Background: Vilanterol (VI) is a novel once-daily long-acting beta₂ agonist with inherent 24-h activity. The aim of this study was to evaluate the efficacy of three once-daily doses and one twice-daily dose of VI used concurrently with ICS in adult patients (≥18 years) with persistent asthma. Safety was also assessed.
Methods: Multicentre, randomised, double-blind, placebo-controlled, five-period crossover study consisting of 7-day treatment periods separated by 7-day wash-out periods. Seventy-five patients, maintained on ICS, received VI 6.25, 12.5 and 25 mcg once-daily (evening), VI 6.25 mcg twice-daily (morning/evening), and placebo. The primary endpoint was trough forced expiratory volume in 1 s (FEV(1)) (mean of 23 h and 24 h post evening dose) on Day 7; secondary endpoint was weighted mean 24-h serial FEV(1) on Day 7.
Results: All VI groups demonstrated statistically significant increases in trough FEV(1) versus placebo (p < 0.001). There was a statistically significant increase in weighted mean 24-h FEV(1) for each VI group versus placebo (p < 0.001). The effects of once-daily VI on trough FEV(1) and weighted mean 24-h FEV(1) were dose dependent. The incidence of adverse events (AEs) was low in each VI treatment group and was not dose dependent (5-9%; placebo = 18%); no drug-related AEs or serious AEs were reported.
Conclusion: Once-daily treatment with VI was well tolerated and associated with improvements in lung function. The VI 6.25 mcg twice-daily dose showed the greatest change in trough FEV(1), however, similar changes in weighted mean 24-h FEV(1) with VI 12.5 mcg once-daily were observed. Although our study was not powered to demonstrate non-inferiority of once- versus twice-daily dosing of VI, the data suggest no advantage over a 24-h period of twice-daily over once-daily dosing for the same total daily dose. ClinicalTrials.gov: NCT00980200.
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