Positioning of Long-Acting Muscarinic Antagonists in the Management of Asthma

Open-inhaler versus single-inhaler triple therapy (long-acting muscarinic antagonist, inhaled corticosteroid, and long-acting β2-agonist) in asthma patients: a narrative review

OBJECTIVE

To review the evidence for the use of open-inhaler (inhaled corticosteroid [ICS] plus long-acting β2-agonist [LABA] with separate add-on long-acting muscarinic antagonist [LAMA]) versus single-inhaler triple therapy (ICS/LABA/LAMA combination) and the merits of add-on LAMA to ICS/LABA in patients with uncontrolled asthma.

DATA SOURCES

Original research articles were identified from PubMed using the search term "triple therapy asthma." Information was also retrieved from the ClinicalTrials.gov website.

STUDY SELECTIONS

Articles detailing the use of add-on LAMA to ICS plus LABA (open-inhaler triple therapy), and closed triple therapy compared with ICS plus LABA dual therapy, addressing patient symptoms, exacerbations, and health-related quality of life.

RESULTS

Open-inhaler triple therapy was associated with a significantly reduced incidence of hospitalizations and emergency department visits and a decrease in ICS dose, oral corticosteroids use, and antibiotics use. Exacerbations and acute respiratory events were also reduced. Single-inhaler triple therapy showed a greater improvement in lung function, asthma control, and health status and was noninferior to open-inhaler triple therapy for Asthma Quality of Life Questionnaire scores. Single-inhaler triple therapy may also lead to improved therapy adherence.

CONCLUSION

Add-on LAMA to ICS plus LABA (open- or single-inhaler triple therapy) improves the response in patients who remain symptomatic and provides a reasonable alternative to ICS dose escalation in treatment-refractory patients.

Effectiveness and tolerability of dual and triple combination inhaler therapies compared with each other and varying doses of inhaled corticosteroids in adolescents and adults with asthma: a systematic review and network meta-analysis

BACKGROUND

Current guidelines recommend a higher-dose inhaled corticosteroids (ICS) or adding a long-acting muscarinic antagonist (LAMA) when asthma is not controlled with medium-dose (MD) ICS/long-acting beta2-agonist (LABA) combination therapy.

OBJECTIVES

To assess the effectiveness and safety of dual (ICS/LABA) and triple therapies (ICS/LABA/LAMA) compared with each other and with varying doses of ICS in adolescents and adults with uncontrolled asthma.

SEARCH METHODS

We searched multiple databases for pre-registered randomised controlled trials (RCTs) of at least 12 weeks of study duration from 2008 to 18 February 2022.

SELECTION CRITERIA

We searched studies, including adolescents and adults with uncontrolled asthma who had been treated with, or were eligible for, MD-ICS/LABA, comparing dual and triple therapies. We excluded cluster- and cross-over RCTs.

DATA COLLECTION AND ANALYSIS

We conducted a systematic review and network meta-analysis according to the previously published protocol. We used Cochrane's Screen4ME workflow to assess search results and Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the certainty of evidence. The primary outcome was steroid-requiring asthma exacerbations and asthma-related hospitalisations (moderate to severe and severe exacerbations).

