Study To Evaluate The Efficacy And Safety Of PH-797804 For 12 Weeks In Adults With Moderate To Severe Chronic Obstructive Pulmonary Disease (COPD) Taking Salmeterol Xinafoate/Fluticasone Propionate Combination

Inclusion Criteria: * Male or female subjects between, and including, the ages of 40 and 80 years. * Subjects with a diagnosis, for at least 6 months, of moderate to severe COPD (GOLD) and who meet the criteria for Stage II-III disease. * Subjects must have a smoking history of at least 10 pack-years and be current smokers or ex-smokers that gave up \> 6 months ago. * Subjects must be treated with a LABA/ICS combination for at least 1 month prior to screening. Exclusion Criteria: * A COPD exacerbation requiring treatment with oral steroids or hospitalization for the treatment of COPD within 3 months of screening. * History or presence of significant cardiovascular disease. * ECG abnormalities. * Significant concomitant clinical disease that could interfere with the conduct, safety or interpretation of results of this study. * Evidence of organ or blood disorders.