“An Anterior Chamber Toxicity Study Evaluating Besivance, AzaSite, ciprofloxacin

and BSS”

Authors: Peter J. Ness, Nick Mamalis, Liliana Werner, Surekha Maddula, Don K. Davis, Eric D. Donnenfeld, Randall J. Olson Authors: Peter J. Ness, Nick Mamalis, Liliana Werner, Surekha Maddula, Don K. Davis, Eric D. Donnenfeld, Randall J. Olson

From the: John A. Moran Eye Center, University of UtahFrom the: John A. Moran Eye Center, University of Utah

- The authors have no financial or proprietary interest in any product mentioned in this poster; Randall J. Olson is a consultant for Allergan, Inc.

- The authors have no financial or proprietary interest in any product mentioned in this poster; Randall J. Olson is a consultant for Allergan, Inc.

- This study is supported by unrestricted grants from Allergan, Inc. and Research to Prevent Blindness, Inc.- This study is supported by unrestricted grants from Allergan, Inc. and Research to Prevent Blindness, Inc.

BackgroundPostoperative endophthalmitis is an uncommon but

devastating complication of cataract surgery.

• Postoperative endophthalmitis prophylaxis1

– Widely used around the world– All antibiotics are used “off-label” in this setting in the

US– Has been shown to decrease risk of endophthalmitis

• Sutureless clear corneal cataract surgery2,3

– Decreases astigmatism – Not all wounds are as well sealed as we wish– Leaky wounds allow the tear film to enter the anterior

chamber– The tear film entering the eye contains antibiotics and

other medications being administered

Background

• Besivance®* (besifloxacin) and AzaSite®** (azithromycin)– The first drugs using the DuraSite®*** bio-adhesive vehicle – Approved in the US to treat bacterial conjunctivitis

• DuraSite benefits: – Prolonged administration of the medication on the ocular

surface as the antibiotic-embedded polymer is slowly broken down

– Less frequent dosing is required for equivalent efficacy4

– Better patient compliance

• Why not use these helpful antibiotics for postoperative endophthalmitis prophylaxis?

* Bausch & Lomb, Rochester, NY, USA ** Inspire Pharmaceuticals, Inc., Durham, NC, USA *** InSite Vision Inc., Alameda, CA, USA

Objective

• No studies, to date, have investigated the effects of DuraSite-based medications in the anterior chamber.

• Our aim in this study was to evaluate the possible toxicity of DuraSite-based medications, delivered as a large bolus, into the anterior chamber of rabbit eyes, simulating an extremely leaky clear corneal wound.

Methods/MaterialsSubjects: 20 New Zealand White RabbitsStudy groups: Besivance 0.6%, AzaSite 1.0%, ciprofloxacin

0.3% and balanced salt solution (BSS) (10 eyes randomized into each group)

Surgical technique: sterile aspiration of 0.1 mL of aqueous from the anterior chamber using a 30 g needle, then injection of 0.1 mL of the study material through the same needle

Postoperative examinations: slit-lamp exams (by a masked physician) at 24 and 48 hours after injection, focusing on inflammatory signs

Sacrifice: each rabbit was humanely euthanized at 48 hours post-injection and all eyes enucleated

Data analysis: – Corneal vital staining: 2 eyes randomized from each group– Histopathology: remaining 8 eyes from each group– Analysis focused on damage to the corneal endothelial cell layer and

other signs of anterior segment damage

Outcome measures: clinical and pathologic signs of toxicity

* Falcon Pharmaceuticals, Fort Worth, TX, USA

ResultsClinical Slit-Lamp Exam (DuraSite-based groups)

– Severe, diffuse corneal edema (20 of 20 eyes)– Corneal ectasia and bullous keratopathy (20 of 20 eyes)– Profound conjunctival injection– Moderate limbal vascularity– Generally increased globe size– No statistically significant difference between Besivance and

AzaSite examination scores

Figure 1. Diffuse corneal edema after injection of Besivance

Figure 2. Ruptured bullae and corneal edema after injection of Besivance

Figure 3. Corneal ectasia and bullous keratopathy after injection of AzaSite

ResultsClinical Slit-Lamp Exam (Non-DuraSite-based groups)

– No corneal opacity (19 of 20 eyes)– Mild conjunctival injection (12 of 20 eyes)– Mild limbal vascularity (16 of 20 eyes)– Mild conjunctival injection & discharge with moderate diffuse

corneal opacification and limbal vascularity (1 eye injected with ciprofloxacin [Figure 6])

