Dual LABA/LAMA bronchodilators in chronic obstructive pulmonary disease: why, when, and how

Asthma management with triple ICS/LABA/LAMA combination to reduce the risk of exacerbation: an umbrella review compliant with the PRIOR statement

INTRODUCTION

According to Global Initiative for Asthma (GINA) guidelines, long-acting muscarinic antagonists (LAMAs) should be considered as add-on therapy in patients with asthma that remains uncontrolled, despite treatment with medium-dose (MD) or high-dose (HD) inhaled corticosteroids (ICS)/long-acting β2-agonist (LABA) combinations. In patients ≥ 18 years, LAMA may be added in triple combination with an ICS and a LABA. To date, the precise efficacy of triple ICS/LABA/LAMA combination remains uncertain concerning the impact on exacerbation risk in patients with uncontrolled asthma. Therefore, an umbrella review was performed to systematically summarize available data on the effect of triple ICS/LABA/LAMA combination on the risk of asthma exacerbation.

METHODS

An umbrella review has been performed according to the PRIOR statement.

RESULTS

The overall results obtained from 5 systematic reviews and meta-analyses suggest that triple ICS/LABA/LAMA combination reduces the risk of asthma exacerbation. HD-ICS showed a greater effect particularly in reducing severe asthma exacerbation, especially in patients with evidence of type 2 inflammation biomarkers.

CONCLUSIONS

The findings of this umbrella review suggest an optimization of ICS dose in triple ICS/LABA/LAMA combination, based on the severity of exacerbation and type 2 biomarkers expression.

The Role of Long-Acting Antimuscarinic Agents in the Treatment of Asthma

The journey of using anticholinergics in the treatment of asthma started with anticholinergic-containing plants such as Datura stramonium and Atropa belladonna, followed by ipratropium bromide and continued with tiotropium, glycopyrronium, and umeclidinium. Although antimuscarinics were used in the maintenance treatment of asthma over a century ago, after a long time (since 2014), it has been recommended to be used as an add-on long-acting antimuscarinic agent (LAMA) therapy in the maintenance treatment of asthma. The airway tone controlled by the vagus nerve is increased in asthma. Allergens, toxins, or viruses cause airway inflammation and inflammation-related epithelial damage, increased sensory nerve stimulation, ganglionic and postganglionic acetylcholine (ACh) release by inflammatory mediators, intensification of ACh signaling at M1 and M3 muscarinic ACh receptors (mAChRs), and dysfunction of M2 mAChR. Optimal anticholinergic drug for asthma should effectively block M3 and M1 receptors, but have minimal effect on M2 receptors. Tiotropium, umeclidinium, and glycopyrronium are anticholinergic agents with this feature. Tiotropium has been used in a separate inhaler as an add-on treatment to inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA), and glycopyrronium and umeclidinium have been used in a single inhaler as a combination of ICS/LABA/LAMA in asthma in recent years. Guidelines recommend this regimen as an optimization step for patients with severe asthma before initiating any biologic or systemic corticosteroid therapy. In this review, the history of antimuscarinic agents, their effectiveness and safety in line with randomized controlled trials, and real-life studies in asthma treatment will be discussed according to the current data.

Experimental drugs in clinical trials for COPD: Artificial Intelligence via Machine Learning approach to predict the successful advance from early-stage development to approval

INTRODUCTION

Therapeutic advances in drug therapy of chronic obstructive pulmonary disease (COPD) really effective in suppressing the pathological processes underlying the disease deterioration are still needed. Artificial Intelligence (AI) via Machine Learning (ML) may represent an effective tool to predict clinical development of investigational agents.

AREAL COVERED

Experimental drugs in Phase I and II development for COPD from early 2014 to late 2022 were identified in the ClinicalTrials.gov database. Different ML models, trained from prior knowledge on clinical trial success, were used to predict the probability that experimental drugs will successfully advance toward approval in COPD, according to Bayesian inference as follows: ≤25% low probability, >25% and ≤ 50% moderate probability, >50% and ≤ 75% high probability, and > 75% very high probability.

EXPERT OPINION

The Artificial Neural Network and Random Forest ML models indicated that, among the current experimental drugs in clinical trials for COPD, only the bifunctional muscarinic antagonist - β₂-adrenoceptor agonists (MABA) navafenterol and batefenterol, the inhaled corticosteroid (ICS)/MABA fluticasone furoate/batefenterol, and the bifunctional phosphodiesterase (PDE) 3/4 inhibitor ensifentrine resulted to have a moderate to very high probability of being approved in the next future, however not before 2025.

