Muscarinic antagonists in early stage clinical development for the treatment of asthma

Introduction: Parasympathetic neurons utilize the neurotransmitter acetylcholine to modulate and constrict airway smooth muscles at the muscarinic acetylcholine receptor. Inhaled agents that antagonize the muscarinic (M) acetylcholine receptor, particularly airway M3 receptors, have increasing data supporting use in persistent asthma.

Areas covered: Use of inhaled long-acting muscarinic antagonists (LAMA) in asthma is explored. The LAMA tiotropium is approved for maintenance in symptomatic asthma patients despite the use of inhaled corticosteroids (ICS), leukotriene receptor antagonists (LTRA) and/or long-acting beta₂ agonists (LABA). LAMA agents currently approved for chronic obstructive pulmonary disease (COPD) include tiotropium, glycopyrrolate/glycopyrronium, umeclidinium and aclidinium. These agents are reviewed for their pharmacological differences and clinical trials in asthma.

Expert opinion: Current guidelines place inhaled LAMAs as adjunctive maintenance therapy in symptomatic asthma not controlled by an ICS and/or a LTRA. LAMA agents will play an increasing role in moderate to severe symptomatic asthma patients. Additional LAMA agents are likely to seek a maintenance indication perhaps as a combined inhaler with an ICS or with an ICS and a LABA. These fixed-dose combination inhalers are being tested in COPD and asthma patients. Once-a-day dosing of inhaled LAMA agents in severe asthma patients will likely become the future standard.     

Advances in asthma and COPD treatment: combination therapy with inhaled corticosteroids and long-acting beta 2-agonists

Asthma treatment guidelines advocate the use of long-acting beta2-agonists (LABA) in addition to inhaled corticosteroids (ICS) in patients whose asthma is uncontrolled by ICS alone, thereby addressing two processes fundamental to asthma: bronchoconstriction and inflammation. Superior control--including a reduction in severe exacerbations--of asthma and COPD by ICS/LABA combination therapy has been demonstrated. Results from clinical studies suggest additive and potentially synergistic effects when the two agents are used in combination. No new safety-related issues have been identified with ICS/LABA compared with the monocomponents. The exact mechanisms for the enhanced efficacy of ICS/LABA combinations are under investigation but likely include drug interactions at the receptor level and interwoven signalling pathways, which may result in improved function of 2- adrenoceptors and steroid receptors. Data from preclinical studies provide evidence of additive, compensatory, complementary and synergistic effects of ICS and LABA in the control of inflammation and airway and lung remodelling. These effects may contribute to the improved efficacy seen when treating asthma and COPD with ICS/LABA combinations in clinical studies. Two ICS/LABA combination products are available: budesonide/formoterol (Symbicort) and salmeterol/fluticasone propionate (SeretideTM). An ICS/LABA combination in a single inhaler represent safe, effective and convenient treatment options for the management of patients with asthma and COPD. Clinical results also suggest that adjustable dosing with budesonide/formoterol provides better asthma control than fixed dosing. Further elucidation of the underlying mechanisms responsible for this superior disease control is needed.     

The efficacy and safety of three types of combination therapies in patients with moderate to very severe COPD: a systematic review and meta-analysis

