Gorana Capkun-Niggli

Summarizing historical information on controls in clinical trials.

Background Historical information is always relevant when designing clinical trials, but it might also be incorporated in the analysis. It seems appropriate to exploit past information on comparable control groups. Purpose Phase IV and proof-of-concept trials are used to discuss aspects of summarizing historical control data as prior information in a new trial. The importance of a fair assessment of the similarity of control parameters is emphasized. Methods The methodology is meta-analytic-predictive. Heterogeneity of control parameters is expressed via the between-trial variation, which is the key parameter determining the prior effective sample size and its upper bound (prior maximum sample size). Results For a Phase IV trial (930 control patients in 11 historical trials) between-trial heterogeneity was fairly small, resulting in a prior effective sample size of approximately 90 patients. For a proof-of-concept trial (363 patients in four historical trials) heterogeneity was moderate to substantial, resulting in a prior effective sample size of approximately 20. For another proof-of-concept trial (14 patients in one historical trial), assuming substantial heterogeneity implied a prior effective sample size of 7. The prior effective sample size can only be large if the amount of historical data is large and between-trial heterogeneity is small. The prior effective sample size is bounded by the prior maximum sample size (ratio of within- to between-trial variance), irrespective of the amount of historical data. Limitations The meta-analytic-predictive approach assumes exchangeability of control parameters across trials. Due to the difficulty to quantify between-trial variability, sensitivity of conclusions regarding assumptions and type of inference should be assessed. Conclusions The use of historical control information is a valuable option and may lead to more efficient clinical trials. The proposed approach is attractive for nonconfirmatory trials, but under certain circumstances extensions to the confirmatory setting could be envisaged as well. Clinical Trials 2010; 7: 5—18. http://ctj.sagepub.com

Relationship between FEV1 change and patient-reported outcomes in randomised trials of inhaled bronchodilators for stable COPD: a systematic review

BackgroundInteractions between spirometry and patient-reported outcomes in COPD are not well understood. This systematic review and study-level analysis investigated the relationship between changes in FEV1 and changes in health status with bronchodilator therapy.MethodsSix databases (to October 2009) were searched to identify studies with long-acting bronchodilator therapy reporting FEV1 and health status, dyspnoea or exacerbations. Mean and standard deviations of treatment effects were extracted for each arm of each study. Relationships between changes in trough FEV1 and outcomes were assessed using correlations and random-effects regression modelling. The primary outcome was St Georges Respiratory Questionnaire (SGRQ) total score.ResultsThirty-six studies (≥3 months) were included. Twenty-two studies (23,654 patients) with 49 treatment arms each contributing one data point provided SGRQ data. Change in trough FEV1 and change in SGRQ total score were negatively correlated (r = -0.46, p < 0.001); greater increases in FEV1 were associated with greater reductions (improvements) in SGRQ. The correlation strengthened with increasing study duration from 3 to 12 months. Regression modelling indicated that 100 mL increase in FEV1 (change at which patients are more likely to report improvement) was associated with a statistically significant reduction in SGRQ of 2.5 (95% CI 1.9, 3.1), while a clinically relevant SGRQ change (4.0) was associated with 160.6 (95% CI 129.0, 211.6) mL increase in FEV1. The association between change in FEV1 and other patient-reported outcomes was generally weak.ConclusionsOur analyses indicate, at a study level, that improvement in mean trough FEV1 is associated with proportional improvements in health status.

A network meta-analysis of the efficacy of inhaled antibiotics for chronic Pseudomonas infections in cystic fibrosis

BACKGROUND Various inhaled antibiotics are currently used for treating chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients, however their relative efficacies are unclear. We compared the efficacy of the inhaled antibiotics tobramycin (TIP, TIS-T, TIS-B), colistimethate sodium (colistin) and aztreonam lysine for inhalation (AZLI) based on data from randomised controlled trials. METHODS In the base case, efficacies of antibiotics were compared using a network meta-analysis of seven trials including change from baseline in forced expiratory volume in 1 second (FEV(1)) % predicted, P. aeruginosa sputum density and acute exacerbations. RESULTS The tobramycin preparations, AZLI and colistin, showed comparable improvements in efficacy in terms of FEV1% predicted at 4 weeks; the difference in % change from baseline (95%CrI) for TIP was compared to TIS-T (-0.55, -3.5;2.4), TIS-B (-0.64, -7.1;5.7), AZLI (3.64, -1.0;8.3) and colistin (5.77, -1.2;12.8). CONCLUSION We conclude that all studied antibiotics have comparable efficacies for the treatment of chronic P. aeruginosa lung infection in CF.

