The efficacy of tiotropium as a steroid-sparing agent in severe asthma

Inhaled long-acting muscarinic antagonists in asthma - A narrative review

Long-acting muscarinic antagonists (LAMAs) have a recognised role in the management of chronic obstructive pulmonary disease. In asthma, muscarinic antagonists (both short- and long-acting) were historically considered less effective than β₂-agonists; only relatively recently have studies been conducted to evaluate the efficacy of LAMAs, as add-on to either inhaled corticosteroid (ICS) monotherapy or ICS/long-acting β₂-agonist (LABA) combinations. These studies led to the approval of the first LAMA, tiotropium, as an add-on therapy in patients with poorly controlled asthma. Subsequently, a number of single-inhaler ICS/LABA/LAMA triple therapies have been approved or are in clinical development for the management of asthma. There is now substantial evidence of the efficacy and safety of LAMAs in asthma that is uncontrolled despite treatment with an ICS/LABA combination. This regimen is recommended by GINA as an optimisation step for patients with severe asthma before any biologic or systemic corticosteroid treatment is initiated. This narrative review summarises the potential mechanisms of action of LAMAs in asthma, together with the initial clinical evidence supporting this use. We also discuss the studies that led to the approval of tiotropium for asthma and the data evaluating the efficacy and safety of the various triple therapies, before considering other potential uses for triple therapy.

Tiotropium in asthma: From bench to bedside

OBJECTIVE

Tiotropium is a long-acting muscarinic antagonist approved for maintenance treatment of asthma in children, adolescents, and adults in the United States, and recommended as add-on treatment for uncontrolled asthma despite treatment with inhaled corticosteroids and/or long-acting beta-2 agonists. This review traces the journey of tiotropium from its historical origins through early preclinical testing to human clinical trials and real-life studies.

DATA SOURCES

A search was performed in PubMed using search terms 'tiotropium' and 'asthma.' Relevant references cited in those articles were reviewed.

STUDY SELECTIONS

English language articles published from December 2008-December 2018 were screened. Articles evaluating the efficacy, cost-effectiveness, real-life evidence, and steroid-sparing effect of tiotropium with inadequately controlled asthma were included.

RESULTS

Anticholinergics have a long history of use in the treatment of obstructive airway diseases. Evidence indicates that tiotropium's mechanism of action consists of bronchodilation and diminished mucus secretion, with preclinical evidence suggesting an anti-inflammatory effect as well. Phase 2 and 3 clinical trials have demonstrated that tiotropium is efficacious and safe, resulting in significant improvements in lung function in adults, adolescents, and children across asthma severities. Emerging evidence suggests that add-on tiotropium might potentially enable reductions in inhaled corticosteroid dose in patients with uncontrolled asthma. Further, tiotropium is a cost-effective treatment option that is also effective in the clinical practice setting.

CONCLUSIONS

An increasing body of evidence indicates that tiotropium can play a significant role in the treatment of patients with uncontrolled asthma.

Role of anticholinergics in asthma management: recent evidence and future needs

PURPOSE OF REVIEW

Anticholinergic antimuscarinic bronchodilators play a major role in the treatment of chronic obstructive pulmonary disease, but their role in asthma has long been limited to acute management. More recently, the role of long-acting antimuscarinic bronchodilators (LAMAs) in chronic asthma management has been explored. This review will examine the pharmacological rationale for use of inhaled anticholinergics in the treatment of asthma, and provide an overview of the current literature supporting this use, as well as describe future research needs in this area.

RECENT FINDINGS

Short-acting anticholinergic bronchodilators have a role as add-on agents in the treatment of acute asthma. Preliminary clinical studies suggest that inhaled LAMAs may be comparable to long-acting beta2-agonists (LABAs) as an add-on therapy in patients not controlled by inhaled corticosteroids (ICS) alone, and may also have added benefit in patients not controlled on combined ICS-LABA. Mechanistic studies suggest that apart from their bronchodilator activity, LAMAs may have anti-inflammatory and antiremodeling influences on the airways. Further research is needed to clarify the clinical relevance of these experimental observations.

SUMMARY

Accumulating evidence supports the use of inhaled LAMAs as an add-on therapy in patients with asthma, who remain symptomatic despite guideline-based therapy with ICS with or without LABAs. Further studies are warranted to help define mechanisms of action of LAMAs, apart from their role as bronchodilators, and determine how these other actions impact asthma outcomes over time. Furthermore, future studies need to examine the long-term efficacy and safety of LAMAs in asthma and identify a subgroup of patients who would benefit from such therapies to facilitate early, personalized therapy.