Inhaled drugs, including long-acting muscarinic antagonists (LAMAs), long-acting β₂-agonists (LABAs) and inhaled corticosteroids (ICSs), are the main therapeutic options for patients with chronic obstructive pulmonary disease (COPD). We conducted a systematic review and meta-analysis to compare the efficacy and safety of LAMA+LABA+ICS, LAMA+LABA and LABA+ICS therapies. The Pubmed, Embase and Cochrane Library databases were searched for randomized controlled trials (RCTs) comparing the efficacy (moderate-to-severe exacerbations, lung function and quality of life) and safety (adverse events (AEs), severe adverse events (SAEs), withdrawals due to AEs, deaths and pneumonia) of LAMA+LABA+ICS, LAMA+LABA and LABA+ICS in COPD patients. Two investigators independently searched eligible studies and extracted relevant information. The data were analyzed using the Review Manager software, and the quality of included studies was assessed using the Cochrane risk of bias tool. A total of 27 studies were included, and majority of the studies showed low risk of bias. Moderate­to­severe exacerbations were lower after LAMA+LABA+ICS therapy compared with the LABA+ICS (RR = 0.66; 95% CI: 0.59–0.74) and LAMA+LABA therapies (RR = 0.88; 95% CI: 0.82–0.94). Lung function was significantly improved after LAMA+LABA+ICS compared with LAMA+ICS treatment. FEV1, peak FEV1 and trough FEV1 were significantly increased by 100 mL, 150 mL and 120 mL, respectively, in LAMA+LABA+ICS therapy compared with LAMA+ICS. In addition, LAMA+LABA therapy resulted in increased FEV1, peak FEV1 and trough FEV1 by 80 mL, 90 mL and 70 mL, respectively, compared with LAMA+ICS. SGRQ-total score was used to assess quality of life of COPD patients, which indicated that LAMA+LABA+ICS therapy was associated with slightly greater decrease compared with LABA+ICS (MD = –1.33; 95% CI: –2.35 to –0.30). No significant differences were found across all three treatment combinations in term of AEs, SAEs, withdrawals due to AEs and deaths. However, the risk of pneumonia was higher in the triple therapy group than that in the LABA+ICS (RR = 1.16; 95% CI: 1.01–1.33) or LAMA+LABA (RR = 1.31; 95% CI: 1.06–1.62) groups, and significantly lower in the LAMA+LABA group compared with LABA+ICS (RR = 0.64; 95% CI: 0.54–0.76). LAMA+LABA+ICS therapy offered greater efficacy and comparable safety compared with the LAMA+LABAor LABA+ICS therapies. However, triple therapy could increase the risk of pneumonia compared with LAMA+LABA or LABA+ICS therapies. People who have higher risk of pneumonia should carefully consider the use of triple therapy. LAMA+LABA therapy offered greater efficacy and lower risk of pneumonia to LABA+ICS therapy. Collectively, LAMA+LABA therapy might be a better choice than LABA+ICS.     

A review of current and developing fixed-dose LABA/LAMA combinations for treating COPD

Introduction: The current GOLD (Global Initiative for Chronic Obstructive Lung Disease) recommendations suggest using long acting β2 agonists (LABA) and long acting muscarinic antagonists (LAMA) in combination for group B COPD patients with persistent symptoms, group C COPD patients with further exacerbations on LAMA therapy alone and for group D COPD patients with or without combination with inhaled corticosteroids (ICS). Thus, there is a lot of interest in developing LABA/LAMA combinations for maintenance therapy of chronic stable COPD.

Areas covered: Many LABA/LAMA combinations have successfully been approved through carefully designed pivotal clinical trials. The current clinical use of LABA/LAMA combinations in COPD will continue to evolve as new trials with and without inhaled corticosteroids are completed.

Expert opinion: Combining different classes of bronchodilators in a single inhaler is an attractive concept that can potentially improve patient adherence to therapy. Because LABA/LAMA combinations are the preferred treatment option for preventing COPD exacerbations in the updated GOLD guidelines for COPD, they will be clinically used. Future treatment of COPD should revolve around a personalized approach based on characterization of the COPD phenotype.     

A re-evaluation of the role of inhaled corticosteroids in the management of patients with chronic obstructive pulmonary disease

Introduction: Inhaled corticosteroids (ICS) (in fixed combinations with long-acting β₂-agonists [LABAs]) are frequently prescribed for patients with chronic obstructive pulmonary disease (COPD), outside their labeled indications and recommended treatment strategies and guidelines, despite having the potential to cause significant side effects.

Areas covered: Although the existence of asthma in patients with asthma–COPD overlap syndrome (ACOS) clearly supports the use of anti-inflammatory treatment (typically an ICS/LABA combination, as ICS monotherapy is usually not indicated for COPD), the current level of ICS/LABA use is not consistent with the prevalence of ACOS in the COPD population. Data have recently become available showing the comparative efficacy of fixed bronchodilator combinations (long-acting muscarinic antagonist [LAMA]/LABA with ICS/LABA combinations). Additionally, new information has emerged on ICS withdrawal without increased risk of exacerbations, under cover of effective bronchodilation.

