Decreased bronchodilating effect of salbutamol in relieving methacholine induced moderate to severe bronchoconstriction during high dose treatment with long acting beta2 agonists

Salbutamol in the Management of Asthma: A Review

Asthma is a common inflammatory disease of the lungs. The prevalence of asthma is increasing worldwide, and the tendency indicates that the number of asthma sufferers will soar in the coming years for several reasons, in particular, the lifestyles we have adopted that expose us to risk factors. Salbutamol is the first selective short-acting β2-agonist (SABA) used as an alternative reliever in the treatment of asthma. Its therapeutic effect is based on its potent smooth muscle relaxant properties, which allow the inhibition of bronchial smooth muscle contraction and subsequent bronchodilation. Salbutamol can be administered orally, intravenously (IV), intramuscularly (IM), subcutaneously, or by inhalation. For this reason, the pharmacokinetic (PK) parameters-absorption, distribution, metabolism, and elimination-are highly diverse and, consequently, the efficacy and adverse effects also differ between each formulation. Here, we review the pharmacological profile of different salbutamol formulations, focusing on their efficacy and adverse effects for its original application, asthma.

Regular treatment with formoterol and an inhaled corticosteroid versus regular treatment with salmeterol and an inhaled corticosteroid for chronic asthma: serious adverse events

BACKGROUND

Asthma is characterised by chronic inflammation of the airways and recurrent exacerbations with wheezing, chest tightness, and cough. Treatment with inhaled steroids and bronchodilators can result in good control of symptoms, prevention of further morbidity, and improved quality of life. However, an increase in serious adverse events with the use of both regular formoterol and regular salmeterol (long-acting beta₂-agonists) compared with placebo for chronic asthma has been demonstrated in previous Cochrane Reviews. This increase was statistically significant in trials that did not randomise participants to an inhaled corticosteroid, but not when formoterol or salmeterol was combined with an inhaled corticosteroid. The confidence intervals were found to be too wide to ensure that the addition of an inhaled corticosteroid renders regular long-acting beta₂-agonists completely safe; few participants and insufficient serious adverse events in these trials precluded a definitive decision about the safety of combination treatments.

OBJECTIVES

To assess risks of mortality and non-fatal serious adverse events in trials that have randomised patients with chronic asthma to regular formoterol and an inhaled corticosteroid versus regular salmeterol and an inhaled corticosteroid.

SEARCH METHODS

We searched the Cochrane Airways Register of Trials, CENTRAL, MEDLINE, Embase, and two trial registries to identify reports of randomised trials for inclusion. We checked manufacturers' websites and clinical trial registers for unpublished trial data, as well as Food and Drug Administration (FDA) submissions in relation to formoterol and salmeterol. The date of the most recent search was  24 February 2021.

SELECTION CRITERIA

We included controlled clinical trials with a parallel design, recruiting patients of any age and severity of asthma, if they randomised patients to treatment with regular formoterol versus regular salmeterol (each with a randomised inhaled corticosteroid) and were of at least 12 weeks' duration.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion in the review, extracted outcome data from published papers and trial registries, and applied GRADE rating for the results. We sought unpublished data on mortality and serious adverse events from study sponsors and authors. The primary outcomes were all cause mortality and non-fatal serious adverse events. We chose not to calculate an average result from all the formulations of formoterol and inhaled steroid, as the doses and delivery devices are too diverse to assume a single class effect.

MAIN RESULTS

Twenty-one studies in 11,572 adults and adolescents and two studies in 723 children met the eligibility criteria of the review. No data were available for two studies; therefore these were not included in the analysis. Among adult and adolescent studies, seven compared formoterol and budesonide to salmeterol and fluticasone (N = 7764), six compared formoterol and beclomethasone to salmeterol and fluticasone (N = 1923), two compared formoterol and mometasone to salmeterol and fluticasone (N = 1126), two compared formoterol and fluticasone to salmeterol and fluticasone (N = 790), and one compared formoterol and budesonide to salmeterol and budesonide (N = 229). In total, five deaths were reported among adults, none of which was thought to be related to asthma. The certainty of evidence for all-cause mortality was low, as there were not enough deaths to permit any precise conclusions regarding the risk of mortality on combination formoterol versus combination salmeterol. In all, 201 adults reported non-fatal serious adverse events. In studies comparing formoterol and budesonide to salmeterol and fluticasone, there were 77 in the formoterol arm and 68 in the salmeterol arm (Peto odds ratio (OR) 1.14, 95% confidence interval (CI) 0.82 to 1.59; 5935 participants, 7 studies; moderate-certainty evidence). In the formoterol and beclomethasone studies, there were 12 adults in the formoterol arm and 13 in the salmeterol arm with events (Peto OR 0.94, 95% CI 0.43 to 2.08; 1941 participants, 6 studies; moderate-certainty evidence). In the formoterol and mometasone studies, there were 18 in the formoterol arm and 11 in the salmeterol arm (Peto OR 1.02, 95% CI 0.47 to 2.20; 1126 participants, 2 studies; moderate-certainty evidence). One adult in the formoterol and fluticasone studies in the salmeterol arm experienced an event (Peto OR 0.05, 95% CI 0.00 to 3.10; 293 participants, 2 studies; low-certainty evidence). Another adult in the formoterol and budesonide compared to salmeterol and budesonide study in the formoterol arm had an event (Peto OR 7.45, 95% CI 0.15 to 375.68; 229 participants, 1 study; low-certainty evidence). Only 46 adults were reported to have experienced asthma-related serious adverse events. The certainty of the evidence was low to very low due to the small number of events and the absence of independent assessment of causation. The two studies in children compared formoterol and fluticasone to salmeterol and fluticasone. No deaths and no asthma-related serious adverse events were reported in these studies. Four all-cause serious adverse events were reported: three in the formoterol arm, and one in the salmeterol arm (Peto OR 2.72, 95% CI 0.38 to 19.46; 548 participants, 2 studies; low-certainty evidence).

AUTHORS' CONCLUSIONS

Overall, for both adults and children, evidence is insufficient to show whether regular formoterol in combination with budesonide, beclomethasone, fluticasone, or mometasone has a different safety profile from salmeterol in combination with fluticasone or budesonide. Five deaths of any cause were reported across all studies and no deaths from asthma; this information is insufficient to permit any firm conclusions about the relative risks of mortality on combination formoterol in comparison to combination salmeterol inhalers. Evidence on all-cause non-fatal serious adverse events indicates that there is probably little to no difference between formoterol/budesonide and salmeterol/fluticasone inhalers. However events for the other formoterol combination inhalers were too few to allow conclusions. Only 46 non-fatal serious adverse events were thought to be asthma related; this small number in addition to the absence of independent outcome assessment means that we have very low confidence for this outcome. We found no evidence of safety issues that would affect the choice between salmeterol and formoterol combination inhalers used for regular maintenance therapy by adults and children with asthma.

Inhaled bronchodilator exposure in the management of bronchopulmonary dysplasia in hospitalized infants

OBJECTIVE

To determine clinical, demographic, and hospital factors associated with inhaled bronchodilator (IB) use in infants with bronchopulmonary dysplasia (BPD) and specifically severe BPD.

STUDY DESIGN

Retrospective multicenter cohort study of 4986 infants born <32 weeks gestation with developing BPD at 28 days of life. We used the Pediatric Health Information System database to compare hospital experience and the demographic and clinical characteristics of infants exposed and not exposed to IBs.

RESULTS

Twenty-five percent of BPD patients (1224/4986) and 48% of severe BPD patients (664/1390) received IBs. IB exposure was higher in infants with the tracheostomy, prolonged steroid and diuretic exposure, and longer duration of respiratory support. IB use varied markedly between hospitals (0-59%). Average annual BPD census was not associated with IB use.

CONCLUSION

Bronchodilator exposure is common in BPD patients with substantial variability in its use. Hospital experience did not account for the between-hospital variation in practice.

Inhaled steroids with and without regular salmeterol for asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between use of beta₂-agonists and increased asthma mortality. Much debate has surrounded possible causal links for this association, and whether regular (daily) long-acting beta₂-agonists (LABAs) are safe, particularly when used in combination with inhaled corticosteroids (ICSs). This is an update of a Cochrane Review that now includes data from two large trials including 11,679 adults and 6208 children; both were mandated by the US Food and Drug Administration (FDA).  OBJECTIVES: To assess risks of mortality and non-fatal serious adverse events (SAEs) in trials that randomised participants with chronic asthma to regular salmeterol and ICS versus the same dose of ICS.

SEARCH METHODS

We identified randomised trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trials registers for unpublished trial data. We also checked FDA submissions in relation to salmeterol. The date of the most recent search was 10 October 2018.

SELECTION CRITERIA

We included parallel-design randomised trials involving adults, children, or both with asthma of any severity who were randomised to treatment with regular salmeterol and ICS (in separate or combined inhalers) versus the same dose of ICS of at least 12 weeks in duration.

DATA COLLECTION AND ANALYSIS

We conducted the review according to standard procedures expected by Cochrane. We obtained unpublished data on mortality and SAEs from the sponsors, from ClinicalTrials.gov, and from FDA submissions. We assessed our confidence in the evidence according to current GRADE recommendations.

MAIN RESULTS

We have included in this review 41 studies (27,951 participants) in adults and adolescents, along with eight studies (8453 participants) in children. We judged that the overall risk of bias was low for all-cause events, and we obtained data on SAEs from all study authors. All except 542 adults (and none of the children) were given salmeterol and fluticasone in the same (combination) inhaler.DeathsEleven of a total of 14,233 adults taking regular salmeterol and ICS died, as did 13 of 13,718 taking regular ICS at the same dose. The pooled Peto odds ratio (OR) was 0.80 (95% confidence interval (CI) 0.36 to 1.78; participants = 27,951; studies = 41; I² = 0%; moderate-certainty evidence). In other words, for every 1000 adults treated for 25 weeks, one death occurred among those on ICS alone, and the corresponding risk among those taking salmeterol and ICS was also one death (95% CI 0 to 2 deaths).No children died, and no adults or children died of asthma, so we remain uncertain about mortality in children and about asthma mortality in any age group.Non-fatal serious adverse eventsA total of 332 adults receiving regular salmeterol with ICS experienced a non-fatal SAE of any cause, compared to 282 adults receiving regular ICS. The pooled Peto OR was 1.14 (95% CI 0.97 to 1.33; participants = 27,951; studies = 41; I² = 0%; moderate-certainty evidence). For every 1000 adults treated for 25 weeks, 21 adults on ICS alone had an SAE, and the corresponding risk for those on salmeterol and ICS was 23 adults (95% CI 20 to 27).Sixty-five of 4229 children given regular salmeterol with ICS suffered an SAE of any cause, compared to 62 of 4224 children given regular ICS. The pooled Peto OR was 1.04 (95% CI 0.73 to 1.48; participants = 8453; studies = 8; I² = 0%; moderate-certainty evidence). For every 1000 children treated for 23 weeks, 15 children on ICS alone had an SAE, and the corresponding risk for those on salmeterol and ICS was 15 children (95% CI 11 to 22).Asthma-related serious adverse eventsEighty and 67 adults in each group, respectively, experienced an asthma-related non-fatal SAE. The pooled Peto OR was 1.15 (95% CI 0.83 to 1.59; participants = 27,951; studies = 41; I² = 0%; low-certainty evidence). For every 1000 adults treated for 25 weeks, five receiving ICS alone had an asthma-related SAE, and the corresponding risk among those on salmeterol and ICS was six adults (95% CI 4 to 8).Twenty-nine children taking salmeterol and ICS and 23 children taking ICS alone reported asthma-related events. The pooled Peto OR was 1.25 (95% CI 0.72 to 2.16; participants = 8453; studies = 8; I² = 0%; moderate-certainty evidence). For every 1000 children treated for 23 weeks, five receiving an ICS alone had an asthma-related SAE, and the corresponding risk among those receiving salmeterol and ICS was seven children (95% CI 4 to 12).

