficacy assessments were performed at 1 and 4 weeks after the last dose. The primary outcome was the late asthmatic response (LAR) fall in forced expiratory volume in 1 s (FEV₁) after allergen challenge at 1-week post-treatment.

Results

AZD8848 significantly reduced average LAR fall in FEV₁ by 27% vs. placebo at 1 week after treatment (p = 0.035). This effect was sustained at 4 weeks post-treatment; however, it did not reach clinical significance. AZD8848 reduced post-allergen challenge methacholine-induced airway hyper-responsiveness (AHR) vs. placebo at 1 week post-dosing (treatment ratio: 2.20, p = 0.024), with no effect at 4 weeks. There was no significant difference between the two groups in plasma cytokine, sputum Th2 cytokine or eosinophil responses post-allergen challenge at 1 week after treatment. The incidence of adverse events was similar in the two groups. AZD8848 was generally well tolerated.

Conclusions and clinical relevance

In patients with allergic asthma, TLR7 agonists could potentially reduce allergen responsiveness by stimulating Type 1 interferon responses to down-regulate the dominant Th2 responses.

Trial registration

clinicaltrials.gov identifier NCT00999466.

Selection and characterization of single-stranded DNA aptamers against interleukin-5

Asthma as a chronic inflammatory disorder is associated with many cytokines like interleukin-5 (IL-5) which plays essential role in eosinophil differentiation and maturation. Accordingly, blockage of IL-5 using mepalizumab has been considered as a promising therapeutic approach for asthma. Despite the monocolonal antibody advantages, some restrictions provided an acceptable background for alternative agents like aptamers which could replace with antibodies. In the current study, aptamer isolation against IL-5 molecule was intended, according to the valuable benefits of aptamers over antibodies. HEK-293T/IL-5 cell was constructed to select aptamer using cell-systematic evolution of ligands by exponential enrichment (SELEX) method. Integration of the IL-5 fragment to genome of the HEK-293T was verified by polymerase chain reaction on the genomic DNA of the transfected cells. Moreover, IL-5 protein expression on the cell surface was confirmed using flow cytometry analysis. Then, cell SELEX was carried out in 12 rounds and isolated aptamers were evaluated by flow cytometry analysis. The selected clones were then sequenced and assessed for any possible secondary structure. The results of this study led to the selection of 19 different single-stranded DNA clones after 12 rounds of selection which were clustered to five groups based on common structural motifs. In conclusion, the findings revealed the isolation of IL-5-specific single-stranded DNA aptamers, which can further be substituted with mepolizumab.

Severe asthma in children-a review of definitions, epidemiology, and treatment options in 2019

Severe asthma is a relatively uncommon condition in children but one which causes morbidity, occasionally mortality, and is a challenging condition to manage. There are several definitions of severe asthma, which have a common theme of poor control despite high dose inhaled corticosteroid treatment. Depending on the definition chosen, the prevalence of severe childhood asthma may be up to 5% within populations with asthma. Collectively, there is some evidence that the treatments used in severe asthma are beneficial, but a solid evidence-base is lacking for many treatments and some treatments have recognized side effects. Evidence supporting the use of maintenance oral prednisolone and intramuscular triamcinolone is weak. Response to systemic corticosteroids is heterogeneous and recognizing phenotypes or endotypes may identify those most likely to gain maximal benefit from treatment. For children aged 6 to 11 years, the anti-IgE biologic omalizumab is effective and anti-IL-5 agent (mepolizumab) has recently been licenced in Europe (but not the US). Biologics, which are licenced for >11 year olds include omalizumab, mepolizumab, benralizumab, reslizumab, and dupilumab. There is plenty that the clinician can offer to the child and adolescent with severe asthma in 2019, including nontherapeutic and therapeutic interventions. To manage severe asthma, practitioners from broad specialities must establish and maintain a close therapeutic relationship with patients. Looking beyond 2019, more treatment options will emerge for severe childhood asthma, and clinical teams will need to continue weighing up benefits and harms.