Expert opinion: For patients with COPD who do not have ACOS, a LAMA/LABA combination may be an appropriate starting therapy, apart from those with mild disease who can be managed with a single long-acting bronchodilator. Patients who remain symptomatic or present with exacerbations despite effectively delivered LAMA/LABA treatment may require additional drug therapy, such as ICS or phosphodiesterase-4 inhibitors. When prescribing an ICS/LABA, the risk:benefit ratio should be considered in individual patients.     

Single inhaler triple therapy with extrafine beclomethasone,formoterol, and glycopyrronium for the treatment of chronic obstructive pulmonary disease

Introduction: Chronic obstructive pulmonary disease (COPD) management focuses on the alleviation of symptoms and prevention of exacerbations. Inhaled long acting bronchodilators and inhaled corticosteroids (ICS) are the main classes of treatment for COPD. Triple therapy with a long acting beta₂-agonist (LABA), long acting muscarinic antagonist (LAMA), and ICS is commonly prescribed for symptomatic COPD patients experiencing regular exacerbations. Triple therapy is usually administered using separate inhalers; there is little clinical trial evidence of an effect on exacerbation prevention with this approach.

Areas covered: This evaluation reviews the single inhaler extrafine combination containing beclometasone diproprionate (BDP), formoterol fumarate (FF), and glycopyrronium bromide (GB) which has been developed as a simplified triple regime. BDP/FF/GB significantly reduced exacerbation rates in three clinical trials (1-year duration) compared against LAMA monotherapy (20% exacerbation reduction), ICS/LABA combination (23% exacerbation reduction), and LAMA/LABA combination (15% exacerbation reduction).

Expert opinion: The practical benefits of single inhaler triple therapy in the real world have not been studied. However, the robust clinical trial evidence that BDP/FF/GB reduces exacerbations compared to double combination treatments and LAMA monotherapy cements triple therapy positioning as an escalation step in COPD management pathways.     

双长效支气管扩张剂在慢性阻塞性肺疾病治疗中的研究进展

长效支气管扩张剂是稳定期慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)治疗的基石。固定剂量长效β2受体激动剂(long actingβ2 agonist,LABA)/长效抗胆碱能药物(long acting muscarinic antagonist,LAMA)复方制剂被慢性阻塞性肺疾病全球倡议推荐用于COPD的治疗。为了更深入了解已经上市的多种LABA/LAMA复方制剂如维兰特罗/乌美溴铵、茚达特罗/格隆溴铵、福莫特罗/格隆溴铵及奥达特罗/噻拖溴铵等的疗效和安全性,本文对LABA/LAMA一些重要临床研究作一综述,旨在为COPD患者提供个体化的治疗方案。     

Long-acting β-agonists in asthma management: what is the current status?

Large surveillance studies or phase IV clinical studies of long-acting β-agonists (LABA) compared with placebo in asthma patients using variable (from nil to regular) doses of inhaled corticosteroids (ICS) have raised the issue of mortality risk in patients with asthma taking regular LABA. There have been a number of meta-analyses and systematic reviews that have examined the risk of LABA in asthma patients, and the general conclusion is that LABA added to ICS reduces asthma-related hospitalizations compared with ICS alone and there is no statistical increase in mortality. However, LABA without ICS do increase mortality risk in asthma. All reviews and analyses show a greater number of LABA deaths, but not all are statistically significant. A recent meta-analysis found LABA with concomitant ICS had a higher mortality rate in asthma than ICS alone. The flaw in the study is the higher doses of ICS in the control arms, but the implicit message remains: the essential need for enough ICS to control airway inflammation. We suggest that the pragmatic solution is to have LABA only available in the same device as ICS for asthma treatment. We do not think that a study comparing the safety of LABA plus ICS versus ICS alone in asthma is necessary. If such a study is conducted, the measurement of morbidity from increased doses of ICS is an essential design consideration. Furthermore, the critical focus in asthma management should not be forgotten - education of health professionals and the community of the critical role of ICS, and the need for good communication between health professionals and the asthma patient to facilitate good asthma control. The same arguments apply to the asthma-with-chronic obstructive pulmonary disease overlap syndrome in older patients. There is an urgent need to provide medical practitioners with the capability to diagnose the overlap syndrome.     

