Optimizing asthma management: Role of long-acting muscarinic antagonists

Long-acting muscarinic antagonists (LAMA) in asthma: What is the best strategy?

The use of long-acting muscarinic antagonists (LAMA) in asthma is supported by their mechanism of action and evidence of drug synergy with inhaled corticosteroids ± long-acting β-agonists. This review discusses the scientific rationale, clinical data, and recommendations for the use of LAMA in the asthma therapeutic strategy. Adding a LAMA to a dual therapy with an inhaled corticosteroid and long-acting β-agonist has been shown to reduce exacerbations, increase asthma control, and improve quality of life, with a good safety profile. In addition, using a single inhaler device containing multiple drugs enhances patients' adherence to therapy. Some predictive factors of the efficacy of this triple therapy have been suggested in the literature: patients with a history of at least one exacerbation within the past 12 months, male patients, those younger than 65 years, and non-smokers have been reported to have a greater improvement from baseline forced expiratory volume in 1 second (FEV1) compared with patients without these characteristics, while patients with high bronchial hyperresponsiveness and persistent airway limitations (PAL) seem to show better gains in the exacerbation rate. However, eosinophil levels do not seem to predict the efficacy of LAMA. The role and long-term benefits of LAMA combined with biologic therapy in severe asthma remain uncertain, with more clinical data needed.

Asthma therapeutics: Past, present, and future

Asthma is a disease of airway inflammation and bronchial hyperresponsiveness affecting over 300 million individuals worldwide. Although described as early as 460 BC, the recognition of asthma as a disease, and the development and implementation of therapies to control it, emerged in the early 1900s. The subsequent century introduced the utilization of immunotherapy, inhaled medications, and anti-inflammatory corticosteroids for disease control. Since the beginning of the 21st century, however, the emergence of novel asthma pharmacotherapies has accelerated greatly. Our understanding of various asthma phenotypes and their underlying mechanisms (endotypes) has crystallized, leading to an era of precision medicine. Management strategies increasingly use targeted biologic medications aimed at interrupting key components of the inflammatory cascade. Monoclonal antibodies targeting the IgE, thymic stromal lymphopoietin, or interleukin-4, -5, and -13 pathways have revolutionized the care we provide our patients, resulting in a reduction in exacerbations and oral corticosteroid (OCS) dose, while improving lung function and asthma-related quality of life. Although they are able to provide relief for many sufferers of severe disease, and even remission in some, these biologic therapies are still in their infancy. Because their roles become further established, new therapeutic targets and modalities offer significant promise of an even greater personalized medicine approach. This review addresses historical standard-of-care strategies for asthma treatment, current recommendations, and a glimpse into future novel therapies that are likely to help millions worldwide. SIGNIFICANCE STATEMENT: Asthma affects hundreds of millions of individuals worldwide. In the last few decades, asthma treatment paradigms have transformed from recommendations to use anti-inflammatory and bronchodilatory inhalation-based therapies including corticosteroids and beta-agonists, to more precisely targeted add-on biologic therapies that employ monoclonal antibodies addressing specific mechanistic pathways associated with specific patient characteristics. Future therapies promise utilization of personalized medicine to a greater extent with novel therapeutic approaches to help improve the health and quality of life of those suffering from asthma.

Results from a UK consensus about the optimal prescribing of medium strength triple therapy in uncontrolled adult asthma patients in the NHS

Context

An inhaled corticosteroid (ICS) in combination with a long-acting β2-agonist (LABA) is a common treatment approach for asthma patients not controlled on ICS alone, but a significant proportion of patients remain uncontrolled on this combination and treatment adherence can also be a challenge. One of the options for adults whose asthma is uncontrolled in an ICS/LABA is the addition of a long-acting muscarinic receptor antagonist (LAMA), an approach commonly referred to as 'triple therapy'. The use of medium-strength ICS/LABA/LAMA is established in treating chronic obstructive pulmonary disease but is less well-established in asthma. Lack of clarity exists regarding who should prescribe ICS/LABA/LAMA and in which patients, and this is compounded by a lack of consistency among guidelines.

