Study evaluates safety of intracameral moxifloxacin

Key Points

Results of a prospective, open-label, randomized, placebo-controlled study provide further evidence supporting the safety of intracameral administration of moxifloxacin for prophylaxis of endophthalmitis following cataract surgery, said Robert H. Osher, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS).

The combined-center study randomly assigned 66 eyes of 54 patients undergoing routine cataract surgery to receive undiluted moxifloxacin 250 µg/0.05 ml (Vigamox, Alcon Laboratories) or an equal volume of balanced salt solution (BSS) intracamerally at the conclusion of surgery, reported Dr. Osher, professor of ophthalmology, University of Cincinnati College of Medicine, and medical director emeritus, Cincinnati Eye Institute. Fifty-seven eyes were included in the per protocol analysis, and the two treatment groups were similar in their baseline characteristics.

Assessment of safety

No statistically significant differences were found between the moxifloxacin and BSS groups in any of the safety endpoints, he said.

"Establishing safety is the first step in determining the potential clinical role of intracameral moxifloxacin for endophthalmitis prophylaxis, and I am satisfied that has been accomplished based on our favorable results combined with previous findings reported in studies conducted outside the United States by Cesar Ramon Espiritu, MD, of the Philippines, and Steve Arshinoff, MD, of Canada. Now, further studies are needed to confirm the efficacy of intracameral moxifloxacin for preventing endophthalmitis after cataract surgery and to determine whether administration via the intracameral route alone is sufficient or whether it must be supplemented with topical therapy," he said.

Dr. Osher noted that prior to initiating this prospective study, he carefully reviewed the data reported by Drs. Espiritu and Arshinoff. Satisfied that it supported the safety of intracameral moxifloxacin, Dr. Osher said he was excited to be involved in the combined-center safety study because of his strong conviction that the intracameral route is superior to topical antimicrobial treatment for endophthalmitis prophylaxis and because he considers moxifloxacin to be an excellent choice as an intracameral antibiotic.

Topical perspective

"Use of topical medications preoperatively and postoperatively is far from perfect," Dr. Osher added. "As I said in my delivery of the Binkhorst Lecture at the 2000 ASCRS symposium, one of the major changes in ocular surgery I expect to see in my lifetime is the obsolescence of topical drops."

He explained that topical treatment represents an inefficient method for delivering medications into the eye considering that unpredictable penetration and patient compliance issues influence intraocular concentrations at the end of surgery and postoperatively.

Furthermore, results of a microbiological study of cataract surgery patients undertaken by Bissen-Miyajima et al. found that, although topical antibiotics were useful for reducing ocular surface microbial contamination, 100% sterilization was not achieved at the time of surgery, even in patients treated with a povidone-iodine prep combined with topical gatifloxacin.

"As an alternative, intracameral injections deliver immediate high levels of antibiotic to the target site and so have the potential to achieve immediate sterilization," Dr. Osher said. "Furthermore, the European Society of Cataract and Refractive Surgeons' study validated the use of intracameral antibiotics for postcataract surgery endophthalmitis prophylaxis. In that study, intracameral cefuroxime reduced the risk of endophthalmitis by five-fold."

Dr. Osher noted, however, that he concurs with those who believe the fourth-generation fluoroquinolone moxifloxacin may be a better choice than cefuroxime for intracameral endophthalmitis prophylaxis. Moxifloxacin offers an excellent spectrum of coverage and is commercially available as a self-preserved ophthalmic preparation that can be used directly from the bottle, he said.

Therefore, it eliminates risks of formulation errors and toxicity associated with extemporaneous compounding, Dr. Osher said.