Endotypes of allergic diseases and asthma: An important step in building blocks for the future of precision medicine

Precision/Personalized Medicine in Allergic Diseases and Asthma

Like many other chronic diseases, every allergic patient has different characteristics based on clinical course, treatment responsiveness and disease outcomes, which are associated with the genetic and epigenetic control of molecular mechanisms and environment. This variability necessitates the establishment of patient-tailored and precision approaches in handling allergic disorders. Better understanding of the underlying pathophysiological mechanisms for the development of allergic disorders will provide more rationale strategies based on individual cases in controlling and treating these disorders. Endotyping, phenotyping, genotyping and theratyping, and biomarkers are keywords in this area and have been gaining lots of attention in the field of precision medicine, which aims to revolutionize patient care and develop better prevention and treatment strategies. In addition, precision health is a new concept that brings precise approaches to the scene for being healthy and prevention of allergic disease and asthma. The specialty of allergy has a leading role in the field, because allergen-specific immunotherapy started 105 years ago, and is historically a leading personalized/precision medicine approach in all medicine disciplines providing the possibility of cure in an individualized manner instead of conventional symptomatic treatments.

Eliciting Dose and Safety Outcomes From a Large Dataset of Standardized Multiple Food Challenges

Background: Food allergy prevalence has continued to rise over the past decade. While studies have reported threshold doses for multiple foods, large-scale multi-food allergen studies are lacking. Our goal was to identify threshold dose distributions and predictors of severe reactions during blinded oral food challenges (OFCs) in multi-food allergic patients. Methods: A retrospective chart review was performed on all Stanford-initiated clinical protocols involving standardized screening OFCs to any of 11 food allergens at 7 sites. Interval-censoring survival analysis was used to calculate eliciting dose (ED) curves for each food. Changes in severity and ED were also analyzed among participants who had repeated challenges to the same food. Results: Of 428 participants, 410 (96%) had at least one positive challenge (1445 standardized OFCs with 1054 total positive challenges). Participants undergoing peanut challenges had the highest ED₅₀ (29.9 mg), while those challenged with egg or pistachio had the lowest (7.07 or 1.7 mg, respectively). The most common adverse event was skin related (54%), followed by gastrointestinal (GI) events (33%). A history of asthma was associated with a significantly higher risk of a severe reaction (hazard ratio [HR]: 2.37, 95% confidence interval [CI]: 1.36, 4.13). Higher values of allergen-specific IgE (sIgE) and sIgE to total IgE ratio (sIgEr) were also associated with higher risk of a severe reaction (1.49 [1.19, 1.85] and 1.84 [1.30, 2.59], respectively). Participants undergoing cashew, peanut, pecan, sesame, and walnut challenges had more severe reactions as ED increased. In participants who underwent repeat challenges, the ED did not change (p = 0.66), but reactions were more severe (p = 0.02). Conclusions: Participants with a history of asthma, high sIgEr, and/or high values of sIgE were found to be at higher risk for severe reactions during food challenges. These findings may help to optimize food challenge dosing schemes in multi-food allergic, atopic patients, specifically at lower doses where the majority of reactions occur. Trials Registration Number: ClinicalTrials. gov number NCT03539692; https://clinicaltrials.gov/ct2/show/NCT03539692.

Controversies and opportunities in severe asthma

PURPOSE OF REVIEW

Despite currently available treatments, many asthma patients remain inadequately controlled, but identifying distinct patient populations (phenotypes/endotypes) may optimize their management. This review discusses some of the controversies and opportunities for improved disease control in severe asthma.

RECENT FINDINGS

Currently approved anti-immunoglobulin E and anti-interleukin 5 biologics, which target specific pathways instead of using a 'one size fits all' strategy, are efficacious and well tolerated therapies for severe asthma. The appropriate use of these biologics, and of those in development (e.g., benralizumab and dupilumab), should be aided by further understanding of asthma phenotypes and endotypes, utilizing appropriate biomarkers.Oral corticosteroids are often added as maintenance therapy for patients with severe uncontrolled asthma, but their use is associated with significant adverse effects and should be considered a last option. The true cost of this therapy, including the cost of morbidities associated with its use, remains to be determined.Severe asthma in pediatrics poses a unique opportunity for possible prevention strategies and the potential for primary prevention. Although several avenues for primary prevention are being explored and are out of the scope of this review, we focus our discussion on the use of omalizumab, which has been recently explored in clinical trials.