Long-acting muscarinic antagonist use in adults with asthma: real-life prescribing and outcomes of add-on therapy with tiotropium bromide

Background

Randomized controlled trials indicate that addition of a long-acting muscarinic antagonist (LAMA) such as tiotropium may improve asthma control and reduce exacerbation risk in patients with poorly controlled asthma, but broader clinical studies are needed to investigate the effectiveness of LAMA in real-life asthma care.

Methods

Medical records of adults with asthma (aged ≥18 years) prescribed tiotropium were obtained from the UK Optimum Patient Care Research Database for the period 2001–2013. Patients diagnosed with chronic obstructive pulmonary disease were excluded, but no other clinical exclusions were applied. Two primary outcomes were compared in the year before (baseline) and the year after (outcome) addition of tiotropium: exacerbations (asthma-related hospital emergency department attendance or inpatient admission, or acute oral corticosteroid course) and acute respiratory events (exacerbation or antibiotic prescription with lower respiratory consultation). Secondary outcomes included lung function test results and short-acting β₂ agonist usage. The Wilcoxon signed-rank test was used for variables measured on the interval scale, the marginal homogeneity test for categorized variables, and the paired t-test for lung function indices.

Results

Of the 2,042 study patients, 83% were prescribed an inhaled corticosteroid and 68% a long-acting β₂ agonist during the baseline year; 67% were prescribed both. Comparing baseline and outcome years, the percentage of patients having at least one exacerbation decreased from 37% to 27% (P<0.001) and the percentage having at least one acute respiratory event decreased from 58% to 47% (P<0.001). There were no significant changes in lung function, and usage of short-acting β₂ agonists (in salbutamol/albuterol equivalents) increased from a median (interquartile range) of 274 (110, 548) to 329 (110, 603) μg/day (P=0.01).

Conclusion

In this real-life asthma population, addition of LAMA therapy was associated with significant decreases in the incidence of exacerbations and antibiotic prescriptions for lower respiratory tract infections in the following year.

Tiotropium may improve asthma symptoms and lung function in asthmatic patients with irreversible airway obstruction: the real-life data

BACKGROUND AND AIMS

Some patients with asthma have poorly controlled disease despite the use of high-dose inhaled corticosteroids (ICS), long-acting β2 agonists (LABAs) and antileukotrienes. The aim of the study was to assess the effectiveness of tiotropium as an add-on therapy to the standard treatment with high-dose ICS/LABA on asthma control and lung function in patients with severe asthma.

METHODS

Of the 633 asthmatic patients, 64 (10.1%) patients with severe asthma who were add-on treated at least for 3 months were evaluated. Number of exacerbations, emergency department visits, hospitalizations and lung functions of patients belonging to 12 months before starting add-on treatment were compared with those of 12 months after starting add-on treatment.

RESULTS

The mean duration of add-on tiotropium treatment was 8.3 ± 0.5 months. For patients with severe asthma that was poorly controlled with standard combination therapy, tiotropium improved asthma control in 42.2%, decreased the number of emergency department visits in 46.9% and decreased the number of hospitalizations in 50.0% of them. The mean baseline forced expiratory volume in 1 s before add-on tiotropium was 57.5 ± 1.9% and forced vital capacity was 74.3 ± 15.6%. However, after 12 months of add-on tiotropium treatment, these rates became 65.5 ± 1.9% and 82.5 ± 15.1%, respectively. The addition of tiotropium significantly improved the percentages of the number of emergency department visits, the number of hospitalizations (P < 0.05).

CONCLUSION

Our study has suggested that, for patients with poorly controlled asthma despite of the use of ICS/LABA, the addition of tiotropium to standard care may be beneficial.

Brain natriuretic peptide protects against hyperresponsiveness of human asthmatic airway smooth muscle via an epithelial cell-dependent mechanism

