Obesity influences the outcomes of anti-IgE (omalizumab) therapy of asthma

Omalizumab is ineffective in regulating proasthmatic serum cytokine and chemokine levels in nonresponders with high BMI

Background

Omalizumab provides clinical benefits to a fraction of patients with asthma. It remains unclear why some patients do not respond to omalizumab therapy.

Objective

We sought to investigate whether omalizumab could alter serum cytokine and chemokine levels that could be associated with asthma pathogenesis. We also investigated why omalizumab is ineffective in controlling proasthmatic serum cytokine and chemokine levels in nonresponders.

Methods

Serum cytokine and chemokine levels in patients with moderate to severe asthma (N = 45; 34 responders and 11 nonresponders) were assessed before and after 26 weeks of omalizumab therapy. Correlations between cytokine and chemokine levels and asthma symptoms as well as characteristics of responders and nonresponders were assessed. Nonasthmatic subjects (N = 22) served as controls for patients with asthma (N = 45).

Results

Omalizumab was more effective in patients with increased serum eotaxin-1 and IL-13 levels than in others at baseline. Omalizumab decreased eotaxin-1 and IL-13, along with levels of most of the cytokines and chemokines tested, including IL-7, CCL17, and CXCL10, in responders, except for CCL5 and CCL22, which can contribute to neutrophilic and type 2 airway inflammation, respectively. In contrast, omalizumab did not decrease such serum cytokine and chemokine levels in nonresponders. Of interest, serum CCL17, CCL22, CXCL10, and IL-7 levels in nonresponders were associated with their body mass index, which could explain why omalizumab was unable to reduce their concentrations in nonresponders.

Conclusions

Omalizumab can regulate most cytokine and chemokine levels in responders. However, in nonresponders, it is unable to modulate specific proasthmatic cytokines and chemokines due to their association with individual body mass index, which is not influenced by omalizumab.

Obesity-related Asthma: A Pathobiology-based Overview of Existing and Emerging Treatment Approaches

Although obesity-related asthma is associated with worse asthma outcomes, optimal treatment approaches for this complex phenotype are still largely unavailable. This state-of-the-art review article synthesizes evidence for existing and emerging treatment approaches for obesity-related asthma and highlights pathways that offer potential targets for novel therapeutics. Existing treatments targeting insulin resistance and obesity, including metformin and GLP-1 (glucagon-like-peptide 1) receptor agonists, have been associated with improved asthma outcomes, although GLP-1R agonist data in asthma are limited to individuals with comorbid obesity. Monoclonal antibodies approved for treatment of moderate to severe asthma generally appear to be effective in individuals with obesity, although this is based on retrospective or secondary analysis of clinical trials; moreover, although most of these asthma biologics are approved for use in the pediatric population, the impact of obesity on their efficacy has not been well studied in youth. Potential therapeutic targets being investigated include IL-6, arginine metabolites, nitro-fatty acids, and mitochondrial antioxidants, with clinical trials for each currently underway. Potential therapeutic targets include adipose tissue eosinophils and the GLP-1-arginine-advanced glycation end products axis, although data in humans are still needed. Finally, transcriptomic and epigenetic studies of "obese asthma" demonstrate enrichment of IFN-related signaling pathways, Rho-GTPase pathways, and integrins, suggesting that these too could represent future treatment targets. We advocate for further study of these potential therapeutic mechanisms and continued investigation of the distinct inflammatory pathways characteristic of obesity-related asthma, to facilitate effective treatment development for this unique asthma phenotype.

Targeting Lipid Metabolism in Obese Asthma: Perspectives and Therapeutic Opportunities

BACKGROUND

Obese asthma represents a unique phenotype of asthma characterized by severe symptoms, poor medication controls, increased frequency of exacerbations, and an overall diminished quality of life. Numerous factors, including the complex interactions between environment, mechanical processes, inflammatory responses, and metabolites disturbance, contribute to the onset of obese asthma.

SUMMARY

Notably, multiple metabolomics studies in the last several years have revealed the significant abnormalities in lipid metabolism among obese asthmatic patients. Several bioactive lipid messengers participate in the development of obese asthma has also been observed. Here, we present and discuss the latest advances regarding how bioactive lipid molecules contribute to the pathogenic process and mechanisms underlying obese asthma. The key roles of potentially significant effector cells and the pathways by which they respond to diverse lipid metabolites are also described. We finally summarize current lipid-related therapeutic options for the treatment of obese asthma and discuss their application prospects.

