Clinically significant variability of serum IgE concentrations in patients with severe asthma

Omalizumab for the treatment of patients with severe allergic asthma with immunoglobulin E levels above >1500 IU/mL

Immunoglobulin E (IgE) plays a critical role in the allergen-initiated inflammatory pathway and thus serves as a viable therapeutic target in allergic or IgE-mediated diseases such as asthma. Omalizumab, an anti-IgE biologic, has been approved in the United States (US, 2003) and in the European Union (EU, 2005) as an add-on therapy in patients with moderate-to-severe persistent asthma and severe allergic asthma (SAA) aged 6 years and older. The dose and frequency of omalizumab are adjusted based on the patient's body weight and baseline IgE levels, as recommended by its dosing tables. Currently, these dosing recommendations are limited to patients with baseline IgE levels of up to 1500 IU/mL in the European Union and 700 IU/mL in the United States. However, many patients with SAA have IgE levels >1500 IU/mL, highlighting an unmet need. This review presents the current evidence on the treatment benefits of omalizumab in patients with IgE levels >1500 IU/mL. The findings from the reviewed studies which included >3000 patients support the efficacy and effectiveness of omalizumab in reducing exacerbations, and improving asthma control, lung function, and quality of life in patients with severe asthma having IgE levels beyond the current dosing range. Omalizumab was well-tolerated in these patients, with no new safety signals. In addition, high IgE levels (>1500 IU/mL) are also reported in several comorbidities of asthma (allergic rhinitis, atopic dermatitis, allergic bronchopulmonary aspergillosis [ABPA], food allergy, and nasal polyposis) and omalizumab has demonstrated efficacy and safety in these indications. These data suggest that omalizumab may be considered for administration in SAA patients, with high IgE levels outside the current dosing tables. A detailed assessment of patients with high IgE levels is needed before deciding on the optimal treatment approach. A management algorithm for SAA patients with IgE >1500 IU/mL is proposed in this review and a suggestion to follow the Delphi consensus is advised.

Expression of LINC00847 in Peripheral Blood Mononuclear Cells of Children with Asthma and Its Prediction between Asthma Exacerbation and Remission

Objective. Asthma is defined as a heterogeneous disease that is usually characterized by chronic airway inflammation. Long noncoding RNAs play important roles in various biological processes including inflammation. To know more about the relationships between lncRNAs and asthma, we sought to the role of LINC00847 in peripheral blood mononuclear cells (PBMCs) of children with asthma exacerbation or asthma remission. Methods. Microarray analysis was performed on GSE143192 and GSE165934 datasets to screen differentially expressed lncRNAs (DElncRNAs) in human PBMCs between asthma patients and normal controls. LINC00847 was selected from DElncRNAs in human PBMCs between asthma patients and normal controls for further investigation. The expression levels of LINC00847 were quantified in PBMCs collected from 54 children with asthma exacerbation, 54 children with asthma remission, and 54 healthy children by real-time qPCR. The forced expiratory volume in the first second in percent predicted values (FEV1%), ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC), and peak expiratory flow rate (PEF%) were tested for evaluation of lung function. The concentration of immunoglobulin E (IgE) and eosinophil count was examined. The serum levels of interleukin-4 (IL-4), interferon-γ (IFN-γ), and IL-17A were determined by the ELISA method. Results. The expression level of LINC00847 in PBMCs of asthma exacerbation children was remarkably higher than that in PBMCs of asthma remission children and healthy children ( $p<0.001$ ); the expression level of LINC00847 in PBMCs of asthma remission children was notably higher than that in PBMCs of healthy children ( $p<0.001$ ). Pearson correlation analysis revealed that the expression levels of LINC00847 in PBMCs of asthma children were negatively correlated with FEV1% (r = −0.489), FEV1/FVC (r = −0.436), PEF% (r = −0.626), and IFN-γ level (r = −0.614) of asthma children, but positively correlated with IgE concentration (r = 0.680), eosinophil count (r = 0.780), IL-4 (r = 0.524), and IL-17A (r = 0.622) levels. When LINC00847 expression was used to distinguish asthma exacerbation from asthma remission, a 0.871 AUC (95% CI: 0.805–0.936) was yielded with sensitivity of 79.63% and specificity of 77.78%. Conclusion. The study demonstrates that increased LINC00847 expression may be associated with the development and progression of asthma, possibly serving as a novel biomarker for predicting asthma exacerbation from asthma remission.

