Concentration-QT analysis of the randomized, placebo- and moxifloxacin-controlled thorough QT study of umeclidinium monotherapy and umeclidinium/vilanterol combination in healthy subjects

The long-acting muscarinic antagonist umeclidinium (UMEC) is approved as a once-daily monotherapy and in combination with the long-acting beta(2) agonist vilanterol (VI) for chronic obstructive pulmonary disease. The objective of this analysis was to assess the relationship between observed plasma UMEC and/or VI concentrations and QT interval corrected using Fridericia's correction (QTcF). 103 subjects were enrolled and 86 (83 %) completed the study. Subjects were randomized to 4 of 5 repeat-dose treatments (days 1-10: n = 77 subjects received placebo, n = 76 UMEC 500 mu g, n = 78 UMEC/VI 125/25 mu g, or n = 76 UMEC/VI 500/100 mu g; day 10: n = 74 oral tablet moxifloxacin 400 mg [positive control]). The concentration-QTcF interval relationship was examined using nonlinear mixed-effects methods. For UMEC, predicted QTcF interval prolongation (at observed geometric mean of maximum plasma concentrations) was -2.38 ms (90 % prediction interval [PI] -3.82, -0.85) with UMEC 500 mu g and -0.50 ms (90 % PI -0.80, -0.18) and -2.01 ms (90 % PI -3.22, -0.72) with UMEC/VI 125/25 mu g and 500/100 mu g, respectively. For VI, estimates were 5.89 ms (90 % PI 4.89, 6.91) and 7.23 ms (90 % PI 5.88, 8.55) with UMEC/VI 125/25 mu g and 500/100 mu g, respectively. Combined additive mean effects were estimated for UMEC/VI 125/25 mu g (5.39 ms [90 % PI 4.40, 6.47]) and 500/100 mu g (5.22 ms [90 % PI 3.72, 6.80]). The model-predicted decrease with UMEC and increase with UMEC/VI combination in QTcF interval suggest that the QT effect is likely attributable to VI. These model-predicted results support those of previously-published traditional statistical analyses.