Efficacy and safety of a CXCR2 antagonist, AZD5069, in patients with uncontrolled persistent asthma: a randomised, double-blind, placebo-controlled trial

Promises and challenges of biologics for severe asthma

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

Neutrophil chemoattractant receptors in health and disease: double-edged swords

Neutrophils are frontline cells of the innate immune system. These effector leukocytes are equipped with intriguing antimicrobial machinery and consequently display high cytotoxic potential. Accurate neutrophil recruitment is essential to combat microbes and to restore homeostasis, for inflammation modulation and resolution, wound healing and tissue repair. After fulfilling the appropriate effector functions, however, dampening neutrophil activation and infiltration is crucial to prevent damage to the host. In humans, chemoattractant molecules can be categorized into four biochemical families, i.e., chemotactic lipids, formyl peptides, complement anaphylatoxins and chemokines. They are critically involved in the tight regulation of neutrophil bone marrow storage and egress and in spatial and temporal neutrophil trafficking between organs. Chemoattractants function by activating dedicated heptahelical G protein-coupled receptors (GPCRs). In addition, emerging evidence suggests an important role for atypical chemoattractant receptors (ACKRs) that do not couple to G proteins in fine-tuning neutrophil migratory and functional responses. The expression levels of chemoattractant receptors are dependent on the level of neutrophil maturation and state of activation, with a pivotal modulatory role for the (inflammatory) environment. Here, we provide an overview of chemoattractant receptors expressed by neutrophils in health and disease. Depending on the (patho)physiological context, specific chemoattractant receptors may be up- or downregulated on distinct neutrophil subsets with beneficial or detrimental consequences, thus opening new windows for the identification of disease biomarkers and potential drug targets.

Chinese Society of Allergy and Chinese Society of Otorhinolaryngology-Head and Neck Surgery Guideline for Chronic Rhinosinusitis

The current document is based on a consensus reached by a panel of experts from the Chinese Society of Allergy and the Chinese Society of Otorhinolaryngology-Head and Neck Surgery, Rhinology Group. Chronic rhinosinusitis (CRS) affects approximately 8% of Chinese adults. The inflammatory and remodeling mechanisms of CRS in the Chinese population differ from those observed in the populations of European descent. Recently, precision medicine has been used to treat inflammation by targeting key biomarkers that are involved in the process. However, there are no CRS guidelines or a consensus available from China that can be shared with the international academia. The guidelines presented in this paper cover the epidemiology, economic burden, genetics and epigenetics, mechanisms, phenotypes and endotypes, diagnosis and differential diagnosis, management, and the current status of CRS in China. These guidelines-with a focus on China-will improve the abilities of clinical and medical staff during the treatment of CRS. Additionally, they will help international agencies in improving the verification of CRS endotypes, mapping of eosinophilic shifts, the identification of suitable biomarkers for endotyping, and predicting responses to therapies. In conclusion, these guidelines will help select therapies, such as pharmacotherapy, surgical approaches and innovative biotherapeutics, which are tailored to each of the individual CRS endotypes.

Targeting neutrophils using novel drug delivery systems in chronic respiratory diseases

Neutrophils are essential effector cells of immune system for clearing the extracellular pathogens during inflammation and immune reactions. Neutrophils play a major role in chronic respiratory diseases. In respiratory diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, lung cancer and others, there occurs extreme infiltration and activation of neutrophils followed by a cascade of events like oxidative stress and dysregulated cellular proteins that eventually result in apoptosis and tissue damage. Dysregulation of neutrophil effector functions including delayed neutropil apoptosis, increased neutrophil extracellular traps in the pathogenesis of asthma, and chronic obstructive pulmonary disease enable neutrophils as a potential therapeutic target. Accounting to their role in pathogenesis, neutrophils present as an excellent therapeutic target for the treatment of chronic respiratory diseases. This review highlights the current status and the emerging trends in novel drug delivery systems such as nanoparticles, liposomes, microspheres, and other newer nanosystems that can target neutrophils and their molecular pathways, in the airways against infections, inflammation, and cancer. These drug delivery systems are promising in providing sustained drug delivery, reduced therapeutic dose, improved patient compliance, and reduced drug toxicity. In addition, the review also discusses emerging strategies and the future perspectives in neutrophil-based therapy.

The role of CXCR2 in acute inflammatory responses and its antagonists as anti-inflammatory therapeutics

PURPOSE OF REVIEW

CXCR2 is key stimulant of immune cell migration and recruitment, especially of neutrophils. Alleviating excessive neutrophil accumulation and infiltration could prevent prolonged tissue damage in inflammatory disorders. This review focuses on recent advances in our understanding of the role of CXCR2 in regulating neutrophil migration and the use of CXCR2 antagonists for therapeutic benefit in inflammatory disorders.

RECENT FINDINGS

Recent studies have provided new insights into how CXCR2 signaling regulates hematopoietic cell mobilization and function in both health and disease. We also summarize several CXCR2 regulatory mechanisms during infection and inflammation such as via Wip1, T-bet, P-selectin glycoprotein ligand-1, granulocyte-colony-stimulating factor, and microbiome. Moreover, we provide an update of studies investigating CXCR2 blockade in the laboratory and in clinical trials.

SUMMARY

Neutrophil homeostasis, migration, and recruitment must be precisely regulated. The CXCR2 signaling pathway is a potential target for modifying neutrophil dynamics in inflammatory disorders. We discuss the recent clinical use of CXCR2 antagonists for controlling inflammation.

Different endotypes and phenotypes drive the heterogeneity in severe asthma

The identification of sputum eosinophilia indicating corticosteroid responsiveness in subjects with severe asthma heralded the beginning of phenotyping asthmatic subjects based on airways inflammation. Since then, the heterogeneity of severe asthma has been explored and the importance of immunobiology has come sharply into focus with the identification of the key type-2 cytokine pathways driving eosinophilic inflammation. The development of molecules targeting these type-2 pathways has transformed severe asthma treatment, but necessitates robust clinical evaluation, biomarker profiling and assessment of comorbid factors to identify subjects most likely to benefit from these therapies. It has also become clear that targeting these pathways does not eradicate asthma symptoms and exacerbation risk; further work is needed to clarify underlying non-type-2 mechanisms in severe asthma pathways and possible therapeutic targets. This review addresses progress to date in clinical assessment and management of severe asthma and some of the challenges and unmet needs in severe asthma to achieve the goal of delivering individualized patient care.

