Lung function, pharmacokinetics, and tolerability of inhaled indacaterol maleate and acetate in asthma patients.

Background: Indacaterol maleate delivered with the Breezhaler® inhalation device is a long-acting β-agonist approved for chronic obstructive pulmonary disease. In the development of a once daily, inhaled fixed dose combination (FDC) of indacaterol, glycopyrronium bromide (a long-acting muscarinic antagonist), and mometasone furoate (an inhaled corticosteroid [ICS]) for the treatment of patients with asthma, the acetate salt of indacaterol is used instead of the maleate salt. Here, we investigated the lung function, pharmacokinetics (PK) and safety of indacaterol maleate 150 μg once daily (o.d.) and indacaterol acetate 150 μg o.d. in comparison with placebo.

Methods: This was a randomised, double-blind, three-period crossover study (ClinicalTrials.gov identifier, NCT03257995) in patients with asthma on background ICS therapy. Patients with percent predicted pre-bronchodilator forced expiratory volume per second (FEV) ≥50% and ≤ 90% were included in the study. Patients received indacaterol maleate 150 μg o.d., indacaterol acetate 150 μg o.d., or placebo on top of stable background ICS in randomised sequence. Trough FEV was assessed after 14 days of treatment. PK of indacaterol salts were assessed at steady state after 14 days of treatment; peak expiratory flow (PEF) rate and rescue medication use were collected with a combined PEF-meter/electronic diary throughout the study.

Results: Of the 54 adult patients (median age of 48 years), 51 patients completed the study. Both indacaterol salts demonstrated statistically significant improvements in trough FEV of 186 mL (maleate) and 146 mL (acetate) compared with placebo (both P < 0.001). FEV AUC improved by 248 mL (maleate) and 245 mL (acetate), and PEF by 33 L/min (maleate) and 30.8 L/min (acetate) versus placebo. Systemic exposure of indacaterol (AUC and C on Day 14) was comparable after administration of both salt forms. Both salt forms demonstrated a good safety profile and were well tolerated, with a difference in the reporting frequency of AEs of coughing (maleate, 23.5%; acetate, 0%).

Conclusions: In patients with asthma, indacaterol maleate and acetate elicited comparable and significant improvements in lung function compared with placebo and achieved comparable systemic exposure. Both indacaterol salts were safe and well tolerated.

Trial Registration: ClinicalTrials.gov NCT03257995 June 06, 2017.