Antioxidant eye drop explored for dry AMD

An antioxidant eye drop (OT-551, Othera) is being investigated totreat geographic atrophy in dry age-related macular degeneration(AMD), said Paul Sternberg, MD, from the Vanderbilt EyeInstitute, Vanderbilt University School of Medicine, Nashville,TN.

The small lipophilic molecule has been shown to penetrate thecornea easily and in animal models, therapeutic levels wereachieved.

"Esterases within the eye convert OT-551 to TEMPOL-H, an agentdeveloped to treat cataracts," Dr. Sternberg said. "WhileTEMPOL-H does not penetrate the cornea, OT-551 does. When[either] eye drop is administered, both get into the vitreouscavity and both have activity inside the eye. The eye drop israpidly distributed within the eye and the levels in the retinahave been measured for up to 16 hours beginning within 15 minutesafter topical administration."

In the Multicenter Evaluation of Geographic Atrophy phase II,2-year study (a randomized, double-masked, dose-ranging,multicenter trial), the efficacy of the eye drop is beingcompared with placebo at doses of 0.45% and 0.3% to determine theeffect of the eye drops in reducing the area of progression ofgeographic atrophy following treatment. Patients administer thedrug four times daily for 2 years in one eye. Investigators willevaluate the changes in best-corrected visual acuity andsafety.

The first patients were randomly selected in June 2007 and thefinal patients were randomly selected in March 2008. Twelve-monthdata are expected in spring 2009.

"Dry AMD remains a major cause of visual loss and probably willincrease in its importance," Dr. Sternberg said. "As a result,there is increased interest in developing pharmacologictreatments. In studying those new agents, we believe thatmorphologic end points may be preferable to functional endpoints. [The eye drop] is one of several drugs that we think ispromising, under study, and applied topically."