Comparison of Monoclonal Antibodies for Treatment of Uncontrolled Eosinophilic Asthma

OBJECTIVE

To summarize the current literature for Food and Drug Administration (FDA)-approved monoclonal antibodies used as add-on maintenance therapy in uncontrolled eosinophilic asthma.

DATA SOURCES

PubMed was searched on December 17, 2018 using keywords: asthma, eosinophilic asthma, omalizumab, reslizumab, mepolizumab, benralizumab, and dupilumab.

STUDY SELECTION

Studies evaluating safety and efficacy of monoclonal antibodies for treatment of severe or eosinophilic asthma were included.

RESULTS

Twenty-one randomized, double-blind, placebo-controlled trials evaluating the current FDA-approved monoclonal antibodies (omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab) for the treatment of uncontrolled eosinophilic asthma were included. The studies demonstrated clinically significant reductions in asthma exacerbations, symptoms, emergency room visits, eosinophil counts, and improvements in pulmonary function and asthma-related quality of life.

CONCLUSION

Five monoclonal antibodies are available for uncontrolled eosinophilic asthma. Choice depends on patient factors. Future studies should focus on cost-effectiveness of treatment, drug-drug comparisons, and long-term efficacy and safety.

Disease burden and efficacy of mepolizumab in patients with severe asthma and blood eosinophil counts of ≥150-300 cells/μL

BACKGROUND

In patients with severe eosinophilic asthma, treatment decisions can be determined by blood eosinophil counts; however, a specific blood eosinophil threshold has not been defined for starting mepolizumab treatment.

METHODS

We summarized the disease burden and efficacy of mepolizumab in patients with severe eosinophilic asthma and baseline blood eosinophil counts of ≥150-300 cells/μL and ≥300 cells/μL using data from the mepolizumab clinical development program (DREAM [NCT01000506], MENSA [NCT01691521], SIRIUS [NCT01691508] and MUSCA [NCT02281318]).

RESULTS

The morbidity of asthma in patients with baseline blood eosinophil counts ≥150-300 cells/μL was similar to that in patients with blood eosinophil counts ≥300 cells/μL, with similar rates of exacerbations (2.8-3.5 events/year versus 2.8-3.8 events/year, respectively), asthma related emergency room visits, intubations and near fatal events. Use of maintenance oral corticosteroids (OCS) was similar across blood eosinophil count subgroups. Reductions in the rates of clinically significant exacerbations with mepolizumab versus placebo ranged from 27 to 49% in patients with blood eosinophil counts of ≥150-300 cells/μL for DREAM, MENSA and MUSCA. The odds of achieving a reduction in OCS in SIRIUS was 2.03 (95% CI: 0.53, 7.75) versus 1.79 (95% CI: 0.71, 4.52) in patients with blood eosinophil counts ≥150-300 cells/μL and ≥300 cells/μL, respectively.

CONCLUSION

There is a high unmet clinical need in patients with blood eosinophil counts ≥150-300 cells/μL, and a clinically meaningful benefit is seen with mepolizumab in this subgroup. Mepolizumab is an efficacious treatment option for patients with blood eosinophil counts ≥150 cells/μL.

Phenotypes/endotypes-driven treatment in asthma

PURPOSE OF REVIEW

Target therapy is the necessary step towards personalized medicine. The definition of asthma phenotypes and underlying mechanisms (endotypes) represent a key point in the development of new asthma treatments. Big data analysis, biomarker research and the availability of monoclonal antibodies, targeting specific cytokines is leading to the rapid evolution of knowledge. In this review, we sought to outline many of the recent advances in the field.

RECENT FINDINGS

Several attempts have been made to identify asthma phenotypes, sometimes with contrasting results. More success has been obtained concerning the pathogenetic mechanism of specific asthma patterns with the consequent identification of biomarkers and development of effective ad hoc treatment.

