AZLI was effective in patients with CF using frequent TIS therapy. AZLI delayed time to need for inhaled or intravenous antipseudomonal antibiotics, improved respiratory symptoms and pulmonary function, and was well tolerated. Clinical trial registered with www.clinicaltrials.gov (NCT 00104520).

Results: After 28 days of treatment, AZLI improved the mean CFQ-R respiratory score (9.7 points; p < 0.001), FEV 1 (10.3% predicted; p < 0.001), and sputum PA density (؊ 1.453 log 10 cfu/g; p < 0.001), compared with placebo. Significant improvements in Eating, Emotional Functioning, Health Perceptions, Physical Functioning, Role Limitation/School Performance, and Vitality CFQ-R scales were observed. Adverse events were consistent with symptoms of CF lung disease and were comparable for AZLI and placebo except the incidence of "productive cough" was reduced by half in AZLI-treated patients. PA aztreonam susceptibility at baseline and end of therapy were similar. Conclusions: In patients with CF, PA airway infection, moderate-to-severe lung disease, and no recent use of antipseudomonal antibiotics or azithromycin, 28-day treatment with AZLI significantly improved respiratory symptoms and pulmonary function, and was well tolerated.

A multidisciplinary committee developed questions about the prevention and treatment of initial P. aeruginosa infection and the use of bronchoscopy to obtain routine airway cultures. The outcome measure of interest was cultures without P. aeruginosa growth. Systematic reviews of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were conducted in May 2012 and August 2013. Searches combined controlled vocabulary terms and text words for CF and terms relevant to each question. The entire committee reviewed the evidence, and final recommendation statements were graded using the U.S. Preventive Services Task Force system. Recommendation 1: The CF Foundation strongly recommends inhaled antibiotic therapy for the treatment of initial or new growth of P. aeruginosa from an airway culture (certainty of net benefit, high; estimate of net benefit, substantial; grade of recommendation, A). The favored antibiotic regimen is inhaled tobramycin (300 mg twice daily) for 28 days. Recommendation 2: The CF Foundation recommends against the use of prophylactic antipseudomonal antibiotics to prevent the acquisition P. aeruginosa (certainty of net benefit, moderate; estimate of net benefit, zero; grade of recommendation, D). Recommendation 3: The CF Foundation recommends routine oropharyngeal cultures rather than bronchoalveolar lavage cultures obtained by bronchoscopy in individuals with CF who cannot expectorate sputum to determine if they are infected with P. aeruginosa (certainty of net benefit, moderate; estimate of net benefit, moderate; grade of recommendation, B).

Summary Chronic airway infection with Pseudomonas aeruginosa (PA) causes morbidity and mortality in patients with cystic fibrosis (CF). Additional anti-PA therapies are needed to improve health status and health-related quality of life. AIR-CF3 was an international 18-month, open-label study to evaluate the safety and efficacy of repeated courses of aztreonam for inhalation solution (AZLI, now marketed as Cayston®) in patients aged ≥6 years with CF and PA infection who previously participated in one of two Phase 3 studies: AIR-CF1 or AIR-CF2. Patients received up to nine courses (28 days on/28 days off) of 75 mg AZLI two (BID) or three times daily (TID) based on randomization in the previous trials. 274 patients, mean age 28.5 years (range: 8–74 years), participated. Mean treatment adherence was high (92.0% BID group, 88.0% TID group). Hospitalization rates were low and adverse events were consistent with CF With each course of AZLI, FEV1 and scores on the Cystic Fibrosis Questionnaire-Revised Respiratory Symptomscale improved and bacterial density in sputum was reduced. Benefits waned in the 28 days off therapy, but weight gain was sustained over the 18months. There were no sustained decreases in PA susceptibility. A dose response was observed; AZLI TID-treated patients demonstrated greater improvements in lung function and respiratory symptoms over 18 months. Repeated intermittent 28-day courses of AZLI treatment were well tolerated. Clinical benefits in pulmonary function, health-related quality of life, and weight were observed with each course of therapy. AZLI is a safe and effective new therapy in patients with CF and PA airway infection.

These data support the continued development of AI for treatment of pulmonary infections in patients with CF.