| Treatment | Subjects n | Change from baseline mL | Difference from placebo mL | p-value versus placebo | Difference from salmeterol mL# | p-value versus salmeterol# |
| Placebo | 71 | -7 | ||||
| Salmeterol | 43 | 71 | 77 (1–153) | 0.046# | ||
| GSK961081 | ||||||
| Twice daily | ||||||
| 100 μg | 47 | 167 | 173 (100–247) | <0.001 | 96 (14–179) | 0.023 |
| 200 μg | 46 | 243 | 249 (175–323) | <0.001 | 172 (89–255) | <0.001 |
| 400 μg | 49 | 251 | 258 (185–330) | <0.001 | 181 (98–263) | <0.001 |
| Once daily | ||||||
| 100 μg | 45 | 148 | 155 (80–229) | <0.001 | 78 (-7–162) | 0.071 |
| 400 μg | 41 | 209 | 215 (139–291) | <0.001 | 138 (53–223) | 0.002 |
| 800 μg | 48 | 270 | 277 (204–350) | <0.001 | 200 (117–282) | <0.001 |
Data are presented as least squares mean or least squares mean (95% CI), unless otherwise stated. For the primary end-point, p-values for GSK961081 doses were compared to placebo at α=0.025 due to separate closed step-down procedures. Least squares means were adjusted for age, sex, smoking status, reversibility stratum, overnight site stratum, concurrent inhaled corticosteroid use, baseline and treatment. #: inferences involving salmeterol were post hoc analyses.