Indacaterol provides 24-hour bronchodilation in COPD: a placebo-controlled blinded comparison with tiotropium

Background

Indacaterol is a novel, inhaled, once-daily, ultra-long-acting β₂-agonist for the treatment of chronic obstructive pulmonary disease (COPD). This randomized, double-blind study compared the bronchodilator efficacy of indacaterol with that of placebo and tiotropium in patients with moderate-to-severe COPD.

Methods

In an incomplete-block, multi-dose, three-period, crossover design, patients received three of the following four treatments: indacaterol 150 μg, indacaterol 300 μg, tiotropium 18 μg and placebo, each once-daily for 14 days. Each treatment period was separated by a 14-day washout. Study drug was supplied daily by blinded, third party study personnel to maintain blinding of patients and investigators. The primary efficacy variable was trough forced expiratory volume in one second (FEV₁) at 24 h post-dose after 14 days. The study was powered to demonstrate non-inferiority of indacaterol to tiotropium for this variable.

Results

A total of 169 patients were randomized (mean age 65 years); 153 (90.5%) completed. Trough FEV₁ after 14 days with indacaterol 150 μg and 300 μg was statistically and clinically superior to placebo, with differences (95% CI) of 170 (120-220) and 150 (100-200) mL respectively (both p < 0.001). For this endpoint, both doses of indacaterol not only met the criterion for non-inferiority compared with tiotropium, but also achieved numerically higher values, with differences versus tiotropium of 40 and 30 mL for indacaterol 150 and 300 μg, respectively. At 5 min post-dose on Day 1, the mean FEV₁ for both indacaterol doses was significantly higher than placebo (by 120 and 130 mL for indacaterol 150 and 300 μg, respectively; p < 0.001) and tiotropium (by 80 mL for both doses; p < 0.001). Adverse events were reported by similar proportions of patients: 31.4%, 29.5%, 28.3% and 28.5% for indacaterol 150 μg and 300 μg, tiotropium and placebo treatments, respectively.

Conclusions

Once-daily indacaterol provided clinically and statistically significant 24-h bronchodilation. Indacaterol was at least as effective as tiotropium, with a faster onset of action (within 5 min) on the first day of dosing. Indacaterol should prove useful in patients with moderate-to-severe COPD, for whom treatment with one or more classes of long-acting bronchodilator is recommended.

Trial registration

ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT00615459","term_id":"NCT00615459"}}NCT00615459, EudraCT number: 2007-004071-19     

Efficacy of once-daily indacaterol 75 mug relative to alternative bronchodilators in COPD: A study level and a patient level network meta-analysis

ABSTRACT: BACKGROUND: The objective of this study was to evaluate the comparative efficacy of indacaterol 75 mug once daily (OD), tiotropium 18 mug OD, salmeterol 50 mug twice daily (BID), formoterol 12 mug BID, and placebo for the treatment of chronic obstructive pulmonary disease (COPD) based on individual patient data (IPD) from randomized controlled trials (RCTs) from the indacaterol trial program and aggregate data (AD) identified from a systematic review of RCTs. METHODS: 21 RCTs were included in the AD analysis that evaluated: indacaterol 75 mug (n = 2 studies), indacaterol 150 mug (n = 3), indacaterol 300 mug (n = 2), tiotropium 18 mug (n = 10), salmeterol 50 mug (n = 6), and formoterol 12 mug (n = 4). All of the studies except for one head-to-head comparison (tiotropium vs. salmeterol) were placebo controlled. Outcomes of interest were trough forced expiratory volume in 1 s (FEV1) and St. George's Respiratory Questionnaire (SGRQ) total score at week 12. The AD from all trials was analysed simultaneously using a Bayesian network meta-analysis (NMA) and relative treatment effects between all regimens were obtained. In a separate analysis, the IPD available from the 6 indacaterol RCTs was analysed in a NMA. Treatment-by-covariate interactions were included in both analyses to improve similarity of the trials. RESULTS: All interventions compared were more efficacious than placebo regarding FEV1 at 12 weeks. Indacaterol 75 mug is expected to result in a comparable FEV1 at 12 weeks to tiotropium and salmeterol based on both IPD and AD analyses. In comparison to formoterol, the IPD and AD results indicate indacaterol 75 mug is more efficacious (IPD = 0.07 L difference; 95%Credible Interval (CrI) 0.02 to 0.11; AD = 0.05 L difference; 95%CrI 0.01; 0.09). In terms of SGRQ total score at 12 weeks, indacaterol 75 mug and formoterol were more efficacious than placebo, whereas for tiotropium and salmeterol the credible intervals included zero for the AD results only (tiotropium: -2.99 points improvement versus placebo; 95%CrI 6.48 to 0.43; salmeterol:-2.52; 95%CrI: -5.34; 0.44). Both IPD and AD results suggest that indacaterol 75 mug is expected to be comparable to all active treatments. CONCLUSIONS: Based on a synthesis of currently available AD RCT evidence as well as an IPD network meta-analysis of six RCTs, indacaterol 75 mug is expected to be at least as efficacious as formoterol and comparable to tiotropium and salmeterol regarding FEV1. Furthermore, indacaterol 75 mug shows comparable level of improvement in health-related quality of life to tiotropium, salmeterol, and formoterol, as measured by the SGRQ.     