SUMMARY

Appropriate use of biologics in severe asthma should be supported by further understanding of biomarkers predicting response to targeted therapy. Because of their association with significant adverse effects, add-on oral corticosteroids should be considered a last treatment option for patients with uncontrolled severe asthma. Finally, severe asthma in pediatrics poses a unique opportunity for potential prevention strategies.

Microbial Insights into Asthmatic Immunopathology. A Forward-Looking Synthesis and Commentary

Asthma is an aberrant inflammatory condition of the airways affecting approximately 1 in 10 children in affluent countries. An increasing body of evidence suggests that microbial exposures during a "critical window" of development in early life play a central role in determining future asthma susceptibility. However, like the disease itself, considerable heterogeneity exists among studies in which researchers have investigated the associations between particular microbial taxa and asthma immunology. As our understanding of asthmatic pathology evolves to enable clearer definition of asthma endotypes, it will be important to consider the impact of various environmental factors on each endotype. Given the strong evidence in support of the hypothesis that early-life microbial exposures predict later disease states such as asthma, consideration of these endotypes when establishing experimental outcomes in epidemiological studies could allow for increased precision when determining exposure-outcome associations and engaging in more focused follow-up mechanistic investigations.

Clinical predictors of the effectiveness of tiotropium in adults with symptomatic asthma: a real-life study

Background

Long-acting muscarinic antagonist (LAMA) tiotropium improved lung function and reduced risks of exacerbation when added on to inhaled corticosteroids (ICS) with or without long-acting B₂ agonists (LABAs) in patients with uncontrolled asthma. However, studies predicting the effectiveness of tiotropium based on patients' clinical characteristics were limited.

Methods

We conducted this retrospective study at a single medical center from July 2016 to July 2017, and used asthma control test (ACT) to evaluate the effectiveness of tiotropium add-on therapy in patients with uncontrolled asthma. The effectiveness was shown by an increase in ACT score from baseline of 3 or greater after 3 months of tiotropium add-on therapy.

Results

Patients with uncontrolled asthma despite the use of low- or medium- to high-dose of ICS plus LABA (n=160) were analyzed. Among patients having good response (n=112, ACT score increased ≥3 points) to tiotropium (TGR group) and patients having poor response (n=48, ACT increased <3 points) to tiotropium (TPR group), their baseline characteristics including age, asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO), cigarette use, initial FEV1, serum IgE level, eosinophil count, and BMI were significantly different. Univariate analysis showed that old age, ACO, cigarette use, initial FEV1 <80%, and BMI >30 were predictors of the effectiveness of tiotropium. Patients with high serum total IgE level >430 µg/L and eosinophil count >0.6×10⁹/L had a negative impact on response to tiotropium. Multivariate logistic regression analysis demonstrated that the independent factor of poor response to tiotropium was high serum IgE level >430 µg/L.

Conclusions

Tiotropium add-on therapy in patients with uncontrolled asthma was effective. However, patients with serum total IgE level >430 µg/L were less likely to benefit from tiotropium.

The MEGA Project: A Study of the Mechanisms Involved in the Genesis and Disease Course of Asthma. Asthma Cohort Creation and Long-Term Follow-Up