Comparative efficacy of indacaterol 150 μg and 300 μg versus fixed-dose combinations of formoterol + budesonide or salmeterol + fluticasone for the treatment of chronic obstructive pulmonary disease – a network meta-analysis

Objective: To compare efficacy of indacaterol to that of fixed-dose combination (FDC) formoterol and budesonide (FOR/BUD) and FDC salmeterol and fluticasone (SAL/FP) for the treatment of chronic obstructive pulmonary disease (COPD) based on the available randomized clinical trials (RCTs). Methods: Fifteen placebo-controlled RCTs were included that evaluated: indacaterol 150 μg (n = 5 studies), indacaterol 300 μg (n = 4), FOR/BUD 9/160 μg (n = 2), FOR/BUD 9/320 μg (n = 3), SAL/FP 50/500 μg (n = 5), and SAL/FP 50/250 μg (n = 1). Outcomes of interest were trough forced expiratory volume in 1 second (FEV1), total scores for St. George’s Respiratory Questionnaire (SGRQ), and transition dyspnea index (TDI). All trials were analyzed simultaneously using a Bayesian network meta-analysis and relative treatment effects between all regimens were obtained. Treatment-by-covariate interactions were included where possible to improve the similarity of the trials. Results: Indacaterol 150 μg resulted in a higher change from baseline (CFB) in FEV1 at 12 weeks compared to FOR/BUD 9/160 μg (difference in CFB 0.11 L [95% credible intervals: 0.08, 0.13]) and FOR/BUD 9/320 μg (0.09 L [0.06, 0.11]) and was comparable to SAL/FP 50/250 μg (0.02 L [−0.04, 0.08]) and SAL/FP 50/500 μg (0.03 L [0.00, 0.06]). Similar results were observed for indacaterol 300 μg at 12 weeks and indacaterol 150/300 μg at 6 months. Indacaterol 150 μg demonstrated comparable improvement in SGRQ total score at 6 months versus FOR/BUD (both doses), and SAL/FP 50/500 μg (−2.16 point improvement [−4.96, 0.95]). Indacaterol 150 and 300 μg demonstrated comparable TDI scores versus SAL/FP 50/250 μg (0.21 points (−0.57, 0.99); 0.39 [−0.39, 1.17], respectively) and SAL/FP 50/500 μg at 6 months. Conclusion: Indacaterol monotherapy is expected to be at least as good as FOR/BUD (9/320 and 9/160 μg) and comparable to SAL/FP (50/250 and 50/500 μg) in terms of lung function. Indacaterol is also expected to be comparable to FOR/BUD (9/320 and 9/160 μg) and SAL/FP 50/500 μg in terms of health status and to SAL/FP (50/250 and 50/500 μg) in terms of breathlessness.

Application of latent growth and growth mixture modeling to identify and characterize differential responders to treatment for COPD.

OBJECTIVE To explore the utility of applying growth mixture models (GMMs) in secondary analyses of clinical trials to identify sources of variability in data reported by patients with COPD. METHODS Analyses were performed on data from two 6-month clinical trials comparing indacaterol and open-label tiotropium or blinded salmeterol and the first six months of a 12-month trial comparing indacaterol and blinded formoterol. Latent growth model (LGM) analyses were conducted to explore the response of the SGRQ Symptoms score from baseline to six months and GMM analyses were evaluated as a method to identify latent classes of differential responders. RESULTS Variability in SGRQ Symptom scores was found suggesting subsets of patients with differential response to treatment. GMM analyses found subsets of non-responders in all trials. When the responders were analyzed separately from non-responders, there were increased treatment effects (e.g., symptoms score improvement over six months for whole groups: indacaterol=8-12 units, tiotropium=7 units, salmeterol=9 units, formoterol=11 units. Responder subgroup improvement: indacaterol=9-21 units, tiotropium=7 units, salmeterol=10 units, formoterol=20 units). Responders had significantly different baseline SGRQ Symptom scores, smoking history, age, and mMRC dyspnea scores than non-responders. CONCLUSIONS Patients with COPD represent a heterogeneous population in terms of their reporting of symptoms and response to treatment. GMM analyses are able to identify sub-groups of responders and non-responders. Application of this methodology could be of value on other endpoints in COPD and in other disease areas.

Efficacy of once-daily indacaterol relative to alternative bronchodilators in COPD: a patient-level mixed treatment comparison.