Mechanisms and therapeutic strategies for non-T2 asthma

Non-T2 asthma is traditionally defined as asthma without features of T2 asthma. The definition is arbitrary and is generally based on the presence of neutrophils in sputum, or the absence (or normal levels) of eosinophils or other T2 markers in sputum (paucigranulocytic), airway biopsies or in blood. This definition may be imprecise as we gain more knowledge from applying transcriptomics and proteomics to blood and airway samples. The prevalence of non-T2 asthma is also difficult to estimate as most studies are cross-sectional and influenced by concomitant treatment with glucocorticosteroids, and by the presence of recognized or unrecognized airway infections. No specific therapies have shown any clinical benefits in patients with asthma that is associated with a non-T2 inflammatory process. It remains to be seen if such an endotype truly exists and to identify treatments to target that endotype. Meanwhile, identifying intense airway neutrophilia as an indicator of airway infection and airway hyperresponsiveness as an indicator of smooth muscle dysfunction, and treating them appropriately, and not increasing glucocorticosteroids in patients who do not have obvious T2 inflammation, seem reasonable.

New insights in neutrophilic asthma

PURPOSE OF REVIEW

Recent advances in both murine models and clinical research of neutrophilic asthma are improving our understanding on the etiology and pathophysiology of this enigmatic endotype of asthma. We here aim at providing an overview of our current and latest insights on the pathophysiology and treatment of neutrophilic asthma.

RECENT FINDINGS

Activation of the NLRP3 inflammasome pathway with increased IL-1β has been demonstrated in various studies involving patients with asthma. It has been suggested that type 3 innate lymphoid cells are implicated in the inflammatory cascade leading to neutrophilic inflammation. The role of neutrophil extracellular traps is only at the start of being understood and might be an attractive novel therapeutic target. A diverse panel of nonallergic stimuli, such as cigarette smoke, intensive exercise, cold air or saturated fatty acids, have been linked with neutrophilic airway inflammation. Azithromycin treatment could reduce asthma exacerbations and quality of life in patients with persistent asthma.

SUMMARY

Research of the last few years has accelerated our insights in mechanisms underlying neutrophilic asthma. This is in stark contrast with the lack of efficacy of different therapies targeting neutrophil chemotaxis and/or signalling cascade, such as IL-17A or CXCR2. Macrolide therapy might be a useful add-on therapy for patients with persistent asthma.

Neutrophil-macrophage cooperation and its impact on tissue repair

Immune cells are rapidly recruited to a site of injury or infection. Although the importance of phagocytic immune cells in clearing bacteria has long been appreciated, the advent of technologies allowing more in-depth analysis of cellular function, such as intravital microscopy and the use of genetically modified animal models, has allowed much deeper insight into the complex roles of these cells play during tissue repair. Many immune cells contribute to the repair process; however, this review will concentrate on the involvement of the phagocytes, namely macrophages and neutrophils, with a particular focus on our more recent understanding of how interactions between these two cell types impact on the final outcome of tissue repair.

Mechanisms and Management of Asthma Exacerbations

Acute asthma remains an important medical emergency, the most frequent cause of acute admissions in children and a major source of morbidity for adults with asthma. In all ages with asthma, the presence of exacerbations is an important defining characteristic of asthma severity. In this review, we assess the epidemiology of acute asthma, the triggers of acute exacerbations, and the mechanisms that underlie these exacerbations. We also assess current treatments that prevent exacerbations, with an emphasis on the role of type 2 airway inflammation in the context of acute exacerbations and the novel treatments that effectively target this. Finally we review current management strategies of the exacerbations themselves.

G Protein-Coupled Receptors in Asthma Therapy: Pharmacology and Drug Action

Asthma is a heterogeneous inflammatory disease of the airways that is associated with airway hyperresponsiveness and airflow limitation. Although asthma was once simply categorized as atopic or nonatopic, emerging analyses over the last few decades have revealed a variety of asthma endotypes that are attributed to numerous pathophysiological mechanisms. The classification of asthma by endotype is primarily routed in different profiles of airway inflammation that contribute to bronchoconstriction. Many asthma therapeutics target G protein-coupled receptors (GPCRs), which either enhance bronchodilation or prevent bronchoconstriction. Short-acting and long-acting β 2-agonists are widely used bronchodilators that signal through the activation of the β 2-adrenergic receptor. Short-acting and long-acting antagonists of muscarinic acetylcholine receptors are used to reduce bronchoconstriction by blocking the action of acetylcholine. Leukotriene antagonists that block the signaling of cysteinyl leukotriene receptor 1 are used as an add-on therapy to reduce bronchoconstriction and inflammation induced by cysteinyl leukotrienes. A number of GPCR-targeting asthma drug candidates are also in different stages of development. Among them, antagonists of prostaglandin D2 receptor 2 have advanced into phase III clinical trials. Others, including antagonists of the adenosine A2B receptor and the histamine H4 receptor, are in early stages of clinical investigation. In the past decade, significant research advancements in pharmacology, cell biology, structural biology, and molecular physiology have greatly deepened our understanding of the therapeutic roles of GPCRs in asthma and drug action on these GPCRs. This review summarizes our current understanding of GPCR signaling and pharmacology in the context of asthma treatment. SIGNIFICANCE STATEMENT: Although current treatment methods for asthma are effective for a majority of asthma patients, there are still a large number of patients with poorly controlled asthma who may experience asthma exacerbations. This review summarizes current asthma treatment methods and our understanding of signaling and pharmacology of G protein-coupled receptors (GPCRs) in asthma therapy, and discusses controversies regarding the use of GPCR drugs and new opportunities in developing GPCR-targeting therapeutics for the treatment of asthma.

Surgical trauma-induced immunosuppression in cancer: Recent advances and the potential therapies

Surgical resection remains the mainstay treatment for solid cancers, especially for localized disease. However, the postoperative immunosuppression provides a window for cancer cell proliferation and awakening dormant cancer cells, leading to rapid recurrences or metastases. This immunosuppressive status after surgery is associated with the severity of surgical trauma since immunosuppression induced by minimally invasive surgery is less than that of an extensive open surgery. The systemic response to tissue damages caused by surgical operations and the subsequent wound healing induced a cascade alteration in cellular immunity. After surgery, patients have a high level of circulating damage-associated molecular patterns (DAMPs), triggering a local and systemic inflammation. The inflammatory metrics in the immediate postoperative period was associated with the prognosis of cancer patients. Neutrophils provide the first response to surgical trauma, and the production of neutrophil extracellular traps (NETs) promotes cancer progression. Activated macrophage during wound healing presents a tumor-associated phenotype that cancers can exploit for their survival advantage. In addition, the amplification and activation of myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs) or the elevated programmed death ligand-1 and vascular endothelial growth factor expression under surgical trauma, exacerbate the immunosuppression and favor of the formation of the premetastatic niche. Therapeutic strategies to reduce the cellular immunity impairment after surgery include anti-DAMPs, anti-postoperative inflammation or inflammatory/pyroptosis signal, combined immunotherapy with surgery, antiangiogenesis and targeted therapies for neutrophils, macrophages, MDSCs, and Tregs. Further, the application of enhanced recovery after surgery also has a feasible outcome for postoperative immunity restoration. Overall, current therapies to improve the cellular immunity under the special condition after surgery are relatively lacking. Further understanding the underlying mechanisms of surgical trauma-related immunity dysfunction, phenotyping the immunosuppressive cells, and developing the related therapeutic intervention should be explored.