Optimization of Long-Acting Bronchodilator Dose Ratios Using Isolated Guinea Pig Tracheal Rings for Synergistic Combination Therapy in Asthma and COPD

The co-administration of a long-acting β2-agonist (LABA), and a long-acting muscarinic antagonist (LAMA), has been shown to be beneficial in the management of non-communicable chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD). The resulting relaxation of the airways can be synergistically enhanced, reducing symptoms and optimizing lung function. This provides an insight into more effective treatments. In this study, the LABAs formoterol fumarate dihydrate (FOR) and indacaterol maleate (IND) were each associated with tiotropium bromide monohydrate (TIO) to assess their synergistic potential. This was done using an appropriate ex vivo model of isolated perfused guinea pig tracheal rings, and pharmacological models of drug interaction. Among the dose ratios studied for both types of combination, a higher synergistic potential was highlighted for FOR/TIO 2:1 (w/w). This was done through three steps by using multiple additions of drugs to the organ baths based on a non-constant dose ratio and then on a constant dose ratio, and by a single addition to the organ baths of specific amounts of drugs. In this way, the synergistic improvement of the relaxant effect on the airways was confirmed, providing a basis for improving therapeutic approaches in asthma and COPD. The synergy found at this dose ratio should now be confirmed on a preclinical model of asthma and COPD by assessing lung function.

A reappraisal of inspiratory capacity in chronic obstructive pulmonary disease: clinical correlates and role of long-acting muscarinic antagonists and long-acting β2 agonists

INTRODUCTION

In patients with chronic obstructive pulmonary disease (COPD), static and dynamic hyperinflation, together with expiratory flow limitation and gas exchange abnormalities, is one of the major causes of dyspnea, decreased exercise performance and ventilatory failure. An increase in functional residual capacity (FRC) is accompanied by a decrease in inspiratory capacity (IC), which is a volume readily available, repeatable, and simple to measure with any spirometer. Changes in IC and FRC after bronchodilation, contrary to changes in FEV₁, have been closely associated with improvements in dyspnea and exercise performance. We systematically searched PubMed and Embase databases for clinical trials that assessed the effects of dual bronchodilation on inspiratory capacity in patients with COPD.

AREAS COVERED

Despite their pivotal role in COPD, IC and static volumes have rarely been considered as primary outcomes in randomized clinical trials assessing the efficacy of bronchodilators. Available studies on dual bronchodilation have shown a significant and persistent positive impact on IC focusing mainly on patients with moderate-to-severe COPD, whereas dynamic hyperinflation is also present at milder disease stages.

EXPERT OPINION

This narrative review discusses the pathophysiological and clinical importance of measuring IC in patients with COPD and how IC can be modified by maximizing bronchodilation combining long-acting muscarinic antagonists and long-acting β2 agonists.

Dual bronchodilation for the treatment of COPD - From bench to bedside

Because there is a solid pharmacological rationale based on positive interactions between long-acting muscarinic receptor antagonists (LAMAs) and long-acting β-agonists (LABAs) for their ability to relax human airway smooth muscle in vitro alongside several randomised controlled trials (RCTs) and real-world observational studies that support the use of LAMA/LABA fixed-dose combinations (FDCs) for the treatment of patients with COPD, in this narrative review we discuss the preclinical and clinical proofs supporting the use of LAMA+LABA therapy in COPD and why this therapeutic approach optimises bronchodilation. Robust evidence indicates that all LAMA/LABA FDCs are consistently more effective than LAMA or LABA administered alone in improving lung function, dyspnoea, quality of life, and exercise capacity in patients with COPD. However, the ability of dual bronchodilation with FDCs of LAMA/LABA to prevent or reduce the risk of COPD exacerbations remains unclear due to conflicting data from large RCTs, despite several mechanisms explaining why such combinations should be of value in decreasing the frequency of COPD exacerbations. Both LABAs and LAMAs mechanistically can affect the cardiovascular system, but from clinical studies to date, LAMA/LABA FDCs have an acceptable cardiovascular safety profile, at least in the COPD population enrolled in RCTs. Indirect evidence suggests that some FDCs may even exert a protective role against serious cardiovascular adverse events compared to monotherapies. Consequently, several LAMA/LABA FDCs have been developed and approved for clinical use as treatments for patients with COPD. However, to date, there are unfortunately very few head-to-head studies comparing the safety and efficacy of different LAMA/LABA FDCs making it difficult to choose the most appropriate combination, although the use of meta-analyses has provided some information in this regard.

