Study of Aztreonam for Inhalation in Children With Cystic Fibrosis and New Infection of the Airways by Pseudomonas Aeruginosa Bacteria

Key Inclusion Criteria:

• Diagnosis of cystic fibrosis (CF) as determined by the 2008 CF Consensus Conferencecriteria: Sweat chloride level ≥ 60 milliequivalents per liter (mEq/L) by quantitativepilocarpine iontophoresis; or a genotype with 2 identifiable mutations consistent withCF; or an abnormal nasal transepithelial potential difference (NPD), and 1 or moreclinical features consistent with CF
• Documented new onset of positive respiratory tract culture for PA within 30 days ofscreening defined as either first lifetime documented PA-positive culture, or PArecovered after at least a 2-year history of PA-negative respiratory cultures (atleast 2 cultures per year)
• Forced expiratory volume in one second (FEV1) ≥ 80% predicted (for subjects ≥ 6 yearsof age who can reliably perform spirometry assessments)
• Clinically stable with no evidence of acute significant respiratory symptoms thatwould require administration of intravenous (IV) antipseudomonal antibiotics, oxygensupplementation, or hospitalization

Key Exclusion Criteria:

• Use of IV or inhaled antipseudomonal antibiotics within 2 years of screening
• Use of oral antipseudomonal antibiotics for a respiratory event within 30 days ofstudy entry (screening visit)
• History of intolerance to inhaled short acting β2 agonists
• History of lung transplantation
• Current requirement for daily continuous oxygen supplementation or requirement of morethan 2 L/minute at night
• Hospitalization for a respiratory event within 30 days prior to screening
• Changes in bronchodilator, corticosteroid, dornase alfa, or hypertonic salinemedications within 7 days prior to screening.
• Significant changes (per investigators discretion) in physiotherapy technique orschedule within 7 days prior to screening
• Abnormal renal or hepatic function results at most recent test within the previous 12months, defined as Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 5 times upper limit of normal (ULN), or Serum creatinine > 2 times ULN for age
• Presence of a condition or abnormality that would compromise the subject's safety orthe quality of the study data, in the opinion of the Investigator
• Known hypersensitivity to aztreonam, its metabolites, or formulation excipients inAZLI
• Respiratory cultures performed within 24 months prior to screening that are positivefor ANY Burkholderia spp. or Non-tuberculous mycobacteria (NTM) Note: Other protocol defined Inclusion/Exclusion criteria may apply