Current maintenance therapies for asthma require twice-daily dosing. Vilanterol (VI) is a novel long-acting beta2 agonist, under development in combination with fluticasone furoate, a new inhaled corticosteroid (ICS). Findings from a previous 4-week study suggested that VI has inherent 24-hour activity and is therefore suitable for once-daily dosing. The study described here was a double-blind, double-dummy, randomised, placebo-controlled trial, the aim of which was to assess the efficacy of once-daily VI compared with placebo in patients with persistent asthma. The primary endpoint was change from baseline in 24-hour weighted mean forced expiratory volume in 1 second after 12 weeks of treatment vs. placebo. An active control arm received salmeterol (SAL) twice daily. All patients were maintained on a stable background dose of ICS.
Patients (n = 347) received VI, placebo or SAL (1:1:1). For the primary endpoint, substantial improvements in lung function were seen with VI (359 ml), SAL (283 ml) and placebo (289 ml). There were no statistically significant treatment differences between either the VI (70 ml, P = 0.244) or SAL (-6 ml, P = 0.926) groups and placebo. Both active treatments were well tolerated, with similarly low rates of treatment-related adverse events compared with placebo. No treatment-related serious adverse events occurred.
This study failed to show a treatment difference between VI and placebo for the primary endpoint, in the presence of a placebo response of unforeseen magnitude. Because the placebo response was so large, it is not possible to draw meaningful conclusions from the data. The reason for this magnitude of effect is unclear but it may reflect increased compliance with the anti-inflammatory therapy regimen during the treatment period.
NCT01181895 at ClinicalTrials.gov.
Asthma; Bronchodilators; Long-acting beta agonist; Lung function; Placebo response; Randomised trial; Salmeterol; Vilanterol
Patients with severe refractory asthma represent a small subset of the asthmatic population (between 5% and 10% of all patients) but are the greatest burden to the health care system. New treatment approaches developed to manage some of the phenotypes of severe refractory asthma have included humanized monoclonal antibodies (hMabs).
To review the evidence and ascertain whether hMabs provide clinical benefit to patients with severe refractory asthma.
Studies that examined the efficacy of hMabs against immunoglobulin (Ig) E, tumour necrosis factor-alpha, interleukin (IL)-5, and IL-4/IL-13 in patients with severe refractory asthma were reviewed and summarized.
Treatment with anti-IgE improved asthma control and reduced severe exacerbations in patients with severe asthma and elevated serum IgE levels. Treatments with hMabs that block tumour necrosis factor-alpha are unlikely to be useful in asthma treatment. In contrast, hMabs that block IL-5 have consistently shown benefit in reducing severe exacerbations in patients with severe refractory asthma with persistent eosinophilia. Finally, hMabs that block IL-13 may provide benefit in patients with elevated blood periostin levels.
hMabs that block IgE are approved for the treatment of allergic asthma. It is likely that blocking IL-5 will also provide benefit in patients with severe asthma with persistent eosinophilia. These studies have emphasized the importance of careful phenotyping of patients with severe refractory asthma before embarking on treatment with hMabs.
Interleukin-5; Interleukin-13; Severe asthma
The combination of fluticasone furoate (FF), a novel inhaled corticosteroid (ICS), and vilanterol (VI), a long-acting β2 agonist, is under development as a once-daily treatment of asthma and COPD. The aim of this study was to compare the efficacy of FF/VI with fluticasone propionate (FP)/salmeterol (SAL) in patients with persistent asthma uncontrolled on a medium dose of ICS.
In a randomized, double-blind, double-dummy, parallel group study, 806 patients received FF/VI (100/25 μg, n = 403) once daily in the evening delivered through ELLIPTA (GlaxoSmithKline) dry powder inhaler, or FP/SAL (250/50 μg, n = 403) bid through DISKUS/ACCUHALER (GlaxoSmithKline). The primary efficacy measure was 0- to 24-h serial weighted mean (wm) FEV1 after 24 weeks of treatment.