OBJECTIVE Indacaterol was evaluated versus placebo, formoterol, and salmeterol in randomized controlled trials. No direct comparisons, however, are available for indacaterol 150 μg with formoterol or indacaterol 300 μg with salmeterol. Indacaterol trial evidence was synthesized to provide coherent estimates of indacaterol 150 μg and indacaterol 300 μg relative to formoterol, salmeterol, and tiotropium. METHODS Four randomized controlled trials were combined with Bayesian mixed treatment comparisons by using individual patient-level data. End points of interest were trough forced expiratory volume in 1 second (FEV(1)), St. Georges Respiratory Questionnaire (SGRQ) total score and response (≥ 4 points), and Transition Dyspnea Index total score and response (≥ 1 point). RESULTS Indacaterol 150 μg demonstrated a higher FEV(1) than did formoterol at 12 weeks and 6 months (0.10 L difference; 95% credible interval [CrI] = 0.06-0.14), as did indacaterol 300 μg versus salmeterol (0.06 L difference at 12 weeks; CrI = 0.02-0.10; 0.06 L at 6 months; CrI = 0.02-0.11). Regarding SGRQ, indacaterol 150 μg demonstrated a comparable proportion of responders versus formoterol, as did indacaterol 300 μg versus salmeterol. In comparison to tiotropium, indacaterol 150 μg demonstrated a greater proportion of responders (odds ratio = 1.52 at 12 weeks; CrI 1.15-2.00). For Transition Dyspnea Index, indacaterol 150 μg and formoterol showed a similar response. Indacaterol 300 μg was more efficacious than salmeterol (odds ratio = 1.65 at 12 weeks; CrI 1.16-2.34). Overall, indacaterol 150 μg showed the greatest efficacy for SGRQ and indacaterol 300 μg for FEV(1) and Transition Dyspnea Index. CONCLUSION Indacaterol is expected to be comparable to formoterol, salmeterol, and tiotropium, providing higher FEV(1) than formoterol and salmeterol and greater improvement in the SGRQ total score than tiotropium. Indacaterol 150 μg provided comparable improvement in dyspnea, while indacaterol 300 μg demonstrated the greatest response overall.

Efficacy of indacaterol 75 μg versus fixed-dose combinations of formoterol-budesonide or salmeterol-fluticasone for COPD: a network meta-analysis

Background The purpose of this study was to update our network meta-analysis in order to compare the efficacy of indacaterol 75 μg with that of a fixed-dose combination of formoterol and budesonide (FOR/BUD) and a fixed-dose combination salmeterol and fluticasone (SAL/FP) for the treatment of chronic obstructive pulmonary disease (COPD) based on evidence identified previously in addition to two new randomized clinical trials. Methods Fifteen randomized, placebo-controlled clinical trials including COPD patients were evaluated: indacaterol 75 μg once daily (n = 2 studies), indacaterol 150 μg once daily (n = 5), indacaterol 300 μg once daily (n = 4), FOR/BUD 9/160 μg twice daily (n = 2), FOR/BUD 9/320 μg twice daily (n = 2), SAL/FP 50/500 μg twice daily (n = 4), and SAL/FP 50/250 μg twice daily (n = 1). All trials were analyzed simultaneously using a Bayesian network meta-analysis and relative treatment effects between all regimens were obtained. Treatment-by-covariate interactions were included where possible to improve the similarity of the trials. Outcomes of interest were trough forced expiratory volume in 1 second (FEV1) and transitional dyspnea index at 12 weeks. Results Based on the results without adjustment for covariates, indacaterol 75 μg resulted in a greater improvement in FEV1 at 12 weeks compared with FOR/BUD 9/160 μg (difference in change from baseline 0.09 L [95% credible interval 0.04–0.13]) and FOR/BUD 9/320 μg (0.07 L [0.03–0.11]) and was comparable with SAL/FP 50/250 μg (0.00 L [−0.07–0.07]) and SAL/FP 50/500 μg (0.01 L [−0.04–0.05]). For transitional dyspnea index, data was available only for indacaterol 75 μg versus SAL/FP 50/500 μg (−0.49 points [−1.87–0.89]). Conclusion Based on results of a network meta-analysis with and without covariates, indacaterol 75 μg is expected to be at least as efficacious as FOR/BUD (9/320 μg and 9/160 μg) and comparable with SAL/FP (50/250 μg and 50/500 μg) in terms of lung function. In terms of breathlessness (transitional dyspnea index) at 12 weeks, the results are inconclusive given the limited data.

66 Efficacy of tobramycin inhalation powder (TIP) versus other inhaled antibiotics in cystic fibrosis (CF) patients with chronic P. aeruginosa infection: a network meta-analysis

Objective: Patients suffering from bacterial infections of the lungs are frequently treated by alternating or combining the inhaled antibiotics tobramycin (aminoglycoside) and colistimethate-sodium (CMS, i.e. polymyxin E). Therefore, patients might feel encouraged to mix solutions of both antibiotics in order to inhale the mixture in one single inhalation session. As the effects of preparing such a mixture on physical and chemical stability of the solution are not known, an evaluation was triggered. Methods: Vials of tobramycin solution (170mg/1.7ml) were mixed with reconstituted CMS (2 Mio. IU CMS dissolved in 4ml of 0.9% saline) and physicochemically characterized with respect to osmolality, viscosity, surface tension and pH. Additionally, the tobramycin content and possible tobramycin related impurities were assayed by HPLC. Results and Conclusion: Mixtures of the antibiotics did not show obvious signs of physicochemical incompatibilities. However, the measured content of tobramycin in the mixture decreased to 70−75% of the initial amount within about 12 hours. Already 10 minutes after mixing a marked decrease of tobramycin content (approx. −7%) was observed indicating a fairly rapid reaction or decomposition immediately after preparation and during treatment. Therefore, mixing of tobramycin containing solutions with CMS prior to inhalation cannot be recommended.