The general aim of this study is to create a cohort of asthma patients with varying grades of severity in order to gain greater insight into the mechanisms underlying the genesis and course of this disease. The specific objectives focus on various studies, including imaging, lung function, inflammation, and bronchial hyperresponsiveness, to determine the relevant events that characterize the asthma population, the long-term parameters that can determine changes in the severity of patients, and the treatments that influence disease progression. The study will also seek to identify the causes of exacerbations and how this affects the course of the disease. Patients will be contacted via the outpatient clinics of the 8 participating institutions under the auspices of the Spanish Respiratory Diseases Networking System (CIBER). In the inclusion visit, a standardized clinical history will be obtained, a clinical examination, including blood pressure, body mass index, complete respiratory function tests, and FENO will be performed, and the Asthma Control Test (ACT), Morisky-Green test, Asthma Quality of Life Questionnaire (Mini AQLQ), the Sino-Nasal Outcome Test 22 (SNOT-22), and the Hospital Anxiety and Depression scale (HADS) will be administered. A specific electronic database has been designed for data collection. Exhaled breath condensate, urine and blood samples will also be collected. Non-specific bronchial hyperresponsiveness testing with methacholine will be performed and an induced sputum sample will be collected at the beginning of the study and every 24 months. A skin prick test for airborne allergens and a chest CT will be performed at the beginning of the study and repeated every 5 years.

Perspectives in allergen immunotherapy: 2017 and beyond

The Future of the Allergists and Specific Immunotherapy (FASIT) workshop provides a regular platform for global experts from academia, allergy clinics, regulatory authorities and industry to review developments in the field of allergen immunotherapy (AIT). The most recent meeting, held in February 2017, had two main themes: advances in AIT and hot topics in AIT from the regulatory point of view. The first theme covered opportunities for personalized AIT, advances in adjuvants and delivery systems, and the development of new molecules and future vaccines for AIT. Key topics in the second part of the meeting were the effects of the enactment of European Directive 2001/83 on the availability of allergens for therapy and diagnosis across the EU, the challenges of conducting Phase 3 studies in the field, the future role of allergen exposure chambers in AIT studies and specific considerations in performing AIT studies in the paediatric population. Finally, the group highlighted the forthcoming EAACI guidelines and their particular importance for the standardization of practice in the treatment of allergies. This review presents a comprehensive insight into those panel discussions and highlights unmet needs and also possible solutions to them for the future.

European Summit on the Prevention and Self-Management of Chronic Respiratory Diseases: report of the European Union Parliament Summit (29 March 2017)

On March 29, 2017, a European Summit on the Prevention and Self-Management of Chronic Respiratory Diseases (CRD) was organized by the European Forum for Research and Education in Allergy and Airway Diseases. The event took place in the European Parliament of Brussels and was hosted by MEP David Borrelli and MEP Sirpa Pietikainen. The aim of the Summit was to correspond to the needs of the European Commission and of patients suffering from CRD to join forces in Europe for the prevention and self-management. Delegates of the European Rhinologic Society, European Respiratory Society, European Academy of Allergy and Clinical Immunology, European Academy of Paediatrics, and European Patients Organization EFA all lectured on their vision and action plan to join forces in achieving adequate prevention and self-management of CRD in the context of Precision Medicine. Recent data highlight the preventive capacity of education on optimal care pathways for CRD. Self-management and patient empowerment can be achieved by novel educational on-line materials and by novel mobile health tools enabling patients and doctors to monitor and optimally treat CRDs based on the level of control. This report summarizes the contributions of the representatives of different European academic stakeholders in the field of CRD.

House dust mite allergen causes certain features of steroid resistant asthma in high fat fed obese mice

Obesity is a high risk factor for diseases such as cardiovascular, metabolic syndrome and asthma. Obese-asthma is another emerging phenotype in asthma which is typically refractive to steroid treatment due to its non-classical features such as non-eosinophilic cellular inflammation. The overall increased morbidity, mortality and economical burden in asthma is mainly due to steroid resistant asthma. In the present study, we used high fat diet induced obese mice which when sensitized with house dust mite (HDM) showed steroid resistant features. While the steroid, dexamethasone (DEX), treatment to high fat fed naïve mice could not reduce the airway hyperresponsiveness (AHR) induced by high fat, DEX treatment to high fat fed allergic mice could not reduce the HDM allergen induced airway remodeling features though it reduced airway inflammation. Further, these HDM induced high fat fed mice with or without DEX treatment had shown the increased activity and expression of arginase as well as the inducible nitric oxide synthase (iNOS) expression. However, DEX treatment had reduced the expressions of high iNOS and arginase I in control chow diet fed mice. Thus, we speculate that the steroid resistance seen in human obese asthmatics could be stemming from altered NO metabolism and its induced airway remodeling and with further investigations, it would encourage new treatments specific to obese-asthma phenotype.

