Continuous alternating inhaled antibiotics for chronic pseudomonal infection in cystic fibrosis

J Cyst Fibros. 2016 Nov;15(6):809-815. doi: 10.1016/j.jcf.2016.05.001. Epub 2016 May 24.


Background: Inhaled antibiotics are standard of care for treating chronic pseudomonal respiratory infections in cystic fibrosis patients, initially approved for intermittent administration. However, use of continuous inhaled antibiotic regimens of differing combinations is growing.

Methods: This double-blind trial compared continuous alternating therapy (CAT) to an intermittent treatment regimen. Subjects were treated with 3cycles of 28-days inhaled aztreonam (AZLI) or placebo 3-times daily alternating with 28-days open-label tobramycin inhalation solution (TIS).

Results: 90 subjects were randomized over 18months. Study enrollment was limited, in part because of evolving practices by clinicians of adopting a CAT regimen in clinical practice; consequently the study was underpowered. AZLI/TIS treatment reduced exacerbation rates by 25.7% (p=0.25; primary endpoint) and rates of respiratory hospitalizations by 35.8% compared with placebo/TIS (p=0.14). AZLI/TIS CAT therapy was well tolerated.

Conclusions: This trial illustrates challenges with studying treatment regimens in a constantly evolving CF care environment. Nonetheless, the results of this trial indicate that AZLI/TIS CAT is well tolerated and may provide additional clinical benefit in CF patients compared with intermittent use of TIS alone. NCT01641822.

Keywords: Aerosol; Antibiotics; Cystic fibrosis; Pseudomonas; Pulmonary exacerbation.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Administration, Inhalation
  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Aztreonam / administration & dosage*
  • Chronic Disease
  • Cystic Fibrosis* / diagnosis
  • Cystic Fibrosis* / drug therapy
  • Double-Blind Method
  • Female
  • Forced Expiratory Volume / drug effects
  • Humans
  • Male
  • Medication Therapy Management
  • Pseudomonas Infections* / diagnosis
  • Pseudomonas Infections* / drug therapy
  • Pseudomonas aeruginosa / isolation & purification*
  • Respiratory Tract Infections* / diagnosis
  • Respiratory Tract Infections* / drug therapy
  • Time Factors
  • Tobramycin / administration & dosage*
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Aztreonam
  • Tobramycin

Associated data