SUMMARY

We are in the middle of an extraordinary revolution of our mode of thinking about and approaching asthma. All the effort in the identification of clusters of patients with different disease clinical patterns, prognosis and response to treatment is closely linked to the identification of endotypes (Th2-low and Th2-high). This approach has allowed the development of the specific treatments (anti IgE, Anti IL5 and IL5R) that are now available and is leading to new ones.

Immunological and hematological effects of IL-5(Rα)-targeted therapy: An overview

IL‐5 is an important cytokine for priming and survival of mature eosinophils and for proliferation and maturation of their progenitors. Hence, IL‐5(Rα) targeting will be increasingly used in diseases where eosinophils are the key immune effector cells such as eosinophilic asthma (EA), hypereosinophilic syndrome (HES), eosinophilic esophagitis (EE), and eosinophilic granulomatosis with polyangiitis (EGPA). Therefore, several neutralizing monoclonal antibodies directed against IL‐5 (mepolizumab and reslizumab) and its receptor IL‐5Rα (benralizumab) have found or will find their way to the clinic. While the clinical effect of these drugs has been extensively investigated and reviewed, the understanding of the underlying immunological and hematological mechanisms remains less clear. This review will discuss the translational outcomes of treatment with these monoclonal antibodies in humans to shed light on the mechanisms underlying the main immunological and hematological findings from these clinical trials in humans.

Precision Medicine in Targeted Therapies for Severe Asthma: Is There Any Place for "Omics" Technology?

According to the current guidelines, severe asthma still represents a controversial topic in terms of definition and management. The introduction of novel biological therapies as a treatment option for severe asthmatic patients paved the way to a personalized approach, which aims at matching the appropriate therapy with the different asthma phenotypes. Traditional asthma phenotypes have been decomposing by an increasing number of asthma subclasses based on functional and physiopathological mechanisms. This is possible thanks to the development and application of different omics technologies. The new asthma classification patterns, particularly concerning severe asthma, include an increasing number of endotypes that have been identified using new omics technologies. The identification of endotypes provides new opportunities for the management of asthma symptoms, but this implies that biological therapies which target inflammatory mediators in the frame of specific patterns of inflammation should be developed. However, the pathway leading to a precision approach in asthma treatment is still at its beginning. The aim of this review is providing a synthetic overview of the current asthma management, with a particular focus on severe asthma, in the light of phenotype and endotype approach, and summarizing the current knowledge about "omics" science and their therapeutic relevance in the field of bronchial asthma.

Bronchial thermoplasty and the role of airway smooth muscle: are we on the right direction?

Asthma is characterized by inflammation of the airways that includes eosinophils, basal membrane thickening, epithelial sloughing, vascular changes, smooth muscle hypertrophy and hyperplasia, and mucous gland hyperplasia. Recently, there have been studies on the role of hypersensitivity and inflammation in asthma, but the role of bronchial smooth muscle remains unclear. Bronchial thermoplasty is an endoscopic procedure that is approved by the US Food and Drug Administration (FDA) for the treatment of severe refractory asthma, based on the local delivery of radio frequency at 65°C to the airways, with the aim of controlling bronchospasm through a reduction of airway smooth muscle (ASM). Several recent studies have shown significant improvement in clinical outcomes of bronchial thermoplasty for asthma, including symptom control, reduction in exacerbation and hospitalization rates, improved quality of life, and reduction in number of working days or school days lost due to asthma. Data from these recent studies have shown reduction in ASM following bronchial thermoplasty and changes in inflammation patterns. It has also been argued that bronchial thermoplasty may have modulating effects on neuroendocrine epithelial cells, bronchial nerve endings, TRPV1 nerve receptors, and type-C unmyelinated fibers in the bronchial mucosa. This may involve interrupting the central and local reflexes responsible for the activation of bronchospasm in the presence of bronchial hyperreactivity. Several questions remain regarding the use of bronchial thermoplasty, mechanism of action, selection of appropriate patients, and long-term effects. In this review, the role of ASM in the pathogenesis of asthma and the key aspects of bronchial thermoplasty are discussed, with a focus on the potential clinical effects of this promising procedure, beyond the reduction in ASM.