Methods and practices to diversify cell-based products

Medicinal signaling cell (MSC)-based products represent emerging treatments in various therapeutic areas including cardiometabolic, inflammation, autoimmunity, orthopedics, wound healing and oncology. Exploring innovation beyond minimally manipulated plastic-adherent ex vivo expanded allogeneic MSCs enables product delineation. Product delineation is on the critical path to maximize clinical benefits and market access. An innovation framework is presented here along various innovation dimensions comprising composition-of-matter by means of positive cell surface markers, formulation varying for example the cell dose or the preservation mode and medium, manufacturing to adapt the secretome of MSCs to the condition of interest, the mode of delivery and corresponding delivery devices, as well as molecular engineering and biomarkers. The rationale of the innovation space thus described applies generally to all cell-based therapies.

Altered fatty acid metabolism and reduced stearoyl-coenzyme a desaturase activity in asthma

BACKGROUND

Fatty acids and lipid mediator signaling play an important role in the pathogenesis of asthma, yet this area remains largely underexplored. The aims of this study were (i) to examine fatty acid levels and their metabolism in obese and nonobese asthma patients and (ii) to determine the functional effects of altered fatty acid metabolism in experimental models.

METHODS

Medium- and long-chain fatty acid levels were quantified in serum from 161 human volunteers by LC/MS. Changes in stearoyl-coenzyme A desaturase (SCD) expression and activity were evaluated in the ovalbumin (OVA) and house dust mite (HDM) murine models. Primary human bronchial epithelial cells from asthma patients and controls were evaluated for SCD expression and activity.

RESULTS

The serum desaturation index (an indirect measure of SCD) was significantly reduced in nonobese asthma patients and in the OVA murine model. SCD1 gene expression was significantly reduced within the lungs following OVA or HDM challenge. Inhibition of SCD in mice promoted airway hyper-responsiveness. SCD1 expression was suppressed in bronchial epithelial cells from asthma patients. IL-4 and IL-13 reduced epithelial cell SCD1 expression. Inhibition of SCD reduced surfactant protein C expression and suppressed rhinovirus-induced IP-10 secretion, which was associated with increased viral titers.

CONCLUSIONS

This is the first study to demonstrate decreased fatty acid desaturase activity in humans with asthma. Experimental models in mice and human epithelial cells suggest that inhibition of desaturase activity leads to airway hyper-responsiveness and reduced antiviral defense. SCD may represent a new target for therapeutic intervention in asthma patients.

Accelerated reactivity of blood granulocytes in patients with atopic bronchial asthma out of exacerbation

Reactive oxygen species (ROS) are important in bronchial asthma (BA) pathogenesis owing to accumulation of activated granulocytes in the lungs. But the ROS-producing activity of the cells is insufficiently understood in the blood of BA patients. This study analyzes the kinetics of phagocyte respiratory burst in the blood to improve the methods of BA patients monitoring. Patients with atopic BA out of exacerbation (n=60) and healthy controls (n=43) were recruited. The time-course of respiratory response to opsonized zymosan (OZ) was recorded in the whole blood using luminol-dependent chemiluminescence (CL), and its activation kinetics (lag-time, rate, amplitude, ROS production) was calculated. The discriminative power of ROS generation kinetics was defined by Receiver Operating Characteristic (ROC) curve analysis. Standard physiological respiratory parameters of patients did not differ from the controls. More rapid response to OZ was recorded in BA patient samples versus the controls. The primed state of phagocytes in the blood of BA patients was corroborated by significant weakening formyl peptide priming effect. The adhesion of granulocytes to cultured human endothelial cells was two-fold higher in BA patients versus controls. ROC curve analysis exhibited good discriminative effectiveness of the CL kinetics to compare BA individuals with the controls. The highest power (86% sensitivity and 90% specificity) was achieved at a linear combination of the parameters. We assume that the assessment of phagocyte reactivity based on the analysis of the response kinetic profile is a good test for monitoring of the state in BA patients.