Improvements from baseline in 0- to 24-h wmFEV1 were observed with both FF/VI (341 mL) and FP/SAL (377 mL); the adjusted mean treatment difference was not statistically significant (−37 mL; 95% CI, −88 to 15, P = 0.162). There were no differences between 0- to 4-h serial wmFEV1, trough FEV1, and asthma control and quality-of-life questionnaire scores. There was no difference in reported exacerbations between treatments. Both treatments were well tolerated, with no clinically relevant effect on urinary cortisol excretion or vital signs and no treatment-related serious adverse events.
The efficacy of once-daily FF/VI was similar to bid FP/SAL in improving lung function in patients with persistent asthma. No safety issues were identified.
ClinicalTrials.gov; No.: NCT01147848; URL: www.clinicaltrials.gov
The imbalance between Th17 and Treg cells has been studied in various diseases including allergic asthma but their roles have not been fully understood in the development of the late phase asthmatic response.
To determine changes in Th17 and Treg cell numbers between isolated early responders (ERs) and dual responders (DRs) undergoing allergen inhalation challenge. To identify gene expression profiles associated with Th17 and Treg cells.
14 participants (8 ERs and 6 DRs) with mild allergic asthma underwent allergen inhalation challenge. Peripheral blood was collected prior to and 2 hours post allergen challenge. DNA methylation analysis was used to quantifiy the relative frequencies of Th17, Tregs, total B cells, and total T cells. Gene expression from whole blood was measured using microarrays. Technical replication of selected genes was performed using nanoString nCounter Elements.
The Th17/Treg ratio significantly increased in DRs compared to ERs post allergen challenge compared to pre-challenge. Genes significantly correlated to Th17 and Treg cell counts were inversely correlated with each other. Genes significantly correlated with Th17/Treg ratio included the cluster of genes of the leukocyte receptor complex located on chromosome 19q 13.4.
Th17/Treg imbalance post-challenge may contribute to the development of the late phase inflammatory phenotype.
Allergen inhalation challenge; Asthma, Asthmatic response; DNA methylation; Epigenetic cell counting; Peripheral blood; Th17/Treg ratio, nCounter Elements
MicroRNAs are small non-coding RNAs that regulate gene expression at the post-transcriptional level. While they have been implicated in various diseases, the profile changes in allergen inhalation challenge are not clarified in human. We aimed to evaluate changes in the microRNA profiles in the peripheral blood of asthmatic subjects undergoing allergen inhalation challenge.
Seven mild asthmatic subjects participated in the allergen inhalation challenge. In addition, four healthy control subjects (HCs) were recruited. MicroRNA profiles in peripheral blood samples (pre-challenge and 2 hours post-challenge) were measured by the NanoString nCounter assay to determine changes in miRNA levels as these asthmatic subjects underwent an allergen inhalation challenge. One common miRNA, miR-192, was significantly expressed in both comparisons; HCs vs. pre-challenge and pre- vs. post-challenge, showing that miR-192 was significantly under-expressed in asthmatics compared to HCs and decreased in post-challenge at an FDR of 1%. Cell-specific statistical deconvolution attributed miR-192 expression in whole blood to PBMCs. MiR-192 was technically validated using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) showing that the level in asthmatics (pre-challenge) was significantly lower than HCs and that post-challenge was significantly lower than pre-challenge. The normalized relative miR-192 expression quantified using RT-qPCR specific to PBMCs was also validated. Ontology enrichment and canonical pathway analyses for target genes suggested several functions and pathways involved in immune response and cell cycle.
The miRNA profile in peripheral blood was altered after allergen inhalation challenge. Change in miR-192 levels may be implicated in asthma mechanisms. These results suggest that allergen inhalation challenge is a suitable method to characterize peripheral miRNA profiles and potentially elucidate the mechanism of human asthma.
