24-h duration of the novel LABA vilanterol trifenatate in asthma patients treated with inhaled corticosteroids

Current guidelines recommend adding a long-acting inhaled &bgr;2-agonist (LABA) to inhaled corticosteroids (ICS) in patients with uncontrolled asthma. This study evaluated the novel, once-daily LABA vilanterol trifenatate (VI) in asthma patients who remained symptomatic despite existing ICS therapy. The study involved a randomised, double-blind, placebo-controlled trial of VI (3, 6.25, 12.5, 25 and 50 μg), administered once daily in the evening by dry powder inhaler for 28 days, in asthma patients aged ≥12 yrs symptomatic on current ICS therapy. The primary end-point was trough (24 h post-dose) forced expiratory volume in 1 s (FEV1); secondary end-points were weighted mean FEV1, peak expiratory flow (PEF), symptom-/rescue-free 24-h periods, and safety. A significant relationship was observed between VI dose and improvements in trough FEV1 (p=0.037). Statistically significant increases in mean trough FEV1, relative to placebo, were documented for VI 12.5–50 μg (121–162 mL; p≤0.016). Dose-related effects of VI were observed on weighted mean (0–24 h) FEV1, morning/evening PEF, and symptom-/rescue-free 24-h periods. All doses of VI were well tolerated with low incidences of recognised LABA-related adverse events (tremor 0–2%; palpitations 0–2%; glucose effects 0–1%; potassium effects 0–<1%). Once-daily VI 12.5–50 μg resulted in prolonged bronchodilation of at least 24 h with good tolerability in asthma patients receiving ICS. Based on the overall efficacy and adverse event profile from this study, the optimum dose of VI appears to be 25 μg.