Efficacy of Tezepelumab in Patients with Severe, Uncontrolled Asthma and Perennial Allergy

BACKGROUND

Tezepelumab is an anti-thymic stromal lymphopoietin monoclonal antibody. In the PATHWAY phase IIb study (NCT02054130), tezepelumab significantly reduced annualized asthma exacerbation rates (AAERs) versus placebo in adults with severe, uncontrolled asthma.

OBJECTIVE

This post hoc analysis assessed the efficacy of tezepelumab in PATHWAY participants with perennial allergy.

METHODS

Adults (N=550) with severe, uncontrolled asthma were randomized to receive tezepelumab (70 mg or 210 mg every 4 weeks or 280 mg every 2 weeks) or placebo, for 52 weeks. The AAER over 52 weeks was analyzed in patients grouped by sensitivity to perennial aeroallergens and by eligibility for omalizumab treatment according to the US or EU prescribing information. Change from baseline to week 52 in pre-bronchodilator forced expiratory volume in 1 second (FEV₁) and type 2 (T2) biomarkers were assessed in the perennial allergy subgroups.

RESULTS

Across doses, tezepelumab reduced the AAER versus placebo by 66-78% in patients with perennial allergy (n=254) and 67-71% in patients without perennial allergy (n=261). Tezepelumab improved pre-bronchodilator FEV₁ and reduced blood eosinophil counts and fractional exhaled nitric oxide levels over 52 weeks, irrespective of perennial allergy status. Tezepelumab reduced the AAER versus placebo by 61-82% in omalizumab-eligible patients (US, n=159; EU, n=101) and 63-70% in omalizumab-ineligible patients (US, n=372; EU, n=440), respectively.

CONCLUSIONS

Treatment with tezepelumab reduced exacerbations, improved lung function and reduced T2 biomarkers versus placebo in patients with severe, uncontrolled asthma with or without perennial allergy, further supporting its efficacy in a broad population of patients with severe, uncontrolled asthma.

Total IgE Variability Is Associated with Future Asthma Exacerbations: A 1-Year Prospective Cohort Study

BACKGROUND

Few prospective studies have investigated the relationship between IgE variability and risk for asthma exacerbations (AEs).

OBJECTIVE

To explore the relationship between IgE variability and AEs.

METHODS

Recruited patients with stable asthma underwent two serum total IgE tests within a month (at screening [baseline IgE] and at 1 month) to obtain the coefficient of variation (CV) of base 10 log-transformed IgE. Patients with IgE CV were divided into IgE CV-high and IgE CV-low cohorts based on the CV median and were observed within 12 months, during which the association between IgE variability and AEs was explored using a negative binomial regression model.

RESULTS

The IgE CV levels obtained from 340 patients classified patients into two groups (n = 170 for the IgE CV-high and IgE CV-low groups, respectively) based on the serum total IgE CV median of 2.12% (quartiles 1 and 3: 0.98% and 3.91%, respectively). The IgE CV-high patients exhibited worse asthma control and lung function and more marked airway inflammation, and received more intensive medication use compared with IgE CV-low patients. The IgE CV-high patients exhibited increased rates of moderate-to-severe (adjusted rate ratio = 2.88; 95% confidence interval, 1.65-5.03; P < .001) and severe (adjusted rate ratio = 2.16; 95% confidence interval, 1.08-4.32; P = .029) AEs during the follow-up year compared with IgE CV-low patients. Furthermore, sputum IL-6 partially mediated the associations between IgE CV with moderate-to-severe and severe AEs.

CONCLUSIONS

Variability in total serum IgE levels is an easily obtained and practical measure for predicting AEs. Future studies are needed to investigate whether IgE variability can be used to guide precision medicine in asthma.

Modeling Pharmacokinetics and Pharmacodynamics of Therapeutic Antibodies: Progress, Challenges, and Future Directions

With more than 90 approved drugs by 2020, therapeutic antibodies have played a central role in shifting the treatment landscape of many diseases, including autoimmune disorders and cancers. While showing many therapeutic advantages such as long half-life and highly selective actions, therapeutic antibodies still face many outstanding issues associated with their pharmacokinetics (PK) and pharmacodynamics (PD), including high variabilities, low tissue distributions, poorly-defined PK/PD characteristics for novel antibody formats, and high rates of treatment resistance. We have witnessed many successful cases applying PK/PD modeling to answer critical questions in therapeutic antibodies’ development and regulations. These models have yielded substantial insights into antibody PK/PD properties. This review summarized the progress, challenges, and future directions in modeling antibody PK/PD and highlighted the potential of applying mechanistic models addressing the development questions.

