Purchase this article with an account.
Brian J Christian, Paul Miller, T Michael Nork, Carol A Rasmussen, Thomas Larsen, Evan A Thackaberry, Helen Booler, Vladimir Bantseev; Determination of a No Observable Effect Level (NOEL) for Endotoxin following a Single Intravitreal Administration to Cynomolgus Macaques. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5164.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The presence of endotoxin in intravitreal ophthalmic formulations is a concern at all stages of therapeutic development. The objective of this study was to characterize the acute ocular inflammatory response and estimate the NOEL in the nonhuman primate to a range of endotoxin doses delivered by intravitreal injection.
Female cynomolgus macaques were treated with a single intravitreal dose at levels ranging from 0.01 to 0.5 endotoxin units/eye (EU/eye; USP standard), one animal/both eyes/dose level. Doses were administered in two 50 µL injections, given approximately 10 min apart for a 100 µL/eye total volume. Animals were monitored for 2 weeks post treatment by clinical ophthalmic exam using the modified standardization of uveitis nomenclature (SUN) Working Group Grading Scheme to score aqueous cell and flare. In addition, the posterior segment was evaluated at 1 and 2 weeks post treatment with color fundus photography and optical coherence tomography (OCT). Ocular histomorphology was evaluated at term.
Intravitreal doses ≥ 0.05 EU/eye caused a generally dose-related acute inflammatory response characterized by an increase in aqueous flare and cell, and vitreal haze and cell. At 0.05 EU/eye, the anterior segment response was greatest by 2 days post dose and resolved by 1 week. Vitreal cell first observed after 4 days increased through 2 weeks and correlated with the presence of mononuclear cell infiltrates observed histologically at higher doses. Thickening of the retinal nerve fiber layer, wrinkling of the inner limiting membrane and mildly swollen optic nerve were noted at ≥ 0.1 EU/eye at 1 week post dose, findings which improved at 2 weeks. With the exception of mild vitreal haze noted by OCT there was no evidence of ocular inflammation at a dose level of 0.01 EU/eye.
Intravitreal administration of a formulation containing endotoxin corresponding to 0.01 EU/eye to the nonhuman primate, was shown to elicit a subclinical inflammatory response identified with OCT. Results from this study compare well with those determined in a similarly designed study conducted in rabbits where 0.01 EU/eye was the NOEL (Streit T, et al, IOVS 2015;56:(7):3368).
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only