In this analysis, 120 patients had reached the 12-month, six treatment course (28 days on and 28 days off) study milestone, with 48 patients in the twice-daily group and 72 patients in the three times daily group. A compliance rate of 95% was observed over six courses of treatment and no difference in compliance was observed between the twice-daily and three times daily regimens.
Patients receiving aztreonam lysine three times daily experienced improvements in FEV1 after completion of six courses of treatment, with a mean change from baseline of 5.2% (SD=18.4; n=70). These patients also experienced a mean improvement from baseline of 4.2 points in the CFQ-R Respiratory Symptoms scale (SD=20.2; n=70) after completion of six courses of treatment.
Mean values for the three times daily group did not drop below baseline FEV1 percent predicted or CFQ-R Respiratory Symptoms scores during any on-treatment or off-treatment interval over the first 12 months of treatment. Over six courses of treatment, aztreonam lysine three times daily was also associated with reductions in Pseudomonas aeruginosa colony forming units, with a mean change from baseline of -0.42 (log reduction, SD=2.11; n=52) in the three times daily group.
No changes in pseudomonas sensitivity to aztreonam lysine were observed (as measured by minimum inhibitory concentrations increased by four fold in either the MIC50 or MIC90) in the three times daily group. Aztreonam lysine was well tolerated with a safety profile consistent with the expected symptoms of a patient with underlying cystic fibrosis disease.