Brain natriuretic peptide (BNP) relaxes airways by activating natriuretic peptide receptor-A and elevating cyclic guanosine monophosphate. BNP is more effective in passively sensitized human bronchi compared with control airways. The molecular and cellular patterns involved in this signaling are unknown. The aim of this study was to investigate the influence of BNP on airway smooth muscle (ASM) cells obtained from donors with asthma and healthy donors and to identify the mechanisms involved in BNP-mediated relaxation. The contractile response of ASM cells was microscopically assessed in vitro in the presence of 1 μM BNP or with supernatant from human bronchial epithelial (BEAS-2B) cells pretreated with 1 μM BNP. We investigated the role of muscarinic M2 receptors and inducible nitric oxide synthase (iNOS), quantified the release of acetylcholine and nitric oxide (NO), and assessed the gene/protein expression of iNOS and myosin phosphatase target subunit 1 (MYPT1). Supernatant from BEAS-2B cells treated with BNP reduced the hyperreactivity of asthmatic ASM cells by shifting the potency of histamine by 1.19-fold but had no effect in healthy ASM cells. BNP was not effective directly on ASM cells. Blocking muscarinic M2-receptors and iNOS abolished the protective role of supernatant from BEAS-2B treated with BNP. BNP stimulated the release of acetylcholine (210.7 ± 11.1%) from BEAS-2B cells that in turn increased MYPT1 and iNOS gene/protein expression and enhanced NO levels in asthmatic ASM supernatant (35.0 ± 13.0%). This study provides evidence that BNP protects against bronchial hyperresponsiveness via an interaction between respiratory epithelium and ASM in subjects with asthma.

Long-acting anticholinergics in the treatment of asthma

PURPOSE OF REVIEW

The use of anticholinergic medications is well established as maintenance therapy for chronic obstructive pulmonary disease (COPD). There is a growing interest in the use of anticholinergic medications in the treatment of moderate to severe asthma. The purpose of this review is to summarize the scientific evidence for the use of anticholinergic therapy in the management of asthma.

RECENT FINDINGS

Early case reports and small studies evaluated the use of the anticholinergic agent, tiotropium bromide, as maintenance therapy in asthma. Included in this review are several recent clinical trials which provide additional evidence for the use of tiotropium as add-on therapy for asthma. The use of tiotropium was demonstrated to be superior to doubling the dose of an inhaled corticosteroid (ICS) and more effective than placebo based on change in morning peak expiratory flow (PEF). Two large multinational trials provide evidence for the use of tiotropium in a subset of asthmatic patients who have not achieved control using combination therapy with an ICS and a long-acting β2 agonist (LABA).

SUMMARY

The use of the long-acting anticholinergic agent, tiotropium, as maintenance of therapy in asthma, has been shown to be effective in some patients with moderate to severe asthma who are uncontrolled on combination therapy with ICS and LABA. Further studies are needed to better define which phenotypic subset of patients would benefit from the use of tiotropium.

Medical utilization and cost in patients with overlap syndrome of chronic obstructive pulmonary disease and asthma

BACKGROUND

Little information is available regarding medical utilization and cost in patients with overlap syndrome of chronic obstructive pulmonary disease (COPD) and asthma. The purpose of this study is to analyze medical utilization and cost in patients with overlap syndrome and to compare them to COPD patients without asthma.

METHODS

Using the 2009 Korean National Health Insurance (NHI) database, COPD patients were identified. Medical utilization and costs were also analyzed.

RESULTS

Of a total of 185,147 patients identified with COPD, 101,004 patients were classified with overlap syndrome of COPD and asthma and 84,143 patients with COPD without asthma. In 2009, the percentages of emergency room visits, admissions, and intensive care unit admissions were 14.6%, 30.5%, and 0.5%, respectively, in the patients with overlap syndrome group and 5.0%, 14.1%, and 0.2%, respectively, in the COPD patients without asthma group (p < 0.05 for all comparisons). The cost of medical utilization was 790 ± 71 US dollars per person and 3,373 ± 4,628 dollars per person for outpatient and inpatient services, respectively, in the patients with overlap syndrome and 413 ± 512 and 3,010 ± 5,013, respectively, in the COPD patients without asthma (p < 0.05 for all comparisons). Multiple linear regression showed that age, sex, overlap syndrome, hospitalization in the last year, low socioeconomic status, and type of hospital use were significant factors affecting medical utilization and cost.

CONCLUSIONS

In patients with overlap syndrome, both medical utilization and cost were higher than in COPD patients without asthma.

The emerging role of tiotropium for patients with asthma

OBJECTIVE

To review clinical data on the use of the long-acting anticholinergic agent tiotropium in patients with asthma.

DATA SOURCES

A literature search was performed via EMBASE and MEDLINE (1966-November 2012). The search was limited to human data published in the English language. Search terms included asthma, tiotropium, and long-acting anticholinergics.

STUDY SELECTION AND DATA EXTRACTION

Relevant information related to the use of tiotropium in patients with asthma was reviewed. Randomized controlled trials and open-label trials were included. The references of published articles identified in the search were also examined for additional studies appropriate to include in the review. Data were prioritized if they originated from human studies, especially if derived from randomized, placebo-controlled trials. Trials and case reports involving the use of long-acting anticholinergic tiotropium in asthma patients were included; conversely, trials involving ipratropium were not.