Comparison of Clinical Efficacy and Safety between Indacaterol and Tiotropium in COPD: Meta-Analysis of Randomized Controlled Trials

Two once-daily inhaled bronchodilators, indacaterol and tiotropium, are widely used as first-line therapy in stable COPD patients. This study was performed to compare the clinical efficacy and safety between indacaterol and tiotropium in patients with moderate-to-severe COPD. MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched to identify all published randomized controlled trials (RCTs). The primary outcome was trough forced expiratory volume in 1 second (FEV₁) at week 12. Four RCTs were eligible for inclusion (three RCTs with moderate-to-severe COPD patients and one RCT with only severe COPD patients). Trough FEV₁ at weeks 12 and 26 were not significantly different between indacaterol and tiotropium by the standardized mean difference with 0.014 (95% CI, -0.036, 0.063, I²= 23.5%) and with 0.037 (95% CI, -0.059 to 0.133, I²= 0%) along with differences in means of 0.003L and 0.014L, respectively. Indacaterol and tiotropium also showed similar St. George`s Respiratory Questionnaire (SGRQ) total scores and percentages of patients with SGRQ improvement (≥ 4 units) at week 26. The incidences of nasopharyngitis, serious cardiovascular events, and serious adverse events were not different between indacaterol and tiotropium, while those of cough (OR = 1.68, P < 0.001, and RR = 1.63) and COPD worsening (OR = 1.18, P = 0.003, and RR = 1.12) were higher for indacaterol than tiotropium. However, when one study with only severe COPD patients was removed from the meta-analysis, the difference in the incidence of COPD worsening between indacaterol and tiotropium became non-significant (OR = 1.13, P = 0.204, and RR = 1.09). The clinical efficacy and serious adverse events between indacaterol and tiotropium were equivocal in patients with moderate-to-severe COPD. Cough is a common complaint associated with indacaterol, and COPD worsening needs to be carefully monitored in severe COPD patients when treated with indacaterol.     

Empirical evidence of bias in treatment effect estimates in controlled trials with different interventions and outcomes: meta-epidemiological study

Objective To examine whether the association of inadequate or unclear allocation concealment and lack of blinding with biased estimates of intervention effects varies with the nature of the intervention or outcome.Design Combined analysis of data from three meta-epidemiological studies based on collections of meta-analyses.Data sources 146 meta-analyses including 1346 trials examining a wide range of interventions and outcomes.Main outcome measures Ratios of odds ratios quantifying the degree of bias associated with inadequate or unclear allocation concealment, and lack of blinding, for trials with different types of intervention and outcome. A ratio of odds ratios <1 implies that inadequately concealed or non-blinded trials exaggerate intervention effect estimates.Results In trials with subjective outcomes effect estimates were exaggerated when there was inadequate or unclear allocation concealment (ratio of odds ratios 0.69 (95% CI 0.59 to 0.82)) or lack of blinding (0.75 (0.61 to 0.93)). In contrast, there was little evidence of bias in trials with objective outcomes: ratios of odds ratios 0.91 (0.80 to 1.03) for inadequate or unclear allocation concealment and 1.01 (0.92 to 1.10) for lack of blinding. There was little evidence for a difference between trials of drug and non-drug interventions. Except for trials with all cause mortality as the outcome, the magnitude of bias varied between meta-analyses.Conclusions The average bias associated with defects in the conduct of randomised trials varies with the type of outcome. Systematic reviewers should routinely assess the risk of bias in the results of trials, and should report meta-analyses restricted to trials at low risk of bias either as the primary analysis or in conjunction with less restrictive analyses.     