Temporal Regulation by Innate Type 2 Cytokines in Food Allergies

PURPOSE OF REVIEW

Food allergies (FAs) are a growing epidemic in western countries with poorly defined etiology. Defined as an adverse immune response to common food allergens, FAs present heterogeneously as a single- or multi-organ response that ranges in severity from localized hives and angioedema to systemic anaphylaxis.

RECENT FINDINGS

Current research focusing on epithelial-derived cytokines contends that temporal regulation by these factors impact initial sensitization and persistence of FA responses upon repeated food allergen exposure. Mechanistic understanding of FA draws insight from a myriad of atopic conditions studied in humans and modeled in mice. In this review, we will highlight how epithelial-derived cytokines initiate and then potentiate FAs. We will also review existing evidence of the contribution of other atopic diseases to FA pathogenesis and whether FA symptoms overlap with other atopic diseases.

Novel Biologicals for the Treatment of Allergic Diseases and Asthma

PURPOSE OF REVIEW

The development of biological therapies has rapidly progressed during the last few years, and major advances were reported for the treatment of allergic diseases, such as atopic dermatitis, allergic rhinitis, urticaria, food allergy, and asthma. Here, we review biologicals targeting the type 2 immune response involving Th2 cells, type 2 innate lymphoid cells, natural killer T cells, mast cells, basophils, and epithelial cells, such as IL-4, IL-5, IL-13, IL-31, tumor necrosis factor alpha (TNF-α), and thymic stromal lymphopoietin (TSLP).

RECENT FINDINGS

The biologicals that have been currently approved for asthma are omalizumab targeting IgE and reslizumab and mepolizumab targeting interleukin (IL)-5. Many other monoclonal antibodies are currently in various phases of clinical development. The new biological therapies for allergic diseases will eventually be tailored to the endotypes of these diseases and the identification of novel biomarkers. Further development of novel biologicals for the treatment of allergic diseases and asthma will be possible upon improved understanding of mechanisms of allergic diseases. Accordingly, further refinement of endotypes of allergen-specific and non-specific type 2 immune response and related inflammatory mediators is needed for optimal treatment of allergic diseases.

Endotype-driven treatment in chronic upper airway diseases

Rhinitis and rhinosinusitis are the two major clinical entities of chronic upper airway disease. Chronic rhinosinusitis (CRS) and allergic rhinitis (AR) affect respectively up to 10 and 30% of the total population, hence being associated with an important socio-economic burden. Different phenotypes of rhinitis and CRS have been described based on symptom severity and duration, atopy status, level of control, comorbidities and presence or absence of nasal polyps in CRS. The underlying pathophysiological mechanisms are diverse, with different, and sometimes overlapping, endotypes being recognized. Type 2 inflammation is well characterized in both AR and CRS with nasal polyps (CRSwNP), whereas type 1 inflammation is found in infectious rhinitis and CRS without nasal polyps (CRSsNP). The neurogenic endotype has been demonstrated in some forms of non-allergic rhinitis. Epithelial barrier dysfunction is shown in AR and CRSwNP. Emerging therapies are targeting one specific pathophysiological pathway or endotype. This endotype-driven treatment approach requires careful selection of the patient population who might benefit from a specific treatment. Personalized medicine is addressing the issue of providing targeted treatment for the right patient and should be seen as one aspect of the promising trend towards precision medicine. This review provides a comprehensive overview of the current state of endotypes, biomarkers and targeted treatments in chronic inflammatory conditions of the nose and paranasal sinuses.

