A phase III clinical trial of 0.5% levofloxacin ophthalmic solution versus 0.3% ofloxacin ophthalmic solution for the treatment of bacterial conjunctivitis

OBJECTIVE: To compare the efficacy and safety of 0.5% levofloxacin ophthalmic solution (QUIXIN) with 0.3% ofloxacin ophthalmic solution for the treatment of bacterial conjunctivitis. DESIGN: Prospective, randomized, active-controlled, double-masked, multicenter study. PARTICIPANTS: Four hundred twenty-three patients with a clinical diagnosis of bacterial conjunctivitis were enrolled. METHODS: Patients were randomly assigned to receive either 0.5% levofloxacin (n = 211) or 0.3% ofloxacin (n = 212) for 5 days (every 2 hours on days 1 and 2 and every 4 hours on days 3-5). Conjunctival cultures were obtained, and ocular signs and symptoms were evaluated on day 1 (baseline), days 3 to 5 (interim), and days 6 to 10 (final). End point was defined as the last evaluable observation. MAIN OUTCOME MEASURES: Primary microbial and clinical outcomes were based on culture results and resolution of cardinal signs, respectively. Secondary efficacy assessments included evaluations of ocular signs and symptoms. RESULTS: Two hundred eight patients (levofloxacin, n = 109; ofloxacin, n = 99) were evaluated for efficacy. Microbial eradication rates were significantly greater in the 0.5% levofloxacin treatment group compared with the 0.3% ofloxacin group at both the final visit (89% vs. 80%, P = 0.034) and at end point (90% vs. 81%; P = 0.038). Treatment with 0.5% levofloxacin was significantly more effective in resolving photophobia than was 0.3% ofloxacin treatment (94% vs. 73%, P = 0.006). Both study medications were well tolerated, with a low incidence of adverse events. CONCLUSIONS: Although clinical cure rates in the 0.5% levofloxacin and 0.3% ofloxacin treatment groups were similar, a 5-day treatment regimen with 0.5% levofloxacin achieved microbial eradication rates that were statistically superior to those attained with 0.3% ofloxacin. Despite the higher concentration of active drug in 0.5% levofloxacin versus 0.3% ofloxacin, there was no difference between treatment groups in the incidence of treatment-related adverse events.