MAIN RESULTS

We included 17,161 patients with uncontrolled asthma from 17 studies (median duration 26 weeks; mean age 49.1 years; male 40%; white 81%; mean forced expiratory volume in 1 second (MEF 1)1.9 litres and 61% predicted). The quality of included studies was generally good except for some outcomes in a few studies due to high attrition rates. Medium-dose (MD) and high-dose (HD) triple therapies reduce steroid-requiring asthma exacerbations (hazard ratio (HR) 0.84 [95% credible interval (CrI) 0.71 to 0.99] and 0.69 [0.58 to 0.82], respectively) (high-certainty evidence), but not asthma-related hospitalisations, compared to MD-ICS/LABA. High-dose triple therapy likely reduces steroid-requiring asthma exacerbations compared to MD triple therapy (HR 0.83 [95% CrI 0.69 to 0.996], [moderate certainty]). Subgroup analyses suggest the reduction in steroid-requiring exacerbations associated with triple therapies may be only for those with a history of asthma exacerbations in the previous year but not for those without. High-dose triple therapy, but not MD triple, results in a reduction in all-cause adverse events (AEs) and likely reduces dropouts due to AEs compared to MD-ICS/LABA (odds ratio (OR) 0.79 [95% CrI 0.69 to 0.90], [high certainty] and 0.50 [95% CrI 0.30 to 0.84], [moderate certainty], respectively). Triple therapy results in little to no difference in all-cause or asthma-related serious adverse events (SAEs) compared to dual therapy (high certainty). The evidence suggests triple therapy results in little or no clinically important difference in symptoms or quality of life compared to dual therapy considering the minimal clinically important differences (MCIDs) and HD-ICS/LABA is unlikely to result in any significant benefit or harm compared to MD-ICS/LABA.

AUTHORS' CONCLUSIONS

Medium-dose and HD triple therapies reduce steroid-requiring asthma exacerbations, but not asthma-related hospitalisations, compared to MD-ICS/LABA especially in those with a history of asthma exacerbations in the previous year. High-dose triple therapy is likely superior to MD triple therapy in reducing steroid-requiring asthma exacerbations. Triple therapy is unlikely to result in clinically meaningful improvement in symptoms or quality of life compared to dual therapy considering the MCIDs. High-dose triple therapy, but not MD triple, results in a reduction in all-cause AEs and likely reduces dropouts due to AEs compared to MD-ICS/LABA. Triple therapy results in little to no difference in all-cause or asthma-related SAEs compared to dual therapy. HD-ICS/LABA is unlikely to result in any significant benefit or harm compared to MD-ICS/LABA, although long-term safety of higher rather than MD- ICS remains to be demonstrated given the median duration of included studies was six months. The above findings may assist deciding on a treatment option when asthma is not controlled with MD-ICS/LABA.

Optimizing asthma management: Role of long-acting muscarinic antagonists

Patients with asthma who are suboptimally responsive to inhaled corticosteroids (ICS) and long-acting β₂-agonists (LABAs) are frequently exposed to oral corticosteroids and high-dose ICS, which can lead to significant side effects. Long-acting muscarinic antagonists (LAMAs) have demonstrated efficacy and safety in a subset of these patients. This review summarizes the results of key studies using LAMAs in patients with asthma aged 12 years or older. LAMA as an add-on treatment improved lung function and asthma control in patients with uncontrolled asthma across studies. The efficacy of LAMAs as an add-on to ICS was superior to that of placebo and ICS dose escalation and comparable with that of LABAs. LAMA plus ICS plus LABA provided modest improvements in bronchodilation and increased the time to first severe exacerbation versus ICS plus LABA. Single-inhaler triple therapy was associated with decreased health care resource utilization and improved cost-effectiveness versus multiple inhalers. LAMAs were generally well tolerated; asthma exacerbations, bronchitis, and nasopharyngitis were common adverse events with LAMA in combination with ICS alone or ICS plus LABA. Thus, the overall evidence presented in this review supports the use of add-on LAMA treatment as a reasonable option in patients with asthma uncontrolled with ICS plus LABA or ICS alone.

Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

Small airway disease is recognized as a cardinal pathological process of chronic obstructive pulmonary disease (COPD), and recently small airways have been recognized as a major site of airflow obstruction also in asthmatic patients. The transversal involvement of small airways in COPD and asthma has warranted research efforts to identify therapeutic strategies able to unlock the small airway compartment. The mainstay of COPD treatment is represented by long-acting β₂-adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs). In asthma, the efficacy of LAMAs administered add-on to inhaled corticosteroids (ICSs) or ICS/LABA combinations has been investigated only in recent years. The aim of this systematic review was to examine the current literature concerning the impact of LAMAs on small airways and their lung deposition in both COPD and asthma. LAMAs administered either alone or in combination induced an effective bronchorelaxant effect of small airways, however the effectiveness of respiratory medications not only relies on the selected drug, but also on the employed inhalation device and patient's adherence. Tiotropium delivered via Respimat® SMI achieved a superior drug deposition in the peripheral lung compared to HandiHaler® dry powder inhaler and metered-dose inhalers (MDIs). The use of co-suspension™ delivery technology for MDIs and the introduction of the eFlow® nebulizer to deliver glycopyrronium improved aerosol drug delivery to the peripheral lung, by achieving uniform distribution of drug particles. This systematic review provides a synthesis of current literature concerning the impact of LAMAs on small airways and an insight on LAMAs distribution within the lung.

A randomized controlled trial of glycopyrrolate administered by metered dose inhaler in patients with uncontrolled asthma despite ICS/LABA treatment

OBJECTIVE

To evaluate the efficacy and safety of three doses of glycopyrrolate metered dose inhaler (GP MDI) in patients with uncontrolled asthma despite treatment with inhaled corticosteroid/long-acting β₂-agonists (ICS/LABA) with or without tiotropium, to characterize the benefit of triple therapy.

METHOD

This phase II/III, double-blind study randomized patients to 24 weeks' treatment with twice-daily GP MDI 36 µg, 18 µg, 9 µg, or placebo MDI (all delivered via Aerosphere inhalers), or once-daily open-label tiotropium 2.5 µg. Patients continued their own ICS/LABA regimen throughout the study. The primary endpoint was change from baseline in forced expiratory volume in 1 s (FEV₁) area under the curve from 0 - 4 h (AUC_0 - 4) at Week 24. Secondary endpoints included patient questionnaires to measure asthma control or symptoms. Safety was also assessed.

RESULTS

The primary analysis (modified intent-to-treat) population included 1066 patients. The primary study endpoint was not met (changes from baseline in FEV₁ AUC_0 - 4 at Week 24 were 294 mL, 284 mL, 308 mL, 240 mL, and 347 mL for GP MDI 36 µg, GP MDI 18 µg, GP MDI 9 µg, placebo, and open-label tiotropium, respectively). There were no significant differences between treatment and placebo in secondary endpoints at Week 24. Post-hoc analyses using post-bronchodilator FEV₁ as the baseline measurement, or averaging values across multiple baseline visits, showed a dose-related response to GP MDI. The incidence of adverse events was low and similar across treatments.

CONCLUSION

Although this study did not meet its primary endpoint, post hoc analyses identified a dose-related response to GP MDI when alternative definitions of baseline FEV₁ were used in the analyses.

Overview of severe asthma, with emphasis on pediatric patients: a review for practitioners

Asthma is the most common life-threatening chronic disease in children. Although guidelines exist for the diagnosis and treatment of asthma, treatment of severe, pediatric asthma remains difficult. Limited studies in the pediatric population on new asthma therapies, complex issues with adolescence and adherence, health disparities, and unequal access to guideline-based care complicate the care of children with severe, persistent asthma. The purpose of this review is to provide an overview of asthma, including asthma subtypes, comorbidities, and risk factors, to discuss diagnostic considerations and pitfalls and existing treatments, and then present existing and emerging therapeutic approaches to asthma management. An improved understanding of asthma heterogeneity, clinical characteristics, inflammatory patterns, and pathobiology can help further guide the management of severe asthma in children. More studies are needed in the pediatric population to understand emerging therapeutics application in children. Effective multimodal strategies tailored to individual characteristics and a commitment to address risk factors, modifiers, and health disparities may help reduce the burden of asthma in the USA.

Can GPCRs Be Targeted to Control Inflammation in Asthma?

