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