Neutrophils restrain allergic airway inflammation by limiting ILC2 function and monocyte-dendritic cell antigen presentation

Neutrophil mobilization, recruitment, and clearance must be tightly regulated as overexuberant neutrophilic inflammation is implicated in the pathology of chronic diseases, including asthma. Efforts to target neutrophils therapeutically have failed to consider their pleiotropic functions and the implications of disrupting fundamental regulatory pathways that govern their turnover during homeostasis and inflammation. Using the house dust mite (HDM) model of allergic airway disease, we demonstrate that neutrophil depletion unexpectedly resulted in exacerbated T helper 2 (TH2) inflammation, epithelial remodeling, and airway resistance. Mechanistically, this was attributable to a marked increase in systemic granulocyte colony-stimulating factor (G-CSF) concentrations, which are ordinarily negatively regulated in the periphery by transmigrated lung neutrophils. Intriguingly, we found that increased G-CSF augmented allergic sensitization in HDM-exposed animals by directly acting on airway type 2 innate lymphoid cells (ILC2s) to elicit cytokine production. Moreover, increased systemic G-CSF promoted expansion of bone marrow monocyte progenitor populations, which resulted in enhanced antigen presentation by an augmented peripheral monocyte-derived dendritic cell pool. By modeling the effects of neutrophil depletion, our studies have uncovered previously unappreciated roles for G-CSF in modulating ILC2 function and antigen presentation. More broadly, they highlight an unexpected regulatory role for neutrophils in limiting TH2 allergic airway inflammation.

Targeting cell signaling in allergic asthma

Asthma is chronic inflammation of the airways characterized by airway hyper-responsiveness, wheezing, cough, and dyspnea. Asthma affects >350 million people worldwide. The Th2 immune response is a major contributor to the pathophysiology of asthma. Targeted therapy modulating cell signaling pathways can be a powerful strategy to design new drugs to treat asthma. The potential molecular pathways that can be targeted include IL-4-IL-13-JAK-STAT-MAP kinases, adiponectin-iNOS-NF-κB, PGD2-CRTH2, IFNs-RIG, Wnt/β-catenin-FAM13A, FOXC1-miR-PI3K/AKT, JNK-Gal-7, Nrf2-ROS, Foxp3-RORγt, CysLTR, AMP, Fas-FasL, PTHrP/PPARγ, PAI-1, FcɛRI-LAT-SLP-76, Tim-3-Gal-9, TLRs-MyD88, PAR2, and Keap1/Nrf2/ARE. Therapeutic drugs can be designed to target one or more of these pathways to treat asthma.

Toward clinically applicable biomarkers for asthma: An EAACI position paper

Inflammation, structural, and functional abnormalities within the airways are key features of asthma. Although these processes are well documented, their expression varies across the heterogeneous spectrum of asthma. Type 2 inflammatory responses are characterized by increased levels of eosinophils, FeNO, and type 2 cytokines in blood and/or airways. Presently, type 2 asthma is the best-defined endotype, typically found in patients with allergic asthma, but surprisingly also in nonallergic patients with (severe) asthma. The etiology of asthma with non-type 2 inflammation is less clear. During the past decade, targeted therapies, including biologicals and small molecules, have been increasingly integrated into treatment strategies of severe asthma. These treatments block specific inflammatory pathways or single mediators. Single or composite biomarkers help to identify patients who will benefit from these treatments. So far, only a few inflammatory biomarkers have been validated for clinical application. The European Academy of Allergy & Clinical Immunology Task Force on Biomarkers in Asthma was initiated to review different biomarker sampling methods and to investigate clinical applicability of new and existing inflammatory biomarkers (point-of-care) to support diagnosis, targeted treatment, and monitoring of severe asthma. Subsequently, we discuss existing and novel targeted therapies for asthma as well as applicable biomarkers.

Targeting Transfusion-Related Acute Lung Injury: The Journey From Basic Science to Novel Therapies

OBJECTIVES

Transfusion-related acute lung injury is characterized by the onset of respiratory distress and acute lung injury following blood transfusion, but its pathogenesis remains poorly understood. Generally, a two-hit model is presumed to underlie transfusion-related acute lung injury with the first hit being risk factors present in the transfused patient (such as inflammation), whereas the second hit is conveyed by factors in the transfused donor blood (such as antileukocyte antibodies). At least 80% of transfusion-related acute lung injury cases are related to the presence of donor antibodies such as antihuman leukocyte or antihuman neutrophil antibodies. The remaining cases may be related to nonantibody-mediated factors such as biolipids or components related to storage and ageing of the transfused blood cells. At present, transfusion-related acute lung injury is the leading cause of transfusion-related fatalities and no specific therapy is clinically available. In this article, we critically appraise and discuss recent preclinical (bench) insights related to transfusion-related acute lung injury pathogenesis and their therapeutic potential for future use at the patients' bedside in order to combat this devastating and possibly fatal complication of transfusion.

DATA SOURCES

We searched the PubMed database (until August 22, 2017).

STUDY SELECTION

Using terms: "Transfusion-related acute lung injury," "TRALI," "TRALI and therapy," "TRALI pathogenesis."

DATA EXTRACTION

English-written articles focusing on transfusion-related acute lung injury pathogenesis, with potential therapeutic implications, were extracted.

DATA SYNTHESIS

We have identified potential therapeutic approaches based on the literature.

CONCLUSIONS

We propose that the most promising therapeutic strategies to explore are interleukin-10 therapy, down-modulating C-reactive protein levels, targeting reactive oxygen species, or blocking the interleukin-8 receptors; all focused on the transfused recipient. In the long-run, it may perhaps also be advantageous to explore other strategies aimed at the transfused recipient or aimed toward the blood product, but these will require more validation and confirmation first.

The RNA-binding protein Mex-3B plays critical roles in the development of steroid-resistant neutrophilic airway inflammation

While most asthma can be treated with steroids, about 10%, called severe asthma, is refractory to steroids. It has recently been shown that in a subgroup of severe asthma cases, neutrophils that infiltrate into the airways play an important role in inflammation. However, the mechanisms underlying this increased neutrophil infiltration are not well understood. Here, using a mouse model of steroid-resistant neutrophilic inflammation, we show that mice deficient for the RNA-binding protein Mex-3B have significantly less neutrophil infiltration in the airways than wild-type mice. We further demonstrate that Mex-3B post-transcriptionally upregulates CXCL2, a chemokine that induces neutrophil chemotaxis and migration. Moreover, we show that treatment with either anti-CXCL2 antibody or anti-Mex-3B antisense oligonucleotide suppresses neutrophilic allergic airway inflammation. These results suggest that Mex-3B-mediated induction of CXCL2 is crucial for steroid-resistant neutrophilic allergic airway inflammation. Our findings suggest new strategies for therapeutic intervention in steroid-resistant severe asthma.

