Study Moli1901-010B is a multi center, parallel group, placebo controlled, double-blind efficacy and safety evaluation of three different dosage schedules of aerosolized Moli1901 in adolescents (12 years of age or older), and adults. Study will start with a screening period (visit 1) followed by an 8 weeks double blind comparative treatment period (visit 2-7). Thereafter, subjects will be observed for additional 4 weeks without treatment (follow-up period and visit 8). Spirometry, pulse oximetry and other safety measurements will be performed up to 120 min after study medication inhalation. The study will be conducted in 30 sites in 9 European countries.