Development of the Asthma Control Composite outcome measure to predict omalizumab response

A robust mRNA signature obtained via recursive ensemble feature selection predicts the responsiveness of omalizumab in moderate-to-severe asthma

BACKGROUND

Not being well controlled by therapy with inhaled corticosteroids and long-acting β2 agonist bronchodilators is a major concern for severe-asthma patients. The current treatment option for these patients is the use of biologicals such as anti-IgE treatment, omalizumab, as an add-on therapy. Despite the accepted use of omalizumab, patients do not always benefit from it. Therefore, there is a need to identify reliable biomarkers as predictors of omalizumab response.

METHODS

Two novel computational algorithms, machine-learning based Recursive Ensemble Feature Selection (REFS) and rule-based algorithm Logic Explainable Networks (LEN), were used on open accessible mRNA expression data from moderate-to-severe asthma patients to identify genes as predictors of omalizumab response.

RESULTS

With REFS, the number of features was reduced from 28,402 genes to 5 genes while obtaining a cross-validated accuracy of 0.975. The 5 responsiveness predictive genes encode the following proteins: Coiled-coil domain- containing protein 113 (CCDC113), Solute Carrier Family 26 Member 8 (SLC26A), Protein Phosphatase 1 Regulatory Subunit 3D (PPP1R3D), C-Type lectin Domain Family 4 member C (CLEC4C) and LOC100131780 (not annotated). The LEN algorithm found 4 identical genes with REFS: CCDC113, SLC26A8 PPP1R3D and LOC100131780. Literature research showed that the 4 identified responsiveness predicting genes are associated with mucosal immunity, cell metabolism, and airway remodeling.

CONCLUSION AND CLINICAL RELEVANCE

Both computational methods show 4 identical genes as predictors of omalizumab response in moderate-to-severe asthma patients. The obtained high accuracy indicates that our approach has potential in clinical settings. Future studies in relevant cohort data should validate our computational approach.

Response to Mepolizumab Treatment in Patients with Severe Eosinophilic Asthma and Atopic Phenotypes

Purpose

Improved understanding of characteristics that may influence treatment response across phenotypes may help guide treatment decisions.

Patients and Methods

This was a post hoc analysis of MENSA, a multicenter, randomized, double-blind, placebo-controlled trial (NCT01691521). Patients aged ≥12 years with severe eosinophilic asthma received mepolizumab (75 mg intravenously or 100 mg subcutaneously) or placebo, plus standard of care, every 4 weeks for 32 weeks. Outcomes assessed were the annualized rate of clinically significant exacerbations and change from baseline in Asthma Control Questionnaire (ACQ)-5 score. Subgroup analyses were performed by baseline blood eosinophil count (<150, ≥150–300, ≥300 cells/μL) within atopic subgroups (non-atopic [specific immunoglobulin E <0.35 kU/L], atopic [≥0.35–17.5 kU/L], strongly atopic [>17.5 kU/L]), and by house dust mite (HDM) sensitivity.

Results

Of 576 patients analyzed, 272 were non-atopic, 181 were atopic and 94 were strongly atopic; 29 had missing atopy data. In patients with blood eosinophil counts ≥300 cells/µL, mepolizumab versus placebo reduced clinically significant exacerbations by 74%, 43% and 25% in the non-atopic, atopic and strongly atopic subgroups. Similar reductions were observed in all atopic subgroups in other blood eosinophil count categories where there were sufficient patient numbers for analysis, except for non-atopic patients with baseline blood eosinophil counts of <150 cells/μL. Improvements in ACQ-5 scores of –0.75, –0.73 and –0.78 with mepolizumab versus placebo were observed in non-atopic, atopic and strongly atopic patients with blood eosinophil counts ≥300 cells/µL; consistent improvements in ACQ-5 were not observed in patients with blood eosinophil counts <150 or ≥150–300 cells/μL. Reductions in clinically significant exacerbations with mepolizumab versus placebo were also observed irrespective of sensitivity to HDMs.