Allergen inhalation challenge; Allergy; Asthma; Blood cells; Hsa-miR-192; MicroRNAs; NanoString nCounter assay
Allergen inhalation challenge has been useful for examining the mechanisms of allergen-induced airway inflammation and the associated physiological changes and for documenting the efficacy of drugs to treat asthma. Allergen inhalation by a sensitized subject results in acute bronchoconstriction, beginning within 15-30 min and lasting 1-3 hr, which can be followed by the development of a late asthmatic response. Individuals who develop both an early and late response after allergen have more marked increases in airway hyperresponsiveness, and greater increases in allergen-induced airway inflammation, particularly in airway eosinophils and basophils. All of the currently available and effective treatments for asthma modify some aspects of allergen-induced responses. These medications include short-acting and long-acting inhaled β2-agonists, inhaled corticosteroids, cromones, methylxanthines, leukotriene inhibitors, and anti-IgE monoclonal antibody. In addition, allergen inhalation challenge has become a useful method which can, in a very limited number of patients, provide key information on the therapeutic potential of new drugs being developed to treat asthma.
asthma; allergen; inflammation; drug development
Allergic asthma is a chronic immune-inflammatory disease of the airways. Despite aeroallergen exposure being universal, allergic asthma affects only a fraction of individuals. This is likely related, at least in part, to the extent of allergen exposure. Regarding house dust mite (HDM), we previously identified the threshold required to elicit allergic responses in BALB/c mice. Here, we investigated the impact of an initial immune perturbation on the response to sub-threshold HDM exposure. We show that transient GM-CSF expression in the lung facilitated robust eosinophilic inflammation, long-lasting antigen-specific Th2 responses, mucus production and airway hyperresponsiveness. This was associated with increased IL-33 levels and activated CD11b+ DCs expressing OX40L. GM-CSF-driven allergic responses were significantly blunted in IL-33-deficient mice. IL-33 was localized on alveolar type II cells and in vitro stimulation of human epithelial cells with GM-CSF enhanced intracellular IL-33 independently of IL-1α. Likewise, GM-CSF administration in vivo resulted in increased levels of IL-33 but not IL-1α. These findings suggest that exposures to environmental agents associated with GM-CSF production, including airway infections and pollutants, may decrease the threshold of allergen responsiveness and, hence, increase the susceptibility to develop allergic asthma through a GM-CSF/IL-33/OX40L pathway.
The allergen challenge has evolved, in less than 150 years, from a crude tool used to document the etiology of allergen-induced disease to a well-controlled tool used today to investigate the pathophysiology and pharmacotherapy of asthma. Highlights of the authors’ involvement with the allergen challenge include confirmation of the immunoglobulin E-dependence of the late asthmatic response, importance of (nonallergic) airway hyper-responsiveness as a determinant of the airway response to allergen, identification of allergen-induced increase in airway hyper-responsiveness, documentation of beta2-agonist-induced increase in airway response to allergen (including eosinophilic inflammation), advances in understanding the pathophysiology and kinetics of allergen-induced airway responses, and development of a muticentre clinical trial group devoted to using the allergen challenge for investigating promising new therapeutic strategies for asthma.
Airway responsiveness; Allergen challenge; Asthma; Eosinophils
Allergic asthma is a complex process arising out of the interaction between the immune system and aeroallergens. Yet, the relationship between aeroallergen exposure, allergic sensitization and disease remains unclear. This knowledge is essential to gain further insight into the origin and evolution of allergic diseases. The objective of this research is to develop a computational view of the interaction between aeroallergens and the host by investigating the impact of dose and length of aeroallergen exposure on allergic sensitization and allergic disease outcomes, mainly airway inflammation and to a lesser extent lung dysfunction and airway remodeling.
Methods and Principal Findings
BALB/C mice were exposed intranasally to a range of concentrations of the most pervasive aeroallergen worldwide, house dust mite (HDM), for up to a quarter of their lifespan (20 weeks). Actual biological data delineating the kinetics, nature and extent of responses for local (airway inflammation) and systemic (HDM-specific immunoglobulins) events were obtained. Mathematical equations for each outcome were developed, evaluated, refined through several iterations involving in vivo experimentation, and validated. The models accurately predicted the original biological data and simulated an extensive array of previously unknown responses, eliciting two- and three-dimensional models. Our data demonstrate the non-linearity of the relationship between aeroallergen exposure and either allergic sensitization or airway inflammation, identify thresholds, behaviours and maximal responsiveness for each outcome, and examine inter-variable relationships.
This research provides a novel way to visualize allergic responses in vivo and establishes a basic experimental platform upon which additional variables and perturbations can be incorporated into the system.