Historically, the drugs used to manage obstructive lung diseases (OLDs), asthma, and chronic obstructive pulmonary disease (COPD) either (1) directly regulate airway contraction by blocking or relaxing airway smooth muscle (ASM) contraction or (2) indirectly regulate ASM contraction by inhibiting the principal cause of ASM contraction/bronchoconstriction and airway inflammation. To date, these tasks have been respectively assigned to two diverse drug types: agonists/antagonists of G protein-coupled receptors (GPCRs) and inhaled or systemic steroids. These two types of drugs "stay in their lane" with respect to their actions and consequently require the addition of the other drug to effectively manage both inflammation and bronchoconstriction in OLDs. Indeed, it has been speculated that safety issues historically associated with beta-agonist use (beta-agonists activate the beta-2-adrenoceptor (β₂AR) on airway smooth muscle (ASM) to provide bronchoprotection/bronchorelaxation) are a function of pro-inflammatory actions of β₂AR agonism. Recently, however, previously unappreciated roles of various GPCRs on ASM contractility and on airway inflammation have been elucidated, raising the possibility that novel GPCR ligands targeting these GPCRs can be developed as anti-inflammatory therapeutics. Moreover, we now know that many GPCRs can be "tuned" and not just turned "off" or "on" to specifically activate the beneficial therapeutic signaling a receptor can transduce while avoiding detrimental signaling. Thus, the fledging field of biased agonism pharmacology has the potential to turn the β₂AR into an anti-inflammatory facilitator in asthma, possibly reducing or eliminating the need for steroids.

Comparing LAMA with LABA and LTRA as add-on therapies in primary care asthma management

The Global Initiative for Asthma recommends a stepwise approach to adjust asthma treatment to the needs of individual patients; inhaled corticosteroids (ICS) remain the core pharmacological treatment. However, many patients remain poorly controlled, and evidence-based algorithms to decide on the best order and rationale for add-on therapies are lacking. We explore the challenges of asthma management in primary care and review outcomes from randomised controlled trials and meta-analyses comparing the long-acting muscarinic antagonist (LAMA) tiotropium with long-acting β₂-agonists (LABAs) or leukotriene receptor antagonists (LTRAs) as add-on to ICS in patients with asthma. In adults, LAMAs and LABAs provide a greater improvement in lung function than LTRAs as add-on to ICS. In children, results were positive and comparable between therapies, but data are scarce. This information could aid decision-making in primary care, supporting the use of add-on therapy to ICS to help improve lung function, control asthma symptoms and prevent exacerbations.

Letter to the editor: indacaterol/glycopyrronium/mometasone furoate compared with salmeterol/fluticasone propionate in patients with asthma: a randomized controlled cross-over study

Abstract

Indacaterol (IND; 150 μg), glycopyrronium (GLY; 50 μg) and mometasone furoate (MF; 160 μg [high-dose ICS] and 80 μg [medium-dose ICS]) have been formulated as a once-daily (o.d.) fixed-dose combination treatment delivered via the Breezhaler® device for the treatment of patients with asthma. In this randomized (n = 116), double-blind, double-dummy, active comparator-controlled, three-period cross-over study we evaluated the benefit of o.d. IND/GLY/MF versus twice daily (b.i.d.) salmeterol/fluticasone propionate combination (SFC; 50/500 μg; high-dose ICS) treatment (NCT03063086). Overall, 107 patients completed the study. The study met its primary objective by demonstrating superiority of o.d. IND/GLY/MF at medium and high-dose ICS over b.i.d. SFC (high-dose ICS) in peak FEV₁ after 21 days of treatment (+ 172 mL with high-dose and + 159 mL with medium-dose IND/GLY/MF versus SFC, p < 0.0001 for each comparison). We also observed that a higher percentage of patients did not need rescue medicine with IND/GLY/MF (high-dose ICS, 58%; medium-dose ICS, 52%) compared with SFC (45%) during the last week of each treatment period. Study treatments were well-tolerated with no relevant differences in tolerability between both IND/GLY/MF doses and SFC. In conclusion, both doses of IND/GLY/MF provided superior lung function benefits compared with twice-daily, standard-of-care SFC at the highest approved dose.