Inflammatory biomarkers for asthma endotyping and consequent personalized therapy

We argue that asthma be considered a syndrome caused by multiple inflammatory pathogenic processes. Bronchial hyperresponsiveness, reversible airflow limitation, and chronic airway inflammation characterize asthma pathophysiology. Personalized Medicine, i.e. a tailored management approach, is appropriate for asthma management and is based on the identification of discrete phenotypes and endotypes. Biomarkers can help define phenotypes and endotypes. Several biomarkers have been described in asthma, but most of them are not commonly available or still need external validation. Areas covered: This review presents useful pragmatic biomarkers available in daily clinical practice for assessing airway inflammation in asthmatic patients. Expert commentary: Eosinophil counts and serum allergen-specific IgE assessments are the most reliable biomarkers. Lung function, mainly concerning FEF25-75, and nasal cytology may be envisaged as ancillary biomarkers in asthma management. In conclusion, biomarkers have a clinical relevance in asthma in identifying asthma endotypes to direct personalized therapy.

Utility of serum periostin in combination with exhaled nitric oxide in the management of asthma

Type-2/eosinophilic inflammation plays a pivotal role in asthma. The identification of severe type-2/eosinophilic asthma is important for improving the management of patients with asthma. Therefore, efforts to develop non-invasive biomarkers for type-2/eosinophilic airway inflammation have been made during this decade. Currently, fraction of exhaled nitric oxide (FeNO) and serum periostin levels are considered markers of type-2/eosinophilic inflammation in asthma. However, a single-marker approach has limited the ability to diagnose severe type-2/eosinophilic asthma accurately and predict disease outcomes precisely. The present article reviews the utility of FeNO and serum periostin levels in a single-marker approach and in a multiple-marker approach in identifying patients with severe type-2/eosinophilic asthma. Furthermore, based on a sub-analysis of the Kinki Hokuriku Airway disease Conference (KiHAC), geno-endo-phenotypes of patients were stratified into four groups according to the FeNO and serum periostin levels.

Epithelial proteome profiling suggests the essential role of interferon-inducible proteins in patients with allergic rhinitis

BACKGROUND

Seasonal allergic rhinitis (SAR) caused by intermittent exposure to seasonal pollen causes itching, nasal congestion, and repeated sneezing, with profound effects on quality of life, work productivity, and school performance. Although both the genotype and environmental factors can contribute to the immunologic basis of allergic reactions, the molecular underpinnings associated with the pathogenesis of allergic rhinitis are not entirely clear.

METHODS

To address these questions, nasal epithelial brushings were collected from 29 patients with SAR and 31 control subjects during and after the pollen season. We then implemented an orbitrap-based, bottom-up, label-free quantitative proteomics approach, followed by multivariate analyses to identify differentially abundant (DA) proteins among the 4 sample groups.

RESULTS

We identified a total of 133 DA proteins for which the most significantly overrepresented functional category was found to be interferon 1 signaling. Two proteins, cystatin 1 and myeloblastin, the former of which protects against protease activity of allergens and the latter with a role in epithelial barrier function, were DA in patients with SAR and control subjects, irrespective of season. Moreover, interferon-inducible protein with tetratricopeptide repeats 1, cystatin 1, and interferon-inducible protein with tetratricopeptide repeats 3 were found to be differentially regulated between patients with SAR and control subjects, with inverse abundance dynamics during the transition from fall to spring.

CONCLUSION

We identified type 1 interferon-regulated proteins as biomarkers in patients with SAR, potentially playing an important role in its pathogenesis. Moreover, when compared with patients with SAR, healthy subjects exhibit an antagonistic proteomic response across seasons, which might prove to be a therapeutic target for disease prevention.

Study of nasal exhaled nitric oxide levels in diagnosis of allergic rhinitis in subjects with and without asthma

Background

The measure of fractional exhaled nitric oxide (FENO) in the airways is a useful tool to guide the diagnosis and titration of inhaled corticosteroids in patients with asthma. However, its role in diagnosis of allergic rhinitis (AR), especially in subjects with asthma, is not well established.

Objective

To study the cutoff of nasal FENO in the diagnosis of subjects with AR and AR-asthma compared to age-matched subjects without AR or asthma and its correlations with the clinical and functional characteristics.