New combination bronchodilators for chronic obstructive pulmonary disease: current evidence and future perspectives Dave Singh

Fixed dose combination (FDC) dual bronchodilators that co-administer a long acting β₂-adrenoceptor agonist (LABA) and a long acting muscarinic antagonist (LAMA) are a new class of inhaled treatment for chronic obstructive pulmonary disease (COPD). This review focuses on the clinical evidence for the benefit of LABA/LAMA FDCs compared with monocomponent treatments, and also compared with active comparators that are widely used for the treatment of COPD, namely tiotropium and salmeterol-fluticasone. Novel FDC dual bronchodilators include QVA149 and umeclidinium/vilanterol (UMEC/VI). Long term clinical trials show that QVA149 and UMEC/VI are superior to monocomponent therapy in terms of trough forced expiratory volume in 1 s (FEV₁), although the FEV₁ improvement was limited to approximately 80–90% of the added monocomponent values. This suggests that the effect of combining a LABA and a LAMA is not fully additive. LABA/LAMA FDC were associated with the largest mean changes in symptoms and health status that were above the minimal clinically important difference, in contrast to the monocomponents. Furthermore, these LABA/LAMA FDCs demonstrated superiority over the active comparators tiotropium and salmeterol-fluticasone in terms of trough FEV₁ and patient-reported outcomes. LABA/LAMA FDCs offer a simplified means of maximizing bronchodilation for COPD patients, with the improvements in lung function being mirrored by benefits in terms of symptoms and exacerbations. The use of LABA/LAMA FDCs in clinical practice is set to grow and further studies are needed to define their optimal place in treatment guidelines.     

Clinical characteristics,treatment patterns,disease burden,and persistence/adherence in patients with asthma initiating inhaled triple therapy: real-world evidence from Japan

Abstract

Objectives: To help optimize triple therapy use, treatment patterns and disease burden were investigated in patients in Japan with persistent asthma who initiated multi-inhaler triple therapy (inhaled corticosteroid/long-acting β₂-agonist/long-acting muscarinic antagonist; ICS/LABA/LAMA).

Methods: This retrospective, observational cohort study using health insurance claims data included adults with persistent asthma who initiated triple therapy in 2016. Patients who were prescribed ICS/LABA in 2016 were included as an ICS/LABA-matched cohort. Patients were stratified into those with asthma only and those with asthma and chronic obstructive pulmonary disease (COPD) codes (asthma-COPD overlap [ACO]). Patient data from 1-year prior to 1 year post index date were analyzed.

Results: For patients with asthma only in the triple therapy and ICS/LABA cohorts, baseline demographics were similar. A higher proportion of the triple-therapy cohort than the ICS/LABA cohort was receiving high-dose ICS at index (68.2% and 27.6%, respectively), and had experienced an exacerbation in the last year (64.0% and 29.4%, respectively). The proportion of patients with asthma only who developed any exacerbation was lower in the year following initiation of triple therapy compared with the year prior to initiation of triple therapy (45.8% vs 64.0%, respectively). For asthma only patients receiving triple therapy, the mean (standard deviation) proportion of days covered and medication possession ratio was 0.51 (0.36) and 0.86 (0.16), respectively. Similar trends were seen in patients with ACO in the triple-therapy and ICS/LABA cohorts.

Conclusion: Evidence from this study may serve as a reference for the use of inhaled triple therapy for asthma.     

Safe use of long-acting β-agonists: what have we learnt?