Observer bias in randomized clinical trials with measurement scale outcomes: a systematic review of trials with both blinded and nonblinded assessors

Background:

Clinical trials are commonly done without blinded outcome assessors despite the risk of bias. We wanted to evaluate the effect of nonblinded outcome assessment on estimated effects in randomized clinical trials with outcomes that involved subjective measurement scales.

Methods:

We conducted a systematic review of randomized clinical trials with both blinded and nonblinded assessment of the same measurement scale outcome. We searched PubMed, EMBASE, PsycINFO, CINAHL, Cochrane Central Register of Controlled Trials, HighWire Press and Google Scholar for relevant studies. Two investigators agreed on the inclusion of trials and the outcome scale. For each trial, we calculated the difference in effect size (i.e., standardized mean difference between nonblinded and blinded assessments). A difference in effect size of less than 0 suggested that nonblinded assessors generated more optimistic estimates of effect. We pooled the differences in effect size using inverse variance random-effects meta-analysis and used metaregression to identify potential reasons for variation.

Results:

We included 24 trials in our review. The main meta-analysis included 16 trials (involving 2854 patients) with subjective outcomes. The estimated treatment effect was more beneficial when based on nonblinded assessors (pooled difference in effect size −0.23 [95% confidence interval (CI) −0.40 to −0.06]). In relative terms, nonblinded assessors exaggerated the pooled effect size by 68% (95% CI 14% to 230%). Heterogeneity was moderate (I² = 46%, p = 0.02) and unexplained by metaregression.

Interpretation:

We provide empirical evidence for observer bias in randomized clinical trials with subjective measurement scale outcomes. A failure to blind assessors of outcomes in such trials results in a high risk of substantial bias.A failure to blind assessors of outcomes in randomized clinical trials may result in bias. Observer bias, sometimes called “detection bias” or “ascertainment bias,” occurs when outcome assessments are systematically influenced by the assessors’ conscious or unconscious predispositions — for example, because of hope or expectations, often favouring the experimental intervention.¹Blinded outcome assessors are used in many trials to avoid such bias. However, the use of non-blinded assessors remains common,^2–4 especially in nonpharmacological trials; for example, non-blinded outcome assessment was used in 90% of trials involving orthopedic traumatology³ and 74% of trials involving strength training for muscles.⁴Unfortunately, the empirical evidence on observer bias in randomized clinical trials has been incomplete. Meta-epidemiological studies have compared double-blind trials with similar trials that were not double-blind.^5,6 However, such studies address blinding crudely because “double-blind” is an ambiguous term.^3,7 Furthermore, the risk of confounding is considerable in indirect between-trial analyses, as “double-blind” trials may have better overall methods and larger sample sizes than trials that are not reported as “double-blind.”A more reliable approach involves analyses of trials that use both blinded and nonblinded outcome assessors, because such a within-trial design provides a direct comparison between blinded and nonblinded assessments of the same outcome in the same patients. Our previous analysis of such trials with binary outcomes found substantial observer bias.⁸Although subjective measurement scales such as illness severity scores are popular, they may be susceptible to observer bias. They are frequently used as outcomes in clinical scenarios with no naturally distinct categories, and adjacent subcategories on a scale typically involve minor and vaguely defined differences.We decided to systematically review trials with both blinded and nonblinded assessment of outcomes using the same measurement scales. Our primary objective was to evaluate the impact of nonblinded outcome assessment on estimated treatment effects in randomized clinical trials. Our secondary objective was to examine reasons for variation in observer bias.     

Indacaterol for Chronic Obstructive Pulmonary Disease: Systematic Review and Meta-Analysis

Background

Inhaled bronchodilators are the first-line therapy for COPD. Indacaterol is a novel addition to existing long-acting bronchodilators.

Objectives

Systematic review of randomized controlled trials (RCT) on efficacy and safety of indacaterol as compared: 1) with placebo at different dosages, 2) with existing bronchodilators; (3) as add-on treatment to tiotropium.

Methods

We searched 13 electronic databases, including MEDLINE, EMBASE and CENTRAL, and contacted the manufacturer for unpublished data. Primary outcome was mean FEV1 change at 12^th week, secondary outcomes included changes in SGRQ, TDI and BODE index at 6 months, exacerbation at 1 year, and worsening of symptoms.

