This is a 52 week study to

evaluate the efficacy of Roflumilast 500ug on exacerbation rate in subjects with severe COPD.

• Male/Female 40 years of age or older with diagnosis of Severe (Stage 3) to Very Severe (Stage 4) COPD.
• At least 2 documented moderate to severe COPD exacerbations within the last 12 months.
• Must be on Advair® (1 puff twice per day) or Symbicort® (2 puffs twice per day