Assess Bronchodilator Effect and Safety of Two Doses of QVM149 Compared to a Fixed Dose Combination of Salmeterol/Fluticasone in Patients With Asthma.

Key Inclusion criteria * Male and female adult patients ≥ 18 years old and ≤ 75 years. * Patients with a documented physician diagnosis of asthma for a period of at least 12 months prior to Visit 1 (Screening). * Patients who have used ICS and LABA combinations for asthma for at least 3 month and at a stable medium or high dose of ICS for at least 1 month prior to Visit 1 (Screening). * Pre-bronchodilator FEV1 of \< 80 % of the predicted normal value at screening Visit 1 (spirometry will not be repeated at baseline prior to randomization). * Patients who demonstrate an increase in FEV1 of ≥ 12 % and 200 mL after administration of 400 µg salbutamol/360 µg albuterol (or equivalent do se) at Visit 1 (Screening). All patients must perform a reversibility test at Visit 1 (Screening). If reversibility is not demonstrated at Visit 1 (Screening), then, reversibility testing may be repeated once during the screening period. * If reversibility is not demonstrated at Visit 1 (retesting allowed once), patients must be screen failed. Spacer devices are not permitted during reversibility testing Key Exclusion criteria * Patients who have smoked or inhaled tobacco products within the 6 month period prior to Visit 1 * Patients who have had an asthma attack/exacerbation requiring systemic steroids or hospitalization or emergency room visit within 6 weeks of Visit 1 * Patients with narrow-angle glaucoma, symptomatic benign prostatic hyperplasia (BPH) or bladder-neck obstruction or severe renal impairment or urinary retention * Patients who have had a respiratory tract infection or asthma worsening within 4 weeks prior to Visit 1 * Patients with any chronic conditions affecting the upper respiratory tract * Patients with a history of chronic lung diseases other than asthma, including (but not limited to) COPD, sarcoidosis, interstitial lung disease, cystic fibrosis, clinically significant bronchiectasis and active tuberculosis. * Patients with Type I diabetes or uncontrolled Type II diabetes (HbA1c \>9% at screening). * Patients who have a clinically significant ECG abnormality at Visit 1 * Patients with a history of hypersensitivity or intolerance to any of the study drugs (including excipients) * Patients with narcolepsy and/or insomnia. * Patients on Maintenance Immunotherapy (desensitization) for allergies for less than 3 months prior to Visit 2 or patients on Maintenance Immunotherapy for more than 3 months prior to Visit 2 but expected to change throughout the course of the study. * Pregnant or nursing (lactating) women * Women of child-bearing potential must use Highly effective contraception methods * Patients who have discontinued LAMA therapy in the past for any safety, tolerability or perceived lack of efficacy reason. * History of paradoxical bronchospasm in response to inhaled medicines. * Patients with a history of clinically relevant bronchoconstriction upon repeated forced expiratory maneuvers. * Patient with a serum potassium level below the laboratory limit of normal at screening.