A-PACT: The Use of Inhaled Aztreonam to Eliminate or Decrease the Bacterial Burden of Pseudomonas Aeruginosa in Children With a Tracheostomy Tube.

Inhalation aztreonam (AZLI) is an aerosolized formulation of the monobactam antibiotic aztreonam with lysine as a synthetic substance in place of arginine. This substitution was made as arginine, which is in the intravenous (IV) formulation of aztreonam, can cause airway inflammation as seen in patients with cystic fibrosis when aerosolized. There have been several published studies on the efficacy and adverse effects of aerosolized aztreonam in CF patients. Two placebo-controlled studies of AZLI revealed a benefit in patients with CF and colonization with PsA. AIR-CF1 revealed that a 28-day course of AZLI given three times daily (TID) resulted in improved respiratory symptoms. They measured this improvement by using a cystic fibrosis questionnaire (CFQ-R), measuring forced expiratory volume in 1 second (FEV 1), and measuring bacterial density in sputum. AIR-CF2 demonstrated that a 28-day course of AZLI followed by a 28-day course of Tobramycin Inhaled Solution (TIS) delayed the time to the need for additional inhaled or systemic anti-pseudomonal antibiotics. They also used the CFQ-R and measured FEV1 and found improvement in both when compared to placebo. In AIR-CF3, an open-label 18-month study was conducted to evaluate the efficacy of AZLI using a month on/month off cycle, and to observe long-term effects of the drug. This protocol found that AZLI did have a long-term suppressive effect on PsA as there was a persistent reduction in Pseudomonas CFUs from baseline each month of the study. As expected, the decreases in bacterial density were consistently occurring during on months; and during off months, the density increased toward baseline. Thrice-daily dosing appeared more efficacious than twice-daily dosing. This was attributed to the mode of action of aztreonam, as bacterial killing is dependent on time above the MIC (minimal inhibitory concentration). Adverse events include: cough, respiratory tract congestion, pharyngolaryngeal pain, nasal congestion, dyspnea, hemoptysis, rhinorrhea, wheezing, chest discomfort, crackles lung, pulmonary function testing decreased, non-cardiac chest pain, sinus congestion, sinus headache, dyspnea exacerbated, exertional dyspnea.

Antibiotics currently on the market as inhaled antibiotics include tobramycin (TOBI), polymyxin E (Colistin), and aztreonam (Cayston). Studies of all of these have shown clinical benefits in those with Cystic Fibrosis. Given these findings, there is a growing interest in the use of inhaled antibiotics in other disease processes in which subjects become colonized with bacteria in the lower respiratory tract.

The investigators propose a two-center, prospective, case control clinical trial on the use of inhaled aztreonam (AZLI) in pediatric patients ages 7-21 years with a tracheostomy who have had one of their previous 3 tracheostomy aspirate cultures positive for PsA. Their past history in the previous year of requirement for systemic antibiotics will be used for each subject as the historical control. A tracheostomy aspirate culture will be collected upon initiation of the study. The investigators will subsequently start the participants on AZLI on a one month on/one month off schedule. Tracheal aspirate cultures will continue to be collected quarterly (every 3 months), and the bacterial density will be used for analysis. Goal is to see if there is a decrease need for systemic antibiotics for PsA infection.