The role of long-acting muscarinic antagonist/long-acting β agonist fixed-dose combination treatment for chronic obstructive pulmonary disease in China: a narrative review

Objective

To provide an overview of the existing international and Chinese evidence regarding dual bronchodilator inhalation therapy and to make recommendations for the further improvement of chronic obstructive pulmonary disease (COPD) management in clinical practice in China.

Background

COPD is a progressive lung disease that is characterized by persistent airflow limitation and is a major contributor to the disease burden in China. Symptoms in Chinese patients are relatively more severe. Currently, many Chinese COPD patients are undertreated. Dual bronchodilator therapy consisting of a long-acting muscarinic antagonist (LAMA) and a long-acting β agonist (LABA) is considered a good choice for COPD patients due to the increased bronchodilation without an increase in adverse events; these combinations can fill in the gap in currently available COPD treatments and provide new pharmacotherapy options for Chinese patients. LAMA/LABA fixed-dose combinations (FDCs) have become more important in clinical practice and guidelines in China regarding their therapeutic effects and safety.

Methods

Clinical trials on LAMA/LABA in COPD were retrieved in ClinicalTrials.gov, while important COPD guidelines published in English or Chinese were found in PubMed and Wanfang Database.

Conclusions

We recommend the adoption of a clinical pathway in China that includes an assessment and management algorithm that considers the clinical characteristics in China and classifies the phenotypic characteristics of COPD according to a suitable system. Based on the current information, we can conclude that LAMA/LABA FDCs are a suitable and economically viable choice to reduce symptoms and improve the quality of life (QoL) of patients.

Why small particle fixed dose triple therapy? An excursus from COPD pathology to pharmacological treatment evolution

Although bronchodilators are the cornerstone in chronic obstructive pulmonary disease (COPD) therapy, the treatment with a single-agent bronchodilator may not provide adequate symptoms control in COPD. The combination of drugs with different mechanisms of action may be more effective in inducing bronchodilation and preventing exacerbations, with a lower risk of side-effects in comparison with the increase of the dose of a single molecule. Several studies comparing the triple therapy with the association of long-acting ß2 agonist (LABA)/inhaled corticosteroid (ICS) or long-acting muscarinic antagonist (LAMA)/LABA reported improvement of lung function and quality of life. A significant reduction in moderate/severe exacerbations has been observed with a fixed triple combination of beclometasone dipropionate (BDP), formoterol fumarate (FF) and glycopyrronium (G) in a single inhaler. The TRILOGY, TRINITY and TRIBUTE studies have provided confirming evidence for a clinical benefit of triple therapy over ICS/LABA combination treatment, LAMA monotherapy and LABA/LAMA combination, with prevention of exacerbations being a key finding. A pooled post hoc analysis of the published clinical studies involving BDP/FF/G fixed combination demonstrated a reduction in fatal events in patients treated with ICS-containing medications, with a trend of statistical significance [hazard ratio = 0.72, 95% confidence interval (CI) 0.50-1.02, p = 0.066], that becomes significant if we consider reduction in fatal events for non-respiratory reasons (hazard ratio = 0.65, 95% CI 0.43-0.97, p = 0.037). In conclusion, a fixed combination of more drugs in a single inhaler can improve long-term adherence to the therapy, reducing the risk of exacerbations and hospital resources utilization. The twice a day administration may provide a better coverage of night, particularly in COPD patients who are highly symptomatic. The inhaled extrafine formulation that allows drug deposition in both large and small - peripheral - airways, is the value added.

Drug interaction and chronic obstructive respiratory disorders

Chronic obstructive respiratory disorders uncontrolled by monotherapy should be given combinations of drugs that act by distinct mechanisms of action. The rationale for combining different classes of drugs should be to elicit a synergistic interaction, lower the dose of the single components in the combinations and, thus, reduce the risk of adverse events.

The aim of this systematic review was to investigate the combined effect of drugs acting on human airways, by including studies that used a validated method for assessing the nature of drug interaction.

