 This is a study of multiple doses of inhaled QBW276 in patients with cystic fibrosis on top of standard of care. The study will be divided into 3 Cohorts. Cohorts 1 and 2 are designed to be a randomized, double-blind, placebo-controlled, parallel arm, multiple dose study to assess the safety, tolerability, pharmacokinetics, and preliminary efficacy of inhaled QBW276 over 1 week cohort 1 or 2 weeks cohort 2 in patients with cystic fibrosis regardless of their genotype. 