Besifloxacin approved

A new topical ophthalmic antibacterial, besifloxacin ophthalmic suspension 0.6% (Besivance, Bausch & Lomb), administered via sterile ophthalmic drops, treats a broad range of eye pathogens including those that most commonly cause bacterial conjunctivitis.

Approved by the FDA May 29, besifloxacin is said to be the first fluoroquinolone specifically developed for ophthalmic use and the first and only ophthalmic fluoroquinolone with no previous systemic use, according to clinical trial outcomes.

Physicians continue to be concerned about bacterial resistance to all anti-infectives, said Marguerite B. McDonald, MD, FACS.

“Bacterial resistance to both systemic and topical anti-infectives is growing, slowly but surely,” said Dr. McDonald, clinical professor of ophthalmology, Department of Ophthalmology, New York University, and adjunct clinical professor of ophthalmology, Tulane University Health Sciences Center, New Orleans. She also is in private practice with Ophthalmic Consultants of Long Island, Lynbrook.

Efficacy evaluated

A series of eight clinical trials was conducted to test the anti-infective’s efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics. Three multicenter, randomized, double-masked trials involving nearly 2,400 patients with bacterial conjunctivitis showed that a greater proportion of patients treated with besifloxacin experienced clinical resolution and microbial eradication than patients treated with its vehicle.

In one trial, patients aged 1 to 98 years were dosed with the drug three times a day for 5 days. Clinical resolution was achieved in 45% of patients in the besifloxacin group versus 33% of patients in the vehicle-treated group. Those patients treated with besifloxacin also experienced an eradication rate for bacterial pathogens of 91% versus 60% for the vehicle-treated group.

Researchers found besifloxacin to be effective against many different bacteria, including the Centers for Disease Control and Prevention coryneform group G, Corynebacterium pseudodiphtheriticum, Corynebacterium striatum, Haemophilus influenzae, Moraxella lacunata, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus lugdunensis, Streptococcus mitis group, Streptococcus oralis, Streptococcus pneumoniae, and Streptococcus salivarius.

MRSA resistance

As an investigator in one of the clinical trials, Paul M. Karpecki, OD, said he has encountered more than one case of MRSA resistance in his private practice, now located in Lexington, KY, and has depended on fortified medications to resolve the infection.

When fourth-generation fluoroquinolones first were approved several years ago, they were sufficient to stop most infections, he said. Recently, however, he has needed to use fortified antibiotics more frequently.

“We alternated fortified antibiotics (such as tobramycin 13 mg/ml in a contact lens related keratitis or vancomycin 50 mg/ml in a non-contact lens related keratitis) with a fluoroquinolone a lot more in the last year because we started to see cases that were not responding to one [fluoroquinolone] or the other,” Dr. Karpecki said. “Now, having this new antibiotic, we’ll have more confidence in starting our patients [with] just one fluoroquinolone again. . . . To be able to [use] a single fluoroquinolone with this kind of potency really will make managing these [infections] much easier-which will be particularly beneficial in pre- and post-surgical cases where an unknown pathogen such as MRSA could develop.”

Dr. McDonald cautioned, “If a recalcitrant MRSA conjunctivitis is suspected or documented with cultures and sensitivities, it is generally recommended to go to vancomycin drops (50 mg/cc), which are not commercially available but can be made up by a compounding pharmacist. For severe cases of recalcitrant MRSA conjunctivitis, oral therapy options also include two double-strength tablets of sulfamethoxazole/trimethoprim by mouth every 12 hours or doxycycline 100 mg by mouth every 12 hours, for 5 to 10 days.”

Years in the making

The approval of besifloxacin marks Bausch & Lomb’s first new drug approval since 2005, when its fluocinolone acetonide intravitreal implant 0.59 mg (Retisert) was approved. Research and development for besifloxacin began 7 years ago, according to Philip Gioia, head of Bausch & Lomb’s North America pharmaceuticals business unit.

Besifloxacin is manufactured in Bausch & Lomb’s Tampa, FL, facility, and shipments to U.S. distributors began in June, he said.

Besifloxacin will be sold by both Bausch & Lomb and Pfizer Ophthalmics under a co-promotion agreement announced in March that allows a combined sales force of 240 sales representatives to offer the treatment to ophthalmologists and optometrists throughout the United States.

With acute bacterial conjunctivitis accounting for 1% to 4% of all physician visits worldwide, Gioia said that an effective antibacterial is needed to augment those treatments that are becoming less effective due to drug-resistance issues.

“The unique thing about [besifloxacin] is that it is specifically designed for ophthalmic use,” Gioia said. “You’re not looking at a product that will contribute in any way to resistance due to systemic use.”

Editor’s Note: There was an editorial error on Pages 11 and 15 in the “Besifloxacin approved” article in the print edition of Ophthalmology Times’ July 1, 2009 issue. Ophthalmology Times misinterpreted data in a study conducted by Paul M. Karpecki, OD, and his colleagues, in a sentence that said besifloxacin (Besivance, Bausch & Lomb) was not as effective against ciprofloxacin-resistant, methicillin-resistant Staphylococcus aureus (MRSA-CR) and ciprofloxacin-resistant, methicillin-resistant S. epidermidis (MRSE-CR) as gatifloxacin (Zymar, Allergan) and moxifloxacin (Vigamox, Alcon Laboratories).The correct article appears here.Ophthalmology Times regrets the error.