KEY MESSAGES

This review underscores the impacts of abnormal lipid metabolism in the etiopathogenesis of obese asthma and asks for further investigation to elucidate the intricate correlations among lipids, obesity, and asthma.

Association of Obesity and Severe Asthma in Adults

The incidence of obesity and asthma continues to enhance, significantly impacting global public health. Adipose tissue is an organ that secretes hormones and cytokines, causes meta-inflammation, and contributes to the intensification of bronchial hyperreactivity, oxidative stress, and consequently affects the different phenotypes of asthma in obese people. As body weight increases, the risk of severe asthma increases, as well as more frequent exacerbations requiring the use of glucocorticoids and hospitalization, which consequently leads to a deterioration of the quality of life. This review discusses the relationship between obesity and severe asthma, the underlying molecular mechanisms, changes in respiratory function tests in obese people, its impact on the occurrence of comorbidities, and consequently, a different response to conventional asthma treatment. The article also reviews research on possible future therapies for severe asthma. The manuscript is a narrative review of clinical trials in severe asthma and comorbid obesity. The articles were found in the PubMed database using the keywords asthma and obesity. Studies on severe asthma were then selected for inclusion in the article. The sections: 'The classification connected with asthma and obesity', 'Obesity-related changes in pulmonary functional tests', and 'Obesity and inflammation', include studies on subjects without asthma or non-severe asthma, which, according to the authors, familiarize the reader with the pathophysiology of obesity-related asthma.

Role of clinical biomarkers in predicting the effectiveness of omalizumab

OBJECTIVE

To explore whether baseline clinical biomarkers and characteristics can be used to predict the responsiveness of omalizumab.

METHODS

We retrospectively analyzed a cohort of patients with severe asthma who received omalizumab treatment and collected their baseline data and relevant laboratory examination results along with case records of omalizumab treatment responsiveness after 16 weeks. We compared the differences in variables between the group of patients that responded to omalizumab therapy and the non-responder group, and then performed univariate and multivariate logistic regression. Finally, we analyzed the difference in response rate for subgroups by selecting cut-off values for the variables using Fisher's exact probability method.

RESULTS

This retrospective, single-center observational study enrolled 32 patients with severe asthma who were prescribed daily high-dose inhaled corticosteroids and long-acting β2 receptor agonists on long-acting muscarinic receptor antagonists with or without OCS. Data on age, sex, BMI, bronchial thermoplasty, FeNO, serum total IgE, FEV1, blood eosinophils, induced sputum eosinophils, blood basophils, and complications were not significantly different between the responder and non-responder groups. In the univariate and multivariate logistic regression, all the variants were not significant, and we were unable to build a regression model. We used normal high values and the mean or median of variables as cut-off values to create patient subgroups for the variables and found no significant difference in the omalizumab response rate between the subgroups.

CONCLUSION

The responsiveness of omalizumab is not associated with pretreatment clinical biomarkers, and these biomarkers should not be used to predict the responsiveness of omalizumab.

Nasal Symptoms in Asthmatic Patients under Treatment with Anti-IL-5 Monoclonal Antibodies. A Real-Life Cohort Study

Currently, some monoclonal antibodies (mAbs) are being studied for chronic rhinosinusitis with nasal polyps (CRSwNP). Three anti-IL-5 mAb: mepolizumab, reslizumab and benralizumab, have been tested through randomized clinical trials. In this real-life study, we aimed to describe the nasal effects of a cohort of asthmatic adults treated with anti-IL-5 mAb. Methods: We carried out an observational study in adults (≥18 years) on anti-IL-5 mAb treatment. Variables included ACT and SNOT−22 questionnaires, nasal polyps score, blood total IgE levels and blood eosinophil count. Results: Overall, 38 participants were included in the study; 19 patients received mepolizumab, 17 were treated with benralizumab and 2 patients were given reslizumab. There was a statistically significant difference in the ACT and SNOT−22 scores before and after mAb treatment. ACT score increased from 11.05 to 21.5 after treatment (p < 0.001). SNOT−22 decreased from 57 to 37.3 after treatment (p = 0.004). No statistically significant differences between mAb groups were observed regarding the ACT or the SNOT−22 (p = 0.775) response (p = 0.775). In addition, 60.53% of patients obtained a minimal clinically important difference (MCID) in SNOT−22. Conclusions: A significant clinical response based on SNOT−22 score evolution after anti-IL-5 mAb treatment was observed. This study also demonstrated that blood eosinophil count, rather than serum total IgE levels, is the best predictor of asthma symptom improvement, which was assessed through the ACT and SNOT−22 questionnaires.