Aims

To define the optimal prescribing of medium-strength ICS/LABA/LAMA triple therapy in adult asthma patients uncontrolled on ICS/LABA.

Methods and Material

Using a modified Delphi method, a panel of experts developed 39 Likert scale statements across six key domains. These statements were used to develop an online survey that was distributed to healthcare providers (HCPs) working with adult asthma throughout the UK. The threshold for consensus was set at 75%.

Results

In total, 314 responses were received from primary and secondary care stakeholders involved in the management of asthma. On analysis, 22/39 statements reached a very strong agreement (≥90%) and 16/39 attained strong agreement (≥75% and < 90). From these results, the panellists developed a set of twelve recommendations to help define how an optimal approach for prescribing triple therapy in patients who are uncontrolled on an ICS/LABA can be achieved.

Conclusions

The strength of agreement shows that HCPs support the use of medium-strength ICS/LABA/LAMA triple therapy in appropriate asthma patients, and that clarity is needed regarding how best this can be achieved. The proposed set of recommendations provides such guidance to support the prescribing of triple therapy in primary care.

Interaction between fluticasone furoate and umeclidinium in passively sensitized isolated human airways

Asthma management often includes inhaled corticosteroids (ICSs), with additional controllers like long-acting muscarinic antagonists (LAMAs) for severe cases. The primary goal of this study was to investigate the pharmacological interaction between various concentrations of fluticasone furoate (FF) and umeclidinium (UME) in isolated human airways to determine the nature of their interaction, whether synergistic or additive. Medium bronchi and small airways obtained from patients undergoing lobectomy were passively sensitized to mimic asthmatic conditions. The effects of FF and UME, alone and in combination, on airway relaxation were evaluated using histamine-induced contraction and electrical field stimulation. Pharmacological interactions were analyzed using the Bliss Independence theory. Results indicated that FF induced a partial, concentration-dependent relaxation of sensitized airways, while UME induced a larger relaxation in medium bronchi but a weaker effect in small airways. The combination of FF and UME resulted in significantly greater relaxation than either drug alone, demonstrating synergism at high concentrations in medium bronchi but only additive effects in small airways. This study suggests that higher doses of FF might be necessary in a fixed dose combination to achieve optimal synergistic bronchodilation with UME. Future research should focus on clinical trials to confirm these findings and explore the molecular mechanisms underlying these interactions, potentially improving personalized asthma therapy.

Involvement of Muscarinic M3 Receptor in the Development of M2 Macrophages in Allergic Inflammation

INTRODUCTION

The muscarinic M3 receptor antagonist, tiotropium, has a bronchodilatory effect on asthma patients. Additionally, tiotropium inhibits allergic airway inflammation and remodeling in a murine asthma model. However, the underlying mechanisms of this M3 receptor antagonist remain unclear. Therefore, we investigated the effect of muscarinic M3 receptor blockage on M2 macrophage development during allergic airway inflammation.

METHODS

BALB/c mice were sensitized and challenged with ovalbumin to develop a murine model of allergic airway inflammation mimicking human atopic asthma. During the challenge phase, mice were treated with or without tiotropium. Lung cells were isolated 24 h after the last treatment and gated using CD68-positive cells. Relm-α and Arginase-1 (Arg1) (M2 macrophage markers) expression was determined by flow cytometry. Mouse bone marrow mononuclear cell-derived macrophages (mBMMacs) and human peripheral blood mononuclear cells (PBMCs)-derived macrophages were stimulated with IL-4 and treated with a muscarinic M3 receptor antagonist in vitro.

RESULTS

The total cells, eosinophils, and IL-5 and IL-13 levels in BAL fluids were markedly decreased in the asthma group treated with tiotropium compared to that in the untreated asthma group. The Relm-α and Arg1 expression in macrophages was reduced considerably in the asthma group treated with tiotropium compared to that in the untreated asthma group, suggesting that the development of M2 macrophages was inhibited by muscarinic M3 receptor blockage. Additionally, muscarinic M3 receptor blockage in vitro significantly inhibited M2 macrophage development in both mBMMacs- and PBMCs-derived macrophages.

