Tiotropium bromide in asthma patients: an alternative to inhaled long-acting beta-agonists?

Long-acting muscarinic antagonists (LAMA) added to combination long-acting beta2-agonists and inhaled corticosteroids (LABA/ICS) versus LABA/ICS for adults with asthma

BACKGROUND

Maintenance treatment with long-acting beta2-agonists and inhaled corticosteroids (LABA/ICS) can relieve asthma symptoms and reduce the frequency of exacerbations, but there are limited treatment options for people who do not gain control on combination LABA/ICS. Long-acting muscarinic antagonists (LAMA) are a class of inhaled drug which have been effective for people with chronic obstructive pulmonary disease and are now becoming available for people with asthma to take alongside their LABA/ICS inhaler.

OBJECTIVES

To assess the effects of adding a long-acting muscarinic antagonist (LAMA) to combination long-acting beta2-agonists (LABA) and inhaled corticosteroids (ICS) in adults whose asthma is not well controlled by LABA/ICS.

SEARCH METHODS

We identified trials from the Cochrane Airways Review Group Specialised Register (CAGR) up to January 2016. We also searched ClinicalTrials.gov, the WHO trials portal, and reference lists of other reviews, and we contacted trial authors for additional information.

SELECTION CRITERIA

We included parallel randomised controlled trials (RCTs) of at least 12 weeks' duration. Studies met the inclusion criteria if they compared LAMA as an add-on to LABA/ICS versus LABA/ICS alone for adults with asthma. We included studies reported as full text, those published as abstract only, and unpublished data. Primary outcomes were exacerbations requiring oral corticosteroids (OCS), validated measures of asthma control, and serious adverse events (including mortality).

DATA COLLECTION AND ANALYSIS

Two review authors screened searches and independently extracted details on risk of bias and numerical data. We analysed dichotomous data as odds ratios (ORs) and continuous data as mean differences (MD) using a random-effects model. We rated all outcomes using GRADE.

MAIN RESULTS

We found four double-blind, double-dummy trials comparing LAMA to placebo, including 1197 people with asthma taking combination LABA/ICS. One of the trials was designed to study glycopyrronium bromide but was withdrawn prior to enrolment, and the other three all studied tiotropium bromide (mostly 5 µg once daily via Respimat) over 48 to 52 weeks. People in the trials had a mean forced expiratory volume in one second (FEV1) of 55% of their predicted value, indicating severe asthma.People randomised to take tiotropium add-on had fewer exacerbations requiring oral corticosteroids than those continuing to take LABA/ICS alone, but the confidence intervals did not rule out no difference (OR 0.76, 95% CI 0.57 to 1.02; moderate quality evidence). Over 48 weeks, 328 out of 1000 people taking their usual LABA/ICS would have to take oral corticosteroids for an exacerbation compared with 271 if they took tiotropium as well (95% CI 218 to 333 per 1000). Analyses comparing the number of exacerbations per patient in each group (rate ratio) and the time until first exacerbation (hazard ratio) were in keeping with the main result. Quality of life, as measured by the Asthma Quality of Life Questionnaire (AQLQ) was no better for those taking tiotropium add-on than for those taking LABA/ICS alone when considered in light of the 0.5 minimal clinically important difference on the scale (MD 0.09, 95% CI - 0.03 to 0.20), and evidence for whether tiotropium increased or decreased serious adverse events in this population was inconsistent (OR 0.60, 95% CI 0.24 to 1.47; I(2) = 76%).Within the secondary outcomes, exacerbations requiring hospital admission were too rare to tell whether tiotropium was beneficial over LABA/ICS alone. There was high quality evidence showing benefits to lung function (trough FEV1 and forced vital capacity (FVC)) and potentially small benefits to asthma control. People taking tiotropium add-on were less likely to experience non-serious adverse events.