Trial registration

ClinicalTrials.gov, (Identifier: NCT03063086),

EudraCT start date: May 11, 2017; First patient first visit / study initiation date: May 31, 2017.

One-year follow up of asthmatic patients newly initiated on treatment with medium- or high-dose inhaled corticosteroid-long-acting β2-agonist in UK primary care settings

INTRODUCTION

Global Initiative for Asthma (GINA) recommends medium- or high-dose inhaled corticosteroid-long-acting β₂-agonist (ICS-LABA) as preferred treatments for patients with moderate-to-severe asthma. Limited data is available on how step 4/5 patients respond to ICS-LABA and how they step up/down in clinical practice.

METHODS

This retrospective cohort study assessed the characteristics, control status, treatment pathways, and healthcare resource utilization in patients with asthma during one year after initiating medium- or high-dose ICS-LABA. Data from the United Kingdom Clinical Practice Research Datalink were analysed between January 01, 2006 and February 28, 2016.

RESULTS

Overall, 29,229 and 16,575 patients initiated medium- and high-dose ICS-LABA, and 35.1% and 45.7% of patients, respectively, remained uncontrolled. The proportions of patients who were adherent to treatment (Medication Possession Ratio ≥80%) were 37.8% and 49.1% in the medium- and high-dose ICS-LABA cohorts, respectively. Among these adherent patients, 63.8% in the medium- and 70% in the high-dose cohorts remained uncontrolled. In patients who stepped up therapy in the medium-dose cohort (19.0%), the common step-up choices were add-on leukotriene receptor antagonist (LTRA) (42.2%), long-acting muscarinic antagonist (LAMA) (23.3%), and increase in ICS dose (22.9%). In patients who stepped up therapy in the high-dose cohort (26.1%), the common step-up choices were add-on LAMA (43.8%) and LTRA (42.1%). Healthcare resource utilization was higher in uncontrolled patients, regardless of the ICS-LABA dose.

CONCLUSIONS

Many patients remain uncontrolled on both medium- or high-dose ICS-LABA, highlighting the need for timely assessment of asthma control to increase treatment intensity, following evidence-based treatment pathways.

Preschool children with persistent asthmatic symptoms

Asthma is the most common chronic airway disease in children, with more than half the reported cases of persistent asthma starting in children below the age of 3 years. Asthma diagnosis in preschool children has proven to be challenging due to the heterogeneity of the disease, the continuing development of the immune system in such a young population, and lack of diagnostic options such as lung function measurement. Early diagnosis and treatment of asthmatic symptoms will improve patients' quality of life and help reduce disease morbidity. However, validated treatment options are scarce due to paucity of data and lack of conclusive studies in such a young patient population. Adjusting study design and endpoints to capture more reliable data with minimal risk of harm to patients is necessary. This thematic series review outlines the current position on preschool asthma, consolidates the current understanding of risk factors and diagnostic hurdles, and emphasizes the importance of early detection and management to help improve patients' quality of life, both present and future. Particular focus was given to anticholinergics and their emerging role in the treatment and control of asthma in pediatric patients.

Clinical efficacy and safety of anticholinergic therapies in pediatric patients

The burden of uncontrolled asthma in children and adolescents is high. Treatment options for pediatric patients (aged under 18 years) with asthma are largely influenced by the Global Initiative for Asthma recommendations. Algorithms for adolescents (12-18 years) and adults are identical, but recommendations for children aged under 6 years and 6-11 years differ. Although the goals of treatment for pediatric patients with asthma are similar to those for adults, relatively few new therapies have been approved for this patient population within the last decade. Designing clinical trials involving children presents several challenges, notably that children are often less able to perform lung function tests, and traditional endpoints used in clinical trials with adults, such as forced expiratory volume in 1 second, asthma exacerbations and questionnaires, have limitations associated with their use in children. There are also ethical considerations related to the performance of longer placebo-controlled exacerbation trials. This review considers additional clinical endpoints to those traditionally reported, including forced expiratory flow at 25%-75% of forced vital capacity, which may help shed light on which treatments are most effective for use in pediatric patients with asthma. The pros and cons of specific and potentially clinically relevant endpoints are considered, along with device considerations and patient preferences that may enhance adherence and quality of life. Recent advances in the management of children and adolescents, including the US Food and Drug Administration and European Medicines Agency approval of tiotropium in patients with asthma aged 6 years and over, are also discussed.