Results

Twelve eligible RCTs of moderate risk of bias included data from 10,977 patients. Compared to placebo, indacaterol improved FEV1 by a weighted mean difference (WMD) of 0.16 L (95%CI: 0.15, 0.18 L, p<0.001), homogeneously above the minimally important difference of 0.10 L. It offered clinically relevant improvement in all secondary outcomes except exacerbation. Magnitude of benefit did not differ significantly by dosage, but one treatment related death was reported at 300 ug. Efficacy of Indacaterol was similar to formoterol and salmeterol (FEV1 WMD = 0.04L, 95%CI: 0.01L, 0.07 L, p = 0.02); and tiotropium (FEV1 WMD = 0.01L, 95%CI: −0.01, 0.03L, p = 0.61). The use of indacaterol on top of tiotropium yielded additional improvement on FEV1 (WMD = 0.07 L, 95%CI: 0.05L, 0.10 L, p<0.001).

Conclusion

Indacaterol is safe and beneficial for patients with COPD at dosage ≤150 ug. It may serve as a good alternative to existing bronchodilators, or as an add-on to tiotropium for unresponsive patients. Use of higher dosage requires further justification.     

动物行为研究中被忽视的盲实验法

被广泛应用于临床医学、药理学和心理学等学科中的盲实验法,是一种为避免由于人为主观性而对实验观测结果产生偏差的实验设计方法.然而,该方法在动物行为研究领域一直不被重视.近年来有学者逐渐意识到这个问题,并通过文献综述和分析,发现大部分需要采用盲实验法的研究均忽略了此设计方法,使得其研究结果的效应量明显高于采用盲实验法的研究,说明实验中观测者的主观偏见对研究结果造成了影响.本文通过对盲实验法的介绍,强调了其在动物行为研究中的重要性,并对其在该研究领域中的应用进行了阐述和建议.     

Study Design and Quality of Reporting of Randomized Controlled Trials of Chronic Idiopathic or Autoimmune Urticaria: Review

Background

The recommended first-line therapy of chronic urticaria is second-generation antihistamines, but the modalities of treatment remains unclear. Numerous recommendations with heterogeneous conclusions have been published. We wondered whether such heterogeneous conclusions were linked to the quality of published studies and their reporting.

Objective

To review the study design and quality of reporting of randomized control trials investigating pharmacological treatment of autoimmune or idiopathic chronic urticaria.

Methodology/Principal Findings

MEDLINE and EMBASE were searched for pharmacological randomized controlled trials involving patients with chronic autoimmune or idiopathic urticaria, with the main outcome being treatment efficacy. Data were collected on general characteristics of the studies, internal validity, studied treatments, design of the trial, outcome measures and “spin” strategy in interpreting results. Spin was defined as use of specific reporting strategies to highlight that the experimental treatment is beneficial, despite statistically nonsignificant results. We evaluated 52 articles that met our criteria. Patients were reported as blinded in 42 articles (81%) and the outcome assessor was blinded in 37 (71%). A placebo was the only comparator in 13 (25%) studies. The study duration was <8 weeks in 39 articles (75%), with no follow-up after discontinuation of treatment in 37 (71%). In 4 articles (8%), blinding was clear because they described blinding of the outcome assessor, the treatment was not recognizable (identical or double-dummy) or had no major secondary effects, and computed randomization was centralized. The primary outcome was specified in 33 articles (63%) and was a score in 31. In total, 15 different scores were used. A spin strategy was used for 10 of 12 studies with a nonsignificant primary outcome.

Conclusion

For establishing guidelines in treatment of chronic urticaria, studies should focus on choosing clinically relevant and reproducible primary outcomes, long-term follow-up, limited use of placebo and avoiding spin strategies.     

A New Framework for Interpreting the Outcomes of Imperfectly Blinded Controlled Clinical Trials