AUTHORS' CONCLUSIONS

We did not find a difference in the risk of death or serious adverse events in either adults or children. However, trial authors reported no asthma deaths among 27,951 adults or 8453 children randomised to regular salmeterol and ICS or ICS alone over an average of six months. Therefore, the risk of dying from asthma on either treatment was very low, but we remain uncertain about whether the risk of dying from asthma is altered by adding salmeterol to ICS.Inclusion of new trials has increased the precision of the estimates for non-fatal SAEs of any cause. We can now say that the worst-case estimate is that at least 152 adults and 139 children must be treated with combination salmeterol and ICS for six months for one additional person to be admitted to the hospital (compared to treatment with ICS alone). These possible risks still have to be weighed against the benefits experienced by people who take combination treatment.However more than 90% of prescribed treatment was taken in the new trials, so the effects observed may be different from those seen with salmeterol in combination with ICS in daily practice.

Physiological and Biological Responses to Short-Term Intermittent Hypobaric Hypoxia Exposure: From Sports and Mountain Medicine to New Biomedical Applications

In recent years, the altitude acclimatization responses elicited by short-term intermittent exposure to hypoxia have been subject to renewed attention. The main goal of short-term intermittent hypobaric hypoxia exposure programs was originally to improve the aerobic capacity of athletes or to accelerate the altitude acclimatization response in alpinists, since such programs induce an increase in erythrocyte mass. Several model programs of intermittent exposure to hypoxia have presented efficiency with respect to this goal, without any of the inconveniences or negative consequences associated with permanent stays at moderate or high altitudes. Artificial intermittent exposure to normobaric hypoxia systems have seen a rapid rise in popularity among recreational and professional athletes, not only due to their unbeatable cost/efficiency ratio, but also because they help prevent common inconveniences associated with high-altitude stays such as social isolation, nutritional limitations, and other minor health and comfort-related annoyances. Today, intermittent exposure to hypobaric hypoxia is known to elicit other physiological response types in several organs and body systems. These responses range from alterations in the ventilatory pattern to modulation of the mitochondrial function. The central role played by hypoxia-inducible factor (HIF) in activating a signaling molecular cascade after hypoxia exposure is well known. Among these targets, several growth factors that upregulate the capillary bed by inducing angiogenesis and promoting oxidative metabolism merit special attention. Applying intermittent hypobaric hypoxia to promote the action of some molecules, such as angiogenic factors, could improve repair and recovery in many tissue types. This article uses a comprehensive approach to examine data obtained in recent years. We consider evidence collected from different tissues, including myocardial capillarization, skeletal muscle fiber types and fiber size changes induced by intermittent hypoxia exposure, and discuss the evidence that points to beneficial interventions in applied fields such as sport science. Short-term intermittent hypoxia may not only be useful for healthy people, but could also be considered a promising tool to be applied, with due caution, to some pathophysiological states.

Medication Regimens for Managing COPD Exacerbations

Exacerbations are a hallmark feature of COPD and contribute to morbidity and mortality. There is general agreement that the pharmacotherapy of COPD exacerbations includes bronchodilators, corticosteroids, and antibiotics. Strong evidence exists for the benefit of corticosteroids for exacerbations and of antibiotics in the acute hospital setting. There remains considerable uncertainty, however, in the best drug selection, dose, route, and duration of treatment. This article reviews the evidence base and expert recommendations for drug treatment of COPD exacerbations in the out-patient and in-patient settings.

Long-acting bronchodilators with or without inhaled corticosteroids and 30-day readmission in patients hospitalized for COPD

BACKGROUND

The ability of a long-acting muscarinic antagonist (LAMA) and long-acting beta 2 agonists (LABAs; long-acting bronchodilators, LABDs) with or without inhaled corticosteroids (ICSs) to reduce early readmission in hospitalized patients with COPD is unknown.

METHODS

We studied a 5% sample of Medicare beneficiaries enrolled in Medicare parts A, B and D and hospitalized for COPD in 2011. We examined prescriptions filled for LABDs with or without ICSs (LABDs±ICSs) within 90 days prior to and 30 days after hospitalization. Primary outcome was the 30-day readmission rate between "users" and "nonusers" of LABDs±ICSs. Propensity score matching and sensitivity analysis were performed by limiting analysis to patients hospitalized for acute exacerbation of COPD (AECOPD). Among 6,066 patients hospitalized for COPD, 3,747 (61.8%) used LABDs±ICSs during the specified period. The "user" and "nonuser" groups had similar rates of all-cause emergency room (ER) visits and readmissions within 30 days of discharge date (22.4% vs 20.7%, P-value 0.11; 18.0% vs 17.8%, P-value 0.85, respectively). However, the "users" had higher rates of COPD-related ER visits (5.3% vs 3.4%, P-value 0.0006), higher adjusted odds ratio (aOR) 1.47 (95% CI, 1.11-1.93) and readmission (7.8% vs 5.0%, P-value <0.0001 and aOR 1.48 [95% CI, 1.18-1.86]) than "nonusers". After propensity score matching, the aOR of COPD-related ER visits was 1.45 (95% CI, 1.07-1.96) and that of readmission was 1.34 (95% CI, 1.04-1.73). The results were similar when restricted to patients hospitalized for AECOPD.

CONCLUSION

Use of LABDs±ICSs did not reduce 30-day readmissions in patients hospitalized for COPD.

Postnatal overnutrition in mice leads to impaired pulmonary mechanics in response to salbutamol

Obesity increases the risk of respiratory disease, which is associated with airway hyperresponsiveness. Although the molecular underpinnings of this phenomenon are not well established, lung remodeling is known as an important factor in this process and could potentially explain compromised lung functions. In the present study, the obesity was induced by postnatal overnutrition in Swiss mice and we investigated the pulmonary mechanics after aerosolization of saline, methacholine, and salbutamol. The lungs were prepared for morphometric analysis. Obese animals showed bronchoconstriction in response to methacholine, as evidenced by airway and tissue resistance, tissue elastance, and hysteresivity. Salbutamol was effective at recovering the response only for airway resistance but not for tissue mechanics. We suggest that this impaired response in obese mice is related to collapsed alveolar, to inflammatory cells, and to elevated deposition collagen fibers in parenchymal tissue.

Bronchodilator response following methacholine-induced bronchoconstriction predicts acute asthma exacerbations

Methacholine bronchial provocation test provides the concentration of methacholine causing a 20% decrease in forced expiratory volume in 1 s (FEV1) from baseline (PC20). The dose-response slope (DRS), and other continuous indices of responsiveness (CIR; the percentage decline from the post-diluent baseline FEV1 after the last dose of methacholine), and per cent recovery index (PRI; the percentage increase from the maximally reduced FEV1 after bronchodilator inhalation) are alternative measures. The clinical relevance of these indices in predicting acute asthma exacerbations has not been fully evaluated.In two prospective cohorts of childhood and elderly asthmatics, baseline PC20, DRS, CIR and PRI were measured and evaluated as predictors of acute asthma exacerbations.We found that PRI was significantly related to the presence of asthma exacerbations during the first year of follow-up in both cohorts of childhood (p=0.025) and elderly asthmatics (p=0.003). In addition, PRI showed a significant association with the total number of steroid bursts during 4.3 years of follow-up in the cohort of childhood asthmatics (p=0.04).We demonstrated that PRI, an index of reversibility following methacholine-induced bronchoconstriction, was a good clinical predictor of acute exacerbations of asthma in both childhood and elderly asthmatics.

Comparison of the effectiveness and safety of formoterol versus salmeterol in the treatment of patients with asthma: A systematic review and meta-analysis

BACKGROUND

Formoterol and salmeterol are two long-acting β2-agonists given by inhalation, with bronchodilating effects lasting for at least 12 h after a single administration. Formoterol has a faster onset of action compared with salmeterol. The aim of this study was to perform a systematic review and meta-analysis on the data published from previous review in order to calculate pooled estimates of effectiveness and safety assessment of formoterol and salmeterol in treatment of patients with asthma.

MATERIALS AND METHODS

In this study, we conducted an electronic search for medical citation databases including Cochrane, PubMed, Scopus, PsycInfo, and IranMedex. Besides manual search of the databases that record randomized clinical trials, conference proceedings, and journals related to asthma were included. Studies were evaluated by two independent people based on inclusion and exclusion criteria, and the common outcomes of studies were entered into the RevMan 5.0.1 software, after evaluation of studies and extraction of data from them; and in cases where there were homogeneous studies, meta-analysis was performed, and for heterogeneous studies, the results were reported qualitatively.

RESULTS

Of the 1539 studies initially found, 13 were included in the study. According to the meta-analysis conducted, no significant difference was found between the inhalation of formoterol 12 μg and salmeterol 50 μg in the two outcomes of mean forced expiratory volume 1 s (FEV1), 12 h after inhalation of medication and Borg score (A frequently used scale for quantifying breathlessness) after inhalation of medication. In addition, salmeterol was more effective than formoterol in the two outcomes of percent decrease in FEV1 after inhalation of methacholine and the number of days without an attack. Since the two outcomes of FEV1 30-60 min after inhalation of medication and morning peak expiratory flow after inhalation of medication were heterogeneous, they had no meta-analysis capabilities, and its results were reported qualitatively.

CONCLUSION

The data from included studies shows that, more efficacy has been achieved with Salmeterol, especially in some outcomes such as the percent decrease in FEV1 after inhalation of Methacholine, and the number of days without an attack; and therefore, the administration of Salmeterol seems to be beneficial for patients, compared with Formoterol.

