Comparison of the Effect on Bronchial Hyperresponsiveness of Beclomethasone Dipropionate Administered via a Novel Multidose Dry-Powder Inhaler or a Conventional Pressurised Metered Dose Inhaler

Abstract

Background: Treatment with inhaled corticosteroids improves symptoms and reduces bronchial hyperresponsiveness (BHR) associated with asthma. Delivery of drugs into the lung is dependent on the inhaler device. Furthermore, environmental concerns regarding the use of chlorofluorocarbon propellants in pressurised inhalers and patient acceptability of inhaler devices both influence the extent of use of different delivery systems. Objectives: To compare the efficacy of beclomethasone dipropionate (BDP) administered via a novel multidose dry-powder inhaler (DPI) and a conventional pressurised metered-dose inhaler (pMDI) with spacer in patients with BHR. Methods: A randomised, double-blind, crossover study was carried out in a group of 27 patients (aged 19–55 years) with a clinical diagnosis of reversible airway disease, who demonstrated BHR to methacholine (PD₂₀ ≤6.4 mg). Each patient received BDP (≤2 mg/day) via the DPI or pMDI, for periods of 4 weeks. The randomised treatment periods were preceded by 3-week washout periods when no corticosteroid was used. Five clinic visits marked the start and end of each study phase. The primary efficacy endpoint was BHR as defined by the pharmacodynamic parameter, PD₂₀, which was determined at the start and end of each treatment period. Clinical endpoints including lung function, symptoms and adverse events were also evaluated. Results: Both treatments caused a significant decrease in BHR (p < 0.05 vs. pre-treatment values). Mean ± SD changes in log PD₂₀ were: DPI 0.59 ± 1.29; pMDI 0.59 ± 0.94 mg. There was no statistically significant difference between treatments and no evidence of a carry-over effect between treatments on BHR. Clinical efficacy and safety parameters also demonstrated no statistically significant treatment differences, and patients found the DPI easier to use. Conclusion: Efficacy of BDP in reducing BHR is comparable via the DPI and pMDI plus spacer.