Impact of body mass index on omalizumab response in adults with moderate-to-severe allergic asthma

BACKGROUND

Effectiveness of asthma treatment, including biologics, may be different in patients with higher body mass index (BMI).

OBJECTIVE

To evaluate response to omalizumab (dosed by serum immunoglobulin E level and weight) by BMI category.

METHODS

Pooled data from 2 randomized, double-blind, placebo-controlled studies of adults with moderate-to-severe allergic asthma were analyzed by BMI category (<25 kg/m² [normal or underweight], n = 397; 25 to <30 kg/m² [overweight], n = 330; ≥ 30 kg/m² [obese], n = 268). Placebo-adjusted exacerbation rate reductions were evaluated by Poisson regression modeling. Changes from baseline in forced expiratory volume in 1 second, beclomethasone dipropionate (BDP) dose, Total Asthma Symptom Score, and Asthma Quality of Life Questionnaire were evaluated by analysis of covariance.

RESULTS

Greater placebo-adjusted exacerbation rate reductions (95% confidence interval) were observed with increasing BMI (normal or underweight, -37.4% [-69.0% to 26.8%]; overweight, -52.7% [-78.4% to 3.7%]; obese, -71.9% [-86.9% to -39.5%]). There were no differences in forced expiratory volume in 1 second improvement between BMI categories at week 16 (normal or underweight, 76.2 [5.3-147.1] mL; overweight, 98.1 [13.9-182.4] mL; obese, 69.1 [-18.9 to 157.2] mL). No differences in BDP dose reduction (µg) were noted between BMI categories (normal or underweight, 23.0 [15.7-30.3]; overweight, 22.5 [13.5-31.5]; obese, 16.6 [5.8-27.3]). Fewer patients in the higher BMI categories eliminated BDP use. There were trends for smaller improvements with higher BMI in Total Asthma Symptom Score (normal/underweight, -0.52 [-0.82 to -0.22]; overweight, -0.50 [-0.80 to -0.20]; obese, -0.39 [-0.77 to 0.00]) and Asthma Quality of Life Questionnaire (normal or underweight, 0.34 [0.16-0.52]; overweight, 0.34 [0.13-0.55]; obese, 0.15 [-0.08 to 0.39]).

CONCLUSION

Omalizumab provides benefit to patients with moderate-to-severe allergic asthma, regardless of BMI.

TRIAL REGISTRATION

Studies 008/009 were conducted before clinical trial registration was required, and therefore clinical trial registration numbers are not available.

Analysis of predictors of response to anti-IgE therapy in patients with severe atopic bronchial asthma in real clinical practice