Inhaled anticholinergics and short-acting beta(2)-agonists versus short-acting beta2-agonists alone for children with acute asthma in hospital

BACKGROUND

Inhaled anticholinergics given in addition to β2-agonists are effective in reducing hospital admissions in children presenting to the emergency department with a moderate to severe asthma exacerbation. It seems logical to assume a similar beneficial effect in children hospitalised for an acute asthma exacerbation.

OBJECTIVES

To assess the efficacy and safety of anticholinergics added to β2-agonists as inhaled or nebulised therapy in children hospitalised for an acute asthma exacerbation. To investigate the characteristics of patients or therapy, if any, that would influence the magnitude of response attributable to the addition of anticholinergics.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register of trials (CAGR), which is derived through systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, AMED and PsycINFO and through handsearching of respiratory journals and meeting abstracts. The search is current to November 2013.

SELECTION CRITERIA

Randomised trials comparing the combination of inhaled or nebulised anticholinergics and short-acting β2-agonists versus short-acting β2-agonists alone in children one to 18 years of age hospitalised for an acute asthma exacerbation were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data; disagreement was resolved by consensus or with the input of a third review author, when needed. Primary outcomes were duration of hospital stay and serious adverse events. Secondary outcomes included admission and duration of stay in the intensive care unit (ICU), ventilation assistance, time to short-acting β2-agonists spaced at four hours or longer, supplemental asthma therapy, duration of supplemental oxygen, change from baseline in asthma severity, relapse after discharge, adverse health effects and withdrawals.

MAIN RESULTS

Seven randomised trials were included, four of which reported usable data on 472 children with asthma one to 18 years of age who were admitted to paediatric wards. No trials included patients admitted to the ICU. The anticholinergic used, ipratropium bromide 250 μg, was given every one to eight hours over a period from four hours to the entire length of the hospital stay. Two of four trials (50%) contributing data were deemed of high methodological quality. The addition of anticholinergics to β2-agonists showed no evidence of effect on the duration of hospital admission (mean difference (MD) -0.28 hours, 95% confidence interval (CI) -5.07 to 4.52, 3 studies, 327 participants, moderate quality evidence) and no serious or non-serious adverse events were reported in any included trials. As a result of the similarity of trials, we could not explore the influence of age, admission site, intensity of anticholinergic treatment and co-interventions on primary outcomes. No statistically significant group difference was noted in other secondary outcomes, including the need for supplemental asthma therapy, time to short-acting β2-agonists spaced at four hours or longer, asthma clinical scores, lung function and overall withdrawals for any reason.

AUTHORS' CONCLUSIONS

In children hospitalised for an acute asthma exacerbation, no evidence of benefit for length of hospital stay and other markers of response to therapy was noted when nebulised anticholinergics were added to short-acting β2-agonists. No adverse health effects were reported, yet the small number of trials combined with inadequate reporting prevent firm reassurance regarding the safety of anticholinergics. In the absence of trials conducted in ICUs, no conclusion can be drawn regarding children with impending respiratory failure. These findings support current national and international recommendations indicating that healthcare practitioners should refrain from using anticholinergics in children hospitalised for acute asthma.

Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta2-agonists and increases in asthma mortality. Much debate has surrounded possible causal links for this association and whether regular (daily) long-acting beta2-agonists are safe when used alone or in conjunction with inhaled corticosteroids. This is an updated Cochrane Review.

OBJECTIVES

To assess the risk of fatal and non-fatal serious adverse events in people with chronic asthma given regular formoterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

SEARCH METHODS

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data; Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was August 2012.

SELECTION CRITERIA

Controlled clinical trials with a parallel design were included if they randomly allocated people of any age and severity of asthma to treatment with regular formoterol and inhaled corticosteroids for at least 12 weeks.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Unpublished data on mortality and serious adverse events were obtained from the sponsors. We assessed the quality of evidence using GRADE recommendations.

MAIN RESULTS

Following the 2012 update, we have included 20 studies on 10,578 adults and adolescents and seven studies on 2788 children and adolescents. We found data on all-cause fatal and non-fatal serious adverse events for all studies, and we judged the overall risk of bias to be low.Six deaths occurred in participants taking regular formoterol with inhaled corticosteroids, and one in a participant administered regular inhaled corticosteroids alone. The difference was not statistically significant (Peto odds ratio (OR) 3.56, 95% confidence interval (CI) 0.79 to 16.03, low-quality evidence). All deaths were reported in adults, and one was believed to be asthma-related.Non-fatal serious adverse events of any cause were very similar for each treatment in adults (Peto OR 0.98, 95% CI 0.76 to 1.27, moderate-quality evidence), and weak evidence suggested an increase in events in children on regular formoterol (Peto OR 1.62, 95% CI 0.80 to 3.28, moderate-quality evidence).In contrast with all-cause serious adverse events, the addition of new trial data means that asthma-related serious adverse events associated with formoterol are now significantly fewer in adults taking regular formoterol with inhaled corticosteroids (Peto OR 0.49, 95% CI 0.28 to 0.88, moderate-quality evidence). Although a greater number of asthma-related events were reported in children receiving regular formoterol, this finding was not statistically significant (Peto OR 1.49, 95% CI 0.48 to 4.61, low-quality evidence).

AUTHORS' CONCLUSIONS

From the evidence in this review, it is not possible to reassure people with asthma that regular use of inhaled corticosteroids with formoterol carries no risk of increasing mortality in comparison with use of inhaled corticosteroids alone. On the other hand, we have found no conclusive evidence of serious harm, and only one asthma-related death was registered during more than 4200 patient-years of observation with formoterol.In adults, no significant difference in all-cause non-fatal serious adverse events was noted with regular formoterol with inhaled corticosteroids, but a significant reduction in asthma-related serious adverse events was observed in comparison with inhaled corticosteroids alone.In children the number of events was too small, and consequently the results too imprecise, to allow determination of whether the increased risk of all-cause non-fatal serious adverse events found in a previous meta-analysis on regular formoterol alone is abolished by the additional use of inhaled corticosteroids.We await the results of large ongoing surveillance studies mandated by the Food and Drug Administration (FDA) for more information. Clinical decisions and information provided to patients regarding regular use of formoterol have to take into account the balance between known symptomatic benefits of formoterol and the degree of uncertainty associated with its potential harmful effects.

Regular treatment with salmeterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta2-agonists and increased asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta2-agonists are safe. This is an updated systematic review.

OBJECTIVES

To assess the risk of mortality and non-fatal serious adverse events in trials which randomised patients with chronic asthma to regular salmeterol and inhaled corticosteroids in comparison to the same dose of inhaled corticosteroids.

SEARCH METHODS

We identified randomised trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trial registers for unpublished trial data. Food and Drug Administration (FDA) submissions in relation to salmeterol were also checked. The date of the most recent search is August 2012.

SELECTION CRITERIA

We included parallel design controlled clinical trials on patients of any age and severity of asthma if they randomised patients to treatment with regular salmeterol and inhaled corticosteroids (in separate or combined inhalers), and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

We conducted the review according to standard procedures expected by the Cochrane Collaboration. We obtained unpublished data on mortality and serious adverse events from the sponsors, and from FDA submissions. We assessed the quality of evidence according to GRADE recommendations.

MAIN RESULTS

We have included 35 studies (13,447 participants) in adults and adolescents, and 5 studies (1862 participants) in children in this review. We judged that the overall risk of bias was low, and we obtained data on serious adverse events from all studies. All except 542 adults (and none of the children) who were randomised to salmeterol were given fluticasone in the same (combination) inhaler.Seven deaths occurred in 6986 adults on regular salmeterol with inhaled corticosteroids (ICS), and seven deaths in 6461 adults on regular inhaled corticosteroids at the same dose. The difference was not statistically significant (Peto odds ratio (OR) 0.90; 95% confidence interval (CI) 0.31 to 2.60, moderate quality evidence). The risk of dying from any cause in adults on ICS was 10 per 10,000, and on salmeterol and ICS we would expect between 3 and 26 deaths per 10,000. No deaths were reported in 1862 children, and no deaths were reported to be asthma-related in adults or children.Non-fatal serious adverse events of any cause were reported in 167 adults on regular salmeterol with ICS, compared to 135 adults on regular ICS; again this was not a statistically significant increase (Peto OR 1.15; 95% CI 0.91 to 1.44, moderate quality evidence). The frequency of serious adverse events was 21 per 1000 in the adults treated with ICS and 24 per 1000 in those treated with salmeterol and ICS. The absolute difference in the risk of non-fatal serious adverse events was an increase of 3 per 1000, that was not statistically significant (risk difference (RD) 0.003; 95% CI -0.002 to 0.008).There were 6 of 930 children with serious adverse events on regular salmeterol with ICS, compared to 5 out of 932 on regular ICS: there was no significant difference between treatments (Peto OR 1.20; 95% CI 0.37 to 3.91, moderate quality evidence).Asthma-related serious adverse events were reported in 29 and 23 adults in each group respectively, a non-significant difference (Peto OR 1.12; 95% CI 0.65 to 1.94, moderate quality evidence), and only 1 asthma-related event was reported in children in each treatment group.

AUTHORS' CONCLUSIONS

We found no statistically significant differences in fatal or non-fatal serious adverse events in trials in which regular salmeterol was randomly allocated with ICS, in comparison to ICS alone at the same dose. Although 13,447 adults and 1862 children have now been included in trials, the frequency of adverse events is too low and the results are too imprecise to confidently rule out a relative increase in all cause mortality or non-fatal adverse events with salmeterol used in conjunction with ICS. However, the absolute difference between groups in the risk of serious adverse events was very small. We could not determine whether the increase in all cause non-fatal serious adverse events reported in the previous meta-analysis on regular salmeterol alone is abolished by the additional use of regular ICS. We await the results of large ongoing surveillance studies mandated by the FDA to provide more information. There were no asthma-related deaths and few asthma-related serious adverse events. Clinical decisions and information for patients regarding regular use of salmeterol have to take into account the balance between known symptomatic benefits of salmeterol and the degree of uncertainty and concern associated with its potential harmful effects.

Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers

BACKGROUND

Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5'-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma.

METHODS

Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject.

RESULTS

A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R(2) = 0.345, p = .001) rather than after the methacholine challenge (R(2) = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R(2) = 0.212, p = .001) than BDR after methacholine challenge (R(2) = 0.002, p = .724). Both BDR after methacholine challenge (R(2) = 0.063, p = .038) and BDR after AMP challenge (R(2) = 0.192, p = .001) were significantly correlated with serum ECP levels.

CONCLUSION

BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.

