A single-dose double-blind study comparing efficacy of two dry powder inhalers containing budesonide and formoterol in asthmatic patients

Background: Therapeutic equivalence of Budesonide/formoterol Easyhaler compared to Symbicort Turbuhaler has been demonstrated with in vitro and pharmacokinetic studies. This study was performed to confirm equivalent bronchodilator efficacy of the products in asthmatics. Methods: A randomised, single dose, double-blind, 4-period crossover study was carried out in 11 sites. The studied doses were 320/9 μg and 1280/36 μg of budesonide/formoterol delivered by Easyhaler and Turbuhaler. Spirometry was performed before and 10 min, 20 min and 1, 2, 3, 4, 6, 8, 10 and 12 h after administration of the study treatments. The primary efficacy endpoint was average 12-h forced expiratory volume in 1 s (FEV 1 ). The secondary efficacy endpoints were maximum FEV 1 and FEV 1 at 12 h post-dose. Results: 72 asthma patients were randomised and 53 patients completed all study periods according to the protocol. The assay sensitivity of the study was shown as the common slope of average 12-h FEV 1 between doses was 0.063 (95% CI 0.032-0.093) and showed statistical significance (p 1 between the treatments (Easyhaler-Turbuhaler) was 0.013 l at the lower dose, and -0.028 l at the higher dose, and the 95% CIs (-0.047 to 0.073 and -0.087 to 0.032, respectively) were within the range of a clinically non-relevant difference. The results of the secondary efficacy endpoints were in line with the primary results. All treatments were well tolerated. Conclusions: The results confirm equivalent bronchodilator efficacy of Budesonide/formoterol Easyhaler compared to Symbicort Turbuhaler.