Study of Denufosol Inhalation Solution in Patients With Mild to Moderate Cystic Fibrosis Lung Disease

Inclusion Criteria: * have confirmed diagnosis of cystic fibrosis * have FEV1 of greater than or equal to 60% of predicted normal for age, gender, and height * be able to reproducibly perform spirometry maneuvers * be clinically stable for at least 4 weeks prior to screening Exclusion Criteria: * have abnormal renal or liver function * have chest x-ray at screening with abnormalities suggesting clinically significant active pulmonary disease * have had a lung transplant