AUTHORS' CONCLUSIONS

Tiotropium add-on may have additional benefits over LABA/ICS alone in reducing the need for rescue oral steroids in people with severe asthma. The effect was imprecise, and there was no evidence for other LAMA preparations. Possible benefits on quality of life were negligible, and evidence for the effect on serious adverse events was inconsistent. There are likely to be small added benefits for tiotropium Respimat 5 µg daily on lung function and asthma control over LABA/ICS alone and fewer non-serious adverse events. The benefit of tiotropium add-on on the frequency of hospital admission is still unknown, despite year-long trials.Ongoing and future trials should clearly describe participants' background medications to help clinicians judge how the findings relate to stepwise care. If studies test LAMAs other than tiotropium Respimat for asthma, they should be at least six months long and use accepted and validated outcomes to allow comparisons of the safety and effectiveness between different preparations.

Long-acting muscarinic antagonists (LAMA) added to inhaled corticosteroids (ICS) versus higher dose ICS for adults with asthma

BACKGROUND

Long-acting muscarinic antagonists (LAMA), a class of drugs with proven effectiveness in chronic obstructive pulmonary disease (COPD), are being considered as an add-on option for adults with asthma whose condition is uncontrolled on inhaled corticosteroids (ICS). It is important to assess the safety and efficacy of LAMA add-on as an alternative to the prolonged use of higher doses of ICS, which are known to cause undesirable side effects in some people.

OBJECTIVES

To compare the effects of adding a LAMA to any dose of ICS versus increasing the dose of ICS, for uncontrolled asthma in adults.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register (CAGR) from its inception in 1995 to April 2015, imposing no restriction on language of publication. We also handsearched trial registries, reference lists of primary studies and existing reviews, as well as manufacturers' websites.

SELECTION CRITERIA

We looked for parallel or cross-over randomised controlled trials lasting at least 12 weeks, in which adults whose asthma was not well controlled on ICS alone were randomised to treatment with LAMA add-on to ICS or with an increased dose of ICS. Trials were excluded if patients were taking long-acting beta2-agonists during the study period.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the searches and extracted data from studies meeting all the inclusion criteria. We used Covidence to manage duplicate screening, data extraction and risk of bias judgements, and to form a consensus where discrepancies arose. We used standard methods expected by The Cochrane Collaboration.The pre-specified primary outcomes were exacerbations requiring a course of oral corticosteroids (OCS), effects on quality of life and serious adverse events.

MAIN RESULTS

One cross-over randomised controlled trial met the inclusion criteria. The trial was performed in 210 patients with moderate to severe asthma and compared the use of the LAMA tiotropium bromide with double dose beclomethasone (an ICS) using a cross-over design and 14-week treatment periods.Compared with people taking a double dose of ICS, fewer people taking a LAMA add-on had an exacerbation requiring treatment with OCS (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.22 to 1.43) or an exacerbation resulting in emergency department admission (OR 0.49, 95% CI 0.09 to 2.77), but the confidence intervals for both outcomes did not exclude the possibility that double dose ICS was more effective. Serious adverse events and exacerbations requiring hospitalisation occurred in similarly low numbers of people taking each treatment, but confidence intervals were too wide to suggest that the two treatment options were equivalent.Asthma-related quality of life was similar in both treatment groups (mean difference (MD) in change from baseline 0.10, 95% CI - 0.07 to 0.27). Those taking LAMA add-on scored slightly better on a scale measuring asthma control than those increasing their ICS dose (MD in change from baseline - 0.18, 95% CI - 0.34 to - 0.02), although the difference was clinically small. Evidence was deemed low quality for both quality of life and asthma control.There was moderate-quality evidence that participants' trough forced expiratory volume in one second (FEV1) was 100 mL better when taking LAMA add-on than with increased ICS dose (MD in change from baseline 0.10, 95% CI 0.03 to 0.17).

AUTHORS' CONCLUSIONS

Only one randomised trial was found, comparing tiotropium add-on to increased dose beclomethasone. Differences between the treatments were too small or imprecise to understand whether adding a LAMA to ICS is safer or more effective than increasing the dose of ICS, and there is a possibility of carry-over effects due to the study's cross-over design. LAMA add-on may lead to more improvement in lung function (FEV1) than an increased dose of ICS.The results of this review, alongside pending results from related reviews assessing the use of LAMA against other treatments, will help to define the role of these drugs in asthma management, and this review should be updated as results from future trials emerge. Studies assessing the role of LAMA add-on should be longer and include a double-ICS treatment arm so that the results can be interpreted in the context of the guideline-recommended treatment options that are available to physicians.