INTRODUCTION: Long-acting β-agonists (LABAs) added to inhaled corticosteroids (ICS) reduce symptoms, improve lung function and enhance overall asthma control. However, several studies have indicated an increased risk of asthma mortality and asthma-related serious adverse events and the FDA recently mandated restrictions to the use of LABAs in asthma. AREAS COVERED: This review highlights the clinical studies on which safety analyses pertaining to salmeterol and formoterol have been based and then focuses on recent meta-analyses of safety outcomes with and without consideration of concomitant ICS. EXPERT OPINION: The phenomenon of masking of inflammation by LABA if ICS dose is insufficient underscores the potential for confounding in determining real safety risks. Under-treatment with ICS and differential dosing of ICS in many trials are major factors driving the LABA safety concern. The FDA meta-analysis, when stratified for mandatory ICS use, found no significant increase in the composite outcome of asthma mortality, intubations and hospitalizations. Add-on therapy with LABA is effective and safe if the dose of ICS is adequate to treat airway inflammation. LABA and ICS given in a single device will negate the possibility of LABA monotherapy which is contraindicated. The FDA has recommended that LABAs be withdrawn when control is achieved with combination therapy but recent evidence suggests this may result in loss of symptom control.     

A safety comparison of LABA+LAMA vs LABA+ICS combination therapy for COPD

Introduction: LABA+LAMA and LABA+ICS combinations are key pharmacological approaches to the treatment of COPD. However, both combination types can induce adverse events (AEs).

Areas covered: Current literature on LABA+LAMA and LABA+ICS combinations has been reviewed with a specific focus on their safety profile in the treatment of COPD.

Expert opinion: Several meta-analyses have compared the pooled safety data from randomized clinical trials (RCTs) of LABA+LAMA combinations with LABA+ICS combinations. LABA+LAMA caused significantly less AEs and SAEs. However, this evidence in real life is less solid because of the lack of appropriate studies. A statistically significant reduction in the risk for pneumonia with LABA+LAMA compared with LABA+ICS has been repeatedly documented by various meta-analyses. The meta-analytic signal indicates that an equal number of patients would die or have cardiac SAEs on LABA+LAMA or LABA+ICS, and in an observational, real-life study the LABA+LAMA combination had similar or lower risk of these events in comparison to LABA+ICS. Nonetheless, since RCTs are conducted under widely varying conditions and, consequently, AE rates of a drug observed in a RCT cannot be directly compared with rates in the RCTs of another drug and may not reflect the rates observed in practice, we need more specific data.     

New and developing non-adrenoreceptor small molecule drugs for the treatment of asthma

Introduction: Inhaled corticosteroids (ICS) alone or in combination with an inhaled long-acting beta₂-agonist (LABA) are the preferred long-term treatment for adults and adolescents with symptomatic asthma. Additional drugs include leukotriene-receptor antagonists, slow-release theophylline and the long-acting muscarinic antagonist (LAMA) tiotropium (approved in 2015). There is a need for more effective therapies, as many patients continue to have poorly controlled asthma.

Areas covered: New and developing long-acting non-adrenoreceptor synthetic drugs for the treatment of symptomatic chronic asthma despite treatment with an ICS alone or combined with a LABA. Data was reviewed from studies published up until November 2016.

Expert opinion: Tiotropium improves lung function and has a modest effect in reducing exacerbations when added to ICS alone or ICS and LABA. The LAMAs umeclidinium and glycopyrronium are under development in fixed dose combination with ICS and LABA. Novel small molecule drugs, such as CRTH2 receptor antagonists, PDE₄ inhibitors, protein kinase inhibitors and nonsteroidal glucocorticoid receptor agonists and ‘off-label’ use of licensed drugs, such as macrolides and statins are under investigation for asthma, although their effectiveness in clinical practice is not established. To better achieve the goal of developing effective novel small molecule drugs for asthma will require greater understanding of mechanisms of disease and the different phenotypes and endotypes of asthma.     

Anticonvulsant hypersensitivity syndrome: an update

Introduction: Long-acting β-agonists (LABAs) added to inhaled corticosteroids (ICS) reduce symptoms, improve lung function and enhance overall asthma control. However, several studies have indicated an increased risk of asthma mortality and asthma-related serious adverse events and the FDA recently mandated restrictions to the use of LABAs in asthma.

Areas covered: This review highlights the clinical studies on which safety analyses pertaining to salmeterol and formoterol have been based and then focuses on recent meta-analyses of safety outcomes with and without consideration of concomitant ICS.