Characteristics of Adult Severe Refractory Asthma in Korea Analyzed From the Severe Asthma Registry

Purpose

Although mild to moderate asthma is much more common, the morbidity and mortality of severe asthma are much higher. This study was performed to identify and analyze the clinical characteristics of severe asthma in Korea.

Methods

We registered patients with severe refractory asthma into the Severe Asthma Registry supported by the Severe Asthma Work Group of the Korean Academy of Asthma, Allergy and Clinical Immunology. Patients were enrolled since 2010 from the 15 university hospitals nationwide in Korea. Severe asthma was defined according to modified European Respiratory Society/American Thoracic Society criteria. Information on demographics, medical history, pulmonary function tests and skin prick tests was collected; the clinical characteristics of severe asthmatics were analyzed from the collected data.

Results

A total of 489 patients were enrolled with a mean age of 62.3; 45% are male. Sixty percent of patients received Global Initiative for Asthma step 4 treatment, and 30% received step 5 treatment. The most common comorbidities were allergic rhinitis (58.7%). Aspirin hypersensitivity was observed in 14.0%. Approximately half (53.9%) are non-smokers. Atopy was proven in 38.5% of the patients. Regarding asthma medications, inhaled corticosteroids and long-acting β-agonist combination inhalers were most commonly prescribed (96.5%), followed by leukotriene antagonists (71.0%). A recombinant anti-immunoglobulin E monoclonal antibody (omalizumab) has been used in 1.8% of the patients. The mean forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and FEV1/FVC were 78.7%, 67.5% and 67.9% of predicted values, respectively. The mean Asthma Control Test and quality of life questionnaire scores were 16.5 out of 25 and 59.5 out of 85, respectively.

Conclusions

The baseline characteristics of severe asthma patients in the Korea Severe Asthma Registry were analyzed and reported for the first time. With this cohort, further prospective studies should be performed to search for ways to improve management of severe refractory asthma.

Add-on Tiotropium in Chinese Patients With Moderate Asthma: A Pooled Subgroup Analysis of MezzoTinA-Asthma 1 and 2

Purpose

Asthma affects approximately 30 million patients in China; however, tiotropium data for Chinese patients is limited. This study aimed to assess the efficacy and safety of tiotropium in Chinese patients with moderate symptomatic asthma.

Methods

A post hoc subgroup analysis was conducted on 430 Chinese patients pooled from two 24-week, replicate phase 3 trials (NCT01172808 and NCT01172821), in which they received once-daily tiotropium 2.5 µg (Tio R2.5) or 5 µg (Tio R5) (n = 106 or 109, respectively), twice-daily salmeterol 50 µg (Sal 50) (n = 110), or placebo (n = 105), while maintaining inhaled corticosteroids (ICS). The co-primary endpoints assessed in week 24 were forced expiratory volume in 1 second (FEV1) peak_0–3h response, trough FEV1 response, and responder rate as assessed using the Asthma Control Questionnaire (ACQ).

Results

For both FEV1 peak_0–3h responses and trough FEV1 responses, the mean treatment differences were greater for Tio R2.5, Tio R5, and Sal 50 compared with placebo at 0.249 L, 0.234 L, and 0.284 L, and 0.172 L, 0.180 L, and 0.164 L, respectively (P< 0.001). The ACQ responder rate in placebo, Tio R2.5, Tio R5, and Sal 50 was 58.7%, 62.3%, 59.3%, and 69.1%, respectively. Furthermore, 11 (2.6%) of 430 patients had serious adverse events (Tio R5, n = 4; Tio R2.5, n = 1; Sal 50, n = 1; and placebo, n = 5).