Asthma guidelines recommend reducing the dose of inhaled corticosteroids after establishing control.
To identify predictors of loss of control and the kinetics of symptoms, and inflammatory and physiological measurements when inhaled corticosteroids are reduced in patients with stable asthma.
PATIENTS AND METHODS
In a single-blind study, the daily dose of inhaled corticosteroid was reduced by one-half at intervals of 20±2 days in 17 adults with controlled asthma until loss of asthma control occurred or until the corticosteroid was replaced with placebo for 20 days. The patients recorded symptoms and peak expiratory flow each day, and forced expiratory volume in 1 s (FEV1), the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20), exhaled nitric oxide, and eosinophils in sputum and blood were measured every 10 days. A loss of asthma control was defined as a worsening of the symptoms score of at least 20%, and either a decrease in FEV1 of at least 15% or a decrease in PC20 of at least fourfold.
Two patients had a respiratory infection and were withdrawn from the study. In eight patients, asthma became uncontrolled after a mean of 33 days (range 13 to 48 days). This was accurately reflected by a worsening of all parameters. The first parameter to change was the sputum eosinophil percentage (20 days before the loss of asthma control). Significant changes in exhaled nitric oxide, FEV1 and methacholine PC20 were observed only when the symptoms became uncontrolled. A high blood eosinophil count at baseline (risk ratio of 2.5, 95% CI 1.0 to 6.5) and an increase in sputum eosinophil count after the reduction of corticosteroids were predictors of loss of asthma control.
In patients whose asthma is controlled on inhaled corticosteroid, it is prudent not to reduce the dose further if the blood eosinophils are increased or if the sputum eosinophils increase by as little as 1% after the reduction of corticosteroids.
Asthma exacerbation; Eosinophils; Induced sputum; Inhaled corticosteroid
The inhaled corticosteroid fluticasone furoate (FF) in combination with the long-acting β2 agonist vilanterol (VI) is in development for asthma and chronic obstructive pulmonary disease.
To assess the safety and tolerability of FF/VI over 52 weeks in patients with asthma.
Patients (aged ≥12 years; on inhaled corticosteroid) were randomised (2:2:1) to FF/VI 100/25 µg or FF/VI 200/25 µg once daily in the evening, or fluticasone propionate (FP) 500 µg twice daily. Safety evaluations included adverse events (AEs), non-fasting glucose, potassium, 24-h urinary cortisol excretion, ophthalmic assessments, heart rate and pulse rate.
On-treatment AEs were similar across groups (FF/VI 66–69%; 73% FP). Oral candidiasis/oropharyngeal candidiasis was more common with FF/VI (6–7%) than FP (3%). Twelve serious AEs were reported; one (worsening hepatitis B on FP) was considered drug related. Statistically significant cortisol suppression was seen with FP compared with both FF/VI groups at Weeks 12 and 28 (ratios [95% CI] to FP ranged from 1.43 [1.11 to 1.84] to 1.67 [1.34 to 2.08]; p≤0.006), but not at Week 52 (ratios to FP were 1.05 [0.83 to 1.33] for FF/VI 100/25 µg and 1.09 [0.87 to 1.38] for FF/VI 200/25 µg). No clinically important changes in non-fasting glucose, potassium, QT interval corrected using Fridericia's formula (QTc[F]) or ophthalmic assessments were reported. Pulse rate (10 min post dose [Tmax], Week 52) was significantly increased with FF/VI versus FP (3.4 bpm, 95% CI 1.3 to 5.6; p=0.002 [FF/VI 100/25 µg]; 3.4 bpm, 95% CI 1.2 to 5.6; p=0.003 [FF/VI 200/25 µg]). Mean heart rate (24-h Holter monitoring) decreased from screening values in all groups (0.2–1.1 bpm FF/VI vs 5 bpm FP; Week 52).
FF/VI (100/25 µg or 200/25 µg) administered once daily over 52 weeks was well tolerated by patients aged ≥12 years with asthma. The overall safety profile of FF/VI did not reveal any findings of significant clinical concern.
