 STUDY DESIGN: This will be a randomized, placebo-controlled crossover study where patients will receive an evening dose of either aclidiniumformoterol ACLFOR or placebo after steady-state conditions on twice-daily ACLFOR have been established. Patients will continue to take the same dosage of inhaled corticosteroid ICS as they did prior to study entry. Subjects will complete 4 visits as part of the study, with a fifth follow-up visit if required to ensure return to pre-study health status. After an initial screening visit Visit 1 to confirm eligibility and a 1-week run-in period on stable triple therapy long-acting beta2-agonistinhaled corticosteroid LABAICS long-acting muscarinic antagonist LAMA, subjects will complete baseline testing Visit 2 which includes: full pulmonary function tests, sleepsymptom questionnaires, and polysomnography which will include periodic measurements of overnight spirometry sitting and supine. Subjects will then receive 2-week treatment with twice-daily ACLFOR and continue on the same ICS as during the baseline run-in. Once stability on treatment with ACLFOR and ICS is established, there will be two overnight treatment visits Visits 3 and 4, conducted 3-7 days apart to allow for return to normal sleep status between. For these visits, the evening dose of ACLFOR versus placebo will be randomized to treatment order. Treatment visits will be similar to visit 2 but will include overnight measurements of respiratory mechanics diaphragm electromyography and respiratory pressures. Short-acting bronchodilators will be withheld for at least 8 hours prior to visits. 