It is well known that the outcome of an intervention is affected both by the inherent effects of the intervention and the patient''s expectations. For this reason in comparative clinical trials an effort is made to conceal the nature of the administered intervention from the participants in the trial i.e. to blind the trial. Yet, in practice perfect blinding is impossible to ensure or even verify post hoc. The current clinical standard is to follow up the trial with an auxiliary questionnaire, which allows trial participants to express in closed form their belief concerning the intervention, i.e. trial group assignment (treatment or control). Auxiliary questionnaire responses are then used to compute the extent of blinding in the trial in the form of a blinding index. If the estimated extent of blinding exceeds a particular threshold the trial is deemed sufficiently blinded; otherwise, the strength of evidence of the trial is brought into question. This may necessitate that the trial is repeated. In this paper we make several contributions. Firstly, we identify a series of problems of the aforesaid clinical practice and discuss them in context of the most commonly used blinding indexes. Secondly, we formulate a novel approach for handling imperfectly blinded trials. We adopt a feedback questionnaire of the same form as that which is currently in use, but interpret the collected data using a novel statistical method, significantly different from that proposed in the previous work. Unlike the previously proposed approaches, our method is void of any ad hoc free parameters and robust to small changes in the participants'' feedback responses. Our method also does not discard any data and is not predicated on any strong assumptions used to interpret participants'' feedback. The key idea behind the present method is that it is meaningful to compare only the corresponding treatment and control participant sub-groups, that is, sub-groups matched by their auxiliary responses. A series of experiments on simulated trials is used to demonstrate the effectiveness of the proposed approach and its superiority over those currently in use.     

Can Acupuncture Treatment Be Double-Blinded? An Evaluation of Double-Blind Acupuncture Treatment of Postoperative Pain

Blinding protects against bias but the success of blinding is seldom assessed and reported in clinical trials including studies of acupuncture where blinding represents a major challenge. Recently, needles with the potential for double-blinding were developed, so we tested if acupuncture can be double-blinded in a randomized study of sixty-seven patients with acute pain ≥ 3 (0-10 scale following third molar removal) who received active acupuncture with a penetrating needle or placebo acupuncture with a non-penetrating needle. To test if acupuncture was administered double-blind, patients and acupuncturists were asked about perceived treatment allocation at the end of the study. To test if there were clues which led to identification of the treatment, deep dull pain associated with needle application and rotation (termed “de qi” in East Asian medicine), and patients’ pain levels were assessed. Perceived treatment allocation depended on actual group allocation (p < 0.015) for both patients and acupuncturists, indicating that the needles were not successful in double-blinding. Up to 68% of patients and 83% of acupuncturists correctly identified the treatment, but for patients the distribution was not far from 50/50. Also, there was a significant interaction between actual or perceived treatment and the experience of de qi (p = 0.027), suggesting that the experience of de qi and possible non-verbal clues contributed to correct identification of the treatment. Yet, of the patients who perceived the treatment as active or placebo, 50% and 23%, respectively, reported de qi. Patients’ acute pain levels did not influence the perceived treatment. In conclusion, acupuncture treatment was not fully double-blinded which is similar to observations in pharmacological studies. Still, the non-penetrating needle is the only needle that allows some degree of practitioner blinding. The study raises questions about alternatives to double-blind randomized clinical trials in the assessment of acupuncture treatment.     

Impact of Including Korean Randomized Controlled Trials in Cochrane Reviews of Acupuncture

Objective

Acupuncture is commonly practiced in Korea and is regularly evaluated in clinical trials. Although many Cochrane reviews of acupuncture include searches of both English and Chinese databases, there is no information on the value of searching Korean databases. This study aimed to investigate the impact of searching Korean databasesand journals for trials eligible for inclusion in existing Cochrane acupuncture reviews.

Methods

We searched 12 Korean databases and seven Korean journals to identify randomised trials meeting the inclusion criteria for acupuncture reviews in the Cochrane Database of Systematic Reviews. We compared risk of bias assessments of the Korean trials with the trials included in the Cochrane acupuncture reviews. Where possible, we added data from the Korean trials to the existing meta-analyses in the relevant Cochrane review and conducted sensitivity analyses to test the robustness of the results.

Results

Sixteen Korean trials (742 participants) met the inclusion criteria for eight Cochrane acupuncture reviews (125 trials; 13,041 participants). Inclusion of the Korean trials provided data for 20% of existing meta-analyses (24 out of 120). Inclusion of the Korean trials did not change the direction of effect in any of the existing meta-analyses. The effect size and heterogeneity remained mostly unchanged. In only one meta-analysis did the significance change. Compared to the studies included in the Cochrane acupuncture reviews, the risk of bias in the Korean trials was higher in terms of outcome assessor blinding and allocation concealment.

Conclusions

Many Korean studies contributed additional data to the existing meta-analyses in Cochrane acupuncture reviews. Although inclusion of these studies did not alter the results of the meta-analyses, comprehensive searches of the literature are important to avoid potential language bias. The identification and inclusion of eligible Korean trials should be considered for reviews of acupuncture.     

