Efficacy and Safety of Inhaled Nitric Oxide (NO) in Cystic Fibrosis (CF) Patients

This is a multi-center, randomized, placebo controlled, phase II clinical study comparing an investigational drug to a placebo control. Screening data will be reviewed to determine subject eligibility. All subjects including screen failure subjects will be recorded on screening logs at their respective sites. Upon successful completion of all screening procedures, a subject will be considered eligible for enrollment. The subject will be enrolled and randomized in as close a time proximity to the first treatment application as is possible in order to minimize the possibility of dropout while enrolled but before undergoing treatment. With a 1:1 investigational treatment to placebo control, subjects will be randomized to one of the two arms. Subjects in the investigational treatment arm will be administered doses of NO (0.5% NO in 99.5% nitrogen) diluted in room air by inhalation four times daily (30-minute inhalations at least 3 hours apart) for 7.5 days on Days 1, 2, 3, 4, 5, 8, 9, and 10 (three treatments on Days 1 and 10). Subjects in the placebo arm will breathe 100% nitrogen diluted in room air in the same proportion as the investigational arm. Subjects will remain in the clinic for 30 minutes after completing the last treatment of each day. All subjects will be asked to return to the clinic for additional evaluations on Days 15 and 36.