Comparison of the bronchodilating effects of inhaled β₂-agonists after methacholine challenge in a human lung reperfusion model

The aim of the present investigation was to compare the onset of action and intrinsic activity of the long-acting β(2)-agonist GW597901 with the fast- and short-acting salbutamol as model compounds using an isolated human lung reperfusion model. Twelve resected human lung lobes were challenged with methacholine (MCh) and subsequently nebulised with either GW597901 or salbutamol. Prostaglandin E(2) (PGE(2)) concentrations in the perfusion fluid were compared with the dose of MCh that was required to induce a bronchoconstriction. After successful MCh provocation, nebulisation of GW597901 and salbutamol fully reversed any observed bronchoconstriction. The bronchodilating effect was more pronounced for GW597901. Salbutamol revealed an immediate onset of action while the effect of GW597901 was observed with an approximate delay of 6 min. Higher doses of MCh were required for a successful bronchial challenge in the presence of elevated PGE(2) levels (r=0.8171, p ≤ 0.05). For the first time, an isolated perfused human lung model has been established for comparing the onset of action and potency of a short- and long-acting β(2)-agonist. We therefore conclude that it is an alternative for determination of drug effect characteristics and suitable for supplementing or predicting clinical data.

Regular treatment with formoterol for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular formoterol versus placebo or regular short-acting beta(2)-agonists.

SEARCH METHODS

We identified trials using the Cochrane Airways Group Specialised Register of trials. We checked websites of clinical trial registers for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol. The date of the most recent search was January 2012.

SELECTION CRITERIA

We included controlled, parallel design clinical trials on patients of any age and severity of asthma if they randomised patients to treatment with regular formoterol and were of at least 12 weeks' duration. Concomitant use of inhaled corticosteroids was allowed, as long as this was not part of the randomised treatment regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. One author extracted outcome data and the second author checked them. We sought unpublished data on mortality and serious adverse events.

MAIN RESULTS

The review includes 22 studies (8032 participants) comparing regular formoterol to placebo and salbutamol. Non-fatal serious adverse event data could be obtained for all participants from published studies comparing formoterol and placebo but only 80% of those comparing formoterol with salbutamol or terbutaline.Three deaths occurred on regular formoterol and none on placebo; this difference was not statistically significant. It was not possible to assess disease-specific mortality in view of the small number of deaths. Non-fatal serious adverse events were significantly increased when regular formoterol was compared with placebo (Peto odds ratio (OR) 1.57; 95% CI 1.06 to 2.31). One extra serious adverse event occurred over 16 weeks for every 149 people treated with regular formoterol (95% CI 66 to 1407 people). The increase was larger in children than in adults, but the impact of age was not statistically significant. Data submitted to the FDA indicate that the increase in asthma-related serious adverse events remained significant in patients taking regular formoterol who were also on inhaled corticosteroids.No significant increase in fatal or non-fatal serious adverse events was found when regular formoterol was compared with regular salbutamol or terbutaline.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular formoterol, and this does not appear to be abolished in patients taking inhaled corticosteroids. The effect on serious adverse events of regular formoterol in children was greater than the effect in adults, but the difference between age groups was not significant.Data on all-cause serious adverse events should be more fully reported in journal articles, and not combined with all severities of adverse events or limited to those events that are thought by the investigator to be drug-related.

Regular treatment with formoterol versus regular treatment with salmeterol for chronic asthma: serious adverse events

BACKGROUND

An increase in serious adverse events with both regular formoterol and regular salmeterol in chronic asthma has been demonstrated in previous Cochrane reviews.

OBJECTIVES

We set out to compare the risks of mortality and non-fatal serious adverse events in trials which have randomised patients with chronic asthma to regular formoterol versus regular salmeterol.

SEARCH METHODS

We identified trials using the Cochrane Airways Group Specialised Register of trials. We checked manufacturers' websites of clinical trial registers for unpublished trial data and also checked Food and Drug Administration (FDA) submissions in relation to formoterol and salmeterol. The date of the most recent search was January 2012.

SELECTION CRITERIA

We included controlled, parallel-design clinical trials on patients of any age and with any severity of asthma if they randomised patients to treatment with regular formoterol versus regular salmeterol (without randomised inhaled corticosteroids), and were of at least 12 weeks' duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review and extracted outcome data. We sought unpublished data on mortality and serious adverse events from the sponsors and authors.

MAIN RESULTS

The review included four studies (involving 1116 adults and 156 children). All studies were open label and recruited patients who were already taking inhaled corticosteroids for their asthma, and all studies contributed data on serious adverse events. All studies compared formoterol 12 μg versus salmeterol 50 μg twice daily. The adult studies were all comparing Foradil Aerolizer with Serevent Diskus, and the children's study compared Oxis Turbohaler to Serevent Accuhaler. There was only one death in an adult (which was unrelated to asthma) and none in children, and there were no significant differences in non-fatal serious adverse events comparing formoterol to salmeterol in adults (Peto odds ratio (OR) 0.77; 95% confidence interval (CI) 0.46 to 1.28), or children (Peto OR 0.95; 95% CI 0.06 to 15.33). Over a six-month period, in studies involving adults that contributed to this analysis, the percentages with serious adverse events were 5.1% for formoterol and 6.4% for salmeterol; and over a three-month period the percentages of children with serious adverse events were 1.3% for formoterol and 1.3% for salmeterol.

AUTHORS' CONCLUSIONS

We identified four studies comparing regular formoterol to regular salmeterol (without randomised inhaled corticosteroids, but all participants were on regular background inhaled corticosteroids). The events were infrequent and consequently too few patients have been studied to allow any firm conclusions to be drawn about the relative safety of formoterol and salmeterol. Asthma-related serious adverse events were rare and there were no reported asthma-related deaths.

Assessment of bronchodilator responsiveness following methacholine-induced bronchoconstriction in children with asthma

Purpose

The aim of this study was to investigate bronchodilator responsiveness (BDR) following methacholine-induced bronchoconstriction and to determine differences in BDR according to clinical parameters in children with asthma.

Methods

The methacholine challenge test was performed in 145 children with mild to moderate asthma, and the provocative concentration causing a 20% decline in FEV1 (PC20) was determined. Immediately after the challenge test, patients were asked to inhale short-acting β2-agonists (SABAs) to achieve BDR, which was assessed as the change in FEV1% predicted×100/post-methacholine FEV1% predicted. For each subject, the asthma medication, blood eosinophil count, serum total IgE, serum eosinophil cationic protein level, and skin prick test result were assessed.

Results

The FEV1 (mean±SD) values of the 145 patients were 90.5±10.9% predicted, 64.2±11.5% predicted, and 86.2±11.2% predicted before and after methacholine inhalation, and following the administration of a SABA, respectively. The BDR did not differ significantly according to asthma medication, age, or gender. However, BDR in the atopy group (37.4±17.7%) was significantly higher than that in the non-atopy group (30.5±10.7%; P=0.037). Patients with blood eosinophilia (38.6±18.1%) displayed increased BDR compared with patients without eosinophilia (32.0±13.8%; P=0.037).

Conclusions

In children with mild to moderate asthma, the responsiveness to short-acting bronchodilators after methacholine-induced bronchoconstriction was not related to asthma medication, but was higher in children with atopy and/or peripheral blood eosinophilia.

MicroRNA let-7 establishes expression of beta2-adrenergic receptors and dynamically down-regulates agonist-promoted down-regulation

Although β(2)-adrenergic receptors (β(2)AR) are expressed on most cell types, mechanisms that establish expression levels and regulate expression by chronic agonist remain unclear. The 3' UTR of ADRB2 has a conserved 8-nucleotide seed region that we hypothesized is targeted by the let-7 family of miRNAs leading to translational repression. In luciferase assays with transfected cells, luc-β(2)WT3'UTR had decreased expression when cotransfected with let-7f, but a mutated luc-β(2)3'UTR lacking the seed was unaffected by let-7f; a mutated let-7f also had no effect on luc-β(2)WT3'UTR expression. ADRB2 mRNA was in greater abundance in immunoprecipitates of Ago2, a core component of the miRNA-induced silencing complex, when cells were transfected with let-7f, but not with a mutated let-7f, indicating a direct interaction with the silencing mechanism. H292 cells transfected with let-7f caused ∼60% decrease in native β(2)AR expression, but transfection with let-7f-specific locked nucleic acid anti-miRNA increased β(2)AR expression by ∼twofold. We considered that an increase in let-7f leading to greater repression of translation contributes to agonist-promoted down-regulation. Paradoxically, in cells and in lungs from mice treated in vivo, an ∼50% decrease in let-7f occurs during long-term agonist exposure, indicating a counterregulatory event. Consistent with this notion, let-7f locked nucleic acid transfection caused depressed agonist-promoted down-regulation. Thus, let-7f miRNA regulates baseline β(2)AR expression and decreases in let-7f evoked by agonist attenuate down-regulation. This positive feedback loop has not previously been described for a G protein-coupled receptor and its miRNA. Methods to decrease let-7f expression in targeted cells may increase therapeutic responses to β-agonist by increasing β(2)AR expression or minimizing tachyphylaxis.

Serum total IgE levels and total eosinophil counts: relationship with treatment response in patients with acute asthma

OBJECTIVE

To determine whether serum total IgE levels and total eosinophil counts have any relationship with the response to routine pharmacological treatment in patients with acute asthma.

METHODS

A cross-sectional study involving 162 patients with acute asthma. Serum total IgE levels, peripheral blood cell counts and eosinophil counts were determined. The treatment was adjusted for each patient according to the severity of asthma. Spirometry was performed at baseline and two weeks after the treatment. The patients were divided into two groups: high IgE (>100 IU/mL) and low IgE (<100 IU/mL). We compared the two groups in terms of the relationships between baseline values and final values (percentage change) for the following parameters: FEV1, FVC, FEF25-75%, peripheral white blood cell counts and eosinophil counts.

RESULTS

There were no significant differences between the groups regarding the percentage changes of the studied parameters. Nor were there significant differences between the groups regarding FEV1, FVC, and FEF25-75% (% of the predicted values) at baseline.

CONCLUSIONS

On the basis of these findings, we conclude that serum total IgE levels, peripheral white blood cell counts and eosinophil counts cannot predict the response to the pharmacological treatment of patients with acute asthma.

Effects of asthma treatment: the present and future

The increasing burden of asthma in both primary and secondary care has led to extensive research into its genetics, pathophysiology and treatment over the past few decades. Inhaled corticosteroids remain an integral component in all but the mildest disease, although despite a low-to-moderate dose, many individuals remain symptomatic. In patients with persistent symptoms despite inhaled corticosteroids, a variety of different nonsteroidal second-line therapies are available as add-on therapy. In this review, existing and potential future pharmacological strategies involved in the management of asthma will be highlighted.