Long-acting muscarinic antagonists (LAMA) added to inhaled corticosteroids (ICS) versus addition of long-acting beta2-agonists (LABA) for adults with asthma

BACKGROUND

Poorly controlled asthma and preventable exacerbations place a significant strain on healthcare, often requiring additional medications, hospital stays or treatment in the emergency department.Long-acting beta2-agonists (LABA) are the preferred add-on treatment for adults with asthma whose symptoms are not well controlled on inhaled corticosteroids (ICS), but have important safety concerns in asthma. Long-acting muscarinic antagonists (LAMA) have confirmed efficacy in chronic obstructive pulmonary disease and are now being considered as an alternative add-on therapy for people with uncontrolled asthma.

OBJECTIVES

To assess the efficacy and safety of adding a LAMA to ICS compared with adding a LABA for adults whose asthma is not well controlled on ICS alone.

SEARCH METHODS

We searched the Cochrane Airways Group's Specialised Register (CAGR) from inception to April 2015, and imposed no restriction on language of publication. We searched additional resources to pick up unpublished studies, including ClinicalTrials.gov, World Health Organization trials portal, reference lists of primary studies and existing reviews, and manufacturers' trial registries. The most recent search was conducted in April 2015.

SELECTION CRITERIA

We searched for parallel and cross-over RCTs in which adults whose asthma was not well controlled with ICS alone were randomised to receive LAMA add-on or LABA add-on for at least 12 weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the electronic and additional searches and extracted data from study reports. We used Covidence for duplicate screening, extraction of study characteristics and numerical data, and risk of bias ratings.The pre-specified primary outcomes were exacerbations requiring oral corticosteroids (OCS), quality of life and serious adverse events.

MAIN RESULTS

We included eight studies meeting the inclusion criteria, but four double-blind, double-dummy studies of around 2000 people dominated the analyses. These four trials were between 14 and 24 weeks long, all comparing tiotropium (usually Respimat) with salmeterol on top of medium doses of ICS.Studies reporting exacerbations requiring OCS showed no difference between the two add-ons, but our confidence in the effect was low due to inconsistency between studies and because the confidence intervals (CI) included significant benefit of either treatment (odds ratio (OR) 1.05, 95% CI 0.50 to 2.18; 1753 participants; 3 studies); three more people per 1000 might have an exacerbation on LAMA, but the CIs ranged from 29 fewer to 61 more. Imprecision was also an issue for serious adverse events and exacerbations requiring hospital admission, rated low (serious adverse events) and very low quality (exacerbations requiring hospital admission), because there were so few events in the analyses.People taking LAMA scored slightly worse on two scales measuring quality of life (Asthma Quality of Life Questionnaire; AQLQ) and asthma control (Asthma Control Questionnaire; ACQ); the evidence was rated high quality but the effects were small and unlikely to be clinically significant (AQLQ: mean difference (MD) -0.12, 95% CI -0.18 to -0.05; 1745 participants; 1745; 4 studies; ACQ: MD 0.06, 95% CI 0.00 to 0.13; 1483 participants; 3 studies).There was some evidence to support small benefits of LAMA over LABA on lung function, including on our pre-specified preferred measure trough forced expiratory volume in one second (FEV1) (MD 0.05 L, 95% CI 0.01 to 0.09; 1745 participants, 4 studies). However, the effects on other measures varied, and it is not clear whether the magnitude of the differences were clinically significant.More people had adverse events on LAMA but the difference with LABA was not statistically significant.

AUTHORS' CONCLUSIONS

Direct evidence of LAMA versus LABA as add-on therapy is currently limited to studies of less than six months comparing tiotropium (Respimat) to salmeterol, and we do not know how they compare in terms of exacerbations and serious adverse events. There was moderate quality evidence that LAMAs show small benefits over LABA on some measures of lung function, and high quality evidence that LABAs are slightly better for quality of life, but the differences were all small. Given the much larger evidence base for LABA versus placebo for people whose asthma is not well controlled on ICS, the current evidence is not strong enough to say that LAMA can be substituted for LABA as add-on therapy.The results of this review, alongside pending results from related reviews assessing the use of LAMA in other clinical scenarios, will help to define the role of these drugs in asthma and it is important that they be updated as results from ongoing and planned trials emerge.