RESUMEN
BACKGROUND: Fluticasone furoate/Vilanterol trifenatate (FF/VI) is an inhaled corticosteroid/long-acting beta-agonist combination with a prolonged bronchodilator duration of action. We characterised the time-course of onset and offset of airway anti-inflammatory action of FF/VI, as assessed by fraction of exhaled nitric oxide (FeNO), and compared this to the bronchodilator duration of action. METHODS: A single-centre, randomised, double-blind, placebo-controlled, two-period, crossover study was undertaken in 28 steroid-naïve adults with asthma. Participants with an FEV1 ≥ 60% predicted, reversible airway disease, and FeNO > 40 ppb received FF/VI 100/25 mcg or placebo once daily for 14 days. FeNO and peak expiratory flow were measured twice-daily during treatment and during a 21-day washout period. FEV1 was measured for five days from treatment cessation. The primary outcome measure was FeNO change from baseline ratio for 21 days following treatment cessation. RESULTS: In the 27 subjects who completed the study, median (range) baseline FeNO was 87 ppb (42-212). FF/VI 100/25 mcg reduced FeNO by day 3, ratio FF/VI versus placebo 0.72 (95% confidence interval 0.61-0.86) with the maximum reduction occurring at day 14, 0.32 (0.27-0.37). Following cessation of treatment FeNO remained suppressed for 18 days, ratio on day 18 0.77 (0.59-1.00), whereas improvements in FEV1 and peak flow were maintained for 3 to 4 days post-treatment. CONCLUSIONS: The anti-inflammatory duration of action of FF/VI is consistent with the high glucocorticoid receptor affinity and long lung retention of fluticasone furoate. The anti-inflammatory effect of FF/VI was of greater duration than its bronchodilator effect in adults with mild asthma. Funding GlaxoSmithKline (201499). TRIAL REGISTRATION: Prospectively registered on ClinicalTrials.gov registry number NCT02712047 .