Regular treatment with formoterol versus regular treatment with salmeterol for chronic asthma: serious adverse events

BACKGROUND

An increase in serious adverse events with both regular formoterol and regular salmeterol in chronic asthma has been demonstrated in previous Cochrane reviews.

OBJECTIVES

We set out to compare the risks of mortality and non-fatal serious adverse events in trials which have randomised patients with chronic asthma to regular formoterol versus regular salmeterol.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Manufacturers' web sites of clinical trial registers were checked for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol and salmeterol were also checked. The date of the most recent search was January 2009.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular formoterol versus regular salmeterol (without randomised inhaled corticosteroids), and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review and extracted outcome data. Unpublished data on mortality and serious adverse events were sought from the sponsors and authors.

MAIN RESULTS

Four studies were included in the review (involving 1116 adults and 156 children). All studies were open label and recruited patients who were already taking inhaled corticosteroids for their asthma, and all studies contributed data on serious adverse events. All studies compared formoterol 12 mug versus salmeterol 50 mug twice daily. The adult studies were all comparing Foradil Aerolizer with Serevent Diskus, and the children's study compared Oxis Turbohaler to Serevent Accuhaler. There was only one death in an adult (which was unrelated to asthma), and none in children, and there were no significant differences in non-fatal serious adverse events comparing formoterol to salmeterol in adults (Peto OR 0.77; 95% CI 0.46 to 1.28), or children (Peto OR 0.95; 95% CI 0.06 to 15.33). Over a six month period in studies involving adults that contributed to this analysis the percentage with serious adverse events were 5.1% for formoterol and 6.4% for salmeterol; and over a 3 month period the percentage of children with serious adverse events were 1.3% for formoterol, and 1.3% for salmeterol.

AUTHORS' CONCLUSIONS

Four studies have been identified comparing regular formoterol to regular salmeterol (without randomised inhaled corticosteroids, but all subjects were on regular background inhaled corticosteroids). The events were infrequent and consequently too few patients have been studied to allow any firm conclusions to be drawn about the relative safety of formoterol and salmeterol. Asthma-related serious adverse events were rare, and there were no reported asthma-related deaths.

[Impact of preventive treatment with long-acting beta(2)-adrenergic agonists and inhaled corticosteroids on the morbidity and mortality of severe asthma exacerbations in 1543 patients]

BACKGROUND AND OBJECTIVES

Recent systematic reviews and meta-analyses examining long-acting #b(2)-adrenergic agonists (LABA) as maintenance treatment for asthma have shown surprisingly conflicting results. The aim of the present study was to determine the impact, in terms of efficacy and safety, of previous maintenance treatment on severe asthma exacerbations.

PATIENTS AND METHODS

We retrospectively evaluated the clinical characteristics of exacerbations experienced by 1543 patients with moderate persistent and severe persistent asthma. Drug therapy was as follows: a combination of inhaled LABAs and corticosteroids (493 patients), an inhaled corticosteroid only (456 patients), and no maintenance treatment (594 patients).

RESULTS

Asthmatic patients taking LABAs did not show higher mortality, longer stay in the intensive care unit, longer hospital stay, lower pH, or worse airflow obstruction than the other 2 groups. On the contrary, they had a higher mean (SD) forced expiratory volume in 1 second at discharge (54% [16%]) than patients taking inhaled corticosteroids (48% [19%]) and patients taking no maintenance treatment (48% [20%]) (P=.009). Patients taking no maintenance treatment also had lower mean (SD) pH values (7.37 [0.11]) than patients taking LABAs (7.39 [0.09]) and patients taking inhaled corticosteroids (7.39 [0.08]) (P=.002), and more admissions to the intensive care unit (11.1% vs 6.5% and 7.7%; P=.002 and P=.018, respectively).

CONCLUSIONS

This study did not reveal higher morbidity or mortality in severe asthma exacerbations in patients with moderate persistent or severe persistent asthma who had received inhaled LABAs combined with inhaled corticosteroids. On the contrary, asthma patients who did not use maintenance treatment experienced more severe asthma exacerbations.

Regular treatment with salmeterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-agonists and increased asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular salmeterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to salmeterol were also checked. The date of the most recent search was October 2008.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular salmeterol and inhaled corticosteroids (in separate or combined inhalers), and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data were independently extracted by two authors. Unpublished data on mortality and serious adverse events were obtained from the sponsors, and from FDA submissions.

MAIN RESULTS

The review included 30 studies (10,873 participants) in adults and adolescents, and three studies (1,173 participants) in children. The overall risk of bias was low and data on serious adverse events were obtained from all studies.Six deaths occurred in 5,710 adults on regular salmeterol with inhaled corticosteroids, and five deaths in 5,163 adults on regular inhaled corticosteroids at the same dose. The difference was not statistically significant (Peto OR 1.05; 95% CI 0.32 to 3.47) and the absolute difference between groups in risk of death of any cause was 0.00005 (95% CI -0.002 to 0.002). No deaths were reported in 1,173 children, and no deaths were reported to be asthma-related.Non-fatal serious adverse events of any cause were reported in 134 adults on regular salmeterol with inhaled corticosteroids, compared to 103 adults on regular inhaled corticosteroids; again this was not a significant increase (Peto OR 1.17; 95% CI 0.90 to 1.52). The absolute difference in the risk of non-fatal serious adverse events was 0.003 (95% CI -0.002 to 0.009).There were three of 586 children with serious adverse events on regular salmeterol with inhaled corticosteroids, compared to four out of 587 on regular inhaled corticosteroids: there was no significant difference between treatments (Peto OR 0.75; 95% CI 0.17 to 3.31).Asthma-related serious adverse events were reported in 23 and 21 adults in each group respectively, a non-significant difference (Peto OR 0.95; 95% CI 0.52 to 1.73), and only one event was reported in children.

AUTHORS' CONCLUSIONS

No significant differences have been found in fatal or non-fatal serious adverse events in trials in which regular salmeterol has been randomly allocated with inhaled corticosteroids, in comparison to inhaled corticosteroids at the same dose. Although 10,873 adults and 1,173 children have been included in trials, the number of patients suffering adverse events is too small, and the results are too imprecise to confidently rule out a relative increase in all-cause mortality or non-fatal adverse events. It is therefore not possible to determine whether the increase in all-cause non-fatal serious adverse events reported in the previous meta-analysis on regular salmeterol alone is abolished by the additional use of regular inhaled corticosteroids. The absolute difference between groups in the risk of serious adverse events was small. There were no asthma-related deaths and few asthma-related serious adverse events. Clinical decisions and information for patients regarding regular use of salmeterol have to take into account the balance between known symptomatic benefits of salmeterol and the degree of uncertainty and concern associated with its potential harmful effects.

Regular treatment with formoterol and inhaled steroids for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta(2)-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe when used alone or in conjunction with inhaled corticosteroids.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular formoterol with inhaled corticosteroids versus the same dose of inhaled corticosteroids alone.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was October 2008.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular formoterol and inhaled corticosteroids, and were of at least 12 weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data were independently extracted by two authors. Unpublished data on mortality and serious adverse events were obtained from the sponsors.

MAIN RESULTS

The review included 14 studies on adults and adolescents (8,028 participants) and seven studies on children and adolescents (2,788 participants). Data on all cause fatal and non-fatal serious adverse events were found for all studies, and the overall risk of bias was low.Four deaths occurred on regular formoterol with inhaled corticosteroids, and none on regular inhaled corticosteroids alone. All the deaths were in adults, and one was reported to be asthma-related. The difference was not statistically significant.Non-fatal serious adverse events of any cause were very similar in adults [Peto Odds Ratio 0.99 (95% CI 0.74 to 1.33)], and an increase in events in children on regular formoterol was not statistically significant [Peto Odds Ratio 1.62 (95% CI 0.80 to 3.28)].Asthma related serious adverse events on formoterol were lower in adults [Peto Odds Ratio 0.53 (95% CI 0.28 to 1.00)] and although they were higher in children [Peto Odds Ratio 1.49 (95% CI 0.48 to 4.61)], this was not statistically significant.

AUTHORS' CONCLUSIONS

It is not possible, from the data in this review, to reassure people with asthma that inhaled corticosteroids with regular formoterol carries no risk of increasing mortality in comparison to inhaled corticosteroids alone as all four deaths occurred among 6,594 people using inhaled corticosteroids with formoterol. On the other hand, we have found no conclusive evidence of harm and there was only one asthma related death registered during over 3,000 patient year observation on formoterol. In adults, the decrease in asthma-related serious adverse events on regular formoterol with inhaled corticosteroids was not accompanied by a decrease in all cause serious adverse events. In children the number of events was too small, and consequently the results too imprecise, to determine whether the increase in all cause non-fatal serious adverse events found in the previous meta-analysis on regular formoterol alone is abolished by the additional use of inhaled corticosteroids. Clinical decisions and information for patients regarding regular use of formoterol have to take into account the balance between known symptomatic benefits of formoterol and the degree of uncertainty and concern associated with its potential harmful effects.

Rates of asthma attacks in patients with previously inadequately controlled mild asthma treated in clinical practice with combination drug therapy: an exploratory post-hoc analysis

Background

Differences could exist in the likelihood of asthma attacks in patients treated with inhaled corticosteroid (ICS), long-acting beta-agonist (LABA), and montelukast (MON) (ICS/LABA/MON) and patients treated with an inhaled corticosteroid (ICS) and montelukast (MON) (ICS/MON).

Methods

This was a post-hoc analysis of a pretest-posttest retrospective cohort study. Patients with mild persistent asthma and allergic rhinitis, who were taking an ICS either alone or in combination with a LABA, started concomitant MON treatment as part of their routine care. Rates of asthma- and allergic rhinitis-related medical resource use in the 12-months after the initial (index) MON prescription were compared in the ICS/MON and ICS/LABA/MON groups. An asthma attack was defined as an asthma-related hospitalization, ER visit, or use of an oral corticosteroid.

Results

Of the total of 344 patients, 181 (53%) received ICS/MON and 163 (47%) received ICS/LABA/MON in the post-index period for means of 10.5 and 11.4 months, respectively, (P < 0.05). Short-acting beta-agonists were used by 74.6% in the ICS/MON and 71.8% in the ICS/LABA/MON groups (P > 0.05). An asthma attack occurred in 4.4% of the ICS/MON group and 6.8% of the ICS/LABA/MON group (P > 0.05). The adjusted odds of an asthma attack in the post-index period in the ICS/LABA/MON group relative to the ICS/MON group was 1.24, 95% confidence interval 0.35–4.44.

Conclusion

In this observational study of combination drug treatment of mild persistent asthma and allergic rhinitis, no difference was observed between LABA/ICS/MON combination therapy and the ICS/MON combination without LABA use, for the rate of asthma attacks over one year.

