Phase 2 Study - Erdosteine in Patients With CB/COPD

Inclusion Criteria: * Adult patients with a clinical diagnosis of stable CB associated with COPD will be entered into this study. CB is diagnosed clinically in patients who have a documented smoking history and who have a daily productive cough for at least 3 months per year over at least 2 consecutive years in the absence of other causes of chronic cough. COPD is defined by the presence of airflow obstruction from spirometry Exclusion Criteria: asthma, bronchiectasis, or cystic fibrosis; active history of lung cancer, respiratory failure, or a need for long-term oxygen therapy;