Precision medicine for the discovery of treatable mechanisms in severe asthma

Although the complex disease of asthma has been defined as being heterogeneous, the extent of its endophenotypes remains unclear. The pharmacological approach to initiating treatment has, until recently, been based on disease control and severity. The introduction of antibody therapies targeting the Type 2 inflammation pathway for patients with severe asthma has resulted in the recognition of an allergic and an eosinophilic phenotype, which are not mutually exclusive. Concomitantly, molecular phenotyping based on a transcriptomic analysis of bronchial epithelial and sputum cells has identified a Type 2 high inflammation cluster characterized by eosinophilia and recurrent exacerbations, as well as Type 2 low clusters linked with IL-6 trans-signalling, interferon pathways, inflammasome activation and mitochondrial oxidative phosphorylation pathways. Systems biology approaches are establishing the links between these pathways or mechanisms, and clinical and physiologic features. Validation of these pathways contributes to defining endotypes and treatable mechanisms. Precision medicine approaches are necessary to link treatable mechanisms with treatable traits and biomarkers derived from clinical, physiologic and inflammatory features of clinical phenotypes. The deep molecular phenotyping of airway samples along with noninvasive biomarkers linked to bioinformatic and machine learning techniques will enable the rapid detection of molecular mechanisms that transgresses beyond the concept of treatable traits.

Discovery of the Oral Leukotriene C4 Synthase Inhibitor (1S,2S)-2-({5-[(5-Chloro-2,4-difluorophenyl)(2-fluoro-2-methylpropyl)amino]-3-methoxypyrazin-2-yl}carbonyl)cyclopropanecarboxylic Acid (AZD9898) as a New Treatment for Asthma

While bronchodilators and inhaled corticosteroids are the mainstay of asthma treatment, up to 50% of asthmatics remain uncontrolled. Many studies show that the cysteinyl leukotriene cascade remains highly activated in some asthmatics, even those on high-dose inhaled or oral corticosteroids. Hence, inhibition of the leukotriene C4 synthase (LTC4S) enzyme could provide a new and differentiated core treatment for patients with a highly activated cysteinyl leukotriene cascade. Starting from a screening hit (3), a program to discover oral inhibitors of LTC4S led to (1S,2S)-2-({5-[(5-chloro-2,4-difluorophenyl)(2-fluoro-2-methylpropyl)amino]-3-methoxypyrazin-2-yl}carbonyl)cyclopropanecarboxylic acid (AZD9898) (36), a picomolar LTC4S inhibitor (IC₅₀ = 0.28 nM) with high lipophilic ligand efficiency (LLE = 8.5), which displays nanomolar potency in cells (peripheral blood mononuclear cell, IC_50,free = 6.2 nM) and good in vivo pharmacodynamics in a calcium ionophore-stimulated rat model after oral dosing (in vivo, IC_50,free = 34 nM). Compound 36 mitigates the GABA binding, hepatic toxicity signal, and in vivo toxicology findings of an early lead compound 7 with a human dose predicted to be 30 mg once daily.

Targeting cytokines to treat asthma and chronic obstructive pulmonary disease

Cytokines play a key role in orchestrating and perpetuating the chronic airway inflammation in asthma and chronic obstructive pulmonary disease (COPD), making them attractive targets for treating these disorders. Asthma and some cases of COPD are mainly driven by type 2 immune responses, which comprise increased airway eosinophils, T helper 2 (T_H2) cells and group 2 innate lymphoid cells (ILC2s) and the secretion of IL-4, IL-5 and IL-13. Clinical trials of antibodies that block these interleukins have shown reduced acute exacerbations and oral corticosteroid use and improvements in lung function and symptoms in selected patients. More recent approaches that block upstream cytokines, such as thymic stromal lymphopoietin (TSLP), show promise in improving patient outcome. Importantly, the clinical trials in cytokine blockade have highlighted the crucial importance of patient selection for the successful use of these expensive therapies and the need for biomarkers to better predict drug responses.

Management of asthma COPD overlap

OBJECTIVE

To review the latest literature on management approaches to patients with asthma chronic obstructive pulmonary disease (COPD) overlap (ACO).

DATA SOURCES

Studies and reports were identified from the databases of PubMed/Medline and ClinicalTrials.gov from the US National Institutes of Health and the Cochrane Register of Controlled Trials.

STUDY SELECTIONS

Studies on the management of asthma, COPD, and ACO were included in this review.

RESULTS

Patients with asthma COPD overlap tend to have greater morbidity than those with asthma or COPD alone, but the information on the best therapeutic approach to this group of patients is still limited. Current treatment recommendations rely on expert opinions, roundtable discussions, and strategy documents, because most clinical studies in asthma and COPD have excluded patients with ACO. Because of the potential risk described in patients with asthma with the use of long-acting 2 agonist monotherapy, initial therapy for patients with ACO is recommended to include a long-acting bronchodilator in conjunction with inhaled corticosteroids. Long-acting muscarinic antagonists are effective in both asthma and COPD and should be considered in ACO as an add-on treatment. If inhaler therapy is not effective, advanced therapies based on phenotyping and identification of treatable traits may be considered.

CONCLUSION

Few studies have evaluated prospectively therapies in the ACO population, and future studies need to determine best strategies for the treatment of these patients, focusing on targeting its different phenotypes and its treatable traits.

Distinct Spatio-Temporal Dynamics of Tumor-Associated Neutrophils in Small Tumor Lesions

Across a majority of cancer types tumor-associated neutrophils (TAN) are linked with poor prognosis. However, the underlying mechanisms, especially the intratumoral behavior of TAN, are largely unknown. Using intravital multiphoton imaging on a mouse model with neutrophil-specific fluorescence, we measured the migration of TAN in distinct compartments of solid tumor cell lesions in vivo. By longitudinally quantifying the infiltration and persistence of TAN into growing tumors in the same animals, we observed cells that either populated the peripheral stromal zone of the tumor (peritumoral TAN) or infiltrated into the tumor core (intratumoral TAN). Intratumoral TAN showed prolonged tumor-associated persistence and reduced motility compared to peritumoral TAN, whose velocity increased with tumor progression. Selective pharmacological blockade of CXCR2 receptors using AZD5069 profoundly inhibited recruitment of TAN into peritumoral regions, while intratumoral infiltration was only transiently attenuated and rebounded at later time points. Our findings unravel distinct spatial dynamics of TAN that are partially and differentially regulated via the CXCR2 signaling pathway.

