Besifloxacin: A topical fluoroquinolone for the treatment of bacterial conjunctivitis

Background: Besifloxacin is a topical ophthalmic fluoroquinolone that was approved by the US Food and Drug Administration (FDA) in May 2009 for the treatment of bacterial conjunctivitis caused by susceptible bacterial strains.Objective: This article provides an overview of the pharmacology, clinical efficacy, and tolerability of ophthalmic besifloxacin when used for the treatment of bacterial conjunctivitis.Methods: Relevant reports pertaining to the pharmacology, efficacy, and tolerability of besifloxacin were identified through a search of MEDLINE (1985–December 2009) and International Pharmaceutical Abstracts (1985–December 2009) using the terms besifloxacin, BOL-303224-A, ophthalmic fluoroquinolones, and bacterial conjunctivitis. Additional publications were identified by reviewing the reference lists of identified articles and searching the FDA Web site.Results: Besifloxacin has potent in vitro inhibitory activity against most common ocular bacterial pathogens (MIC90 values generally ≤4 μg/mL), including Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. In an ocular pharmacokinetic study in 64 healthy volunteers, the Cmax in tears (mean [SD], 610 [540] μg/mL) was reached 10 minutes after a single ocular instillation of besifloxacin; concentrations ≥1.6 μg/g of tear were sustained for at least 24 hours; and the elimination t1/2 was ~3.4 hours. In a study in 24 patients with a clinical diagnosis of bilateral bacterial conjunctivitis, systemic exposure (Cmax) after administration of besifloxacin ophthalmic suspension 3 times daily for 5 days was <0.5 ng/mL. In 2 randomized, double-masked, vehicle-controlled clinical trials, besifloxacin ophthalmic suspension was well tolerated and significantly more efficacious than vehicle in achieving clinical resolution (73.3% vs 43.1%, respectively, in one of the studies [P < 0.001]; 45.2% vs 33.0% in the other [P = 0.008]) and microbial eradication (88.3% vs 60.3% [P < 0.001] and 91.5% vs 59.7% [P < 0.001], respectively). In a randomized, double-masked, parallel-group, noninferiority trial comparing besifloxacin ophthalmic suspension 0.6% with moxifloxacin ophthalmic solution 0.5%, besifloxacin was found to be noninferior to moxifloxacin (predefined cutoff for noninferiority = −15), with no significant differences in rates of clinical resolution (58.3% and 59.4%, respectively; 95% CI, −9.48 to 7.29) or microbial eradication (93.3% and 91.1%; 95% CI, −2.44 to 6.74). Besifloxacin was generally well tolerated in these clinical trials, with the most common (≥1.5%) ocular adverse events being nonspecific conjunctivitis (2.6%), blurred vision (2.1%), bacterial conjunctivitis (1.8%), and eye pain (1.5%). The recommended dose of besifloxacin is 1 drop in the affected eye(s) 3 times daily (4–12 hours apart) for 7 days.Conclusion: Besifloxacin ophthalmic suspension 0.6% appeared to be well tolerated in the populations studied and was efficacious in the treatment of bacterial conjunctivitis caused by susceptible isolates.