Understanding Inter-Individual Variability in Monoclonal Antibody Disposition

Monoclonal antibodies (mAbs) are currently the largest and most dominant class of therapeutic proteins. Inter-individual variability has been observed for several mAbs; however, an understanding of the underlying mechanisms and factors contributing to inter-subject differences in mAb disposition is still lacking. In this review, we analyze the mechanisms of antibody disposition and the putative mechanistic determinants of inter-individual variability. Results from in vitro, preclinical, and clinical studies were reviewed evaluate the role of the neonatal Fc receptor and Fc gamma receptors (expression and polymorphism), target properties (expression, shedding, turnover, internalization, heterogeneity, polymorphism), and the influence of anti-drug antibodies. Particular attention is given to the influence of co-administered drugs and disease, and to the physiological relevance of covariates identified by population pharmacokinetic modeling, as determinants of variability in mAb pharmacokinetics.

Variability in total serum IgE over 1 year in severe asthmatics

Background

Immunoglobulin E (IgE) is the treatment target of omalizumab, a monoclonal antibody indicated in the treatment of severe allergic asthma. Long-term variability of serum total IgE (sIgE_tot) in asthmatics remains poorly documented.

Methods

In this prospective study, sIgE_tot levels were measured over 1 year at 7 time points in 41 severe asthmatics treated with high-dose of inhaled corticosteroids and long-acting β₂ agonists. 33 patients were atopic based on at least one positive RAST to common aeroallergens. Patients were divided into three groups according to their baseline sIgE_tot level: low (< 76 IU/mL; n = 10), intermediate (76-700 IU/mL; n = 20) or high (> 700 IU/mL; n = 11). Patients also completed the six-item Juniper Asthma Control Questionnaire (ACQ₆). The sIgE_tot variability and factors predictive for this variability were studied, as well as ACQ₆ outcomes.

Results

The variation in sIgE_tot level was mostly the consequence of between patient-variability, which represented 96%, 71% and 96% of the total variability in the low, intermediate and high sIgE_tot subgroups, respectively. The residual within-patient variability was therefore limited. In 10/41 patients, sIgE_tot levels increased or decreased, for at least one visit, beyond the predefined range of the subgroups to which they were assigned (< 76 IU/mL; 76-700 IU/mL; > 700 IU/mL). There was a significant but weak correlation between sIgE_tot and ACQ₆ score over all time points (r = 0.15, p = 0.02), but sIgE_tot failed to associate with severe exacerbation. sIgE_tot decreased by 3% with any additional year of age for the whole group (p = 0.01) and increased by 5% per one unit of allergen exposure score in atopic patients (p = 0.002).

Conclusion

In severe asthmatics, limited within-patient variability of sIgE_tot levels was observed over 1 year as opposed to marked between-subject variability. sIgE_tot decreases with age. Variation in sIgE_tot weakly associates with asthma control but not with exacerbation.

Intrasubject Variability in Total IgE Levels in Patients with Moderate to Severe Persistent Allergic Asthma Over 1 Year

BACKGROUND

Longitudinal variability in serum IgE levels has not been prospectively studied in people with moderate to severe allergic asthma.

OBJECTIVE

We investigated change in serum IgE concentrations over 1 year, and its relationship with lung function, asthma control, asthma pharmacotherapy, allergy season, asthma exacerbations, body mass index, and demographic factors.

METHODS

Seventeen patients with moderate to severe persistent allergic asthma were followed for 1 year. Variability in serum IgE level was explored using a linear mixed regression model treating a change of 10% or more in IgE concentration and combined change of 10% or more and an absolute change of 50 IU/mL as dichotomous variables.

RESULTS

For consecutive visits every 2 months, the mean percent change in serum IgE level was 23 ± 3 (P < .001). Probability of having a greater than 10% change in serum IgE level in a subsequent visit was 69% (95% CI, 58%-78%; P < .001). Variability in IgE level could have affected clinical decisions for anti-IgE treatment (dosing and/or treatment candidacy) in 7 of 17 patients. There were no statistically significant associations of IgE level variability with demographic characteristics and lung function, exacerbations, allergy season, Asthma Control Test scores, peak flow rates, pharmacotherapy, or body mass index.