The emergence of new biologics for severe asthma

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

Current and future targeted therapies for severe asthma: Managing treatment with biologics based on phenotypes and biomarkers

Asthma is a respiratory disorder with considerable heterogeneity in aetiology, triggers, clinical characteristics and response to therapy. This diversity reflects different inflammatory pathways that can be subdivided into clinically similar categories called phenotypes, or pathogenically comparable groups called endotypes. In recent years, a great amount of research has been dedicated to the investigation and understanding of the heterogeneity of asthma pathophysiology and to the identification of treatable traits, biomarkers, mediators and therapeutic targets. Severe asthma is defined as an uncontrolled disease despite a maximal conventional therapeutic approach. While, to date, some target therapies showing improvements in lung function, asthma symptoms and a reduction of the annual rate of exacerbations in patients with severe asthma have been already approved, other treatments are currently being studied, specifically targeting Type 2 asthma. Further progress however, is still needed to tackle the molecular pathways for non-Type 2 asthma. The aim of the present narrative review is to discuss and examine the indication, mechanisms of action and therapeutic effects of currently available and emerging biologic agents for the treatment of severe asthma.

Partners in Crime: Neutrophil-CTC Collusion in Metastasis

A recent study in Nature (Szczerba et al. 2019;566:553-557) reports that the association of neutrophils with circulating tumor cells (CTCs) in the blood of patients with breast cancer can promote CTC proliferation and metastasis. These findings reveal a new mechanism by which the innate immune system may be co-opted to drive tumor progression.

Discriminatory Molecular Biomarkers of Allergic and Nonallergic Asthma and Its Severity

Asthma is a complex disease comprising various phenotypes and endotypes, all of which still need solid biomarkers for accurate classification. In a previous study, we defined specific genes related to asthma and respiratory allergy by studying the expression of 94 genes in a population composed of 4 groups of subjects: healthy control, nonallergic asthmatic, asthmatic allergic, and nonasthmatic allergic patients. An analysis of differential gene expression between controls and patients revealed a set of statistically relevant genes mainly associated with disease severity, i.e., CHI3L1, IL-8, IL-10, MSR1, PHLDA1, PI3, and SERPINB2. Here, we analyzed whether these genes and their proteins could be potential asthma biomarkers to distinguish between nonallergic asthmatic and asthmatic allergic subjects. Protein quantification was determined by ELISA (in serum) or Western blot (in protein extracted from peripheral blood mononuclear cells or PBMCs). Statistical analyses were performed by unpaired t-test using the Graph-Pad program. The sensitivity and specificity of the gene and protein expression of several candidate biomarkers in differentiating the two groups (and the severity subgroups) was performed by receiver operating characteristic (ROC) curve analysis using the R program. The ROC curve analysis determined single genes with good sensitivity and specificity for discriminating some of the phenotypes. However, interesting combinations of two or three protein biomarkers were found to distinguish the asthma disease and disease severity between the different phenotypes of this pathology using reproducible techniques in easy-to-obtain samples. Gene and protein panels formed by single biomarkers and biomarker combinations have been defined in easily obtainable samples and by standardized techniques. These panels could be useful for characterizing phenotypes of asthma, specifically when differentiating asthma severity.

Inhibiting myeloid-derived suppressor cell trafficking enhances T cell immunotherapy

Recruitment of myeloid-derived suppressor cells (MDSCs) into tumors induces local immunosuppression in carcinomas. Here, we assessed whether SX-682, an orally bioavailable small-molecule inhibitor of CXCR1 and CXCR2, could block tumor MDSC recruitment and enhance T cell activation and antitumor immunity following multiple forms of immunotherapy. CXCR2+ neutrophilic MDSCs (PMN-MDSCs) were the most abundant myeloid cell subset within oral and lung syngeneic carcinomas. PMN-MDSCs demonstrated greater suppression of tumor-infiltrating lymphocyte killing of targets compared with macrophages. SX-682 significantly inhibited trafficking of PMN-MDSCs without altering CXCR2 ligand expression. Trafficking of CXCR1+ macrophages was unaltered, possibly due to coexpression of CSF1R. Reduced PMN-MDSC tumor infiltration correlated with enhanced accumulation of endogenous or adoptively transferred T cells. Accordingly, tumor growth inhibition or the rate of established tumor rejection following programed death-axis (PD-axis) immune checkpoint blockade or adoptive cell transfer of engineered T cells was enhanced in combination with SX-682. Despite CXCR1/2 expression on tumor cells, SX-682 appeared to have little direct antitumor effect on these carcinoma models. These data suggest that tumor-infiltrating CXCR2+ PMN-MDSCs may prevent optimal responses following both PD-axis immune checkpoint blockade and adoptive T cell transfer therapy. Abrogation of PMN-MDSC trafficking with SX-682 enhances T cell-based immunotherapeutic efficacy and may be of benefit to patients with MDSC-infiltrated cancers.

[Clinical and inflammatory phenotypic features of asthmatic patients sensitive to cold stimulation]

OBJECTIVE

To explore the clinical symptoms, lung function and airway inflammation phenotype characteristics of asthmatic patients who are sensitive to cold stimulation.

METHODS

Eighty patients with newly diagnosed bronchial asthma or with mild to moderate acute exacerbation of previously diagnosed bronchial asthma but without regular treatment were selected. According to whether cold air stimulation could induce respiratory symptoms such as cough and wheeze, the patients were divided into cold-insensitive group (45 cases) and cold-sensitive group (35 cases). All the patients were treated with inhaled corticosteroid (ICS), long-acting β2 receptor agonist (LABA; salmeterol xinafoate and fluticasone propionate powder for inhalation, 50 μg/250 μg, twice daily) and montelukast sodium tablets (10 mg, once daily); short-acting β2 receptor agonist (SABA) and/or systemic glucocorticoid (prednisone acetate tablets, 10 mg, once daily; or injection of methylprednisolone sodium succinate, 40 mg) were given if necessary. Asthma Control Test (ACT) score before treatment and at 3 months of treatment was used to assess the clinical symptoms such as cough and wheeze; spirometry was performed to determine lung function impairment and recovery. Blood and induced sputum cell counts were examined to determine the characteristics of airway inflammation.

RESULTS

The two groups were comparable for age, gender, BMI, proportion of smokers and allergic rhinitis before treatment. The cold-sensitive patients experienced significantly more frequent acute exacerbations than the cold-insensitive patient within 1 year before the visit (P < 0.05), but the use of SABA and glucocorticoid for symptom control during the treatment did not differ significantly between the two groups (P > 0.05). The ACT scores of the cold-sensitive group were significantly lower than those of the cold-insensitive group both before and after the treatment (P < 0.01). Compared with the cold-insensitive patients, the cold-sensitive patients had more obvious impairment of FEV1/FVC% and FEV1%pred before treatment (P < 0.01), and also showed poorer recovery after treatment (P < 0.05). The percentages of eosinophils in blood and induced sputum samples did not differ significantly between the two groups either before and after the treatment, but the percentage of neutrophils was significantly higher in the cold-sensitive group (P < 0.01). In the induced sputum samples collected before treatment, the cell populations consisted mainly of eosinophilic subtype (60%) and neutrophilic subtype (20%) in the cold-insensitive group; in the cold-sensitive patients, the sputum neutrophilic subtype cells increased significantly to 42.86% (P=0.03) and the eosinophilic subtype cells were lowered to 31.43% (P=0.01).

