Tolerability and Safety of Inhaled Colistimethate Sodium (CMS) Administered Once Daily Compared to Twice Daily Dosing in Adult and Adolescent Subjects with Cystic Fibrosis and Chronic Pseudomonas Aeruginosa Lung Infection (COPILOT)

Cystic fibrosis (CF) causes mucus to build up in the lungs, creating an environment where bacteria — particularly a bug called Pseudomonas aeruginosa — can thrive and cause repeated chest infections. Inhaled antibiotics like colistimethate sodium (CMS) are commonly used to suppress these infections, but they are typically given twice a day. This study (COPILOT) is testing whether taking CMS just once a day is just as safe and tolerable as the standard twice-daily dose. Participants with CF and chronic Pseudomonas infection will be randomly assigned to either once-daily or twice-daily inhaled CMS for 28 days. Safety, lung function, and tolerability are carefully monitored throughout the trial. You may be eligible if you are 12 or older (adults first, then adolescents in a later step), have confirmed cystic fibrosis with a chronic Pseudomonas lung infection, have an FEV1 of at least 30% predicted, and have been on a stable treatment regimen for at least two months. Simplifying dosing to once daily could make treatment more manageable for people with CF and improve adherence.