Objective: The aim of this study was to investigate the dose-response for inhaled budesonide via Turbuhaler in Japanese patients with mild to moderate asthma.
Methodology: Inhaled budesonide 100 microg, 200 microg, 400 microg or placebo was administered twice daily via Turbuhaler for 6 weeks, to 267 adult Japanese patients (mean age 51 years) with mild-to-moderate, non-steroid-dependent bronchial asthma, in a double-blind, placebo-controlled, randomized, parallel group study. The patients had to be symptomatic for more than 3 days/week and have an average morning peak expiratory flow (PEF) 50-80% of predicted normal value.
Results: The response to budesonide was rapid, all treatments showing a significant improvement in morning PEF after 1 week (P<0.05). During week 6, mean improvements of 15, 45, 53 and 71 L/min were observed for the placebo, 200 microg, 400 microg and 800 microg budesonide groups, respectively. Compared with placebo all improvements in the budesonide groups were statistically significant and a significant dose-response was demonstrated (P<0.001). The difference between the 200 microg and 800 microg doses was significant. Also, for several secondary efficacy variables (e.g. evening PEF, symptom score, treatment score, daily activity score and sleep score) significant dose-responses were shown. Other variables included the investigators' assessments of improvement and usefulness. They also showed statistically significant dose-response relationships and confirmed the rapid onset of action. Budesonide was well tolerated at all tested doses, with a low incidence of adverse events, all of which were minor in severity.
Conclusions: Budesonide Turbuhaler in the doses 100 microg to 400 microg twice daily was effective, well tolerated and showed a rapid onset of action in patients with mild-to-moderate asthma. Dose-response was demonstrated for several variables of clinical efficacy.