A 24-wk Dose Ranging Study to Evaluate the Efficacy and Safety of 4 Doses of a New PDE4 Inhibitor in Patients With COPD

Inclusion Criteria: * COPD patients * Non- childbearing potential or woman permanently sterilized or on one or more highly effective contraception * Current/ex smokers (history \> 10 pack years) * Post bronchodilatator FEV1 \>=30% and \<=70% predicted normal value and FEV1/FVC ratio \<0.7 * Documented history of at least 1 moderate or severe exacerbation in the 12 months prior to study entry * Symptomatic patients (MMRC score ≥2 and a CAT score ≥10) * Patients on daily maintenance therapy with an ICS/LABA . Exclusion Criteria: * Diagnosis of asthma or other respiratory disorders * Maintenance bronchodilators therapy only (eg LABA alone) * Maintenance triple therapy. * Occurrence of a moderate or severe COPD exacerbation within 6 weeks prior to study entry or during the run-in period. * Patients requiring long term oxygen therapy. * Concomitant or recent pulmonary rehabilitation programme * Known respiratory disorders other than COPD * Lung cancer or a history of lung cancer, active or history of cancer with less than 5 years disease free survival time * Hypersensitivity to β2-agonist, corticosteroids, PDE4 inhibitors or any of the excipients * Depression, generalised anxiety disorder, suicidal ideation * Any clinically significant cardiovascular disease (IM, CHF III/IV; AF not controlled by therapy, etc) within 1 year of study entry * Any relevant clinically significant cardiovascular condition, clinically abnormal significant 12-lead ECG (QTcF\>450 ms for male and \>470 for female) or clinically significant laboratory abnormalities * Serum potassium value ≤3.5 mEq/L or \>5.5mEq/L and/or a fasting serum glucose value ≥140 mg/dL. * History or symptoms of significant neurological disease * Unstable concurrent disease: eg uncontrolled Thyroid disease or other endocrine diseases, gastrointestinal uncontrolled disease, uncontrolled immune diseases * Renal impairment. * Patients with abnormal alanine aminotransferase and/ or aspartate aminotransferase and/or bilirubin * Current or chronic history of liver disease, or known hepatic or biliary abnormalities and patients receiving treatment with any drug known to have a well defined potential for hepatotoxicity before Study entry * Severely obese (BMI ≥35 kg/m2) or have experienced excessive weight loss recently * History of alcohol abuse and/or substance/drug abuse within 12 months prior to screening visit. * Any recent participation to a clinical Study with other investigational drug