The inhaled corticosteroid fluticasone furoate (FF) and the long-acting β2 agonist vilanterol (VI) are in development as a combined once-daily therapy for asthma and chronic obstructive pulmonary disease. Our study objectives were to compare the efficacy and safety of once-daily FF/VI with FF alone and twice-daily fluticasone propionate (FP) in patients aged ≥12 years with moderate-to-severe persistent asthma.
Patients (n=586) received FF/VI 200/25 μg or FF 200 μg once-daily (evening dosing), or FP 500 μg twice-daily for 24 weeks. Co-primary end-points were change from baseline in trough forced expiratory volume in 1 s (FEV1) weighted mean (wm) 0–24 h serial FEV1. Secondary end-points included change from baseline in percentage of rescue-free 24-h periods, percentage of symptom-free 24-h periods and total Asthma Quality of Life Questionnaire (AQLQ). Safety assessments included adverse events, 24-h urinary cortisol excretion, vital signs and ECG.
FF/VI significantly improved trough FEV1 and wmFEV1
versus FF and FP. Significantly more rescue-free and symptom-free 24-h periods were reported with FF/VI versus FF. Treatment differences for AQLQ were not significant. Incidence of adverse events was similar across groups. No clinically significant differences were seen for 24-h urinary cortisol excretion, vital signs or ECG.
FF/VI resulted in statistically greater improvements in lung function and symptomatic end-points versus FF, and was well tolerated in this asthma population.
Fluticasone furoate (FF)/vilanterol improved lung function and symptomatic end-points compared with FF alone
Combination therapy with an inhaled corticosteroid (ICS) and long-acting β2 agonist (LABA) is recommended for patients with asthma symptomatic on ICS alone. However, there is ongoing debate regarding the risk-benefit ratio of using LABA in asthma.
To evaluate the effect of the addition of a novel LABA, vilanterol (VI), to a once-daily ICS, fluticasone furoate (FF), on the risk of severe asthma exacerbations in patients with uncontrolled asthma.
This randomised double-blind comparative study of variable duration (≥24–78 weeks) was designed to finish after 330 events (each patient's first on-treatment severe asthma exacerbation). 2019 patients with asthma aged ≥12 years with ≥1 recorded exacerbation within 1 year were randomised and received FF/VI 100/25 μg or FF 100 μg, administered once daily in the evening. The primary endpoint was time to first severe exacerbation; secondary endpoints were rate of severe asthma exacerbations per patient per year and change in trough evening forced expiratory volume in 1 s (FEV1) from baseline.
Compared with FF, FF/VI delayed the time to first severe exacerbation (HR 0.795, 95% CI 0.642 to 0.985) and reduced the annualised rate of severe exacerbations (rate reduction 25%, 95% CI 5% to 40%). Significantly greater improvements in trough FEV1 (p<0.001) were observed with FF/VI than with FF at weeks 12, 36, 52 and at endpoint. Both treatments were well tolerated with similar rates of treatment-related adverse events and on-treatment serious adverse events.
Once-daily FF/VI reduced the risk of severe asthma exacerbations and improved lung function compared with FF alone, with good tolerability and safety profile in adolescents and adults with asthma currently receiving ICS.
Asthma; Asthma Pharmacology
Some asthmatic individuals undergoing allergen inhalation challenge develop an isolated early response whereas others develop a dual response (early plus late response). In the present study we have used transcriptomics (microarrays) and metabolomics (mass spectrometry) of peripheral blood to identify molecular patterns that can discriminate allergen-induced isolated early from dual asthmatic responses. Peripheral blood was obtained prior to (pre-) and 2 hours post allergen inhalation challenge from 33 study participants. In an initial cohort of 14 participants, complete blood counts indicated significant differences in neutrophil and lymphocyte counts at pre-challenge between early and dual responders. At post-challenge, significant genes (ALOX15, FADS2 and LPCAT2) and metabolites (lysolipids) were enriched in lipid metabolism pathways. Enzymes encoding for these genes are involved in membrane biogenesis and metabolism of fatty acids into pro-inflammatory and anti-inflammatory mediators. Correlation analysis indicated a strong negative correlation between ALOX15, FADS2, and IL5RA expression with 2-arachidonoylglycerophosphocholine levels in dual responders. However, measuring arachidonic acid and docosahexaenoic acid levels in a validation cohort of 19 participants indicated that the free form of DHA (nmoles/µg of protein) was significantly (p = 0.03) different between early and dual responders after allergen challenge. Collectively these results may suggest an imbalance in lipid metabolism which dictates pro- (anti-) inflammatory and pro-resolving mechanisms. Future studies with larger sample sizes may reveal novel mechanisms and therapeutic targets of the late phase asthmatic response.
