Evaluation of (R)-Roscovitine Safety and Effects in Subjects With Cystic Fibrosis, Homozygous for the F508del-CFTR Mutation

Inclusion Criteria: * Male or female aged over 18 years of age on the date of informed consent; * Diagnosed CF patients. Confirmed diagnosis of CF (Rosenstein and Cutting, 1998); * Patients carrying 2 Cystic Fibrosis causing mutations with at least one F508del-CFTR mutation, genotype to be confirmed at screening; * Forced expiratory volume at 1 second (FEV1) 40% * Chronic lung Pseudomonas aeruginosa infection according to the definition from the French Consensus Conference; * Able to understand and comply with all protocol requirements, restrictions and instructions and likely to complete the study as planned (as judged by the investigator); * Provide written informed consent prior to the performance of any study-related procedure; Exclusion Criteria: * Acute upper or lower respiratory infection, pulmonary exacerbation or changes in therapy (including antibiotics) for pulmonary disease within 4 weeks before V2; * Recent patient reported history of: * non recovered viral upper respiratory tract infection * solid organ or hematological transplantation * Burkholderia cepacia complex or Non Tuberculous Mycobacteria (NTM) respiratory tract infection; * Undergone major surgery within 1 month prior to screening; * Currently treated allergic broncho-pulmonary aspergillosis (ABPA); * Diabetic patients whose blood glucose is poorly controlled as evidenced by HbA1C \>8%; * Hemoptysis more than 60 mL at any time within 4 weeks prior to first study drug administration (V2); * Hi…