CONCLUSIONS

The cold-sensitive asthmatic patients experience frequent recurrent and/or aggravated symptoms and have obvious lung function impairment. Different from that in patients with classic asthma, the airway inflammatory phenotype in these patients is characterized by the domination by neutrophilic subtype.

Extracellular acidification-induced CXCL8 production through a proton-sensing receptor OGR1 in human airway smooth muscle cells: a response inhibited by dexamethasone

Background

Human airway smooth muscle cells (ASMCs) contribute to bronchial contraction and airway hyperresponsiveness in patients with bronchial asthma. They also generate cytokines, chemokines, and matricellular proteins. Ovarian cancer G protein-coupled receptor 1 (OGR1) senses extracellular protons and mediates the production of interleukin-6 (IL-6) and connective tissue growth factor (CTGF) in ASMCs.

Methods

ASMCs were stimulated for the indicated time by pH 6.3 or pH 7.4-adjusted Dulbecco’s Modified Eagle Medium (DMEM) containing 0.1% bovine serum albumin (BSA) (0.1% BSA-DMEM). As a control stimulant, pH 7.4-adjusted 0.1% BSA-DMEM containing 10 ng/mL tumor necrosis factor-α (TNF-α) was used. Interleukin-8/C-X-C motif chemokine ligand 8 (CXCL8) mRNA expression in ASMCs was quantified by RT-PCR using real-time TaqMan technology. CXCL8 secreted from ASMCs was measured by enzyme-linked immunosorbent assay (ELISA). Phosphorylation at serine 536 of NF-κB p65 and binding of p65 to oligonucleotide containing an NF-κB consensus binding site were analyzed by Western blotting and an ELISA-based kit.

Results

Acidic pH induced a significant increase of CXCL8 mRNA expression and CXCL8 protein secretion in ASMCs. ASMCs transfected with small interfering RNA (siRNA) targeted for OGR1 produced less CXCL8 compared with those transfected with non-targeting siRNA. Protein kinase C (PKC) inhibitor, MEK1/2 inhibitor, and the inhibitor of IκB phosphorylation reduced acidic pH-stimulated CXCL8 production in ASMCs. Dexamethasone also inhibited acidic pH-stimulated CXCL8 production of ASMCs in a dose-dependent manner. Dexamethasone did not affect either phosphorylation or binding to the consensus DNA site of NF-κB p65.

Conclusions

CXCL8 released from ASMCs by extracellular acidification may play a pivotal role in airway accumulation of neutrophils. Glucocorticoids inhibit acidic pH-stimulated CXCL8 production independent of serine 536 phosphorylation and the binding to DNA of NF-κB p65, although NF-κB activity is essential for CXCL8 production in ASMCs.

An evaluation of roflumilast and PDE4 inhibitors with a focus on the treatment of asthma

INTRODUCTION

Asthma is a common chronic airway inflammatory disease characterized by diverse inflammatory events leading to airway hyperresponsiveness and reversible airflow obstruction. Corticosteroids have been the mainstay for asthma treatment due to their broad anti-inflammatory actions; however, other medications such as phosphodiesterase 4 inhibitors also demonstrate anti-inflammatory activity in the airways.

AREAS COVERED

This review describes tissue expression of phosphodiesterase 4 in the airways, the different phosphodiesterase 4 isoenzymes identified, and the anti-inflammatory activities of phosphodiesterase 4 inhibition in asthma and related findings in chronic obstructive pulmonary disease (COPD). The authors further review clinical trials demonstrating that drugs such as roflumilast have an excellent safety profile and efficacy in patients with asthma and COPD.

EXPERT OPINION

Phosphodiesterase 4 inhibitors suppress the activity of immune cells, an effect similar to corticosteroids although by acting through different anti-inflammatory pathways and uniquely blocking neutrophilic inflammation. Roflumilast and other phosphodiesterase 4 inhibitors have been shown to provide additive protection in asthma when added to corticosteroid and anti-leukotriene treatment. Developmental drugs with dual phosphodiesterase 3 and 4 inhibition are thought to be able to provide bronchodilation and anti-inflammatory activities and will consequently be pushed forward in their clinical development for the treatment of asthma and COPD.

NETopathic Inflammation in Chronic Obstructive Pulmonary Disease and Severe Asthma

Neutrophils play a central role in innate immunity, inflammation, and resolution. Unresolving neutrophilia features as a disrupted inflammatory process in the airways of patients with chronic obstructive pulmonary disease (COPD) and severe asthma. The extent to which this may be linked to disease pathobiology remains obscure and could be further confounded by indication of glucocorticoids or concomitant respiratory infections. The formation of neutrophil extracellular traps (NETs) represents a specialized host defense mechanism that entrap and eliminate invading microbes. NETs are web-like scaffolds of extracellular DNA in complex with histones and neutrophil granular proteins, such as myeloperoxidase and neutrophil elastase. Distinct from apoptosis, NET formation is an active form of cell death that could be triggered by various microbial, inflammatory, and endogenous or exogenous stimuli. NETs are reportedly enriched in neutrophil-dominant refractory lung diseases, such as COPD and severe asthma. Evidence for a pathogenic role for respiratory viruses (e.g., Rhinovirus), bacteria (e.g., Staphylococcus aureus) and fungi (e.g., Aspergillus fumigatus) in NET induction is emerging. Dysregulation of this process may exert localized NET burden and contribute to NETopathic lung inflammation. Disentangling the role of NETs in human health and disease offer unique opportunities for therapeutic modulation. The chemokine CXCR2 receptor regulates neutrophil activation and migration, and small molecule CXCR2 antagonists (e.g., AZD5069, danirixin) have been developed to selectively block neutrophilic inflammatory pathways. NET-stabilizing agents using CXCR2 antagonists are being investigated in proof-of-concept studies in patients with COPD to provide mechanistic insights. Clinical validation of this type could lead to novel therapeutics for multiple CXCR2-related NETopathologies. In this Review, we discuss the emerging role of NETs in the clinicopathobiology of COPD and severe asthma and provide an outlook on how novel NET-stabilizing therapies via CXCR2 blockade could be leveraged to disrupt NETopathic inflammation in disease-specific phenotypes.

Exacerbations of chronic respiratory diseases

Respiratory viral infections including human rhinovirus (RV) infection have been identified as the most important environmental trigger of exacerbations of chronic lung diseases. While well established as the most common viral infections associated with exacerbations of asthma and chronic obstructive pulmonary disease, RVs and other respiratory viruses are also now thought to be important in triggering exacerbations of cystic fibrosis and the interstitial lung diseases. Here, we summarize the epidemiological evidence the supports respiratory viruses including RV as triggers of exacerbations of chronic lung diseases. We propose that certain characteristics of RVs may explain why they are the most common trigger of exacerbations of chronic lung diseases. We further highlight the latest mechanistic evidence supporting how and why common respiratory viral infections may enhance and promote disease triggering exacerbation events, through their interactions with the host immune system, and may be affected by ongoing treatments. We also provide a commentary on how new treatments may better manage the disease burden associated with respiratory viral infections and the exacerbation events that they trigger.