Phosphodiesterase 4 (PDE4) inhibitors increase intracellular cyclic adenosine monophosphate (cAMP), leading to regulation of inflammatory cell functions. Roflumilast is a potent and targeted PDE4 inhibitor. The objective of this study was to evaluate the effects of roflumilast on bronchoconstriction, airway hyperresponsiveness (AHR), and airway inflammation in mild asthmatic patients undergoing allergen inhalation challenge.
25 subjects with mild allergic asthma were randomized to oral roflumilast 500 mcg or placebo, once daily for 14 days in a double-blind, placebo-controlled, crossover study. Allergen challenge was performed on Day 14, and FEV1 was measured until 7 h post challenge. Methacholine challenge was performed on Days 1 (pre-dose), 13 (24 h pre-allergen), and 15 (24 h post-allergen), and sputum induction was performed on Days 1, 13, 14 (7 h post-allergen), and 15.
Roflumilast inhibited the allergen-induced late phase response compared to placebo; maximum % fall in FEV1 (p = 0.02) and the area under the curve (p = 0.01). Roflumilast had a more impressive effect inhibiting allergen-induced sputum eosinophils, neutrophils, and eosinophil cationic protein (ECP) at 7 h post-allergen (all p = 0.02), and sputum neutrophils (p = 0.04), ECP (p = 0.02), neutrophil elastase (p = 0.0001) and AHR (p = 0.004) at 24 h post-allergen.
This study demonstrates a protective effect of roflumilast on allergen-induced airway inflammation. The observed attenuation of sputum eosinophils and neutrophils demonstrates the anti-inflammatory properties of PDE4 inhibition and supports the roles of both cell types in the development of late phase bronchoconstriction and AHR.
Allergic asthma; allergen challenge; PDE4 inhibitor; inflammation; sputum; neutrophils; eosinophils
Adjusting medication for uncontrolled asthma involves selecting one of several options from the same or a higher treatment step outlined in asthma guidelines. We examined the relative benefit of introducing budesonide/formoterol (BUD/FORM) maintenance and reliever therapy (Symbicort SMART® Turbuhaler®) in patients previously prescribed treatments from Global Initiative for Asthma (GINA) Steps 2, 3 or 4.
This is a post hoc analysis of the results of five large clinical trials (>12000 patients) comparing BUD/FORM maintenance and reliever therapy with other treatments categorised by treatment step at study entry. Both current clinical asthma control during the last week of treatment and exacerbations during the study were examined.
At each GINA treatment step, the proportion of patients achieving target levels of current clinical control were similar or higher with BUD/FORM maintenance and reliever therapy compared with the same or a higher fixed maintenance dose of inhaled corticosteroid/long-acting β2-agonist (ICS/LABA) (plus short-acting β2-agonist [SABA] as reliever), and rates of exacerbations were lower at all treatment steps in BUD/FORM maintenance and reliever therapy versus same maintenance dose ICS/LABA (P < 0.01) and at treatment Step 4 versus higher maintenance dose ICS/LABA (P < 0.001). BUD/FORM maintenance and reliever therapy also achieved significantly higher rates of current clinical control and significantly lower exacerbation rates at most treatment steps compared with a higher maintenance dose ICS + SABA (Steps 2-4 for control and Steps 3 and 4 for exacerbations). With all treatments, the proportion of patients achieving current clinical control was lower with increasing treatment steps.
BUD/FORM maintenance and reliever therapy may be a preferable option for patients on Steps 2 to 4 of asthma guidelines requiring a more effective treatment and, compared with other fixed dose alternatives, is most effective in the higher treatment steps.