Phase 3 safety comparisons for 1.0% azithromycin in polymeric mucoadhesive eye drops versus 0.3% tobramycin eye drops for bacterial conjunctivitis.

PURPOSE To compare the safety and tolerability of 1.0% azithromycin in a polymeric mucoadhesive delivery system with 0.3% tobramycin ophthalmic solution for the treatment of bacterial conjunctivitis. METHODS This study was a prospective, randomized, active-controlled, double-masked, phase 3 trial conducted from August 6, 2004, to October 6, 2005, at 47 sites. Subjects with a clinical diagnosis of bacterial conjunctivitis were randomly assigned to receive either 1% azithromycin in DuraSite (AzaSite; InSite Vision, Alameda, CA) (n = 365) or 0.3% tobramycin (n = 378). Both groups received masked medication four times daily for 5 days, but participants received an active dose of 1% azithromycin in DuraSite only twice a day on days 1 and 2 and daily on days 3 to 5. Conjunctival cultures were taken, and ocular signs and symptoms were evaluated at baseline and at two follow-up visits. RESULTS A total of 743 patients were randomized, and 710 (96%) completed the trial. Both study medications were well tolerated. The most frequently observed ocular adverse events in the azithromycin group were eye irritation (1.9%), conjunctival hyperemia (1.1%), and worsening bacterial conjunctivitis (1.1%). These rates compared favorably with those obtained with tobramycin. Rates of microbial eradication (an efficacy parameter) and bacterial infection recurrence (a safety parameter) were the same in both groups. CONCLUSIONS This is the first report of the safety and tolerability of a commercially manufactured preparation of azithromycin for ophthalmic use. Azithromycin 1% in DuraSite is safe and can be administered in a regimen of less frequent doses than can tobramycin, while producing an equivalent clinical outcome. The formulation is well tolerated in patients over the age of 1 year for the eradication of bacteria commonly associated with conjunctivitis. (ClinicalTrials.gov number, NCT00105469.).