OMEGA Study extended for topical GA treatment; no 1-year data released

Fort Lauderdale, FL-Twelve-month evaluations were completed recently for a topical formulation (OT-551, Othera Pharmaceuticals) being studied to treat geographic atrophy (GA), the late stage of dry age-related macular degeneration estimated to affect 1 million patients. One-year data, however, will not be released based on a recommendation by the safety and monitoring committee, according to investigators.

The safety and monitoring committee recommended continuing the study with no changes to obtain longer-term follow-up and to determine the durability of the treatment effect. The outcomes data will not be presented until month 24, said Al Reaves, PhD, senior vice president for clinical development, Othera Pharmaceuticals. A second smaller study, a fellow eye comparison study ongoing at the National Eye Institute, will be completed later in 2009.

The penetration of OT-551 is one of its major advantages, he said.

“With a topical formulation, the question of efficacy arises,” he added. Thirty minutes after application, there was a measurable retinal concentration of the drug and TP-H, the active metabolite, in the rabbit retina; 16 hours after application, the drug was still measurable in the retina. The drug is absorbed by two routes: through the anterior chamber and through the sclera. The topical drug scavenges free radicals, inhibits membrane lipid peroxidation, and down-regulates several pathways of oxidative stress.

The primary morphologic end point of the phase II OMEGA Study (OT-551 Multicenter Evaluation of Geographic Atrophy) is the mean rate of change in the area of GA and the functional end points the loss of 15 or more letters of visual acuity and visual field deterioration. In this multicenter, randomized, placebo-controlled dose-ranging trial, 137 patients are undergoing treatment in one eye with four applications of the drug daily for at least 2 years. The fellow eyes are left untreated. Two doses of the drug, 0.45% and 0.3%, are being evaluated and compared with placebo.