Abstract
Purpose :
We assessed the efficacy of ST266 in an established model of allergic conjunctivitis compared to an antihistamine. ST266 is a novel biologic shown to be anti-inflammatory, anti-apoptotic, neuroprotective and able to reduce vascular permeability in various animal models. These properties suggested that ST266 could control inflammation in allergic conjunctivitis.
Methods :
Guinea pigs were sensitized by egg albumin (EA) and aluminum hydroxide intraperitoneal injection for 18 days. 19 days after sensitization, animals were challenged by EA topical ocular instillation in the lower conjunctival cul-de-sac of both eyes. Animals were assigned to one of three topical treatment groups (N=6/group): Balanced Salt Solution (BSS), ST266 or olopatadine (OLPD) 0.1%. 25µl of each treatment was instilled 15 minutes prior to and after the EA challenge. Clinical assessments were performed at 0, 30, 60 and 90 minutes by two masked observers. Clinical scoring of conjunctival hyperemia, conjunctival edema and ocular discharge was performed using standard grading system. Non-sensitized and unchallenged animals were assessed at each time point as controls.
Results :
Significant reductions in conjunctival hyperemia and edema were observed for animals treated with ST266 or OLPD compared to BSS. The maximal total mean score effects were observed at 90 minutes post-challenge. The overall mean + SD score was 2.7±0.6 for the BSS group; 0.6 ± 0.1 for OLPD; and 0.6 ± 0.1 for ST266. p values at 90 minutes showed significant differences for BSS vs. OLPD 0.1% (p < 0.05) and BSS vs. ST266 (p < 0.05). No significant difference was observed between OLPD 0.1% and ST266 (p>0.05). No significant inflammation was observed for non-sensitized and unchallenged controls.
Conclusions :
Results demonstrate that the anti-allergic properties of ST266 were comparable in magnitude to OLPD. Results suggest that ST266 may provide a safe and effective alternative to conventional antihistamine/mast cell stabilizers for treatment of allergic conjunctivitis. Additional studies are underway to elucidate the mechanism by which ST266 attenuates inflammation in this model of allergic conjunctivitis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.