Current evidence indicates that drug combinations modulating the bronchial contractility induce a synergistic relaxant effect when the individual components are combined at isoeffective concentrations. There are several mechanisms of action underlying drug interactions. Pharmacological research has been directed to elucidate what causes the synergism between long-acting β₂-adrenoceptor (β₂-AR) agonists (LABAs), long-acting muscarinic antagonist (LAMAs), and inhaled corticosteroids (ICS) administered as dual or triple combination. Conversely, the mechanisms behind the additive interaction between phosphodiesterase 3 and 4 inhibitors and LAMAs, and the synergistic interaction between proliferator-activated receptor gamma ligands and β₂ agonists have been only hypothesized. Overall, the synergism elicited by combined drugs for the treatment of chronic respiratory disorders is an effect of class, rather than specific for drug combinations. Optimal synergy can be achieved only when the single agents are combined at isoeffective concentrations, and when monocomponents are given concurrently to reach together the same levels of the bronchial tree.

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Drug interaction should be identified with validated pharmacological models.

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Synergistic efficacy is the rationale for combining drugs for respiratory diseases.

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Synergy is favored when combined agents act by distinct mechanisms of action.

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Optimal synergy is achieved when drugs are combined at isoeffective concentrations.

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Synergy is a class effect and is not specific for single drug combinations.

The novel bronchodilator navafenterol: a phase 2a, multi-centre, randomised, double-blind, placebo-controlled crossover trial in COPD

Background

Navafenterol (AZD8871) belongs to a new class of bronchodilator, the single-molecule muscarinic antagonist and β-agonist, developed for the treatment of COPD. This study aimed to evaluate the efficacy, pharmacokinetics and safety of navafenterol versus placebo and an active comparator treatment for moderate-to-severe COPD.

Methods

This phase 2a, randomised, multicentre (Germany and UK), double-blind, double-dummy, three-way complete crossover study (ClinicalTrials.gov identifier: NCT03645434) compared 2 weeks’ treatment of once-daily navafenterol 600 µg via inhalation with placebo and a fixed-dose combination bronchodilator (umeclidinium/vilanterol (UMEC/VI); 62.5 µg/25 µg) in participants with moderate-to-severe COPD. The primary outcome was change from baseline in trough forced expiratory volume in 1 s (FEV₁) on day 15. Secondary end-points included change from baseline in peak FEV₁; change from baseline in Breathlessness, Cough and Sputum Scale (BCSS); change from baseline in COPD Assessment Tool (CAT); adverse events; and pharmacokinetics.

Results

73 participants were randomised. After 14 days, trough FEV₁ was significantly improved with navafenterol compared with placebo (least-squares (LS) mean difference 0.202 L; p<0.0001). There was no significant difference in FEV₁ between navafenterol and UMEC/VI (LS mean difference −0.046 L; p=0.075). COPD symptoms (CAT and BCSS) showed significantly greater improvements with both active treatments versus placebo (all p<0.005). Novel objective monitoring (VitaloJAK) showed that cough was reduced with both active treatments compared with placebo. Safety profiles were similar across the treatment groups and no serious adverse events were reported in the navafenterol treatment period.

Conclusion

Once-daily navafenterol was well tolerated, improved lung function and reduced COPD-related symptoms, similar to an established once-daily fixed-dose combination bronchodilator.

Navafenterol, a novel dual-pharmacology bronchodilator for COPD, improved lung function, reduced COPD symptoms and decreased objective cough counts, to a similar extent to umeclidinium/vilanterolhttps://bit.ly/3lV886y

Functional respiratory imaging assessment of glycopyrrolate and formoterol fumarate metered dose inhalers formulated using co-suspension delivery technology in patients with COPD

Background:

Functional respiratory imaging (FRI) is a quantitative postprocessing imaging technique used to assess changes in the respiratory system. Using FRI, we characterized the effects of the long-acting muscarinic antagonist (LAMA), glycopyrrolate metered dose inhaler (GP MDI), and the long-acting β₂-agonist (LABA), formoterol fumarate metered dose inhaler (FF MDI), on airway volume and resistance in patients with moderate-to-severe chronic obstructive pulmonary disease.