Introduction. Guidelines on Biological Therapy for Bronchial Asthma of the European Academy of Allergy and Clinical Immunology (EAACI) identified a number of controversial issues for additional outcome analysis using randomized clinical trials and data from routine clinical practice. In particular, there is unmet need to clarify algorithms for prescribing biologicals using predictors of response and its timing, taking into account risk factors and multimorbidity. Omalizumab is a recombinant humanized monoclonal anti-IgE antibody of IgG1 class used for the treatment of severe refractory atopic bronchial asthma (BA) and a variety of IgE-mediated diseases. Among biological agents, this "pioneer molecule" has the greatest experience in the "allergology and immunology" profile. Detailed description of the "nonresponders" portraits will allow to perform the therapy response assessment on time and facilitate rational planning of individual therapy, which is a prerequisite for biologicals era. Using only routine methods, it is possible to perform initial and dynamic screening to phenotype a heterogeneous cohort of patients with severe asthma and chose the optimal strategy. Aim. To identify predictors of nonresponse to omalizumab anti-IgE therapy in patients with severe atopic BA and to establish optimal timing of efficacy assessment using retrospective analysis of data from the Biologic Therapy Registry of Allergology and Immunology in routine clinical practice. Materials and methods. A retrospective single-center registry study was conducted at the Allergy and Immunology Reference Center from June 2017 to August 2021. 135 patients with severe BA, with confirmed perennial sensitization, who received omalizumab according to the recommendations of the current version of GINA, were selected from the clinical and dynamic observational system (registry). Dosing regimen and administration frequency of omalizumab were determined in accordance with the instructions for the drug. Assessment of therapy efficacy was performed at the time point 4, 6 and 12 months. Patients were subgrouped into "responders" and "non-responders" according to the following criteria: ACT score less than 19 and/or difference between initial ACT score in dynamics less than 3 points; forced expiratory volume in the first second less than 80%; combination of these two criteria. Nonparametric methods of descriptive statistics were used in data processing: median, interquartile range. Differences were considered significant at p0.05. MannWhitney U-test, KruskalWallis one-way analysis of variance, and Fisher's 2 test were used to compare quantitative characteristics. Results. Heterogeneous subgroups of patients differing in reaching the criteria of "non-responders" to treatment were identified; the informativity of modifiable and unmodifiable factors differed at time-points of dynamic observation. In the differential analysis, two profiles of "nonresponders" were defined in combination with the most significant predictors of "nonrsponse" to omalizumab. According to the data obtained, one of the clinical phenotypes, namely the combination of severe asthma with the Samters triad, corresponded to the characteristics of the patient "nonresponders": age of onset is about 30 years, females, severe exacerbations of BA while taking non-steroidal anti-inflammatory drugs, accompanied with high levels of eosinophilia. Conclusion. The data obtained illustrates the hypothesis of pathogenetic heterogeneity of severe BA with the phenomenon of overlapping phenotypes and can serve as an additional orienteer for creating the individual plan of anti-IgE therapy in real clinical practice.

Obesity and Asthma

Obesity is a major risk factor for the development of asthma, and the prevalence of obesity is higher in people with asthma than in the general population. Obese people often have severe asthma-recent studies in the United States suggest that 60% of adults with severe asthma are obese. Multiple mechanisms link obesity and asthma, which are discussed in this article, and these pathways contribute to different phenotypes of asthma among people with obesity. From a practical aspect, changes in physiology and immune markers affect diagnosis and monitoring of disease activity in people with asthma and obesity. Obesity also affects response to asthma medications and is associated with an increased risk of co-morbidities such as gastroesophageal reflux disease, depression, and obstructive sleep apnea, all of which may affect asthma control. Obese people may be at elevated risk of exacerbations related to increased risk of severe disease in response to viral infections. Interventions that target improved dietary quality, exercise, and weight loss are likely to be particularly helpful for this patient population.

Sex, Allergic Diseases and Omalizumab

Gender differences are increasingly emerging in every area of medicine including drug therapy; however, specific gender-targeted studies are infrequent. Sex is a fundamental variable, which cannot be neglected. When optimizing therapies, gender pharmacology must always be considered in order to improve the effectiveness and safety of the use of drugs. Knowledge of gender differences promotes appropriate use of therapies and greater health protection for both genders. Further development of gender research would make it possible to report on differences in the assimilation and response of the female organism as compared to the male, in order to identify potential risks and benefits that can be found between genders. Furthermore, a better understanding of sex/gender-related influences, with regard to pharmacological activity, would allow the development of personalized “tailor-made” medicines. Here, we summarize the state of knowledge on the role of sex in several allergic diseases and their treatment with omalizumab, the first biologic drug authorized for use in the field of allergology.

Predictors of a Minimal Clinically Important Difference Following Omalizumab Treatment in Adult Patients With Severe Allergic Asthma

Several factors have been found to be predictors of a good response following omalizumab treatment in patients with severe allergic asthma (SAA). However, it remains unclear whether clinical characteristics can predict a minimal clinically important difference (MCID) following omalizumab treatment in this population. Therefore, the aim of this study was to investigate the features associated with an MCID following omalizumab treatment in adult patients with SAA. Of the 124 participants enrolled in this retrospective, cross-sectional study, 94, 103, 20 and 53 achieved the MCID following treatment with omalizumab and were considered to be responders of exacerbation reduction (no exacerbation during the 1-year follow-up period or ≧50% reduction in exacerbations from baseline), oral corticosteroid (OCS) sparing (no use of OCS to control asthma during the study period or a reduction of the monthly OCS maintenance dose to <50% of baseline), lung function (an increase of ≧230 ml in the forced expiratory volume in 1 s from baseline) and asthma control (an increase of ≧3 points in the asthma control test score from baseline), respectively. Normal weight [<25 vs. ≧30 kg/m², odds ratio (OR) = 3.86, p = 0.024] was predictive of a responder of reduction in exacerbations following omalizumab treatment while subjects with a blood eosinophil level of <300 cells/μL (<300 vs. ≧300 cells/μL, OR = 5.81, p = 0.001) were more likely to exhibit an MCID in OCS sparing. No factor was found to be a predictor of lung function or asthma control. When choosing treatment for adult patients with SAA, our findings may help to select those who may benefit the most from omalizumab treatment.

