Study to Evaluate the Effect of KB001-A on Time-to-Need for Antibiotic Treatment

Inclusion Criteria: * Individuals with CF who are older than 50 years of age may participate if treated with 2 or more courses of antibiotics (IV and/or oral) for respiratory sign and symptoms (CF exacerbation) in the 12 months before the Screening Visit * Confirmed diagnosis of CF * At least 2 respiratory tract cultures in the previous 12 months, with Pa present. The most recent positive Pa culture must be within 12 weeks before the Screening Visit (or obtain a positive culture at screening) * FEV1 % levels within acceptable ranges (per the study protocol) * Received inhaled ABX for equivalent of 8 weeks or greater in the 26 weeks before the Day 0 Visit Exclusion Criteria: * Treatment with antibiotics for acute illness within the 4 weeks before the Day 0 Visit * Use of systemic corticosteroids within the 4 weeks before the Day 0 Visit * Any change in regimen of CF maintenance therapies within the 4 weeks before the Day 0 Visit * History of sputum cultures positive for B. cepacia complex in the 2 years before the Screening Visit * History of organ transplantation * Current smoker (tobacco, marijuana, or any other material). Use of smokeless inhalers/vaporizers for these materials is also prohibited * History of drug addiction or alcohol abuse in the 12 months before the Screening Visit * History of hepatic disease (clinical cirrhosis or portal hypertension), renal dysfunction * Breast-feeding or pregnancy as evidenced by a positive blood pregnancy test * Receiving any investigational drug in the 16 weeks (or 5 half lives) before the Day 0 Visit, whichever is longer