AzaSite comparable to tobramycin in phase 3 trial

ALAMEDA, Calif. — A topical solution of azithromycin in a sustained-delivery vehicle showed a similar clinical resolution rate with a lower dosing schedule than topical tobramycin, according to a press release.

InSite Vision’s AzaSite (1% azithromycin in the DuraSite drug-delivery vehicle) is a topical anti-infective that offers the possibility of a lower dosing schedule, according to the company. InSite reported the results of a phase 3, double-masked, randomized, active-controlled study including 746 patients ranging in age from 1 to 93 years old who had been diagnosed with bacterial conjunctivitis. The international study was conducted at 47 clinical sites in the United States and six in Latin America.

Patients with presumed bacterial conjunctivitis were enrolled and on day 1 underwent a conjunctival culture; of the 746 subjects, 316 had positive bacterial cultures. Patients were treated with either AzaSite dosed twice daily for the first 2 days, followed by once a day for the next 3 days, or were treated with 0.3% tobramycin dosed four times daily for 5 days.

AzaSite demonstrated a clinical resolution rate of 80% and tobramycin 78%. The bacterial eradication rate was equivalent in both groups, the company said.

Preliminary safety data from the trial indicated no reports of systemic drug sensitivity and no serious adverse events. Ocular adverse events were “minimal in frequency and equivalent” between the groups, the release said.

InSite said it expects final results of the study next year, and it will file an application for U.S. marketing approval some time in 2006.