Alcon Laboratories is sponsoring the ongoing Phase II study of Pharmacyclics Inc.'s motexafin lutetium (Optrin) for use in photodynamic therapy (PDT) for wet age-related macular degeneration (AMD).

"The preliminary results of this trial are encouraging," said Mark S. Blumenkranz, M.D., of the Stanford University School of Medicine, one of the four ophthalmology centers where the study is being conducted. "The stabilization of visual acuity is promising, though longer follow-up is needed. Optrin's fluorescence properties may allow us to image and visualize the diseased tissue, potentially enabling us to better pinpoint the treatment."

In this dose-ranging study, 54 patients with wet AMD received a single intravenous injection of Optrin, followed by light delivered to the retina. Fluorescence imaging was performed to evaluate pharmacokinetics and drug uptake in choroidal neovascularization (CNV) and clearance from normal retinal tissues. PDT with Optrin was generally well tolerated at drug doses of 2.0 mg/kg and light doses of 50, 65 or 95 joules/cm2. Some patients experienced tingling in the fingertips, eye discomfort and transient retinal damage. There were no cases of skin phototoxicity or retinal vessel closure.

Clinical activity was assessed by fluorescein angiography and measurements of visual acuity. Optrin was shown to be present in the CNV and, in selected patients, resulted in complete or partial closure of diseased vessels following activation with light. At 1-month follow-up, visual acuity improved or remained stable in nearly all of the patients.

Pharmacyclics and Alcon have an evaluation and license agreement for the commercialization of Optrin.