Modulation of allergen-induced bronchoconstriction by fluticasone furoate and vilanterol alone or in combination

BACKGROUND: This placebo-controlled study assessed the effects of the once-daily inhaled corticosteroid (ICS) fluticasone furoate (FF) and long-acting beta(2)-agonist (LABA) vilanterol (VI) on early and late asthmatic responses (EAR/LAR) and airway hyper-responsiveness (AHR). METHODS: Patients (n = 27) were randomized to FF (100 μg), VI (25 μg), FF/VI (100/25 μg), and placebo for 21 days (four periods). Allergen challenge was performed 1 h post-dose on day 21. AHR was assessed on day 22 using methacholine. RESULTS: Allergen challenge caused an early change (0–2 h) in minimum forced expiratory volume in 1 s (FEV(1)) of −1.091 l (95% CI: −1.344; −0.837) following placebo therapy; changes were −0.955 l (−1.209; −0.702), −0.826 l (−1.070; −0.581), and −0.614 l (−0.858; −0.370) following VI, FF, or FF/VI therapy, respectively. Treatment differences were significant for all comparisons between therapies. Mean changes in 0–2 h %FEV(1) were as follows: −28.05 (placebo), −23.10 (VI), −22.33 (FF), and −16.10 (FF/VI). Following placebo, the late change (4–10 h) in weighted mean FEV(1) was −0.466 l (−0.589; −0.343) and −0.298 l (−0.415; −0.181) after VI, and was +0.018 l with both FF/VI (−0.089; 0.124) and FF (−0.089; 0.125). Treatment differences were significant for all comparisons between therapies except FF/VI vs FF. Mean changes in 4–10 h %FEV(1) were as follows: −21.08 (placebo), −14.30 (VI), −5.02 (FF), and −5.83 (FF/VI). AHR 24 h after allergen challenge was significantly reduced with FF/VI and FF vs placebo, and FF/VI was superior to either component. CONCLUSION: Combined treatment with FF/VI provides additive protection from the EAR relative to its components, significant protection over VI alone from the LAR, and confers sustained protection from hyper-responsiveness 24 h post-dose.