Methods:

Patients in this phase IIIb, randomized, double-blind crossover study received twice-daily GP MDI (18 μg) and FF MDI (9.6 μg). Primary endpoints were specific (i.e. corrected for lobar volume) image-based airway volume (siVaw) and specific image-based airway resistance (siRaw), measured using FRI. Secondary and other endpoints included additional FRI, spirometry, and body plethysmography parameters. Postdose efficacy assessments were performed within 60–150 min of dosing on day 15.

Results:

A total of 23 patients were randomized and 19 completed both treatment periods. GP MDI and FF MDI both achieved significant improvements from baseline to day 15 in siVaw [11% (p = 0.0187) and 23% (p < 0.0001) increases, respectively] and siRaw [25% (p = 0.0219) and 44% (p < 0.0001) reductions, respectively]. Although, on average, improvements were larger for FF MDI than GP MDI, some individuals displayed greater responses with each of the two treatments. These within-patient differences increased with airway generation number. Spirometry and body plethysmography endpoints showed significant improvements from baseline in inspiratory capacity for both treatments, and numeric improvements for other endpoints.

Conclusion:

Both GP MDI and FF MDI significantly improved siRaw and siVaw at day 15 versus baseline. FRI endpoints demonstrated increased sensitivity relative to spirometry and body plethysmography in detecting differences between treatments in a small number of patients. Intra-patient differences in treatment response between the LAMA and the LABA provide further support for the benefit of dual bronchodilator therapies.

ClinicalTrials.gov registration number:

NCT02937584

The reviews of this paper are available via the supplemental material section.

Co-delivery of inhalable therapies: Controlling active ingredients spatial distribution and temporal release

The management of respiratory diseases relies on the daily administration of multiple active pharmaceutical ingredients (APIs), leading to a lack of patient compliance and impaired quality of life. The frequency and dosage of the APIs result in increased side effects that further worsens the overall patient condition. Here, the manufacture of polymer-polymer core-shell microparticles for the sequential delivery of multiple APIs by inhalation delivery is reported. The microparticles, composed of biodegradable polymers silk fibroin (shell) and poly(L-lactic acid) (core), incorporating ciprofloxacin in the silk layer and ibuprofen (PLLA core) as the antibiotic and anti-inflammatory model APIs, respectively. The polymer-polymer core-shell structure and the spatial distribution of the APIs have been characterized using cutting-edge synchrotron macro ATR-FTIR technique, which was correlated with the respective API sequential release profiles. The APIs microparticles had a suitable size and aerosol properties for inhalation therapies (≤4.94 ± 0.21μm), with low cytotoxicity and immunogenicity in healthy lung epithelial cells. The APIs compartmentalization obtained by the microparticles not only could inhibit potential actives interactions but can provide modulation of the APIs release profiles via an inhalable single administration.

Comparative studies of dual bronchodilation in COPD

Dual bronchodilation therapy is becoming the cornerstone for the treatment of COPD because the clinical benefits of LABA/LAMA fixed-dose combinations (FDCs) are now extensively established. Therefore, it not surprising that a number of LAMA/LABA combinations in a single inhaler have now been approved for clinical use as treatments for patients with COPD. Regrettably, very few head-to-head studies between all of the available LABA/LAMA FDCs have been carried out. This makes choosing the most appropriate FDC difficult. Comparative effectiveness research that also uses conventional meta-analyses to compare different care strategies can help generate useful information. A bidimensional comparative analysis across LAMA/LABA FDCs has suggested constant superiority for tiotropium/olodaterol. However, considering that there is not an equivalent amount of evidence on efficacy outcomes for all LAMA/LABA FDCs, a proper comparison between the different LAMA/LABA FDCs cannot be made yet, and the information available is still rather inconsistent.

Synergy across the drugs approved for the treatment of asthma

INTRODUCTION

Inhaled corticosteroids are the cornerstone for the treatment of stable asthma, however, when disease severity increases, escalating therapy to combinations of drugs acting on distinct signalling pathways is required. It is advantageous to providing evidence of a synergistic interaction across drug combinations, as it allows optimizing bronchodilation while lowering the dose of single agents. In the respiratory pharmacology field, two statistical models are accepted as gold standard to characterize drug interactions, namely the Bliss Independence criterion and the Unified Theory. In this review, pharmacological interactions across drugs approved for the treatment of asthma have been systematically assessed.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for studies that used a validated pharmacological method for assessing drug interaction. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 45 studies were identified from literature search and 5 met the inclusion criteria. Current evidence coming from ex vivo models of asthma indicates that drug combinations modulating bronchial contractility induce a synergistic bronchorelaxant effect. In murine models of lung inflammation, the combination between inhaled corticosteroids and β2- adrenoceptor agonists synergistically improve lung function and the inflammatory profile.

