Abstract
Purpose :
Corticosteroid-induced ocular hypertension and the potential for steroid-induced glaucoma is among the leading drawbacks of topical corticosteroid therapy. ST266 is a biologic shown to be anti-inflammatory, anti-apoptotic, neuroprotective, and able to reduce vascular permeability. We compared the efficacy of ST266 to dexamethasone in a rabbit model of ocular abrasion.
Methods :
25 New Zealand White Rabbits (2-3kg, n=5/group, had a surgical procedure in the left eye in which an 8 mm central corneal wound made with a trephine removed epithelium and 10-15% of the superficial corneal stroma. 25µL of test article was dosed prior to surgery, followed by a second dose 15 minutes after surgery, continuing 4x/day for 4 weeks. The 5 groups were: balanced salt solution (BSS, n=5), dexamethasone 0.1% (DEX, n=5), ST266 (n=5), DEX for the first 24h post-surgery followed by ST266 (n=5) and ST266 + DEX combined (dosed 4x/day; ≥ 2 hrs between doses, n =4). The right eye did not have surgery or treatment.
Results :
All 4 treatment groups, (ST266, DEX alone, DEX + ST266 or a single dose of DEX followed by ST266) resulted in significantly lower Ocular Examination scores compared to BSS at 12 h and 1 day (p<0.02). Corneal wound healing assessed by fluorescein staining on day 3 indicated that ST266 resulted in faster corneal healing compared to chronic DEX groups (p<0.007). The lowest OCT (Optical Coherence Tomography) fibrosis scores were observed in the single DEX dose followed by chronic administration of ST266 group.
Conclusions :
Our results demonstrate that treatment with ST266 following a single DEX dose resulted in faster corneal healing, reduced corneal inflammation and the lowest fibrosis scores among the five treatment groups. These results suggest that a single topical steroid dose followed by ST266 could be a novel and safer treatment regimen to avoid the potential untoward side effects of chronic ocular steroid therapy.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.