Microbiological Efficacy of a New Ophthalmic Formulation of Moxifloxacin Dosed Twice-Daily for Bacterial Conjunctivitis

Introduction: An alternative formulation of 0.5% moxifloxacin ophthalmic solution (Moxeza®, MOXI-AF, Alcon Laboratories, Inc., Fort Worth, TX, USA) containing xanthan gum to prolong retention on the eye has been developed. MOXI-AF was designed to optimize the treatment regimen for bacterial conjunctivitis for the convenience of the patient with twice-daily dosing. Methods: A safety and efficacy clinical study was conducted as a multicenter, vehicle- controlled, randomized, double-masked, parallel group study in clinically diagnosed bacterial conjunctivitis patients aged >28 days. MOXI-AF or its vehicle was dosed one drop twice-daily for 3 days. Microbiological specimens were obtained from affected eyes on day 1, prior to the initial dose, and on day 4 after 3 days of dosing, and processed using routine clinical microbiology laboratory methods. All recovered bacteria were identified to the species level. Results: This paper reports on the microbiological success rate, a secondary efficacy variable in the trial. All patients (1180) were randomized to treatment. Patient age ranged from 30 days to 92 years. The microbiological success rate for patients treated topically with MOXI-AF twice-daily for 3 days was 74.5%, compared with 56.0% of patients treated with its vehicle control (P<0.0001). MOXI-AF was also statistically more effective than vehicle in eradicating the three principle conjunctivitis pathogens, Haemophilus influenzae (98.5% vs. 59.6%, respectively), Streptococcus pneumoniae (86.4% vs. 50.0%, respectively), and Staphylococcus aureus (94.1% vs. 80.0%, respectively) (P<0.001). Conclusion: The xanthan gum-based 0.5% moxifloxacin ophthalmic formulation, MOXI-AF, provides effective eradication of the three principle causative pathogens of bacterial conjunctivitis across all age groups when dosed twice-daily for 3 days.