CONCLUSIONS

There is still limited knowledge regarding the mechanistic basis underlying pharmacological interactions across drugs approved for asthma. The synergism elicited by combined agents is an effect of class. Specifically designed clinical trials are needed to confirm the results coming from preclinical evidence, but also to establish the minimal dose for combined agents to induce a synergistic interaction and maximize bronchodilation.

Small airways in asthma: from bench-to-bedside

INTRODUCTION

Historically, asthma was considered a disease predominantly of the large airways, but gradually small airways have been recognized as the major site of airflow obstruction. Small airway dysfunction (SAD) significantly contributes to the pathophysiology of asthma and it is present across all asthma severities. Promising pre-clinical findings documented enhanced beneficial effects of combination therapies on small airways compared to monocomponents, thus it was questioned whether this could translate into further clinical implications from bench-to-bedside. The aim of this review was to systematically assess the state of the art of small airway involvement in asthma, especially in response to different pharmacological treatments acting on the respiratory system.

EVIDENCE ACQUISITION

A comprehensive literature search was performed in MEDLINE for randomized controlled trials (RCTs) characterizing the impact on small airways of different pharmacological treatments acting on the respiratory system. The results were extracted and reported via qualitative synthesis.

EVIDENCE SYNTHESIS

Overall, 63 studies were identified from the literature search, whereas 23 RCTs met the inclusion criteria. Evidence confirms that both drug particle size and the type of inhalation devices represent two of the most important variables for an effective peripheral lung distribution.

CONCLUSIONS

Despite the numerous methodological tools to detect SAD, there is still no gold standard diagnostic method to assess small airways, especially in severe asthma. Further research should be directed to improve primary and secondary prevention strategies by supporting the combined approach of different non-invasive techniques for an early detection of peripheral abnormalities and optimization of asthma therapy.

Pharmacology and Therapeutics of Bronchodilators Revisited

Bronchodilators remain the cornerstone of the treatment of airway disorders such as asthma and chronic obstructive pulmonary disease (COPD). There is therefore considerable interest in understanding how to optimize the use of our existing classes of bronchodilator and in identifying novel classes of bronchodilator drugs. However, new classes of bronchodilator have proved challenging to develop because many of these have no better efficacy than existing classes of bronchodilator and often have unacceptable safety profiles. Recent research has shown that optimization of bronchodilation occurs when both arms of the autonomic nervous system are affected through antagonism of muscarinic receptors to reduce the influence of parasympathetic innervation of the lung and through stimulation of β ₂-adrenoceptors (β ₂-ARs) on airway smooth muscle with β ₂-AR-selective agonists to mimic the sympathetic influence on the lung. This is currently achieved by use of fixed-dose combinations of inhaled long-acting β ₂-adrenoceptor agonists (LABAs) and long-acting muscarinic acetylcholine receptor antagonists (LAMAs). Due to the distinct mechanisms of action of LAMAs and LABAs, the additive/synergistic effects of using these drug classes together has been extensively investigated. More recently, so-called "triple inhalers" containing fixed-dose combinations of both classes of bronchodilator (dual bronchodilation) and an inhaled corticosteroid in the same inhaler have been developed. Furthermore, a number of so-called "bifunctional drugs" having two different primary pharmacological actions in the same molecule are under development. This review discusses recent advancements in knowledge on bronchodilators and bifunctional drugs for the treatment of asthma and COPD. SIGNIFICANCE STATEMENT: Since our last review in 2012, there has been considerable research to identify novel classes of bronchodilator drugs, to further understand how to optimize the use of the existing classes of bronchodilator, and to better understand the role of bifunctional drugs in the treatment of asthma and chronic obstructive pulmonary disease.

New perspectives on the role of muscarinic antagonists in asthma therapy

INTRODUCTION

There is increasing evidence that tiotropium, a long-acting muscarinic agent (LAMA), is useful in the presence of severe-uncontrolled asthma despite the optimization of therapy with inhaled corticosteroids (ICSs) and long-acting β₂ agonists (LABAs) as recommended by the current guidelines. Furthermore, in recent years there have been several  preclinical and clinical studies on the pharmacological and therapeutic impact of other LAMAs in asthma.