DATA SYNTHESIS

Two large randomized controlled trials support the safety and efficacy of adding tiotropium to the treatment regimen of select patients with poorly controlled asthma already receiving combination high-dose glucocorticosteroid/long-acting β-agonist (LABA) therapy. Pharmacogenomic studies have shown that patients with polymorphisms of the β2-adrenoreceptor (ADRB2; 16 Arg/Arg and 16 Arg/Gly) are particularly responsive to treatment with tiotropium. Smaller studies indicate that the advantages may be most pronounced in patients with a predominance of sputum neutrophils and that tiotropium can assist with decreasing the inhaled corticosteroid (ICS) dose. An increased risk of cardiovascular events was not identified.

CONCLUSIONS

Tiotropium should be considered in patients with asthma who remain symptomatic while receiving high-dose ICS and LABA therapy. Specifically, patients with high sputum neutrophil levels or with 16 Arg/Arg or 16 Arg/Gly polymorphism of the ADRB2 gene appear to respond best.

Tiotropium for adults with inadequately controlled persistent asthma

OBJECTIVE

To review the literature evaluating the efficacy and steroid-sparing effect of tiotropium for inadequately controlled persistent asthma in adults.

DATA SOURCES

Information was obtained through a search of MEDLINE/PubMed (1966-October 2012), using the terms asthma and tiotropium. A further review of reference citations was performed to identify other relevant articles.

STUDY SELECTION AND DATA EXTRACTION

English-language case reports and clinical trials were reviewed. Publications evaluating the efficacy and steroid-sparing effect of tiotropium in adults with inadequately controlled persistent asthma were included in the review. One case report and 5 clinical trials met our criteria.

DATA SYNTHESIS

The ultimate goal for asthma management is to maintain disease control by preventing acute exacerbations while avoiding adverse medication effects. Inhaled corticosteroids (ICS) are part of all preferred maintenance regimens for persistent asthma. Unfortunately, persistent asthma remains inadequately controlled in some patients and concerns about serious adverse effects with long-term high-dose ICS treatment exist. Interest in the use of tiotropium to control asthma symptoms and reduce steroid requirements in inadequately controlled persistent asthma is emerging. Results of several trials indicate that tiotropium improves pulmonary function markers and reduces corticosteroid requirements. Moreover, the largest and longest published trial not only showed improvements in pulmonary function tests but also a reduction in corticosteroid use and an increase in the time to first exacerbation.

CONCLUSIONS

Although tiotropium use in treatment of persistent asthma appears to be promising, more robust clinical trials are needed to assess whether improved pulmonary function tests as well as a decrease in asthma exacerbations and corticosteroid requirements translate into improvements in quality of life. Additionally, the optimal patient population, long-term efficacy, and safety of tiotropium when delivered by various methods need to be determined before it can be recommended over current alternative asthma therapies.

Therapeutic options for severe asthma

As the overall prevalence of asthma has escalated in the past decades, so has the population of patients with severe asthma. This condition is often difficult to manage due to the relative limitation of effective therapeutic options for the physician and the social and economic burden of the disease on the patient. Management should include an evaluation and elimination of modifiable risk factors such as smoking, allergen exposure, obesity and non-adherence, as well as therapy for co-morbidities like gastro-esophageal reflux disease and obstructive sleep apnea. Current treatment options include conventional agents such as inhalational corticosteroids, long acting β(2) agonists, leukotriene antagonists, and oral corticosteroids. Less conventional treatment options include immunotherapy with methotrexate, cyclosporine and tacrolimus, biological drugs like monoclonal antibodies, tumor necrosis factor-α blockers and oligonucleotides, phosphodiesterase inhibitors, antimicrobials and bronchial thermoplasty.

Pharmacology and therapeutics of bronchodilators

Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.

Tiotropium is noninferior to salmeterol in maintaining improved lung function in B16-Arg/Arg patients with asthma

BACKGROUND

The efficacy and safety of inhaled long-acting β(2)-adrenergic agonists in asthmatic patients with the B16-Arg/Arg genotype has been questioned, and the use of antimuscarinics has been proposed as an alternative in patients whose symptoms are not controlled by inhaled corticosteroids (ICSs).

OBJECTIVE

We compared the efficacy and safety of the long-acting anticholinergic tiotropium with salmeterol and placebo added to an ICS in B16-Arg/Arg patients with asthma that was not controlled by ICSs alone.