Expert opinion: The phenomenon of masking of inflammation by LABA if ICS dose is insufficient underscores the potential for confounding in determining real safety risks. Under-treatment with ICS and differential dosing of ICS in many trials are major factors driving the LABA safety concern. The FDA meta-analysis, when stratified for mandatory ICS use, found no significant increase in the composite outcome of asthma mortality, intubations and hospitalizations. Add-on therapy with LABA is effective and safe if the dose of ICS is adequate to treat airway inflammation. LABA and ICS given in a single device will negate the possibility of LABA monotherapy which is contraindicated. The FDA has recommended that LABAs be withdrawn when control is achieved with combination therapy but recent evidence suggests this may result in loss of symptom control.     

β(2) -adrenoceptor agonists: current and future direction

Despite the passionate debate over the use of β(2) -adrenoceptor agonists in the treatment of airway disorders, these agents are still central in the symptomatic management of asthma and COPD. A variety of β(2) -adrenoceptor agonists with long half-lives, also called ultra long-acting β(2) -adrenoceptor agonists (ultra-LABAs; indacaterol, olodaterol, vilanterol, carmoterol, LAS100977 and PF-610355) are currently under development with the hopes of achieving once-daily dosing. It is likely that the once-daily dosing of a bronchodilator would be a significant convenience and probably a compliance-enhancing advantage, leading to improved overall clinical outcomes. As combination therapy with an inhaled corticosteroid (ICS) and a LABA is important for treating patients suffering from asthma, and a combination with an inhaled long-acting antimuscarinic agent (LAMA) is important for treating COPD patients whose conditions are not sufficiently controlled by monotherapy with a β(2) -adrenoceptor agonist, some novel once-daily combinations of LABAs and ICSs or LAMAs are under development.     

Pediatric asthma controller therapy

The treatment of children with asthma has historically relied upon expert opinion using data extrapolated from adult studies. Over the past few years, landmark studies have been completed providing healthcare professionals with evidence on which a reasonable approach can be made for children suffering from this common and serious disease. Asthmatic phenotype in children, unlike adults, tends to differ according to age, which must be taken into account as well as triggers, severity, and level of control. The care of the child with asthma is complex, but accumulating data have demonstrated that we are on the right path for optimizing control while reducing the burden of side effects. The newest Global Initiative for Asthma (GINA) guidelines, as well as recent updates from the landmark CAMP (Childhood Asthma Management Program) study and information from the PACT (Pediatric Asthma Control Trial) and budesonide/formoterol controller and reliever studies, along with recent comparisons of higher dose inhaled corticosteroids (ICS), and ICS/long-acting β(2)-adrenoceptor agonist (LABA) combination and leukotriene receptor antagonist (LTRA) therapies in children have clarified a few of the big questions in pediatric asthma. For children with asthma aged 5 years and older, the CAMP trial demonstrated that regular use of ICS reduces the frequency of symptoms; however, height was adversely affected and there is no evidence for altering the natural history of asthma. In patients aged 6 years and over whose asthma is uncontrolled on ICS alone, combination therapy with ICS and a LABA has been recently compared with the use of higher dose ICS and the addition of an LTRA in pediatric patients. The addition of a LABA statistically will be of most benefit; however, some children will have optimal control with doubling the baseline dose of ICS or addition of an LTRA. Use of budesonide/formoterol as a controller and reliever therapy extends the time to first exacerbation versus contemporary use of this medication in patients aged 4 years and older. Ciclesonide, a newer ICS, has demonstrated acceptable efficacy but has the added benefit of not affecting growth. Certainly, with mounting evidence, the care-map in pediatric asthma control is becoming clearer.     

