Related Experiment Video
Updated: Feb 9, 2026

Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice
Published on: March 17, 2014
Azithromycin for Early Pseudomonas Infection in Cystic Fibrosis. The OPTIMIZE Randomized Trial
Nicole Mayer-Hamblett1,2,3, George Retsch-Bogart4, Margaret Kloster3
11 Department of Pediatrics and.
Rationale:
New isolation of Pseudomonas aeruginosa (Pa) is generally treated with inhaled antipseudomonal antibiotics such as tobramycin inhalation solution (TIS). A therapeutic approach that complements traditional antimicrobial therapy by reducing the risk of pulmonary exacerbation and inflammation may ultimately prolong the time to Pa recurrence.
Objectives:
To test the hypothesis that the addition of azithromycin to TIS in children with cystic fibrosis and early Pa decreases the risk of pulmonary exacerbation and prolongs the time to Pa recurrence.
Methods:
The OPTIMIZE (Optimizing Treatment for Early Pseudomonas aeruginosa Infection in Cystic Fibrosis) trial was a multicenter, double-blind, randomized, placebo-controlled, 18-month trial in children with CF, 6 months to 18 years of age, with early Pa. Azithromycin or placebo was given 3× weekly with standardized TIS.
Measurements And Main Results:
The primary endpoint was the time to pulmonary exacerbation requiring antibiotics and the secondary endpoint was the time to Pa recurrence, in addition to other clinical and safety outcomes. A total of 221 participants (111 placebo, 110 azithromycin) out of a planned 274 were enrolled. Enrollment was stopped early by the NHLBI because the trial had reached the prespecified interim boundary for efficacy. The risk of pulmonary exacerbation was reduced by 44% in the azithromycin group as compared with the placebo group (hazard ratio, 0.56; 95% confidence interval, 0.37-0.83; P = 0.004). Weight increased by 1.27 kg in the azithromycin group compared with the placebo group (95% confidence interval, 0.01-2.52; P = 0.046). No significant differences were seen in microbiological or other clinical or safety endpoints.
Conclusions:
Azithromycin was associated with a significant reduction in the risk of pulmonary exacerbation and a sustained improvement in weight, but had no impact on microbiological outcomes in children with early Pa. Clinical trial registered with clinicaltrials.gov (NCT02054156).
Insights
Adding azithromycin to tobramycin inhalation solution (TIS) significantly reduced pulmonary exacerbations in children with cystic fibrosis and early Pseudomonas aeruginosa (Pa) infection. This combination therapy also improved weight gain but did not affect bacterial recurrence.
Area of Science:
- Pediatric Pulmonology
- Infectious Diseases
- Clinical Trials
Background:
- Pseudomonas aeruginosa (Pa) infection is a significant concern in cystic fibrosis (CF) management.
- Early Pa infection in CF is typically treated with inhaled antipseudomonal antibiotics like tobramycin inhalation solution (TIS).
- Complementary therapies reducing pulmonary exacerbations and inflammation may prolong time to Pa recurrence.
Purpose of the Study:
- To evaluate if adding azithromycin to TIS reduces pulmonary exacerbations and delays Pa recurrence in children with CF and early Pa.
- To assess the impact of this combination therapy on clinical and safety outcomes.
Main Methods:
- The OPTIMIZE trial was an 18-month, multicenter, double-blind, randomized, placebo-controlled study.
- Participants (6 months to 18 years) with early Pa received azithromycin or placebo three times weekly alongside standardized TIS.
- Primary endpoint: time to pulmonary exacerbation; secondary endpoint: time to Pa recurrence.
Main Results:
- Enrollment was stopped early due to demonstrated efficacy.
- Azithromycin significantly reduced the risk of pulmonary exacerbation by 44% (HR, 0.56; P=0.004).
- A significant increase in weight was observed in the azithromycin group (1.27 kg, P=0.046), with no impact on microbiological outcomes.
Conclusions:
- Azithromycin combined with TIS significantly reduces pulmonary exacerbations in children with CF and early Pa.
- This regimen also leads to sustained weight improvement.
- Azithromycin did not influence microbiological outcomes or time to Pa recurrence in this population.
More Related Videos
11:20Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos
Published on: May 12, 2020
07:46Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung
Published on: June 5, 2012
Related Concept Videos
Cystic Fibrosis: Pathogenesis
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation,...
Cystic Fibrosis: Management
Sinus disease and chronic...
Clinical Trials: Overview
Trial and Error and Algorithm
Clinical Trials
There are four phases in a clinical trial. A phase one...
Random Error