Conclusion

Mepolizumab was associated with a trend for reductions in clinically significant exacerbations and improved asthma control versus placebo in patients with severe eosinophilic asthma, irrespective of atopic status or HDM sensitivity.

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Whole blood transcriptional variations between responders and non-responders in asthma patients receiving omalizumab

BACKGROUND

Anti-IgE (omalizumab) has been used for the treatment of moderate-to-severe asthma that is not controlled by inhaled steroids. Despite its success, it does not always provide patients with significant clinical benefits.

OBJECTIVE

To investigate the transcriptional variations between omalizumab responders and non-responders and to study the mechanisms of action of omalizumab.

METHODS

The whole blood transcriptomes of moderate-to-severe adult asthma patients (N = 45:34 responders and 11 non-responders) were analysed over the course of omalizumab treatment. Non-asthmatic healthy controls (N = 17) were used as controls.

RESULTS

Transcriptome variations between responders and non-responders were identified using the genes significant (FDR < 0.05) in at least one comparison of each patient response status and time point compared with control subjects. Using gene ontology and network analysis, eight clusters of genes were identified. Longitudinal analyses of individual clusters revealed that responders could maintain changes induced with omalizumab treatment and become more similar to the control subjects, while non-responders tend to remain more similar to their pre-treatment baseline. Further analysis of an inflammatory gene cluster revealed that genes associated with neutrophil/eosinophil activities were up-regulated in non-responders and, more importantly, omalizumab did not significantly alter their expression levels. The application of modular analysis supported our findings and further revealed variations between responders and non-responders.

CONCLUSION AND CLINICAL RELEVANCE

This study provides not only transcriptional variations between omalizumab responders and non-responders, but also molecular insights for controlling asthma by omalizumab.

Long-term evaluation of response to omalizumab therapy in real life by a novel multimodular approach: The Real-life Effectiveness of Omalizumab Therapy (REALITY) study

BACKGROUND

The evidence on long-term real-life response measures to omalizumab therapy in moderate to severe asthma is limited. A universal assessment tool is needed to adequately evaluate response to omalizumab in these patients.

OBJECTIVE

To design a multimodular response assessment tool and use it to measure and define response to omalizumab therapy in real-world settings.

METHODS

The Real-life Effectiveness of Omalizumab Therapy (REALITY) study is a retrospective, long-term, real-life clinical study that evaluates response in individuals with allergic asthma who received omalizumab between 2004 and 2011. The Standardized Measure to Assess Response to Therapy (SMART) tool was designed to define response (1 year before to after treatment) by 3 modules: (1) physician's subjective assessment of asthma symptoms and control; (2) objective assessment of 6 parameters: improvement by 50% or more for asthma exacerbation, steroid bursts, emergency department visits, and hospitalizations; increase in forced expiratory volume in 1 second of 200 mL or greater; and improved Asthma Control Test score of 3 or higher; -and (3) true responders (patient meeting both module 1 and 2 criteria). Response was assessed and compared for 3 modules at desired time points.

RESULTS

A total of 198 patients (mean age, 31.7 years [range, 3-77 years]; 98 [49%] female; mean omalizumab therapy duration, 2.49 years [range, 3 months to 8 years]; mean omalizumab dosage, 473 mg every 4 weeks; median baseline IgE level, 433 IU/mL) were included in this analysis. Overall visit adherence was 78%, although the adherence rate decreased annually by 20%. Response rates assessed by SMART modules were 61.3%, 60.8%, and 41.8% at 16 weeks, 84.8%, 72.2%, and 64.6% at 1 year, 82.4%, 71.2%, and 63.2% at 2 years, and 95.1%, 87.8%, and 85.4% at 5 years for modules 1, 2, and 3, respectively. There were no significant adverse reactions.

CONCLUSION

The REALITY study has demonstrated long-term effectiveness of omalizumab therapy in individuals with allergic asthma in real-life settings. The SMART tool is promising as a potential standard assessment tool to measure and define response to asthma therapy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01776177.

