Safety of AZLI in Children With Cystic Fibrosis (CF) and Chronic Pseudomonas Aeruginosa in the Lower Airways

Inclusion Criteria: * Diagnosis of CF as determined by the 1997 CF Consensus Conference criteria: * Documented sweat chloride ≥ 60 mEq/L by quantitative pilocarpine iontophoresis test OR * Abnormal nasal transepithelial potential difference (NPD) test OR * A genotype with 2 identifiable mutations consistent with CF AND * One or more clinical features consistent with CF. * Documented positive lower respiratory tract culture for PA at the screening visit plus two documented positive lower respiratory tract cultures for PA within 12 months prior to study entry (must have been a minimum 3 months apart.) * Clinically stable with no evidence of significant respiratory symptoms or, if obtained for clinical evaluation, no chest radiograph findings at screening that would have required administration of IV antipseudomonal antibiotics, oxygen supplementation, or hospitalization. Exclusion Criteria: * Use of IV or inhaled antipseudomonal antibiotics within 14 days of study entry * Presence of a condition or abnormality that would have compromised the participant's safety or the quality of study data, in the opinion of the investigator * History of sputum or throat swab culture yielding Burkholderia spp. within 2 years prior to screening visit * History of hypersensitivity/adverse reaction to aztreonam * History of hypersensitivity/adverse reaction to beta-agonists * History of lung transplantation * Administration of any investigational drug or device within 30 days prior to screening visit or within 6 half-lives of the investigational drug (whichever was longer) * Hospitalization for pulmonary-related illness within 28 days prior to screening visit * Changes in or initiation of chronic azithromycin treatment within 28 days prior to screening visit * Changes in or initiation of hypertonic saline treatment within 7 days prior to screening visit; for subjects on a stable regimen of hypertonic saline (28 days on/28 days off), beginning or ending a cycle of hypertonic saline was allowed * Changes in antimicrobial, bronchodilator (BD), corticosteroid or dornase alfa medications within 7 days prior to screening visit; * Changes in physiotherapy technique or schedule within 7 days prior to screening visit * Abnormal renal or hepatic function results at most recent test within the previous 90 days