Severe refractory asthma: current treatment options and ongoing research

Patients with severe asthma have a greater risk of asthma-related symptoms, morbidities, and exacerbations. Moreover, healthcare costs of patients with severe refractory asthma are at least 80% higher than those with stable asthma, mainly because of a higher use of healthcare resources and chronic side effects of oral corticosteroids (OCS). The advent of new promising biologicals provides a unique therapeutic option that could achieve asthma control without OCS. However, the increasing number of available molecules poses a new challenge: the identification and selection of the most appropriate treatment. Thanks to a better understanding of the basic mechanisms of the disease and the use of predictive biomarkers, especially regarding the Th2-high endotype, it is now easier than before to tailor therapy and guide clinicians toward the most suitable therapeutic choice, thus reducing the number of uncontrolled patients and therapeutic failures. In this review, we will discuss the different biological options available for the treatment of severe refractory asthma, their mechanism of action, and the overlapping aspects of their usage in clinical practice. The availability of new molecules, specific for different molecular targets, is a key topic, especially when considering that the same targets are sometimes part of the same phenotype. The aim of this review is to help clarify these doubts, which may facilitate the clinical decision-making process and the achievement of the best possible outcomes.

Systematic literature review of the clinical, humanistic, and economic burden associated with asthma uncontrolled by GINA Steps 4 or 5 treatment

OBJECTIVE

This study sought to characterize the epidemiologic, clinical, humanistic, and economic burden of patients with asthma uncontrolled by GINA Steps 4 or 5 treatment (severe, uncontrolled asthma [SUA]).

METHODS

A systematic literature review adhering to PRISMA guidelines was performed. Relevant publications were searched for in MEDLINE and EMBASE from January 2004 to September 2016 and in a conference proceedings database from January 2012 to October 2016. Studies were screened using the Population, Intervention, Comparator, Outcomes, Study Design, and Time (PICOS-T) framework. Studies of SUA with observational (prospective and retrospective), randomized, or nonrandomized study designs; adult patient populations; sample sizes ≥20 patients; epidemiologic or clinical outcomes, patient-reported outcomes (PROs), or economic outcomes were included. For our analysis, SUA was defined as inadequate control of asthma, despite the use of medium- to high-dosage inhaled corticosteroids and at least one additional treatment.

RESULTS

A total of 195 articles reporting unique study populations were included. Prevalence of SUA was as great as 87.4% for patients with severe asthma, although values varied depending on the criteria used to define asthma control. Compared with patients with severe asthma who were controlled, patients with SUA experienced more symptoms, night-time awakenings, rescue medication use, and worse PROs. SUA-associated costs were 3-times greater than costs for patients with severe, controlled disease.

CONCLUSION

Despite the availability of approved asthma treatments, this literature analysis confirms that SUA poses a substantial epidemiologic, clinical, humanistic, and economic burden. Published data are limited for certain aspects of SUA, highlighting a need for further research.

Non-eosinophilic asthma: current perspectives

Although non-eosinophilic asthma (NEA) is not the best known and most prevalent asthma phenotype, its importance cannot be underestimated. NEA is characterized by airway inflammation with the absence of eosinophils, subsequent to activation of non-predominant type 2 immunologic pathways. This phenotype, which possibly includes several not well-defined subphenotypes, is defined by an eosinophil count <2% in sputum. NEA has been associated with environmental and/or host factors, such as smoking cigarettes, pollution, work-related agents, infections, and obesity. These risk factors, alone or in conjunction, can activate specific cellular and molecular pathways leading to non-type 2 inflammation. The most relevant clinical trait of NEA is its poor response to standard asthma treatments, especially to inhaled corticosteroids, leading to a higher severity of disease and to difficult-to-control asthma. Indeed, NEA constitutes about 50% of severe asthma cases. Since most current and forthcoming biologic therapies specifically target type 2 asthma phenotypes, such as uncontrolled severe eosinophilic or allergic asthma, there is a dramatic lack of effective treatments for uncontrolled non-type 2 asthma. Research efforts are now focusing on elucidating the phenotypes underlying the non-type 2 asthma, and several studies are being conducted with new drugs and biologics aiming to develop effective strategies for this type of asthma, and various immunologic pathways are being scrutinized to optimize efficacy and to abolish possible adverse effects.

Potential new targets for drug development in severe asthma

In recent years there has been increasing recognition of varying asthma phenotypes that impact treatment response. This has led to the development of biological therapies targeting specific immune cells and cytokines in the inflammatory cascade. Currently, there are two primary asthma phenotypes, Type 2 hi and Type 2 lo, which are defined by eosinophilic and neutrophilic/pauci- granulocytic pattern of inflammation respectively. Most biologics focus on Type 2 hi asthma, including all four biologics approved for treatment of uncontrolled asthma in the United States — omalizumab, mepolizumab, reslizumab, and benralizumab. Potential new targets for drug development are being investigated, such as IL-13, IL-4α receptor, CRTH2, TSLP, IL-25, IL-13, IL-17A receptor, and CXCR2/IL-8. This review will discuss the role of these molecules on the inflammatory response in uncontrolled asthma and the emerging biologics that address them. Through the delineation of distinct immunological mechanisms in severe asthma, targeted biologics are promising new therapies that have the potential to improve asthma control and quality of life.

Pharmacokinetics of the Oral Selective CXCR2 Antagonist AZD5069: A Summary of Eight Phase I Studies in Healthy Volunteers

OBJECTIVE

The aim of this study was to summarise the pharmacokinetic findings from eight phase I studies in healthy volunteers given oral AZD5069, a selective small-molecule CXCR2 antagonist.

METHODS

240 healthy volunteers across eight phase I studies received single (0.1-200 mg) or multiple once- or twice-daily (10-120 mg) oral AZD5069 as solution, suspension, capsules or tablets. Pharmacokinetics were evaluated using non-compartmental analysis methods.

RESULTS

AZD5069 was rapidly absorbed (time to maximum concentration ~ 2 h) under fasting conditions. A high-fat, high-calorie meal delayed and reduced the peak plasma AZD5069 concentration (C_max) by 50%, but total exposure (AUC) was unchanged (fed:fasting geometric mean ratio 90% confidence interval within 0.80-1.25). The plasma concentration of AZD5069 declined with an initial half-life of 4 h and terminal half-life of 11 h. Steady-state plasma concentrations were achieved within 2-3 days and accumulation was ~ 1.1-fold with twice-daily dosing. Systemic exposure was approximately proportional to dose. Intra- and inter-subject variability in AUC was 3-11 and 29-64%, respectively. Less than 5% of the AZD5069 dose was excreted as parent drug in the urine. Elderly subjects had 39% higher AZD5069 AUC and 21% higher C_max than younger adults. Japanese subjects had similar or slightly higher exposure to AZD5069 than Caucasian subjects. Co-administration with ketoconazole resulted in 2.1-fold higher AUC and 1.6-fold higher C_max. All formulations had similar bioavailability.