Stratified approaches to the treatment of asthma

While asthma is a chronic inflammatory disorder that is managed with inhaled controller and reliever drugs, there remains a large unmet need at the severe end of the disease spectrum. Here, a novel stratified approach to its treatment is reviewed, based upon identification of causal pathways, with a focus on biologics. A systematic search of the literature was made using Medline, and publications were selected on the basis of their relevance to the topic. Despite strong preclinical data for many of the more recently identified asthma targets, especially those relating to the T-helper 2 allergic pathway, clinical trials with specific biologics in moderate to severe asthma as a group have been disappointing. However, subgroup analyses based upon pathway-specific biomarkers suggest specific endotypes that are responsive. Application of hypothesis-free analytical approaches (the 'omics') to well-defined phenotypes is leading to the stratification of asthma along causal pathways. Refinement of this approach is likely to be the future for diagnosing and treating this group of diseases, as well as helping to define new causal pathways. The identification of responders and nonresponders to targeted asthma treatments provides a new way of looking at asthma diagnosis and management, especially with biologics that are costly. The identification of novel biomarkers linked to well-phenotyped patients provides a stratified approach to disease management beyond simple disease severity and involving causal pathways. In order to achieve this effectively, a closer interaction will be required between industry (therapeutic and diagnostic), academia and health workers.

Exploring the effects of omalizumab in allergic asthma: an analysis of biomarkers in the EXTRA study

RATIONALE

For many patients with asthma, allergic airway inflammation is primarily a Th2-weighted process; however, heterogeneity in patterns of inflammation suggests phenotypic distinctions exist that influence disease presentation and treatment effects.

OBJECTIVES

To assess the potential of fractional exhaled nitric oxide (FE(NO)), peripheral blood eosinophil count, and serum periostin as biomarkers of Th2 inflammation and predictors of treatment effects of omalizumab.

METHODS

The EXTRA omalizumab study enrolled patients (aged 12-75 yr) with uncontrolled severe persistent allergic asthma. Analyses were performed evaluating treatment effects in relation to FE(NO), blood eosinophils, and serum periostin at baseline. Patients were divided into low- and high-biomarker subgroups. Treatment effects were evaluated as number of protocol-defined asthma exacerbations during the 48-week treatment period (primary endpoint).

MEASUREMENTS AND MAIN RESULTS

A total of 850 patients were enrolled. Data were available from 394 (46.4%), 797 (93.8%), and 534 (62.8%) patients for FE(NO), blood eosinophils, and serum periostin, respectively. After 48 weeks of omalizumab, reductions in protocol-defined exacerbations were greater in high versus low subgroups for all three biomarkers: FE(NO), 53% (95% confidence interval [CI], 37-70; P = 0.001) versus 16% (95% CI, -32 to 46; P = 0.45); eosinophils, 32% (95% CI, 11-48; P = 0.005) versus 9% (95% CI, -24 to 34; P = 0.54); and periostin, 30% (95% CI, -2 to 51; P = 0.07) versus 3% (95% CI, -43 to 32; P = 0.94).

CONCLUSIONS

The difference in exacerbation frequency between omalizumab and placebo was greatest in the three high-biomarker subgroups, probably associated with the greater risk for exacerbations in high subgroups. Additional studies are required to explore the value of these biomarkers in clinical practice. Clinical trial registered with www.clinicaltrials.gov (NCT00314574).