Regular treatment with formoterol for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular formoterol versus placebo or regular short-acting beta(2)-agonists.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and Food and Drug Administration (FDA) submissions in relation to formoterol were also checked. The date of the most recent search was July 2008.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular formoterol and were of at least 12 weeks duration. Concomitant use of inhaled corticosteroids was allowed, as long as this was not part of the randomised treatment regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data were extracted by one author and checked by the second author. Unpublished data on mortality and serious adverse events were sought.

MAIN RESULTS

The review includes 22 studies (8,032 participants) comparing regular formoterol to placebo and salbutamol. Non-fatal serious adverse event data could be obtained for all participants from published studies comparing formoterol and placebo but only 80% of those comparing formoterol with salbutamol or terbutaline.Three deaths occurred on regular formoterol and none on placebo; this difference was not statistically significant. It was not possible to assess disease specific mortality in view of the small number of deaths. Non-fatal serious adverse events were significantly increased when regular formoterol was compared with placebo (Odds Ratio 1.57 [95% CI: 1.05 to 2.37]). One extra serious adverse event occurred over 16 weeks for every 179 people treated with regular formoterol [95% CI: 75 to 2022]. The increase was larger in children than in adults, but the impact of age was not statistically significant. Data submitted to the FDA indicates that the increase in asthma-related serious adverse events remained significant in patients taking regular formoterol who were also on inhaled corticosteroids.No significant increase in fatal or non-fatal serious adverse events was found when regular formoterol was compared with regular salbutamol or terbutaline.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular formoterol, and this does not appear to be abolished in patients taking inhaled corticosteroids. The effect on serious adverse events of regular formoterol in children was greater than the effect in adults, but the difference between age-groups was not significant.Data on all-cause serious adverse events should be more fully reported in journal articles, and not combined with all adverse events or limited to those events that are thought by the investigator to be drug-related.

Regular treatment with salmeterol for chronic asthma: serious adverse events

BACKGROUND

Epidemiological evidence has suggested a link between beta-agonists and increases in asthma mortality. There has been much debate about possible causal links for this association, and whether regular (daily) long-acting beta(2)-agonists are safe.

OBJECTIVES

The aim of this review is to assess the risk of fatal and non-fatal serious adverse events in trials that randomised patients with chronic asthma to regular salmeterol versus placebo or regular short-acting beta(2)-agonists.

SEARCH STRATEGY

Trials were identified using the Cochrane Airways Group Specialised Register of trials. Web sites of clinical trial registers were checked for unpublished trial data and FDA submissions in relation to salmeterol were also checked. The date of the most recent search was October 2007.

SELECTION CRITERIA

Controlled parallel design clinical trials on patients of any age and severity of asthma were included if they randomised patients to treatment with regular salmeterol and were of at least 12 weeks duration. Concomitant use of inhaled corticosteroids was allowed, as long as this was not part of the randomised treatment regimen.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion in the review. Outcome data was extracted by one author and checked by the second author. Unpublished data on mortality and serious adverse events was sought.

MAIN RESULTS

The review includes 26 trials comparing salmeterol to placebo and 8 trials comparing with salbutamol. These included 62,630 participants with asthma (including 2,380 children). In 6 trials (2,766 patients), no serious adverse event data could be obtained. All cause mortality was higher with regular salmeterol than placebo but the increase was not significant, Odds Ratio 1.33 [95% CI: 0.85, 2.10]. Non-fatal serious adverse events were significantly increased when regular salmeterol was compared with placebo, Odds Ratio 1.14 [95% CI: 1.01, 1.28]. One extra serious adverse event occurred over 28 weeks for every 188 people treated with regular salmeterol [95% CI: 95 to 2606]. There is insufficient evidence to assess whether the risk in children is higher or lower than in adults. No significant increase in fatal or non-fatal serious adverse events was found when regular salmeterol was compared with regular salbutamol. Individual patient data from the SNS study have been combined with the results of the SMART study; in patients who were not taking inhaled corticosteroids, compared to regular salbutamol or placebo, there was a significant increase in risk of asthma-related death with regular salmeterol, Odds Ratio 9.52 [95% CI: 1.24, 73.09]. The confidence interval for patients taking inhaled corticosteroids is too wide to rule out an increase in asthma mortality in this group.

AUTHORS' CONCLUSIONS

In comparison with placebo, we have found an increased risk of serious adverse events with regular salmeterol. There is also a clear increase in risk of asthma-related mortality in patients not using inhaled corticosteroids in the two large surveillance studies. Although the increase in asthma-related mortality was smaller in patients taking inhaled corticosteroids at baseline, the confidence interval is wide, so it cannot be concluded that the inhaled corticosteroids abolish the risks of regular salmeterol. The adverse effects of regular salmeterol in children remain uncertain due to the small number of children studied.

Population pharmacodynamic model of bronchodilator response to inhaled albuterol in children and adults with asthma

BACKGROUND

Because interpatient variability in bronchodilation from inhaled albuterol is large and clinically important, we characterized the albuterol dose/response relationship by pharmacodynamic modeling and quantified variability.

METHODS

Eighty-one patients with asthma (24% African American [AA]; 8 to 65 years old; baseline FEV1, 40 to 80% of predicted) received 180 microg of albuterol from a metered-dose inhaler (MDI), and then 90 microg every 15 min until maximum improvement or 540 microg was administered; all then received 2.5 mg of nebulized albuterol. FEV1 was measured 15 min after each dose. The population cumulative dose/response data were fitted with a sigmoid maximum effect of albuterol (Emax) [maximum percentage of predicted FEV1 effect] model by nonlinear mixed-effects modeling. The influence of covariates on maximum percentage of predicted FEV1 reached after albuterol administration (Rmax) and cumulative dose of albuterol required to bring about 50% of maximum effect of albuterol (ED50) and differences between AA and white patients were explored.

RESULTS

ED50 was 141 microg, and Emax was 24.0%. Coefficients of variation for ED50 and Emax were 40% and 56%, respectively. Ethnicity was a statistically significant covariate (p < 0.05). AA and white patients reached 82.4% and 91.9% of predicted FEV1, respectively (p = 0.0004); and absolute improvement in percentage of predicted FEV1 was 16.6% in AA patients vs 26.7% in white patients (p < 0.0003). There were no baseline characteristic differences between AA and white patients. Nebulized albuterol increased FEV1 > or = 200 mL in 21% of participants. Heart rate and BP were unchanged from baseline after maximal albuterol doses.

CONCLUSIONS

Our model predicts that 180 microg of albuterol by MDI produces a 14.4% increase in percentage of predicted FEV1 over baseline (11.7% in AA patients, and 17.5% in white patients). Emax varies widely between asthmatic patients. AA patients are less responsive to maximal doses of inhaled albuterol than white patients.

Airway injury as a mechanism for exercise-induced bronchoconstriction in elite athletes

Exercise-induced bronchoconstriction (EIB) is a consequence of evaporative water loss in conditioning the inspired air. The water loss causes cooling and dehydration of the airway surface. One acute effect of dehydration is the release of mediators, such as prostaglandins, leukotrienes, and histamine, that can stimulate smooth muscle, causing contraction and a change in vascular permeability. Inspiring cold air increases dehydration of the surface area and causes changes in bronchial blood flow. This article proposes that the pathogenesis of EIB in elite athletes relates to the epithelial injury arising from breathing poorly conditioned air at high flows for long periods of time or high volumes of irritant particles or gases. The evidence to support this proposal comes from many markers of injury. The restorative process after injury involves plasma exudation and movement of cells into the airways, a process repeated many times during a season of training. This process has the potential to expose smooth muscle to a wide variety of plasma- and cell-derived substances. The exposure to these substances over time can lead to an alteration in the contractile properties of the smooth muscle, making it more sensitive to mediators of bronchoconstriction. It is proposed that cold-weather athletes have airway hyperresponsiveness (AHR) to pharmacologic agents as a result of epithelial injury. In those who are allergic, AHR can also be expressed as EIB. The role of beta(2)-receptor agonists in inhibiting and enhancing the development of AHR and EIB is discussed.

Rationale for the major changes in the pharmacotherapy section of the National Asthma Education and Prevention Program guidelines

Numerous changes have been incorporated into the new National Asthma Education and Prevention Program's Expert Panel Report 3. In the pharmacotherapy section of the report, many of these changes are minor in that they do not alter the basic philosophy of treatment recommendations from the previous Expert Panel Report but only add new formulations, change dosing or dosage forms, or add discussion of risks. However, 4 major changes have been identified, and the rationales for 3 are discussed in detail here. The treatment of childhood asthma is divided into 2 distinct age groups, infants less than 5 years of age and children 5 to 12 years of age, because of the availability of more data suggesting differences in response in these patients, as well as a relative paucity of quality data in the younger patients. Omalizumab, a humanized mAb to IgE, is the only new entity approved for the treatment of asthma since the previous guidelines, and its recommendations were reviewed. The indication for combination therapy with inhaled corticosteroids and long-acting inhaled beta(2)-agonists (LABAs) has been modified in lieu of the recent black box warning concerning the increased risk of severe asthma exacerbations and death associated with LABA use. However, the inhaled corticosteroids/LABAs are still recommended for patients with moderate-to-severe persistent asthma. The rationale for the continued recommendation is provided.

Efficacy and safety of formoterol for the treatment of chronic obstructive pulmonary disease

Formoterol is a selective long-acting beta2-adrenergic receptor agonist (LABA) that provides significant and sustained bronchodilatory effect for up to 12h following a single dose. The onset of effect is significantly faster with formoterol compared with an alternative LABA, salmeterol, although both have a similar duration of action. The overall efficacy of formoterol in improving lung function and controlling symptoms of chronic obstructive pulmonary disease (COPD) is comparable to that of salmeterol and potentially superior to that of ipratropium or theophylline. Formoterol provides additional benefit when administered in combination with other bronchodilators or inhaled corticosteroids. In clinical studies, formoterol was well tolerated and had an adverse-event profile similar to that of other beta2-adrenergic receptor agonists. Formoterol is a rapidly acting, well-tolerated, effective beta2-adrenergic receptor agonist that can be regularly used as a long-acting bronchodilator for patients with moderate to severe COPD, as per recommendations of the current treatment guidelines.

Effect of different antiasthmatic treatments on exercise-induced bronchoconstriction in children with asthma

BACKGROUND

Exercise-induced bronchoconstriction occurs in a large proportion of children with asthma, limiting everyday activities important for their physical and social development.

OBJECTIVE

The purpose of this randomized, double-blind, placebo-controlled study was to compare the ability of different patterns of antiasthmatic treatment, recommended in childhood asthma, to protect patients from exercise-induced bronchoconstriction.

