Original ArticleContinuous alternating inhaled antibiotics for chronic pseudomonal infection in cystic fibrosis

BackgroundInhaled 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.MethodsThis double-blind trial compared continuous alternating therapy (CAT) to an intermittent treatment regimen. Subjects were treated with 3 cycles of 28-days inhaled aztreonam (AZLI) or placebo 3-times daily alternating with 28-days open-label tobramycin inhalation solution (TIS).Results90 subjects were randomized over 18 months. 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.ConclusionsThis 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.Clinicaltrials.gov: NCT01641822.