AREAS COVERED

We have conducted an extensive search on muscarinic antagonists in asthma therapy throughout several sources and discuss what has emerged in the last 3 years (January 2017-March 2020).

EXPERT OPINION

New evidence indicates that the effectiveness of adding a LAMA, at least tiotropium, is independent of the degree of the type 2 inflammation and age of patient. Therefore, tiotropium can be administered without the need for patient phenotyping. Umeclidinium and glycopyrronium also appear effective in asthma. Initial treatment with LAMA+ICS for those with mild asthma may be an equally effective therapeutic option as LABA+ICS but this hypothesis should be confirmed by statistically powered trials.

Beclomethasone dipropionate, formoterol fumarate and glycopyrronium bromide: Synergy of triple combination therapy on human airway smooth muscle ex vivo

BACKGROUND AND PURPOSE

Combining inhaled corticosteroids (ICSs), long-acting β₂ -adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) is recommended to treat severe forms of asthma and chronic obstructive pulmonary disease (COPD). Clinical benefits have been demonstrated for ICS/LABA/LAMA combinations. This study characterized the interaction between the ICS beclomethasone dipropionate, the LABA formoterol fumarate and the LAMA glycopyrronium bromide in human airways.

EXPERIMENTAL APPROACH

Human passively sensitized airways and bronchi from COPD donors were stimulated with histamine or carbachol. Tissues were incubated overnight with beclomethasone and then treated with formoterol and glycopyrronium, alone or in triple combination. The interaction was assessed by using Bliss Independence and Unified Theory theorems.

KEY RESULTS

Beclomethasone/formoterol/glycopyrronium combination synergistically relaxed medium bronchi and small airways. Beclomethasone/formoterol/glycopyrronium combination at 100:6:12.5 combination ratio was a balanced drug mixture leading to very strong synergistic effect on relaxation of medium bronchi (Combination Index: from 0.042 to 0.96) and middle to very strong synergy in small airways (Combination Index: from 0.018 to 0.310). The synergy was related with the activation of intracellular glucocorticoid receptors and G_sα subunit G-protein of β₂ -adrenoceptors, leading to the modulation of cyclic AMP-dependent PKA pathway.

CONCLUSION

Triple beclomethasone/formoterol/glycopyrronium combination induces synergistic bronchorelaxant effect in medium and small human airways, at least in ex vivo experiments. Further research is needed to confirm these findings in clinical studies in patients with asthma or COPD.

Optimizing the Development Strategy of Combination Therapy in Respiratory Medicine: From Isolated Airways to Patients

The current recommendations for the treatment of chronic obstructive pulmonary disease (COPD) are pushing towards triple combination therapy based on the combination of an inhaled corticosteroid (ICS) associated with two bronchodilator agents. However, dual bronchodilation remains the cornerstone for the treatment of most COPD patients. Combining a long-acting β₂ adrenoceptor agonist (LABA) with a long-acting muscarinic antagonist (LAMA) induces appreciable synergistic bronchorelaxant effect in human airways, especially when the medications are combined at isoeffective concentrations. Thus, each LABA/LAMA combination is characterized by a specific range of concentration-ratio at which the drug mixture may induce sustained synergistic interaction. Results of a recent randomized controlled trial (RCT, NCT00696020) and evidences from pre-clinical studies in human isolated airways poses the question whether combining tiotropium 5 μg with olodaterol 5 μg is the best combination option: tiotropium/olodaterol 5/5 μg has the same efficacy profile of tiotropium/olodaterol 5/2 μg, and it is less effective than tiotropium/olodaterol 5/10 μg. Furthermore, tiotropium/olodaterol 5/2 μg, 5/5 μg, and 5/10 μg combinations are generally characterized by the same safety profile. Indeed tiotropium/olodaterol 5/5 μg is effective and safe in COPD, but a different development strategy based on solid data obtained from human isolated airways would have driven towards a better-balanced FDC to be tested in Phase III RCTs. Accurate bench-to-bedside plans are needed also in the development of triple combination therapies for asthma and COPD, in which the presence of an ICS in the formulation may further modulate the beneficial interaction between the LABA and the LAMA.