This is a multi-center, double-blind, randomized, placebo-controlled, parallel-group, outpatient, safety study to evaluate the long-term safety of arformoterol 15 mcg twice daily (BID) in the treatment of subjects with moderate-to-severe COPD. The administration of arformoterol in subjects with moderate to severe COPD will not result in a meaningfully greater incidence of respiratory death and COPD exacerbation -related hospitalizations compared to placebo (nebulized saline and non-long-acting beta2-agonist [LABA] COPD standard of care treatments). This study was previously posted by Sepracor Inc. In October 2009, Sepracor Inc. was acquired by Dainippon Sumitomo Pharma., and in October 2010, Sepracor Inc's name was changed to Sunovion Pharmaceuticals Inc.