1. Methacholine challenge tests to demonstrate therapeutic equivalence of terbutaline sulfate via different Turbuhaler ® devices in patients with mild to moderate asthma: Appraisal of a four-way crossover design.
- Author
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Bjermer L, Gauvreau GM, Postma DS, O'Byrne PM, van den Berge M, Boulet LP, Beckman O, Persson T, Román J, Carlholm M, Schützer KM, and Eckerwall G
- Subjects
- Administration, Inhalation, Adolescent, Adult, Bronchial Provocation Tests, Bronchoconstriction drug effects, Bronchoconstrictor Agents administration & dosage, Bronchoconstrictor Agents pharmacology, Bronchodilator Agents pharmacology, Cross-Over Studies, Dose-Response Relationship, Drug, Double-Blind Method, Equipment Design, Female, Forced Expiratory Volume, Humans, Male, Methacholine Chloride administration & dosage, Methacholine Chloride pharmacology, Middle Aged, Nebulizers and Vaporizers, Terbutaline pharmacology, Young Adult, Asthma drug therapy, Bronchodilator Agents administration & dosage, Terbutaline administration & dosage
- Abstract
Background/objective: To demonstrate therapeutic equivalence of terbutaline via two different Turbuhaler
® devices by evaluating its protective effect against methacholine-induced bronchoconstriction in stable asthma., Methods: In this double-blind, double-dummy, multicentre, single-dose, 4-way crossover study, patients with stable mild-to-moderate asthma (FEV1 ≥80% predicted) were randomised to 0.5 or 1.5 mg terbutaline via either Turbuhaler® M2 or Turbuhaler® M3 followed by a methacholine challenge test. The primary outcome variable was the concentration of methacholine causing a 20% drop in FEV1 (PC20 ). Patients had a PC20 methacholine <8 mg/mL that was reproducible after 2 weeks, and a stable baseline FEV1 at all visits (90-110% of enrolment value)., Results: 60 patients (mean age 31.1 years [range:18-64]; mean FEV1 92.1% predicted normal [78.4-120.6%]) were randomised to treatment; all completed the study. There was a clear dose-response for both devices. The within-device ratios (1.5 mg:0.5 mg) were 1.79 and 1.87 for Turbuhaler® M3 and M2, respectively (both p < 0.001). The between-device ratios (M3:M2) were 0.92 (95% CI: 0.75-1.13) for 0.5 mg and 0.88 (95% CI 0.72-1.08) for 1.5 mg. Both confidence intervals lie inside the interval 0.67-1.50, which was the pre-specified condition for equivalent effect., Conclusions: Bronchoprotection using a standardised methacholine challenge model proved to be an effective design to elucidate therapeutic equivalence between devices in patients with mild-to-moderate asthma. The findings indicate that patients may switch from one type of Turbuhaler® to the other without adjustment of therapy. Moreover, they show the robustness and utility of this study design and its suitability for investigating therapeutic equivalence., Eudract Number: 2014-001457-16. CLINICALTRIALS., Gov Identifier: NCT02322788., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2017
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