Methods

The study was cross sectional and descriptive. Subjects were grouped into control subjects, AR, and AR-asthma, based on the inclusion criteria. Exhaled NO (nasal FENO, bronchial FENO, and alveolar concentration of NO) was measured by multiple flow electro-luminescence device.

Results

Six hundred twenty-eight subjects were included: 217 control subjects (children: n=98, 10±4 years; adults: n=119, 50±16 years), 168 subjects with AR (children: n=54, 10±3 years; adults: n=114, 49±15 years), and 243 subjects with AR-asthma (children: n=115, 10±3 years; adults: n=128, 51±14 years). Nasal peak inspiratory flow and peak expiratory flow were lower in subjects with AR and AR-asthma than in control subjects (P<0.01 and P<0.01; and P<0.05 and P<0.01, respectively). Nasal FENO levels were significantly higher in subjects with AR and AR-asthma than in control subjects (1614±629 and 1686±614 ppb vs 582±161 ppb; P<0.001 and P<0.001, respectively). In subjects with AR non-asthma, the cutoffs of nasal FENO for those diagnosed with AR were 775 ppb in children, 799 ppb in adults, and 799 in the general population (sensitivity: 92.68%, 92.63%, and 92.65%, respectively; specificity: 91.67%, 95.00%, and 96.87%, respectively). In subjects with AR-asthma, the cutoffs of nasal FENO were higher, especially in asthma children (1458 ppb; sensitivity: 72.97% and specificity: 95.83%).

Conclusion

Nasal FENO measurement is a useful technique for the diagnosis of AR in subjects with and without asthma.

Biologic response modifiers: Indications, implications, and insights

The field of biologic immune modulators is currently mushrooming at a dizzying pace. Although most of these biologics are tested and approved for one or a few indications, their unanticipated side effects and off-label use have contributed significantly to our understanding of basic immune mechanisms, the involvement of cytokines in several apparently nonimmunologic diseases, and the importance of compartmentalized immune responses. In this review we attempt to give a bird's-eye view of the major biologics and to highlight insights and implications derived from their secondary effects and adverse reactions.

Current Status of Companion and Complementary Diagnostics: Strategic Considerations for Development and Launch

US Food and Drug Administration (FDA)‐approved diagnostic assays play an increasingly common role in managing patients to prolong lifespan while also enhancing quality of life. Diagnostic assays can be essential for the safe and effective use of therapeutics (companion diagnostic), or may inform on improving the benefit/risk ratio without restricting drug access (complementary diagnostic). This tutorial reviews strategic considerations for drug and assay development resulting in FDA‐approved companion or complementary diagnostic status.

Subtypes of asthma based on asthma control and severity: a latent class analysis

BACKGROUND

Asthma subtyping is a complex new field of study. Usually both etiological and outcome factors of asthma have been used simultaneously for subtyping thus making the interpretation of the results difficult. Identification of subtypes of asthma based on questionnaire data only will be useful for both treatment of asthma and for research. Our objective was to identify asthma subtypes that capture both asthma control and severity based on easily accessible variables.

METHODS

We applied latent class analysis for the 1995 adult asthmatics, 692 men and 1303 women, of the Northern Finnish Asthma Study (NoFAS). The classifying variables included use of asthma medication within the last 12 months, St. George's Respiratory Questionnaire score, and asthma-related healthcare use within the last 12 months. Covariates adjusted for included COPD, allergic rhinitis/allergic eczema, BMI, age and sex. All information was based on self-administered questionnaires.

RESULTS

We identified four subtypes for women: Controlled, mild asthma (41% of participants); Partly controlled, moderate asthma (24%); Uncontrolled asthma, unknown severity (26%), and Uncontrolled, severe asthma (9%). For men we identified three subtypes: Controlled, mild asthma (31%); Poorly controlled asthma, unknown severity (53%); and Partly controlled, severe asthma (17%). For almost 96% of the subjects this subtyping was accurate. The covariates fitted in the model were based on clinical judgment and were good predictors of class membership.