A pivotal registration phase III, multicenter, randomized tuberculosis controlled trial: design issues and lessons learnt from the Gatifloxacin for TB (OFLOTUB) project

ABSTRACT: BACKGROUND: There have been no major advances in tuberculosis (TB) drug development since the first East African/British Medical Research Council short course chemotherapy trial 35 years ago. Since then, the landscape for conducting TB clinical trials has profoundly changed with the emergence of HIV infection, the spread of resistant TB bacilli strains, recent advances in mycobacteriological capacity, and drug discovery. As a consequence questions have arisen on the most appropriate approach to design and conduct current TB trials. To highlight key issues discussed: Is a superiority, equivalence, or non-inferiority design most appropriate? What should be the primary efficacy outcome? How to consider re-infections in the definition of the outcome? What is the optimal length of patient follow-up? Is blinding appropriate when treatment duration in test arm is shorter? What are the appropriate assumptions for sample size calculation? METHODS: Various drugs are currently in the development pipeline. We are presenting in this paper the design of the most recently completed phase III TB trial, the OFLOTUB project, which is the pivotal trial of a registration portfolio for a gatifloxacin-containing TB regimen. It is a randomized, open-label, multicenter, controlled trial aiming to evaluate the efficacy and safety of a gatifloxacin-containing 4-month regimen (trial registration: ClinicalTrial.gov database: NCT00216385). RESULTS: In the light of the recent scientific and regulatory discussions, we discuss some of the design issues in TB clinical trials and more specifically the reasons that guided our choices, in order to best answer the trial objectives, while at the same time satisfying regulatory authority requirements. CONCLUSION: When shortening TB treatment, we are advocating for a non-inferiority, non-blinded design, with a composite unfavorable endpoint assessed 12 months post treatment completion, and added trial procedures specifically aiming to: (1) minimize endpoint unavailability; and (2) distinguish between relapse and re-infection.     

Comparative efficacy of long-acting bronchodilators for COPD - a network meta-analysis

Background

Clinicians are faced with an increasingly difficult choice regarding the optimal bronchodilator for patients with chronic obstructive pulmonary disease (COPD) given the number of new treatments. The objective of this study is to evaluate the comparative efficacy of indacaterol 75/150/300 μg once daily (OD), glycopyrronium bromide 50 μg OD, tiotropium bromide 18 μg/5 μg OD, salmeterol 50 μg twice daily (BID), formoterol 12 μg BID, and placebo for moderate to severe COPD.

Methods

Forty randomized controlled trials were combined in a Bayesian network meta-analysis. Outcomes of interest were trough and post-dose forced expiratory volume in 1 second (FEV₁), St. George’s Respiratory Questionnaire (SGRQ) score and responders (≥4 points), and Transition Dyspnea Index (TDI) score and responders (≥1 point) at 6 months.

Results

Indacaterol was associated with a higher trough FEV₁ than other active treatments (difference for indacaterol 150 μg and 300 μg versus placebo: 152 mL (95% credible interval (CrI): 126, 179); 160 mL (95% CrI: 133, 187)) and the greatest improvement in SGRQ score (difference for indacaterol 150 μg and 300 μg versus placebo: -3.9 (95% CrI -5.2, -2.6); -3.6 (95% CrI -4.8, -2.3)). Glycopyrronium and tiotropium 18 μg resulted in the next best estimates for both outcomes with minor differences (difference for glycopyrronium versus tiotropium for trough FEV₁ and SGRQ: 18 mL (95% CrI: -16, 51); -0.55 (95% CrI: -2.04, 0.92).

Conclusion

In terms of trough FEV₁ and SGRQ score indacaterol, glycopyrronium, and tiotropium are expected to be the most effective bronchodilators.     

The identification of 7-[(R)-2-((1S,2S)-2-benzyloxycyclopentylamino)-1-hydroxyethyl]-4-hydroxybenzothiazolone as an inhaled long-acting β2-adrenoceptor agonist

The optimisation of two series of 4-hydroxybenzothiazolone derived β₂-adrenoceptor agonists, bearing α-substituted cyclopentyl and β-phenethyl amino-substituents, as inhaled long-acting bronchodilators is described. Analogues were selected for synthesis using a lipophilicity based hypothesis to achieve the targeted rapid onset of action in combination with a long duration of action. The profiling of the two series led to identification of the α-substituted cyclopentyl analogue 2 as the optimal compound with a comparable profile to the inhaled once-daily long-acting β₂-adrenoceptor agonist indacaterol. On the basis of these data 2 was promoted as the backup development candidate to indacaterol from the Novartis LABA project.     

