- Severity of Disease: Subjects with an established clinical history of COPD and severity defined as: FEV1/forced vital capacity (FVC) ratio of <0.70; At Screening (Visit 1a/b), post bronchodilator FEV1 must be <80% predicted normal value, calculated using NHANES III (Third National Health and Nutrition Examination Survey) reference equations; the measured FEV1 must also be ≥30% of predicted normal value; at Visit 2, the average of the 60 minutes and 30 minutes pre dose FEV1 assessments must be <80% predicted normal value calculated using NHANES III reference equations