噻托溴铵喷雾剂替换沙美特罗替卡松治疗老年慢性阻塞性肺疾病的临床研究

目的：研究应用噻托溴铵喷雾剂替换吸入糖皮质激素/长效β2激动剂治疗老年COPD的疗效和安全性。方法：72例肺功能GOLD 3级或4级、并正使用沙美特罗替卡松粉吸入剂的老年COPD患者随机分为2组,1组换为噻托溴铵喷雾剂（LAMA组）,另1组（ICS/LABA组）继续原治疗方案,比较12个月后两组的肺功能变化值、COPD评估测试评分变化值、年急性加重人数和次数、药物不良事件。结果：用药12个月时LAMA组的FEV1、FVC年下降值低于ICS/LABA组,COPD评估测试评分改善值高于ICS/LABA组,差异具有显著性（P<0.05）;12个月内LAMA组急性加重入院的病人数和总次数低于ICS/LABA组;12个月内LAMA组肺炎的发生率低于ICS/LABA组。结论：老年COPD患者吸入噻托溴铵喷雾剂可减少急性加重和改善日常症状,并具有良好的安全性和依从性。     

吸入糖皮质激素和长效β2-受体激动剂复方制剂治疗哮喘的研究进展

联合使用吸入糖皮质激素和长效β2-受体激动剂对控制哮喘的气道炎症和改善气道平滑肌功能具有协同和互补作用。吸入糖皮质激素和长效β2-受体激动剂复方制剂是目前哮喘维持治疗的重要药物,主要包括丙酸氟替卡松/沙美特罗、布地奈德/福莫特罗、二丙酸倍氯松/福莫特罗和糠酸莫米松/福莫特罗等。本文就此类复方制剂在哮喘治疗中的临床地位和研究进展作一概述。     

Inhaled corticosteroids as combination therapy with β-adrenergic agonists in airways disease: present and future

Inhaled corticosteroid (ICS) therapy in combination with long-acting β-adrenergic agonists represents the most important treatment for chronic airways diseases such as asthma and chronic obstructive pulmonary disease (COPD). ICS therapy forms the basis for treatment of asthma of all severities, improving asthma control, lung function and preventing exacerbations of disease. Use of ICS has also been established in the treatment of COPD, particularly symptomatic patients, who experience useful gains in quality of life, likely from an improvement in symptoms such as breathlessness and in reduction in exacerbations, and an attenuation of the yearly rate of deterioration in lung function. The addition of long-acting β-agonist (LABA) therapy with ICS increases the efficacy of ICS effects in moderate-to-severe asthma. Thus, a 800 μg daily dose of the ICS budesonide reduced severe exacerbation rates by 49% compared to a low dose of 200 μg daily, and addition of the LABA formoterol to budesonide (800 μg) led to a 63% reduction. In COPD, the effects of ICS are less prominent but there are beneficial effects on the decline in FEV₁ and the rate of exacerbations. A reduction in the rate of decline in FEV₁ of 16 ml/year with a 25% reduction in exacerbation rate has been reported with the salmeterol and fluticasone combination. A non-significant 17.5% reduction in all-cause mortality rate with ICS and LABA is reported. Chronic inflammation is a feature of both asthma and COPD, although there are site and characteristic differences. ICS targets this inflammation although this effect of ICS is less effective in patients with severe asthma and with COPD; however, addition of LABA may potentiate the anti-inflammatory effects of ICS. An important consideration is the presence of corticosteroid insensitivity in these patients. Currently available ICS have variably potent binding activities to specific glucocorticoid receptors, leading to inhibition of gene expression by either binding to DNA and inducing anti-inflammatory genes or by repressing the induction of pro-inflammatory mediators. Local side effects of ICS include oral candidiasis, hoarseness and dysphonia, while systemic side effects, such as easy bruising and reduction in growth velocity or bone mineral densitometry, are usually restricted to doses above maximally recommended doses. Use of LABA alone in patients with asthma increases the risk of asthma-related events including deaths, but this is less observed with the combination of ICS and LABA. Therefore, use of LABA alone is not recommended for asthma therapy. Future progress in ICS development will be characterised by the introduction of ICS with greater efficacy with a limited side-effect profile, and by longer-acting ICS that can be used in combination with once-daily LABAs. Other agents that could improve the efficacy of corticosteroids or reverse corticosteroid insensitivity may be added to ICS. ICS in combination with LABAs will continue to remain the main focus of treatment of airways diseases.