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 < or =4 microg/mL), including Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae. In an ocular pharmacokinetic study in 64 healthy volunteers, the C(max) in tears (mean [SD], 610 [540] microg/mL) was reached 10 minutes after a single ocular instillation of besifloxacin; concentrations > or =1.6 microg/g of tear were sustained for at least 24 hours; and the elimination t(1/2) was ~3.4 hours. In a study in 24 patients with a clinical diagnosis of bilateral bacterial conjunctivitis, systemic exposure (C(max)) 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 (> or =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.