Developments in the field of allergy in 2020 through the eyes of Clinical and Experimental Allergy

While 2020 will be remembered for the global coronavirus pandemic, there were also important advances in the field of allergy. In this review article, we summarize key findings reported in Clinical and Experimental Allergy during 2020. We hope this provides readers with an accessible snapshot of the work published in our journal during this time.

Follicular T Helper and Breg Cell Balance in Severe Allergic Asthma Before and After Omalizumab Therapy

BACKGROUND

Severe allergic asthma (SAA) is based on type 2 (T2-high) immune responses to allergens promoting type 2 T helper (Th2) cell cytokine responses and production of IgE antibodies. Omalizumab was the first biological drug licensed for clinical use in the management of IgE-mediated SAA. Despite emerging evidence supporting the prominent role of follicular T cells (Tfh), Breg and Treg subsets, in the development and progression of SAA, no data are available on the impact of omalizumab therapy.

METHODS

Ten SAA patients monitored at the Respiratory Diseases Unit of Siena University Hospital and ten healthy sex- and age-matched controls were enrolled in the study. Clinical and functional parameters were collected at baseline (T0) and after 6 months of therapy (T6). Cellular population analysis was determined through multicolour flow cytometry.

RESULTS

SAA patients showed higher percentages of Th17.1, Tfh and Tfh2 while CD24hiCD27hi Breg cell, Treg and Tfr percentages were significantly lower than in controls. Higher percentages of Tfh2 in patients with nasal polyps than in those without and in controls were observed. At T6, significant decreases in Tfh and Tfh2 compared with T0 were observed. A slightly significant increase in Teffs was reported at T6 compared to T0. ΔIgE levels in serum were correlated with ΔCD19+CD24+CD27+ Breg cell percentages (r = - 0.86, p = 0.0022).

CONCLUSIONS

Our data explored the changes in Tfh cells, Tregs and Bregs in severe asthma. The restoration of immunological imbalance in SAA patients after omalizumab is certainly intriguing and represents a glimpse into the comprehension of immunological effects of treatment.

Anti-IgE for the Treatment of Chronic Urticaria

Urticaria and angioedema are very common. Management of chronic urticaria subtypes, which usually persist for many years, is challenging. Recent years have demonstrated that targeting IgE with antibodies provides a safe and efficient treatment approach. Whilst several anti-IgE antibodies have been developed, omalizumab is currently the only one approved for use. International and national guidelines recommend its use after failure of antihistamines at standard and increased dose. Whilst not yet approved, many new anti-IgE approaches are currently being investigated in pre-clinical studies or clinical trials. This non-systematic focused review summarizes current knowledge of omalizumab and other anti-IgE biologics in chronic urticaria using data extracted from PubMed, Google Scholar and clinical trial databases, clinicaltrials.gov and clinicaltrials.eu. For adults, there is good evidence from randomized clinical trials and real-world data that symptomatic treatment with omalizumab is efficacious and safe in chronic spontaneous urticaria (CSU), whereas evidence in chronic inducible urticaria (CINDU) and special populations is limited. Easy-to-use tools to identify non-responders and predict the required duration of treatment have not been established yet. Phase 2 b results of ligelizumab have not only demonstrated efficacy and safety but also superiority to omalizumab. Indeed, there is preliminary evidence that omalizumab non- or partial responders benefit from ligelizumab. Whereas further development of quilizumab was discontinued, other approaches, eg UB-221 or DARPins are under investigation. Anti-IgE treatment with omalizumab represents a landmark in the treatment of chronic urticaria, with and without angioedema, and there is light on the horizon suggesting success may come with various next-generation anti-IgE approaches.