Evaluation of Tolerability and Pharmacokinetics of Roflumilast, 250μg and 500μg, as add-on to Standard COPD Treatment to Treat Severe COPD

The purpose of this study is to evaluate discontinuation rates of roflumilast using an up-titration regimen for the first 4 weeks of treatment compared with continuous treatment of 500 μg one daily (OD) during the entire 12-week main period, and to evaluate if participants who do not tolerate roflumilast 500 μg OD have a drug exposure with 250 μg roflumilast OD similar to that observed in other participants with the 500 μg OD dose.