CONCLUSIONS

Muscarinic M3 receptor blockage inhibits M2 macrophage development and prevents allergic airway inflammation. Moreover, muscarinic M3 receptors might be involved in the differentiation of immature macrophages into M2 macrophages.

Ethanol Extracts from the Aerial Parts of Inula japonica and Potentilla chinensis Alleviate Airway Inflammation in Mice That Inhaled Particulate Matter 10 and Diesel Particulate Matter

Air pollution causes various airway diseases. However, many commonly used treatments can have high risks of side effects or are costly. To examine the anti-inflammatory properties of Inula japonica Thunb. and Potentilla chinensis Ser., a mouse model was generated via inhalation of both particulate matter 10 and diesel particulate matter, and 30% ethanol extracts of either I. japonica (IJ) or P. chinensis (PC) and a mixture of both ethanol extracts (IP) were orally administered to BALB/c mice for 12 days. IJ, PC, and IP inhibited immune cell numbers and their regulation in both the bronchoalveolar lavage fluid (BALF) and lungs. These agents suppressed the levels of interleukin (IL)-1α, IL-17, tumor necrosis factor (TNF)-α, C-X-C motif chemokine ligand (CXCL)-1, and CXCL-2 in BALF, and also inhibited F4/80 and IL-1 receptor-associated kinase (IRAK)-1 in lungs. They reduced the gene expression of TNF-α, CXCL-1, inducible NOS, COX-2, Mucin 5AC, and transient receptor potential cation channel subfamily V member 1 in lungs. These extracts also reduced histopathological changes and inflammatory progression, manifested as decreased cell infiltration, collagen deposition, and respiratory epithelial cell thickness. I. japonica and P. chinensis show potential for development as pharmaceuticals that suppress inflammatory progression and alleviate airway inflammation diseases caused by air pollutants.

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.

Delivery technology of inhaled therapy for asthma and COPD

Inhaled therapy is the cornerstone of the management of asthma and chronic obstructive pulmonary disease (COPD). Drugs such as bronchodilators and corticosteroids are administered directly to the airways for local effect and rapid onset of action while systemic exposure and side effects are minimized. There are four major types of inhaler devices used clinically to generate aerosols for inhalation, namely, pressurized metered-dose inhalers (pMDIs), nebulizers, Soft Mist™ inhalers (SMIs) and dry powder inhalers (DPIs). Each of them has its own unique characteristics that can target different patient groups. For instance, patients' inhaler technique is critical for pMDIs and SMIs to achieve proper drug deposition in the lung, which could be challenging for some patients. Nebulizers are designed to deliver aerosols to patients during tidal breathing, but they require electricity to operate and are less portable than other devices. DPIs are the only device that delivers aerosols in dry powder form with better stability, but they rely on patients' inspiration effort for powder dispersion, rendering them unsuitable for patients with compromised lung function. Choosing a device that can cater for the need of individual patient is paramount for effective inhaled therapy. This chapter provides an overview of inhaled therapy for the management of asthma and COPD. The operation principles, merits and limitations of different delivery technologies are examined. Looking ahead, the challenges of delivering novel therapeutics such as biologics through the pulmonary route are also discussed.

Asthma Management in Adults

Management of asthma in adults has advanced in the past 10 years. Central to these advances has been further clarification of type (T) 2 mechanisms of airway inflammation and utilization of T2 biomarkers, that is, eosinophils and fractional exhaled nitric oxide. In addition, epithelial cells are emerging as significant contributors to inflammation through generation of alarmins to initiate local injury as well as downstream pathways. Five new biologics, mepolizumab, benralizumab, reslizumab, dupilumab, and tezepelumab, were approved to join omalizumab and revolutionize severe asthma treatment. These biologics significantly prevent exacerbations to spare systemic corticosteroids use and their side effects. Guidelines attest to the effectiveness of inhaled corticosteroids/long-acting β-agonists (formoterol) for both maintenance and rescue therapy. Focused updates to the Expert Panel Report addressed limited but specific questions relevant to asthma control. Future guidelines should include phenotype/endotype-directed therapeutics to gain more precision-directed treatment.