METHODS

In a double-blind, double-dummy, placebo-controlled trial, after a 4-week run-in period with 50 μg of twice-daily salmeterol administered through a metered-dose inhaler, 388 asthmatic patients were randomized 1:1:1 to 16 weeks of treatment with 5 μg of Respimat tiotropium administered daily in the evening, 50 μg of salmeterol administered twice daily through a metered-dose inhaler, or placebo. Patients aged 18 to 67 years demonstrated reversibility to bronchodilators, and their symptoms were uncontrolled by regular ICSs (400-1000 μg of budesonide/equivalent). ICS regimens were maintained throughout the trial. The mean weekly morning peak expiratory flow (PEF) before randomization was 358 ± 115.7 L/min (range, 80.3-733.0 L/min).

RESULTS

Changes in weekly PEF from the last week of the run-in period to the last week of treatment (primary end point: change in PEF) were -3.9 ± 4.87 L/min (n = 128) for tiotropium and -3.2 ± 4.64 L/min (n = 134) for salmeterol, and these were superior to placebo (-24.6 ± 4.84 L/min, n = 125, P < .05). Tiotropium was noninferior to salmeterol (estimated difference, -0.78 L/min [95% CI, -13.096 to 11.53]; P = .002; α = .025, 1-sided; noninferiority, 20 L/min). Tiotropium and salmeterol were numerically superior to placebo in some patient-reported secondary outcomes. Adverse events were comparable across treatments.

CONCLUSION

Tiotropium was more effective than placebo and as effective as salmeterol in maintaining improved lung function in B16-Arg/Arg patients with moderate persistent asthma. Safety profiles were comparable.

Tiotropium improves lung function in patients with severe uncontrolled asthma: a randomized controlled trial

BACKGROUND

Some patients with severe asthma remain symptomatic and obstructed despite maximal recommended treatment. Tiotropium, a long-acting inhaled anticholinergic agent, might be an effective bronchodilator in such patients.

OBJECTIVE

We sought to compare the efficacy and safety of 2 doses of tiotropium (5 and 10 μg daily) administered through the Respimat inhaler with placebo as add-on therapy in patients with uncontrolled severe asthma (Asthma Control Questionnaire score, ≥ 1.5; postbronchodilator FEV₁, ≤ 80% of predicted value) despite maintenance treatment with at least a high-dose inhaled corticosteroid plus a long-acting β₂-agonist.

METHODS

This was a randomized, double-blind, crossover study with three 8-week treatment periods. The primary end point was peak FEV₁ at the end of each treatment period.

RESULTS

Of 107 randomized patients (54% female patients; mean, 55 years of age; postbronchodilator FEV₁, 65% of predicted value), 100 completed all periods. Peak FEV₁ was significantly higher with 5 μg (difference, 139 mL; 95% CI, 96-181 mL) and 10 μg (difference, 170 mL; 95% CI, 128-213 mL) of tiotropium than with placebo (both P < .0001). There was no significant difference between the active doses. Trough FEV₁ at the end of the dosing interval was higher with tiotropium (5 μg: 86 mL [95% CI, 41-132 mL]; 10 μg: 113 mL [95% CI, 67-159 mL]; both P < .0004). Daily home peak expiratory flow measurements were higher with both tiotropium doses. There were no significant differences in asthma-related health status or symptoms. Adverse events were balanced across groups except for dry mouth, which was more common on 10 μg of tiotropium.

CONCLUSION

The addition of once-daily tiotropium to asthma treatment, including a high-dose inhaled corticosteroid plus a long-acting β₂-agonist, significantly improves lung function over 24 hours in patients with inadequately controlled, severe, persistent asthma.

Pharmacogenomic approaches to asthma treatment

Major classes of medication in asthma management include bronchodilating beta2-agonists, anti-inflammatory inhaled corticosteroids, leukotriene modifiers and theophyllines. However, all asthmatics do not respond to the same extent to a given medication. Available data suggest that a substantial range of individual variability, as much as 70%, may be due to genetic characteristics of each patient. Pharmacogenomics offers the potential to optimize medications for individual asthmatics by using genetic information to improve efficacy or avoid adverse effects. The best-studied case of the potential contribution of pharmacogenomics to treatment response in asthma comes from studies on human beta2 adrenergic receptors. In addition, genetic variation in beta2-adrenergic receptor (Arg16Gly) may predict response to anticholinergics for the treatment of asthma. In case of inhaled corticosteroids, a recent investigation using a traditional SNP-based approach identified a gene for corticotropin releasing hormone receptor 1 as a potential marker of response. Another major pathway that has been investigated is the pathway underlying response to cysteinyl leukotriene receptor antagonist. It is likely that in the near future, pharmacogenomic approaches based on individual genetic information will be introduced into an asthma treatment guideline and this guideline will allow us to identify those who have the best chance to respond to a specific medication.