CONCLUSIONS

AZD5069 demonstrated predictive linear pharmacokinetics with low intra- and moderate inter-subject variability and no major influences from ethnicity, age, food or formulation. Half-life data indicated suitability for twice-daily dosing. CLINICALTRIALS.

GOV IDENTIFIERS

NCT00953888, NCT01051505, NCT01083238, NCT01100047, NCT01332903, NCT01480739, NCT01735240, NCT01989520.

The enigmatic role of the neutrophil in asthma: Friend, foe or indifferent?

Whilst severe asthma has classically been categorized as a predominantly Th2-driven pathology, there has in recent years been a paradigm shift with the realization that it is a heterogeneous disease that may manifest with quite disparate underlying inflammatory and remodelling profiles. A subset of asthmatics, particularly those with a severe, corticosteroid refractory disease, present with a prominent neutrophilic component. Given the potential of neutrophils to impart extensive tissue damage and promote inflammation, it has been anticipated that these cells are closely implicated in the underlying pathophysiology of severe asthma. However, uncertainty persists as to why the neutrophil is present in the asthmatic lung and what precisely it is doing there, with evidence supporting its role as a protagonist of pathology being primarily circumstantial. Furthermore, our view of the neutrophil as a primitive, indiscriminate killer has evolved with the realization that neutrophils can exhibit a marked anti-inflammatory, pro-resolving and wound healing capacity. We suggest that the neutrophil likely exhibits pleiotropic and potentially conflicting roles in defining asthma pathophysiology-some almost certainly detrimental and some potentially beneficial-with context, timing and location all critical confounders. Accordingly, indiscriminate blockade of neutrophils with a broad sword approach is unlikely to be the answer, but rather we should first seek to understand their complex and multifaceted roles in the disease state and then target them with the same subtleties and specificity that they themselves exhibit.

Precision medicine in asthma: linking phenotypes to targeted treatments

PURPOSE OF REVIEW

Asthma is a heterogeneous disease consisting of different phenotypes that are driven by different mechanistic pathways. The purpose of this review is to emphasize the important role of precision medicine in asthma management.

RECENT FINDINGS

Despite asthma heterogeneity, the approach to management has been on the basis of disease severity, with the most severe patients reserved for the maximum treatments with corticosteroids and bronchodilators. At the severe end, the recent availability of biologic therapies in the form of anti-IgE (omalizumab) and anti-IL5 therapies (mepolizumab and reslizumab) has driven the adaptation of precision medicine. These therapies are reserved for severe asthma with defined either allergic or eosinophilic background, respectively.

SUMMARY

Unbiased definition of phenotypes or endotypes (which are phenotypes defined by mechanisms) is an important step towards the use of precision medicine in asthma. Although T2-high asthma has been defined with targets becoming available for treating allergic or eosinophilic asthma, the definition of non-T2 phenotypes remains a priority. Precision medicine is also dependent on the definition of biomarkers that can help differentiate between these phenotypes and pinpoint patients suitable for specific-targeted therapies. Thus, precision medicine links phenotypes (endotypes) to targeted treatments for better outcomes.

Characterization and allergic role of IL-33-induced neutrophil polarization

Neutrophils are involved in the pathogenesis of allergy. However, the contribution of the different functionally polarized neutrophils in allergy needs to be clarified. We sought to define the characteristics of interleukin (IL)-33-induced neutrophils and the involvement of this subset of polarized neutrophils in allergic pathogenesis. Freshly isolated neutrophils were treated with different cytokines and the cytokine expression levels were detected by real-time PCR. The gene expression profile of IL-33-induced neutrophils was determined by microarray assay. Adoptive transfer assay was used to investigate the function of IL-33-induced neutrophils in an ovalbumin (OVA)-induced allergic asthma model. IL-33-treated neutrophils selectively produced IL-4, IL-5, IL-9 and IL-13 (referred as to N(IL-33) cells) and displayed a distinctive gene expression profile in sharp contrast to resting and lipopolysaccharide (LPS)-treated neutrophils. IL-33-induced neutrophils expressed high Levels of IL-1R2 on cell surface, whereas resting and LPS-treated neutrophils did not, indicating IL-1R2 might be used as a biomarker for N(IL-33) cells. Importantly, N(IL-33) neutrophils exist in the lungs of OVA-induced allergic asthma mice. Adoptive transfer of N(IL-33) neutrophils significantly promotes the severity of the lung pathogenesis in this model. IL-33 induces neutrophil polarization through c-Jun N-terminal kinase- and nuclear factor-κB-dependent pathways. A previously unappreciated neutrophil polarization driven by IL-33 with unique cell surface markers and cytokine/chemokine-producing gene profile was defined. The newly identified N(IL-33) subpopulation may have significant contribution to IL-33-related pathogenesis.

Nonallergic Asthma and Its Severity: Biomarkers for Its Discrimination in Peripheral Samples

Asthma is a complex and heterogeneous respiratory disorder characterized by chronic airway inflammation. It has generally been associated with allergic mechanisms related to type 2 airway inflammation. Nevertheless, between 10 and 33% of asthmatic individuals have nonallergic asthma (NA). Several targeted treatments are in clinical development for patients with Th2 immune response, but few biomarkers are been defined for low or non-Th2-mediated inflammation asthma. We have recently defined by gene expression a set of genes as potential biomarkers of NA, mainly associated with disease severity: IL10, MSR1, PHLDA1, SERPINB2, CHI3L1, IL8, and PI3. Here, we analyzed their protein expression and specificity using sera and isolated peripheral blood mononuclear cells (PBMCs). First, protein quantification was carried out using ELISA (in sera) or Western blot (proteins extracted from PBMCs by Trizol procedure), depending on the biomarker in 30 healthy controls (C) subjects and 30 NA patients. A receiver operating characteristic curve analysis was performed by using the R program to study the specificity and sensitivity of the candidate biomarkers at a gene- and protein expression level. Four kinds of comparisons were performed: total NA group vs C group, severe NA patients vs C, moderate-mild NA patients vs C, and severe NA patients vs moderate-mild NA patients. We found that all the single genes showed good sensitivity vs specificity for some phenotypic discrimination, with CHI3L1 and PI3 exhibiting the best results for C vs NA: CHI3L1 area under the curve (AUC) (CI 95%): 0.95 (0.84-1.00) and PI3 AUC: 0.99 (0.98-1.00); C vs severe NA: PI3 AUC: 1 (0.99-1.00); and C vs moderate-mild NA: CHI3L1 AUC: 1 (0.99-1.00) and PI3 AUC: 0.99 (0.96-1.00). However, the results for discriminating asthma disease and severity with protein expression were better when two or three biomarkers were combined. In conclusion, individual genes and combinations of proteins have been evaluated as reliable biomarkers for classifying NA subjects and their severity. These new panels could be good diagnostic tests.