Blinded and unblinded internal pilot study designs for clinical trials with count data

Internal pilot studies are a popular design feature to address uncertainties in the sample size calculations caused by vague information on nuisance parameters. Despite their popularity, only very recently blinded sample size reestimation procedures for trials with count data were proposed and their properties systematically investigated. Although blinded procedures are favored by regulatory authorities, practical application is somewhat limited by fears that blinded procedures are prone to bias if the treatment effect was misspecified in the planning. Here, we compare unblinded and blinded procedures with respect to bias, error rates, and sample size distribution. We find that both procedures maintain the desired power and that the unblinded procedure is slightly liberal whereas the actual significance level of the blinded procedure is close to the nominal level. Furthermore, we show that in situations where uncertainty about the assumed treatment effect exists, the blinded estimator of the control event rate is biased in contrast to the unblinded estimator, which results in differences in mean sample sizes in favor of the unblinded procedure. However, these differences are rather small compared to the deviations of the mean sample sizes from the sample size required to detect the true, but unknown effect. We demonstrate that the variation of the sample size resulting from the blinded procedure is in many practically relevant situations considerably smaller than the one of the unblinded procedures. The methods are extended to overdispersed counts using a quasi‐likelihood approach and are illustrated by trials in relapsing multiple sclerosis.     

Room for improvement in conducting and reporting non-inferiority randomized controlled trials on drugs: a systematic review

Background

A non-inferiority (NI) trial is intended to show that the effect of a new treatment is not worse than the comparator. We conducted a review to identify how NI trials were conducted and reported, and whether the standard requirements from the guidelines were followed.

Methodology and Principal Findings

From 300 randomly selected articles on NI trials registered in PubMed at 5 February 2009, we included 227 NI articles that referred to 232 trials. We excluded studies on bioequivalence, trials on healthy volunteers, non-drug trials, and articles of which the full-text version could not be retrieved. A large proportion of trials (34.0%) did not use blinding. The NI margin was reported in 97.8% of the trials, but only 45.7% of the trials reported the method to determine the margin. Most of the trials used either intention to treat (ITT) (34.9%) or per-protocol (PP) analysis (19.4%), while 41.8% of the trials used both methods. Less than 10% of the trials included a placebo arm to confirm the efficacy of the new drug and active comparator against placebo, and less than 5.0% were reporting the similarity of the current trial with the previous comparator''s trials. In general, no difference was seen in the quality of reporting before and after the release of the CONSORT statement extension 2006 or between the high-impact and low-impact journals.

Conclusion

The conduct and reporting of NI trials can be improved, particularly in terms of maximizing the use of blinding, the use of both ITT and PP analysis, reporting the similarity with the previous comparator''s trials to guarantee a valid constancy assumption, and most importantly reporting the method to determine the NI margin.     

Rethinking Clinical Trials of Transcranial Direct Current Stimulation: Participant and Assessor Blinding Is Inadequate at Intensities of 2mA

Background

Many double-blind clinical trials of transcranial direct current stimulation (tDCS) use stimulus intensities of 2 mA despite the fact that blinding has not been formally validated under these conditions. The aim of this study was to test the assumption that sham 2 mA tDCS achieves effective blinding.

Methods

A randomised double blind crossover trial. 100 tDCS-naïve healthy volunteers were incorrectly advised that they there were taking part in a trial of tDCS on word memory. Participants attended for two separate sessions. In each session, they completed a word memory task, then received active or sham tDCS (order randomised) at 2 mA stimulation intensity for 20 minutes and then repeated the word memory task. They then judged whether they believed they had received active stimulation and rated their confidence in that judgement. The blinded assessor noted when red marks were observed at the electrode sites post-stimulation.

Results

tDCS at 2 mA was not effectively blinded. That is, participants correctly judged the stimulation condition greater than would be expected to by chance at both the first session (kappa level of agreement (κ) 0.28, 95% confidence interval (CI) 0.09 to 0.47 p = 0.005) and the second session (κ = 0.77, 95%CI 0.64 to 0.90), p = <0.001) indicating inadequate participant blinding. Redness at the reference electrode site was noticeable following active stimulation more than sham stimulation (session one, κ = 0.512, 95%CI 0.363 to 0.66, p<0.001; session two, κ = 0.677, 95%CI 0.534 to 0.82) indicating inadequate assessor blinding.

Conclusions

Our results suggest that blinding in studies using tDCS at intensities of 2 mA is inadequate. Positive results from such studies should be interpreted with caution.     