METHODS

Children 6 to 18 years of age with atopic asthma were randomized to a 4-week, placebo-controlled, double-blind trial. Patients were randomly allocated to receive daily 200 microg budesonide (twice daily, 100 microg per dose) + 9 microg formoterol (twice daily, 4.5 microg per dose; n = 20); 200 microg budesonide + 5 or 10 mg montelukast (once daily at bedtime; n = 20); 5 or 10 mg montelukast (n = 20); 200 microg budesonide (n = 20); or placebo (n = 20). A standardized treadmill exercise challenge was performed before and after treatment.

RESULTS

Exercise-induced bronchoconstriction, reflected by area under the curve for the FEV1 values from exercise over the 20-minute period and by maximum percent fall in FEV1 after exercise, was significantly diminished after 4 weeks in all active treatment groups, and compared with placebo. Exercise-induced bronchoconstriction protection improved more significantly in the budesonide + montelukast and montelukast groups compared with other therapeutic options.

CONCLUSION

These data indicate differences in effects on exercise-induced bronchoconstriction between therapeutic options recommended in childhood asthma. Control of childhood asthma with exercise-induced bronchoconstriction can be obtained by using regular controller treatment.

Non-corticosteroid therapy for the long-term control of asthma

The non-corticosteroids approved for the maintenance therapy of persistent asthma include the long-acting inhaled beta(2) agonists (LABAs), leukotriene modifiers, chromones, theophylline and omalizumab. This review assesses the benefits and risks of each in relation to the inhaled corticosteroids and each other. Neither the LABAs nor omalizumab should be used as monotherapy for persistent asthma. There is no evidence of clinically significant differences in efficacy between the chromones, theophylline and leukotriene modifiers as monotherapy in mild-moderate persistent asthma; thus the choice of one therapy over the other is a clinical decision based upon differences in safety, acceptability to the patient and ease of use. Although there is significant variability in response to various therapies, non response to one therapy is not predictive of response to another. Neither studies of phenotypes nor genotypes have provided acceptable determinants of response as yet. As adjunctive therapy to the inhaled corticosteroids for moderate-severe persistent asthma, the LABAs provide superior improvement in lung function and reduction in exacerbations relative to higher doses of inhaled corticosteroids and the other noncorticosteroids used as adjunctive therapy. Thus, LABAs remain the adjunctive therapy of choice in patients not adequately controlled on low-medium dose inhaled corticosteroids. Omalizumab has not been compared with the other adjunctive therapies, so its relative efficacy is unknown. However, it is the only adjunctive therapy added to the combination of an inhaled corticosteroid plus LABA to demonstrate further improvement in a controlled clinical trial.

Safety and tolerability of indacaterol in asthma: a randomized, placebo-controlled 28-day study

The safety and tolerability of indacaterol, a novel once-daily beta(2)-agonist bronchodilator with a fast onset of action, were assessed in 156 asthma patients in a multicentre, randomized, double-blind, placebo-controlled study. Patients received indacaterol 200, 400 or 600 microg or placebo once daily for 28 days. Adverse events (AEs), laboratory assessments, vital signs, electrocardiograms, spirometry and physical examinations were monitored. Indacaterol pharmacokinetics were assessed. There was no evidence of dose-related increases in AE incidence or clinically significant hypokalaemia or hyperglycaemia in indacaterol-treated patients. Mean pulse rate changes were minor in any group, with maximum 1-h post-dose changes from baseline of -3.7, -3.3 and -2.2 bpm for indacaterol 200, 400 and 600 microg, respectively, and -2.9 bpm for placebo. Mean QTc interval was similar between groups; change from baseline >60 ms occurred in only two patients. Mean FEV(1) increased after the first indacaterol dose; baseline-adjusted pre-dose (trough) values remained >or=166 mL higher than placebo at all subsequent visits, supporting a 24-h bronchodilator effect. Pre-dose (but not post-dose) serum indacaterol concentrations indicated a slight trend for accumulation. Once-daily indacaterol 200-600 microg has a favourable therapeutic index. It is well tolerated, and is not associated with any adverse cardiac or metabolic effects, while providing effective 24-h bronchodilation.

Heterogeneity of transcription factor expression and regulation in human airway epithelial and smooth muscle cells

Transcription factors represent a major mechanism by which cells establish basal and conditional expression of proteins, the latter potentially being adaptive or maladaptive in disease. The complement of transcription factors in two major structural cells of the lung relevant to asthma, airway epithelial and smooth muscle cells, is not known. A plate-based platform using nuclear extracts from these cells was used to assess potential expression by binding to oligonucleotide consensus sequences representing >300 transcription factors. Four conditions were studied: basal, beta-agonist exposure, culture under proasthmatic conditions (IL-13, IL-4, TGF-beta, and leukotriene D(4)), and the dual setting of beta-agonist with proasthmatic culture. Airway epithelial cells expressed 70 transcription factors, whereas airway smooth muscle expressed 110. High levels of multiple transcription factors not previously recognized as being expressed in these cells were identified. Moreover, expression/ binding patterns under these conditions revealed extreme discordance in the direction and magnitude of change between the cell types. Singular (one cell type displayed regulation) and antithetic (both cell types underwent expression changes but in opposite directions) regulation dominated these patterns, with concomitant regulation in both cell types being rare (<10%). beta-Agonist evoked up- and downregulation of transcription factors, which was highly influenced by the proasthmatic condition, with little overlap of factors regulated by beta-agonists under both conditions. Together, these results reveal complex, cell type-dependent networks of transcription factors in human airway epithelium and smooth muscle that are dynamically regulated in unique ways by beta-agonists and inflammation. These factors may represent additional components in asthma pathophysiology or potential new drug targets.

Getting to the heart of asthma: can "beta blockers" be useful to treat asthma?

beta(2)-adrenoceptor agonists are the mainstay for the acute symptomatic treatment of asthma and provide effective bronchoprotection to a wide range of bronchoconstrictor agents. However, over the past 4 decades there has been a continuing debate concerning whether regular chronic treatment with these drugs may be doing more harm than good. The FDA's recent decision to add black box warnings concerning the regular use of salmeterol- and formoterol-containing compounds, as well as their decision not to recommend agents containing long-acting beta(2)-adrenoceptor agonists as first-line therapy, seems to confirm the concerns regarding the regular use of the long-acting beta(2)-adrenoceptor agonists. A similar debate arose in the late 1980s concerning the use of beta-adrenoceptor agonists in the treatment of heart failure. In this disease, short-term use of beta agonists is associated with increased cardiac index and stroke volume, yet their long-term use is associated with increased morbidity and mortality. Moreover, certain beta blockers that are initially detrimental when used short term are now considered beneficial in the treatment of this disease when used chronically. Here, there is a parallel, as beta blockers are contraindicated in patients with asthma but the use of beta blockers chronically has never been evaluated. This begs the question of whether a similar paradigm shift is applicable in the treatment of asthma and whether under certain circumstances the long-term use of certain beta blockers may be useful in the treatment of this disease.

Overcoming beta-agonist tolerance: high dose salbutamol and ipratropium bromide. Two randomised controlled trials

BACKGROUND

Asthmatics treated with long-acting beta-agonists have a reduced bronchodilator response to moderate doses of inhaled short acting beta-agonists during acute bronchoconstriction. It is not known if the response to higher doses of nebulised beta-agonists or other bronchodilators is impaired. We assessed the effect of long-acting beta-agonist treatment on the response to 5 mg nebulised salbutamol and to ipratropium bromide.

METHODS

Two double-blind, placebo-controlled, crossover studies of inhaled formoterol 12 mug twice daily in patients with asthma.High-dose salbutamol: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled methacholine to produce a 20% fall in FEV1. Salbutamol 5 mg was then administered via nebuliser and the FEV1 was monitored for 20 minutes. Ipratropium: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled 4.5% saline to produce a 20% fall in FEV1. Salbutamol 200 mug or ipratropium bromide 40 mug was then inhaled and the FEV1 was monitored for 30 minutes. Four study arms compared the response to each bronchodilator after formoterol and placebo. Analyses compared the area under the bronchodilator response curves, adjusting for changes in pre-challenge FEV1, dose of provocational agent and FEV1 fall during the challenge procedure.

RESULTS

The response to nebulised salbutamol was 15% lower after formoterol therapy compared to placebo (95% confidence 5 to 25%, p = 0.008). The response to ipratropium was unchanged.

CONCLUSION

Long-acting beta-agonist treatment induces tolerance to the bronchodilator effect of beta-agonists, which is not overcome by higher dose nebulised salbutamol. However, the bronchodilator response to ipratropium bromide is unaffected.

Regulation of mast cells by beta-agonists

The human lung mast cell is known to be a critical effector cell in the mediation of asthma. Activation of the mast cell by allergens and other stimuli leads to the release and generation of a wide variety of autacoids that cause bronchoconstriction, promote inflammation, and may influence airway remodeling. Therefore, the stabilization of mast cells has obvious value in the prevention of asthma. Among the drugs used to treat asthma, only beta-agonists are effective stabilizers of mast cells. Both short- and long-acting beta-agonists are effective against mast cells, but there are differences between agonists regarding the extent of inhibitory activity attained. Consequently, the type of beta-agonist prescribed influences the degree of mast cell stabilization possible. Despite the potential value of attenuating mast cell activity with beta-agonists, this benefit may diminish with time because of the development of tolerance. Both short- and long-acting beta-agonists can induce tolerance to mast cell stabilization, and generally, higher efficacy agonists tend to induce greater levels of tolerance; however, weaker agonists induce greater levels of tolerance than might be expected. Tolerance to the mast-cell-stabilizing effects of beta- agonists may be an issue clinically, because this occurs more readily than tolerance to smooth muscle relaxation. This could lead to a situation in which beta-agonists fail to prevent the release of mediators from mast cells but can still effectively relax airway smooth muscle. The continued ability to bronchodilate could mask the unfavorable consequences of unchecked mediator release from mast cells.

