Nebulized Versus Dry Powder Long-Acting Muscarinic Antagonist Bronchodilators in Patients With COPD and Suboptimal Peak Inspiratory Flow Rate.

Background Patients with chronic obstructive pulmonary disease (COPD) and suboptimal peak inspiratory flow rate (sPIFR) may not benefit optimally from dry powder inhalers (DPI) because of inadequate inspiratory flow. Nebulized bronchodilators may provide a better alternative. We compared bronchodilation with the long-acting muscarinic antagonist (LAMA) revefenacin for nebulization versus the DPI LAMA tiotropium, in patients with COPD and sPIFR (< 60 L/min against the resistance of Diskus®). Methods This was a randomized, double-blind, double-dummy, 28-day Phase 3b study in patients with COPD enrolled based on sPIFR. The primary endpoint was trough forced expiratory volume in 1 second (FEV1) on Day 29 for revefenacin for nebulization versus tiotropium HandiHaler® DPI. Results We enrolled 206 patients with mean (standard deviation) age, 65 (8) years; percent predicted FEV1, 37 (16)%; PIFR, 45 (12) L/min. In the intent-to-treat (ITT) population, revefenacin improved trough FEV1 from baseline; however, the difference versus tiotropium was not significant (least squares [LS] mean difference [standard error], 17.0 [22.4] mL, P=0.4461). In a prespecified analysis of patients with FEV1 < 50% predicted, revefenacin produced an LS mean difference (95% confidence interval [CI]), 49.1 (6.3-91.9) mL in trough FEV1 and 103.5 (7.7-199.3) mL in forced vital capacity versus tiotropium. Revefenacin produced >100 mL increase in FEV1 in 41.6% versus 34.4% of patients with tiotropium in ITT and 41.4% versus 25.7% of patients in FEV1 < 50% predicted populations. Conclusions Revefenacin did not produce significant improvements in FEV1 versus tiotropium in the ITT population, but increased trough FEV1 in patients with FEV1 < 50% predicted and sPIFR. Clinical Trial Registration (www.Clinicaltrials.gov): Study 0149 (NCT03095456).