Phase 3 Study of Aztreonam for Inhalation Solution (AZLI) in a Continuous Alternating Therapy Regimen for the Treatment of Chronic Pseudomonas Aeruginosa Infection in Patients With CF

The primary objective of this study is to evaluate the safety and efficacy of a CAT regimen with aztreonam for inhalation solution (AZLI) and tobramycin inhalation solution (TIS) in adult and pediatric subjects with cystic fibrosis (CF) and pulmonary Pseudomonas aeruginosa (PA) infection. Participants will be enrolled in a 28 day TIS run-in phase, and will be eligible for randomization in the comparative phase if they have not received non-study oral antibiotics for a respiratory event, or IV or inhaled antibiotics for any indication between Visits 2 and 3, have not developed a condition requiring hospitalization or other change in clinical status which, in the opinion of the investigator would preclude their ability to continue in the study, and have demonstrated at least 50% TIS compliance. Participants enrolled in the comparative phase will be randomized to receive 3 cycles of treatment, each cycle consisting alternating regimens: AZLI or placebo for 28 days followed by TIS for 28 days.