Concluding remarks: can we explain the association of beta-agonists with asthma mortality? A hypothesis

Beta-agonists have clearly demonstrated benefits for the treatment of both acute and chronic asthma. Therefore, it is perhaps surprising that many of the articles in this issue have focused on concerns about their safety. Much of this concern can be traced back to the "beta-agonist controversy"--the association of high-dose isoprenaline and fenoterol inhalers with asthma mortality in the 1960s and 1970s. Although a causal link was never proven, lingering doubts about the safety of beta-agonists remain. It is unclear whether a similar adverse effect is responsible for recently reported association of long-acting beta-agonists with asthma deaths. No mechanism for the beta-agonist controversy was established, but the evidence presented in this collection of articles points to a number of contributing factors. I suggest that a combination of these effects provides a plausible mechanism for the association of frequent beta-agonist use with asthma mortality. Rebound bronchoconstriction and bronchial hyperresponsiveness occur on withdrawal of regular beta-agonist treatment. Regular use of fenoterol is associated with a reduction in morning peak flow suggesting that the overnight interval between doses is sufficient to allow rebound bronchoconstriction. This has not been observed with terbutaline or salbutamol, although rebound phenomena do occur when these drugs are withdrawn for slightly longer periods. Regular use of beta-agonists also leads to tolerance to their bronchoprotective and bronchodilator effects. Tolerance becomes more apparent with worsening bronchoconstriction. In severe asthma, this could result in a poor response to emergency treatment. The combination of rebound deterioration of asthma and a poor response to beta-agonist treatment resulting from tolerance could explain the increased mortality associated with fenoterol and isoprenaline. Both effects are probably caused by downregulation of beta-receptors which occurs with all beta-agonists. Long-acing beta-agonists cause a similar degree of tolerance to short-acting beta-agonists, but avoid the problem of overnight withdrawal. Long-acting beta-agonists have also been shown to improve asthma control when taken in combination with inhaled corticosteroids. The clinical significance of tolerance in this context remains to be determined.

Recovery from bronchoconstriction and bronchodilator tolerance

Until recently, researchers believed that tolerance or tachyphylaxis to the bronchodilator effects of beta-agonists did not occur. However, recent studies examining the recovery from bronchoconstriction have clearly shown that an impaired response to beta-agonists occurs in patients who have been using regular beta-agonist treatment. This tolerance develops with both long- and short-acting beta-agonists and is not affected by treatment with inhaled steroids. It develops rapidly, reaching a maximum within 1 wk of starting beta-agonists, and has been demonstrated after methacholine, hypertonic saline, mannitol, and exercise-induced bronchoconstriction. The observed reduction in the bronchodilator response is proportional to the severity of bronchoconstriction. Therefore, although individuals with stable asthma show little evidence of tolerance, those with severe bronchospasm have a markedly reduced bronchodilator response to beta-agonists. Almost all asthmatics show evidence of tolerance when tested in the setting of bronchoconstriction, although the extent of this tolerance varies. The reasons for this interindividual variation are not understood. Bronchodilator tolerance is difficult to study in the clinical setting because nearly every patient has used multiple doses of beta-agonist before seeking medical attention. However, there is compelling evidence that the response to rescue beta-agonist treatment is reduced in those who use regular long- or short-acting beta-agonists. The extent to which this phenomenon contributes to asthma morbidity and mortality remains to be determined.

Summing up 100 years of asthma

In this review, we aim to lead the readers through the historical highlights of pathophysiological concepts and treatment of asthma. Understanding the nature and links of asthma has modeled our diagnostic, pathophysiological and therapeutic thinking and acting. The recognition of its heterogeneous nature in combination with several refined and sophisticated technologies will mark a new era of phenotype-specific approach and treatment of asthma.

Long-acting beta2-agonists for chronic asthma in adults and children where background therapy contains varied or no inhaled corticosteroid

BACKGROUND

Asthma is a common respiratory disease among both adults and children and short acting inhaled beta-2 agonists are used widely for 'reliever' bronchodilator therapy. Long acting beta-2 agonists (LABA) were introduced as prospective 'symptom controllers' in addition to inhaled corticosteroid 'preventer' therapy (ICS). In this updated review we have included studies in which patients were either not on ICS as a group, or in which some patients, but not all, were on ICS to complement previous systematic reviews of studies where LABA was given in patients uniformly receiving ICS. We have focussed particularly on serious adverse events, given previous concerns about potential risks, especially of death, from regular beta-2 agonist use.

OBJECTIVES

This review aimed to determine the benefit or detriment on the primary outcome of asthma control with the regular use of LABA compared with placebo, in mixed populations in which only some were taking ICS and in populations not using ICS therapy.

SEARCH STRATEGY

We carried out searches using the Cochrane Airways Group trial register, most recently in October 2005. We searched bibliographies of identified RCTs for additional relevant RCTs and contacted authors of identified RCTs for other published and unpublished studies.

SELECTION CRITERIA

All randomised studies of at least four weeks duration, comparing a LABA given twice daily with a placebo, in chronic asthma. Selection criteria to this updated review have been altered to accommodate recently published Cochrane reviews on combination and addition of LABA to ICS therapy. Studies in which all individuals were uniformly taking ICS were excluded from this review.

DATA COLLECTION AND ANALYSIS

Two reviewers performed data extraction and study quality assessment independently. We contacted authors of studies for missing data.

MAIN RESULTS

Sixty-seven studies (representing 68 experimental comparisons) randomising 42,333 participants met the inclusion criteria. Salmeterol was used as long-acting agent in 50 studies and formoterol fumarate in 17. The treatment period was four to nine weeks in 29 studies, and 12 to 52 weeks in 38 studies. Twenty-four studies did not permit the use of ICS, and forty permitted either inhaled corticosteroid or cromones (in three studies this was unclear). In these studies between 22% and 92% were taking ICS, with a median of 62%. There were significant advantages to LABA treatment compared to placebo for a variety of measurements of airway calibre including morning peak expiratory flow (PEF), evening PEF and FEV1. They were associated with significantly fewer symptoms, less use of rescue medication and higher quality of life scores. This was true whether patients were taking LABA in combination with ICS or not. Findings from SMART (a recently published surveillance study) indicated significant increases in asthma related deaths, respiratory related deaths and combined asthma related deaths and life threatening experiences. The absolute increase in asthma-related mortality was consistent with an increase of around one per 1250 patients treated with LABA for six months, but the confidence intervals are wide (from 700 to 10,000). Post-hoc exploratory subgroups suggested that African-Americans and those not on inhaled corticosteroids were at particular risk for the primary end-point of death or life-threatening asthma event. There was also a suggestion of an increase in exacerbation rate in children. Pharmacologically predicted side effects such as headache, throat irritation, tremor and nervousness were more frequent with LABA treatment.

AUTHORS' CONCLUSIONS

LABA are effective in the control of chronic asthma in the "real-life" subject groups included. However there are potential safety issues which call into question the safety of LABA, particularly in those asthmatics who are not taking ICS, and it is not clear why African-Americans were found to have significant differences in comparison to Caucasians for combined respiratory-related death and life threatening experiences, but not for asthma-related death.

Risk versus benefit considerations for the beta(2)-agonists

Short-acting beta(2)-agonists are the mainstay of therapy for acute bronchospasm associated with asthma and chronic obstructive pulmonary disease, whereas long-acting beta(2)-agonists are used in maintaining disease control in these respiratory disorders. This review describes and compares the pharmacology of the beta(2)-agonists and explains how these differences translate into differences in efficacy and beta(2)-adrenergic-mediated adverse effects. Questions commonly asked by clinicians regarding the efficacy and safety of short- and long-acting beta(2)-agonists include issues about cardiovascular effects, tolerance to their bronchodilator and bronchoprotective effects, blunting of albuterol response by long-acting beta(2)-agonists, potential masking of worsening asthma control, and the role of long-acting beta(2)-agonists as adjunctive therapy with inhaled corticosteroids in maintaining asthma control. Pharmacogenetics may play a role in determining which patients may be at risk for a reduced response to a beta(2)-agonist. The continued use of racemic albuterol, which contains a mixture of R-albuterol and S-albuterol, has been questioned because of data from preclinical and clinical studies suggesting that S-albuterol causes proinflammatory effects and may increase bronchial hyperreactivity. The preclinical and clinical effects of these two stereoisomers are reviewed. Data describing the efficacy and safety of levalbuterol (R-albuterol) and racemic albuterol are presented.

Long-acting beta2-agonists in asthma: not so SMART?

Asthma is a worldwide chronic disorder that is characterised by airway inflammation and hyper-responsiveness, which results in intermittent airflow obstruction and subsequent perception of symptoms and exacerbations. Inhaled corticosteroids are a fundamental component in the prevention of the short- and long-term complications associated with inadequately controlled asthma. However, many individuals experience persistent symptoms and exacerbations despite receiving low-to-medium doses of an inhaled corticosteroid (400-800 microg/day of beclometasone or equivalent). In these symptomatic asthmatic patients, guidelines advocate the initiation of a long-acting beta2-adrenoceptor agonist (LABA) as additional second-line controller therapy. The recent SMART (Salmeterol Multi-centre Asthma Research Trial) study was designed to compare the effects of add-on salmeterol 42 microg (ex-actuator) twice daily with placebo over 28 weeks in a randomised, double-blind, parallel-group fashion, with the intention to enrol 60,000 asthmatic patients. However, the study was halted prematurely because preliminary data revealed an increased mortality associated with regular use of salmeterol. Moreover, concerning rates of respiratory-related deaths, asthma-related deaths and life-threatening events were observed among African Americans, who constituted up to 18% of the study population. This in turn prompted the US FDA to announce important safety information regarding inhalers containing LABAs and advise that new labelling be produced outlining the "small but significant risk in asthma-related deaths" associated with their regular use. This evidence-based review discusses the data from SMART and highlights potentially important drawbacks with regular use of LABAs in persistent asthma.

The role of intrinsic efficacy in determining response to a beta2-agonist in acute severe asthma

BACKGROUND

Current guidelines recommend repeated doses of albuterol for the emergency treatment of acute asthma. However, approximately one-third of patients show little or no initial response to this partial beta(2)-agonist.

METHODS

We conducted a randomized, double-blind, proof-of-concept study to investigate whether a full beta(2)-agonist, isoproterenol, offers a therapeutic advantage in adults presenting with acute severe asthma (FEV(1)<50%) who fail to respond to an initial treatment of the partial beta(2)-agonist, albuterol. Study subjects were randomized to receive a 2-h continuous nebulization of either albuterol (7.5mg/h) (n=10, mean FEV(1)=37% predicted) or isoproterenol (7.5mg/h) (n=9, mean FEV(1)=33% predicted). Respiratory symptoms, vital signs and pulmonary function measures were collected.

RESULTS

Subjects from both treatment groups had similar baseline characteristics. The percent improvements from baseline FEV(1) at 60 and 120min were significantly higher in subjects receiving isoproterenol than those receiving albuterol (44 vs. 17% and 63 vs. 24%, respectively, P<0.05). The change in symptoms measured by the modified Borg score was also significantly greater in subjects receiving isoproterenol (P<0.01). Both treatments were well tolerated, though the mean increase in pulse rate at 60 and 120min (21 vs. 1 and 23 vs. 6beats/min, respectively, P<0.05) and the mean change in serum potassium at 120min (-0.52 vs. -0.07meq/L, P<0.05) from baseline were significantly greater in the isoproterenol group.

CONCLUSIONS

Our data suggest that in subjects presenting with acute severe asthma who fail to show an initial response to albuterol, the use of a beta(2)-agonist of higher intrinsic efficacy can be more effective in improving lung function and symptoms.