CONCLUSIONS

Our results show that it is possible to form meaningful and accurate asthma subtypes based on questionnaire data, and that separate classification should be applied for men and women.

Relationship of Allergy with Asthma: There Are More Than the Allergy "Eggs" in the Asthma "Basket"

Asthma and allergy share a similar and very close course, especially through childhood. Considerable research effort has been put in untangling these associations; however, it is now becoming obvious that this is an exceedingly difficult task. In fact, each research breakthrough further perplexes this picture, as we are steadily moving toward the era of personalized medicine and we begin to appreciate that what we thought to be a single disease, asthma, is in fact an accumulation of distinct entities. In the context of this "syndrome," which is characterized by several, as of yet poorly defined endotypes and phenotypes, the question of the link of "asthma" with allergy probably becomes non-relevant. In this review, we will revisit this question while putting the emphasis on the multifaceted nature of asthma.

Asthma Biomarkers: Do They Bring Precision Medicine Closer to the Clinic?

Measurement of biomarkers has been incorporated within clinical research of asthma to characterize the population and to associate the disease with environmental and therapeutic effects. Regrettably, at present, there are no specific biomarkers, none is validated or qualified, and endotype-driven choices overlap. Biomarkers have not yet reached clinical practice and are not included in current asthma guidelines. Last but not least, the choice of the outcome upholding the value of the biomarkers is extremely difficult, since it has to reflect the mechanistic intervention while being relevant to both the disease and the particular person. On the verge of a new age of asthma healthcare standard, we must embrace and adapt to the key drivers of change. Disease endotypes, biomarkers, and precision medicine represent an emerging model of patient care building on large-scale biologic databases, omics and diverse cellular assays, health information technology, and computational tools for analyzing sizable sets of data. A profound transformation of clinical and research pattern from population to individual risk and from investigator-imposed subjective disease clustering (hypothesis driven) to unbiased, data-driven models is facilitated by the endotype/biomarker-driven approach.

New opportunities and challenges in the assessment of drugs for atopic diseases

Atopic conditions (atopic dermatitis, rhinitis, and asthma) belong to the most common noncommunicable diseases and are driven by chronic inflammatory reactions. They have a strong impact on the quality of life and represent a substantial and growing socio-economic burden. Interestingly, there is an increasing interest in the development of new therapeutic options with a number of biologics and small molecules targeting potential key mechanisms in atopic conditions. However, besides the safety issue, most of the new active substances are still evaluated according to the traditional efficacy paradigm focusing on the success in treating exacerbations and flares. Instead, the future approaches in drug development and assessment should rather concentrate on the long-term control of these diseases and consider their potential as disease-modifying strategies in the era of precision medicine. To reach this goal, a number of unsolved issues have to be addressed and consensually accepted by the stakeholders in this field. Thus, a successful and rapid development of new treatments requests a paradigm shift and a new way of thinking in the mind of physicians, pharmaceutical industry, regulators, and HTAs. This seems mandatory in order to optimize drug development and to facilitate the accessibility of new therapies to the growing population of patients suffering from atopic conditions on a global level.

Allergies - A T cells perspective in the era beyond the TH1/TH2 paradigm

Allergic diseases have emerged as a major health care burden, especially in the western hemisphere. They are defined by overshooting reactions of an aberrant immune system to harmless exogenous stimuli. The T_H1/T_H2 paradigm assumes that a dominance of T_H2 cell activation and an inadequate T_H1 cell response are responsible for the development of allergies. However, the characterization of additional T helper cell subpopulations such as T_H9, T_H17, T_H22, T_HGM-CSF and their interplay with regulatory T cells suggest further layers of complexity. This review summarizes state-of-the-art knowledge on T cell diversity and their induction, while revisiting the T_H1/T_H2 paradigm. With respect to these numerous contributors, it offers a new perspective on the pathogenesis of asthma, allergic rhinitis (AR) and atopic dermatitis (AD) incorporating recent discoveries in the field of T cell plasticity.