Conclusions

Once-daily tiotropium, as add-on to medium-dose ICS, was effective and well tolerated for Chinese patients with moderate symptomatic asthma, consistent with the main analysis.

Long-acting muscarinic antagonists for the treatment of asthma in children-a new kid in town

BACKGROUND

Asthma is the most prevalent chronic airway disease observed in children and adolescents, yet the variety of treatment options available for this age group is limited. With many factors influencing therapeutic efficacy including patient knowledge, adherence, and therapy choice as well as delivery device, it is important to have more options to tailor to individual patient needs.

METHODS

This article is an overview of recent scientific articles using a systematic literature search in PubMed and specialist databases.

RESULTS

Tiotropium is the first long-acting muscarinic antagonist to be licensed for treatment of asthma and has been demonstrated to be an effective add-on therapy across all age groups. Its therapeutic success in clinical trials resulted in Food and Drug Administration and the European Medicines Agency approval for asthma treatment in people over the age of 6 years in the US and EU.

CONCLUSION

Further studies into the use of tiotropium, especially in younger children, could be of interest for future treatment decisions.

Efficacy, safety, and dose response of glycopyrronium administered by metered dose inhaler using co-suspension delivery technology in subjects with intermittent or mild-to-moderate persistent asthma: A randomized controlled trial

OBJECTIVES

This randomized, double-blind, placebo-controlled, cross-over, Phase II dose-ranging study investigated the efficacy and safety of GP MDI (glycopyrronium administered by metered dose inhaler formulated using co-suspension delivery technology) compared with an open-label active comparator, salmeterol dry powder inhaler (SAL DPI), in subjects with intermittent or mild-to-moderate persistent asthma.

METHODS

Subjects were randomized to receive five of seven treatments (GP MDI 28.8, 14.4, 7.2, 3.6, and 1.9 μg, placebo MDI, and SAL DPI 50 μg), each for a 14-day period. The primary endpoint was peak change from baseline in forced expiratory volume in 1 s (FEV₁) on Day 15. Secondary endpoints included additional lung function parameters and symptoms (Asthma Control Questionnaire-5). Safety was monitored throughout.

RESULTS

Of 248 subjects randomized, 211 completed the study. All doses of GP MDI resulted in significant improvements in the primary endpoint compared with placebo MDI in a dose-ordered fashion (range 85-155 mL, p < .0001), without appreciable differences between the two highest doses of GP MDI (28.8 and 14.4 μg) and SAL DPI 50 μg. Improvements in secondary lung function endpoints and symptoms were generally dose-ordered, with GP MDI 28.8 μg showing the greatest improvements. Similar results were observed when endpoints were analyzed based on subjects' background use of inhaled corticosteroids (yes/no). All GP MDI doses were well tolerated with no evidence of a dose-related effect on adverse events.

CONCLUSIONS

The results of this study suggest that GP MDI could offer an important treatment option for maintenance therapy of asthma, and warrants further investigation in Phase III clinical trials.

CRTH2 antagonists in asthma: current perspectives

Chemoattractant receptor-homologous molecule expressed on T_H2 cells (CRTH2) binds to prostaglandin D₂. CRTH2 is expressed on various cell types including eosinophils, mast cells, and basophils. CRTH2 and prostaglandin D₂ are involved in allergic inflammation and eosinophil activation. Orally administered CRTH2 antagonists are in clinical development for the treatment of asthma. The biology and clinical trial data indicate that CRTH2 antagonists should be targeted toward eosinophilic asthma. This article reviews the clinical evidence for CRTH2 involvement in asthma pathophysiology and clinical trials of CRTH2 antagonists in asthma. CRTH2 antagonists could provide a practical alternative to biological treatments for patients with severe asthma. Future perspectives for this class of drug are considered, including the selection of the subgroup of patients most likely to show a meaningful treatment response.