Redefining approaches to asthma: developing targeted biologic therapies

Asthma is a chronic respiratory disorder canonically associated with type 2 airway inflammation as characterized by elevated levels of eosinophils, immunoglobulin E, and cytokines including interleukin (IL) 4, IL5, IL9, and IL13 and tumor necrosis factor (TNF) α. However, mounting evidence has shown that considerable heterogeneity exists in human asthma in terms of the nature and intensity of airway inflammation. While many asthma patients achieve acceptable control of symptoms with standard-of-care therapies such as β₂-adrenergic agonists and inhaled corticosteroids, a minority remains symptomatic despite maximal standard-of-care therapy and constitutes a significant unmet medical need. A growing number of investigational therapeutics under clinical development for asthma are biologic therapies that specifically target mediators of type 2 airway inflammation. In this chapter, we consider the biological functions of therapeutic targets in asthma and data from clinical trials of biologic agents directed against these targets. We discuss recent clinical trial results in terms of four key components of drug development: target selection, molecule selection, outcome selection, and patient selection, with particular attention paid to the emerging role of biomarkers in clinical development for asthma.

Targeting IgE in asthma

PURPOSE OF REVIEW

IgE plays a pivotal role in allergic asthma especially in the acute response to antigen and in the propagation of airway inflammation. Therefore, it has become apparent that targeting this antibody and blocking its function may lead to significant clinical effects in some patients with the disease. In this review, we describe the role of IgE in asthma and provide an update on the therapeutic implications of targeting this mediator in patients with severe allergic disease. We also outline future needs of research in this area.

RECENT FINDINGS

Several randomized clinical trials as well as observational real-world studies have confirmed the long-term efficacy of omalizumab in improving clinical outcomes when added to guideline-recommended maintenance of asthma medications (inhaled corticosteroids and long-acting β2-agonists) in patients with moderate-to-severe asthma. Recent pooled data from randomized clinical trials and from a large prospective cohort study provide reassurance about the long-term safety of omalizumab. Future research should explore the long-term effects of omalizumab on the natural history of the disease and identify more accurate predictors of response to this treatment.

SUMMARY

The anti-inflammatory effects of omalizumab at different sites of allergic inflammation and its clinical benefits in patients with allergic asthma emphasize the fundamental importance of IgE in allergic inflammation.

A 26-week, randomized, double-blind, placebo-controlled, multicenter study to evaluate the effect of omalizumab on asthma control in patients with persistent allergic asthma

OBJECTIVE

The 2007 National Heart, Lung, and Blood Institute (NHLBI) asthma guidelines shifted the focus of care from asthma severity to ongoing assessment of asthma control using the components of impairment and risk. We evaluated the effect of omalizumab on asthma control in patients with persistent allergic asthma inadequately controlled with NHLBI Step 4 or above asthma therapy.

METHODS

In this double-blind, placebo-controlled study, patients ≥12 years (n = 271) received omalizumab (n = 136) or placebo (n = 135) every 2 or 4 weeks for 24 weeks. The primary efficacy variable, change from baseline in Asthma Control Test (ACT) total score, and Investigator's Global Evaluation of Treatment Effectiveness (IGETE, secondary efficacy variable) were evaluated at week 24.

RESULTS

ACT score improved more with omalizumab compared with placebo (least squares means [LSMs]: 5.01, 4.36); however, the difference was not significant (p = .1779). Similarly, IGETE was not significantly different (p = .1177), but more patients treated with omalizumab (26/127, 20%) compared with placebo (19/131, 15%) had IGETE rated as "Excellent." Significant benefits were observed for omalizumab compared with placebo for change in ACT score (LSMs: 6.66, 5.27; p = .0334) and IGETE (p = .0321) at week 24 in a subgroup of patients with very poorly controlled asthma (ACT ≤ 15) at baseline. There were no significant differences for the subgroup of patients with forced expiratory volume in 1 second ≤ 80% predicted at baseline. Adverse events (AEs) were similar between groups with no drug-related serious AEs or deaths.

CONCLUSIONS

For allergic asthma patients with NHLBI Step 4 or above asthma therapy, omalizumab consistently improved asthma control; however, compared with placebo, differences were not significant. Placebo-treated patients had substantial improvement in their ACT score, which may have limited the ability to detect differences between treatment groups. Subgroup analyses showed significant improvements with omalizumab versus placebo in patients with very poorly controlled asthma.