CONCLUSIONS

Serum IgE concentrations exhibit variability over time among individuals with moderate to severe persistent allergic asthma. The factors that contribute to IgE level variability and the impact of these findings on clinical outcomes deserve further study.

Increases in peripheral SIRT1: a new biological characteristic of asthma

BACKGROUND AND OBJECTIVE

Silent information regulator 1 (SIRT1) is a class III histone deacetylase that exerts both anti-inflammatory and anti-aging effects. However, no data are available regarding SIRT1 expression in patients with asthma. Here, we studied SIRT1 levels in the serum of patients with asthma and analysed the distribution of SIRT1 in both the serum and the lungs in an asthmatic mouse model to determine its clinical significance.

METHODS

Serum SIRT1 levels, total immunoglobulin E (IgE) levels and peripheral blood eosinophil percentages as well as pulmonary function were quantified in 97 patients with asthma and 118 healthy volunteers. BALB/c mice were sensitized and challenged using ovalbumin (OVA) to produce the asthmatic model, and SIRT1 levels in both the serum and the lung tissues were subsequently measured.

RESULTS

The serum SIRT1 levels were significantly elevated in the patients with asthma compared with the controls. Serum SIRT1 levels positively correlated with total IgE levels and negatively correlated with pulmonary function. In the OVA-sensitized and challenged mice, an increased serum SIRT1 level was confirmed, whereas decreased SIRT1 expression was observed in the lung tissues.

CONCLUSIONS

These data indicate that lung SIRT1 expression decreased while serum SIRT1 increased in the setting of asthma. Serum SIRT1 levels correlate positively with both IgE levels and negatively with pulmonary function, suggesting that increased peripheral SIRT1 levels represent a new biological characteristic of asthma. Increased serum SIRT1 may be an auxiliary index for the diagnosis of asthma and elevating lung SIRT1 levels may be a new strategy for asthma therapy.

Diagnostic accuracy of minimally invasive markers for detection of airway eosinophilia in asthma: a systematic review and meta-analysis

BACKGROUND

Eosinophilic airway inflammation is associated with increased corticosteroid responsiveness in asthma, but direct airway sampling methods are invasive or laborious. Minimally invasive markers for airway eosinophilia could present an alternative method, but estimates of their accuracy vary.

METHODS

We did a systematic review and searched Medline, Embase, and PubMed for studies assessing the diagnostic accuracy of markers against a reference standard of induced sputum, bronchoalveolar lavage, or endobronchial biopsy in patients with asthma or suspected asthma (for inception to Aug 1, 2014). Unpublished results were obtained by contacting authors of studies that did not report on diagnostic accuracy, but had data from which estimates could be calculated. We assessed risk of bias with QUADAS-2. We used meta-analysis to produce summary estimates of accuracy.

FINDINGS

We included 32 studies: 24 in adults and eight in children. Of these, 26 (81%) showed risk of bias in at least one domain. In adults, three markers had extensively been investigated: fraction of exhaled nitric oxide (FeNO) (17 studies; 3216 patients; summary area under the receiver operator curve [AUC] 0·75 [95% CI 0·72-0·78]); blood eosinophils (14 studies; 2405 patients; 0·78 [0·74-0·82]); total IgE (seven studies; 942 patients; 0·65 [0·61-0·69]). In children, only FeNO (six studies; 349 patients; summary AUC 0·81 [0·72-0·89]) and blood eosinophils (three studies; 192 patients; 0·78 [0·71-0·85]) had been investigated in more than one study. Induced sputum was most frequently used as the reference standard. Summary estimates of sensitivity and specificity in detecting sputum eosinophils of 3% or more in adults were: 0·66 (0·57-0·75) and 0·76 (0·65-0·85) for FeNO; 0·71 (0·65-0·76) and 0·77 (0·70-0·83) for blood eosinophils; and 0·64 (0·42-0·81) and 0·71 (0·42-0·89) for IgE.

INTERPRETATION

FeNO, blood eosinophils, and IgE have moderate diagnostic accuracy. Their use as a single surrogate marker for airway eosinophilia in patients with asthma will lead to a substantial number of false positives or false negatives.

FUNDING

None.