– No statistically significant difference between ciprofloxacin and BSS examination scores

Figure 4. Clear cornea and mild conjunctival injection after injection of ciprofloxacin

Figure 5. Clear cornea with no signs of inflammation after injection of ciprofloxacin

Figure 6. Diffuse moderate corneal edema after injection of ciprofloxacin

Results

Corneal vital staining• DuraSite-based eyes revealed:

– Severe alteration of endothelial cell size and shape indicative of damage• Non-DuraSite-based eyes showed:

– Mild intracellular edema – Iintact hexagonal shape of endothelial cells

Figure 7. Corneal vital staining with morphologically damaged endothelial cells after injection of AzaSite

Figure 8. Corneal vital staining with mild intracellular edema after injection of BSS

Besivance AzaSite Ciprofloxacin BSS

Globe volume (standard

deviation) [cm3]3.05 (0.17) 3.16 (0.52) 2.46 (0.13) 2.56 (0.17)

Table. Globe volume by gross measurements after enucleation

Results

Figure 9. Histopathologic slide showing fibrin, amorphous material in iridocorneal angle and acute inflammatory cells after injection of Besivance, H&E, 100x

Figure 10. Histopathologic slide showing a large epithelial bulla, corneal edema and fibrin in the anterior chamber after injection of Besivance, H&E, 40x

Histopathology• DuraSite-based eyes showed (to varying degrees in each eye):

– Bullous keratopathy– Corneal stromal thinning– Anterior chamber fibrin– Extensive endothelial cell attenuation– Peripheral anterior synechia (in some eyes) – Amorphous eosinophilic material within the iridocorneal angle and trabecular

meshwork• Non-DuraSite-based eyes showed:

– No signs of inflammation or anterior segment damage

Discussion• Although the literature has clearly shown benefits of

Besivance and AzaSite, their safety in the setting of sutureless clear corneal wounds (i.e. post cataract surgery) has not been investigated.

• DuraSite medications seem to cause glaucomatous and toxic damage in the anterior chamber when injected intracamerally as a large bolus.

• The difference in effect between DuraSite-based and non-DuraSite-based medications was statistically significant.

Discussion/Conclusions• Each medication is composed of various components: antibiotic, benzalkonium

chloride (BAK) preservative, vehicle and other inactive ingredients.

• BAK is contained in all 3 medications at differing concentrations (Besivance: 0.01%, AzaSite: 0.003%, ciprofloxacin: 0.006%)

– These concentrations are within the range previously reported to possibly cause endothelial toxicity in rabbits5; therefore, it is logical to conclude that BAK caused the toxic reaction

– If BAK had caused this toxicity, we would expect some dose-response relationship, BUT instead there was a poor correlation between BAK concentration and toxicity (e.g. Besivance and AzaSite appeared equally toxic); therefore, it is unlikely to have caused the noted toxicity

• The vehicle (DuraSite) alone was not used as a control due to commercial unavailability, so the authors used a variety of DuraSite and non-DuraSite medications (all commonly used in ophthalmic practice) for comparison

• We deduce that the DuraSite component of Besivance and AzaSite caused the toxicity and glaucomatous damage

• We recommend:– Further study of these medications at lower volumes in the anterior chamber– Until the safety is better established, surgeons should consider placing a suture over a clear

corneal wound if DuraSite-based medications may be used

References1. O'Brien TP, Arshinoff SA, Mah FS. Perspectives on antibiotics for

postoperative endophthalmitis prophylaxis: potential role of moxifloxacin. J Cataract Refract Surg 2007;33:1790-1800.

2. Herretes S, Stark WJ, Pirouzmanesh A, Reyes JM, McDonnell PJ, Behrens A. Inflow of ocular surface fluid into the anterior chamber after phacoemulsification through sutureless corneal cataract wounds. Am J Ophthalmol 2005;140:737-740.

3. Taban M, Sarayba MA, Ignacio TS, Behrens A, McDonnell PJ. Ingress of India ink into the anterior chamber through sutureless clear corneal cataract wounds. Arch Ophthalmol 2005;123:643-648.

4. McDonald MB, Protzko EE, Brunner LS, et al. Efficacy and safety of besifloxacin ophthalmic suspension 0.6% compared with moxifloxacin ophthalmic solution 0.5% for treating bacterial conjunctivitis. Ophthalmology 2009;116:1615-1623 e1.

5. Green K, Hull D, Vaughn E, Malizia A, Bowman K. Rabbit endothelial response to toxic preservatives. Arch Ophthalmol 1977;95:2218-2221.