Blinded and unblinded sample size reestimation in crossover trials balanced for period

The determination of the sample size required by a crossover trial typically depends on the specification of one or more variance components. Uncertainty about the value of these parameters at the design stage means that there is often a risk a trial may be under‐ or overpowered. For many study designs, this problem has been addressed by considering adaptive design methodology that allows for the re‐estimation of the required sample size during a trial. Here, we propose and compare several approaches for this in multitreatment crossover trials. Specifically, regulators favor reestimation procedures to maintain the blinding of the treatment allocations. We therefore develop blinded estimators for the within and between person variances, following simple or block randomization. We demonstrate that, provided an equal number of patients are allocated to sequences that are balanced for period, the proposed estimators following block randomization are unbiased. We further provide a formula for the bias of the estimators following simple randomization. The performance of these procedures, along with that of an unblinded approach, is then examined utilizing three motivating examples, including one based on a recently completed four‐treatment four‐period crossover trial. Simulation results show that the performance of the proposed blinded procedures is in many cases similar to that of the unblinded approach, and thus they are an attractive alternative.     

The Method Quality of Cross-Over Studies Involved in Cochrane Systematic Reviews

Background

It is possible that cross-over studies included in current systematic reviews are being inadequately assessed, because the current risk of bias tools do not consider possible biases specific to cross-over design. We performed this study to evaluate whether this was being done in cross-over studies included in Cochrane Systematic Reviews (CSRs).

Methods

We searched the Cochrane Library (up to 2013 issue 5) for CSRs that included at least one cross-over trial. Two authors independently undertook the study selection and data extraction. A random sample of the CSRs was selected and we evaluated whether the cross-over trials in these CSRs were assessed according to criteria suggested by the Cochrane handbook. In addition we reassessed the risk of bias of these cross-over trials by a checklist developed form the Cochrane handbook.

Results

We identified 688 CSRs that included one or more cross-over studies. We chose a random sample of 60 CSRs and these included 139 cross-over studies. None of these CSRs undertook a risk of bias assessment specific for cross-over studies. In fact items specific for cross-over studies were seldom considered anywhere in quality assessment of these CSRs. When we reassessed the risk of bias, including the 3 items specific to cross-over trials, of these 139 studies, a low risk of bias was judged for appropriate cross-over design in 110(79%), carry-over effects in 48(34%) and for reporting data in all stages of the trial in 114(82%).Assessment of biases in cross-over trials could affect the GRADE assessment of a review’s findings.

Conclusion

The current Cochrane risk of bias tool is not adequate to assess cross-over studies. Items specific to cross-over trials leading to potential risk of bias are generally neglected in CSRs. A proposed check list for the evaluation of cross-over trials is provided.     

Prognostic factors of improvement in health-related quality of life in atomoxetine-treated children and adolescents with attention-deficit/hyperactivity disorder,based on a pooled analysis

The objective of this study is to identify prognostic factors of treatment response to atomoxetine in improvement of health-related quality of life (HR-QoL), measured by the Child Health and Illness Profile-Child Edition Parent Report Form (CHIP-CE PRF) Achievement and Risk Avoidance domains, in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Pooled data from 3 placebo-controlled trials and separate data from 3 open-label trials of atomoxetine in children and adolescents with ADHD were analyzed using logistic regression methods. Based on baseline impairment in the Achievement and/or Risk Avoidance domains (CHIP-CE PRF < 40 points), 2 subsamples of subjects were included. Treatment outcome was categorized as <5 points or ≥5 points increase in the CHIP-CE PRF Achievement and Risk Avoidance domains. Data of 190 and 183 subjects from the pooled sample, and 422 and 355 subjects from the open-label trials were included in the analysis of Achievement and Risk Avoidance domains. Baseline CHIP-CE subdomain scores proved to be the most robust prognostic factors for treatment outcome in both domains, based on data from the pooled sample of double-blind studies and from the individual open-label studies (odds ratios [OR] 0.74–1.56, p < 0.05; OR < 1, indicating a worse baseline score associated with worse odds of responding). Initial treatment response (≥25 % reduction in ADHD Rating Scale scores in the first 4–6 weeks) was another robust prognostic factor, based on data from the open-label studies (OR 2.99–6.19, p < 0.05). Baseline impairment in HR-QoL and initial treatment response can be early prognostic factors of atomoxetine treatment outcome in HR-QoL in children and adolescents with ADHD.