For Immediate Release

Oculex Announces Positive Clinical Results for Posurdex® - The First Biodegradable Ocular Implant in Clinical Trial

Posurdex® Provides Significant Vision Improvement for Patients with Persistent Macular Edema and Meets Trial's Primary Endpoint

May 8, 2003

FORT LAUDERDALE, Fla., /PRNewswire/ -- Oculex Pharmaceuticals, Inc., a developer of innovative therapeutic products for the treatment of major, sight-threatening diseases of the eye, announced that results will be presented today from a Phase 2 clinical trial of the company's lead product, Posurdex®. Preliminary findings from this trial demonstrate that Posurdex is highly effective in improving vision in patients with persistent macular edema (PME). The study data will be presented in three separate oral presentations at the 2003 meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Fort Lauderdale, Florida. Based on these preliminary results, and pending discussions with the United States Food and Drug Administration (FDA), Oculex plans to initiate Phase 3 clinical trials for Posurdex during the fourth quarter of 2003.

A total of 306 patients were enrolled in this randomized, multi-center, dose ranging study, making it the largest Phase 2 pharmaceutical trial for macular edema conducted to date. Patients in this trial received either a single Posurdex implant containing 350 or 700 micrograms of dexamethasone, or no treatment (observation). The primary efficacy endpoint of this study was to determine whether Posurdex could provide a two-line or greater improvement in visual acuity versus observation. Preliminary results reported today indicate that 90 days after receiving the 700 microgram Posurdex implant, patients experienced a statistically significant improvement in visual acuity of 2 lines or more as measured on a standard (ETDRS) eye chart when compared to patients who did not receive a Posurdex implant (p=0.019). Measures of edema correlated with improvement in visual acuity, with statistically significant decreases in both retinal thickness and fluorescein leakage (p<0.001). Patients treated with the 350 microgram Posurdex also showed statistically significant decreases in retinal thickness (p=0.015) and fluorescein leakage (p=0.002), with a trend towards improvement in visual acuity, indicating a dose response to the treatment.

"The significant improvement in vision demonstrated by Posurdex is very encouraging," said Mark Blumenkranz, M.D., Professor and Chairman of the Department of Ophthalmology, Stanford University School of Medicine, and Oculex board member. "When considering that this study enrolled patients with only the most serious, persistent cases of macular edema, these results appear even more compelling."

The study was designed to evaluate the safety and efficacy of Posurdex. This micro-sized biodegradable product provides sustained delivery of dexamethasone, a corticosteroid known for its anti-inflammatory and anti-angiogenic properties, directly to the targeted disease site. The study enrolled patients with macular edema that persisted despite prior laser or medical treatment. Persistent macular edema treated in the trial was associated with diabetic retinopathy, retinal vascular occlusive disease, cataract surgery, and uveitis.

"We are particularly interested in the study outcomes as they relate to the various underlying disease sub-populations, especially the diabetic retinopathy group," stated study investigator Julia Haller, M.D., Katharine Graham Professor of Ophthalmology, Wilmer Eye Institute, The Johns Hopkins University School of Medicine. "Diabetic retinopathy is the most common cause of macular edema. Therefore, the ability to safely and effectively treat this patient population is essential for any potential macular edema therapy."

The preliminary data presented revealed no major safety issues related to Posurdex treatment. "Potential safety concerns expected with the use of steroids in the eye are increased intraocular pressure and cataract development," said Baruch Kuppermann, M.D., Ph.D., Associate Professor of Ophthalmology at the University of California at Irvine and lead investigator for the trial. "Posurdex displayed a remarkable safety profile with only 4% of patients experiencing a mild rise in intraocular pressure following Posurdex treatment, all of which responded to temporary topical therapy, and no significant progression of cataracts over the 90 day period."

"These results clearly support the continued clinical development of Posurdex," said David Weber, Ph.D., Executive Vice President, Oculex Pharmaceuticals. "Further, these findings validate Oculex's drug delivery technology as a means to administer and maintain effective concentrations of therapeutics in the eye to treat major, sight-threatening diseases."

ABOUT POSURDEX

Posurdex, Oculex's lead product, is a proprietary biodegradable sustained-release implant that delivers dexamethasone directly to the targeted disease site at the back of the eye. Dexamethasone is a well-known and potent corticosteroid recognized for both its anti-inflammatory and anti-angiogenic properties. In addition to persistent macular edema, Oculex is planning to initiate clinical trials in late 2003 to evaluate Posurdex in the treatment

for age-related macular degeneration.

ABOUT MACULAR EDEMA AND PME

Macular edema is a sight-threatening condition that results from the swelling of the central retina or macula and is associated with diseases such as diabetic retinopathy, retinal vein occlusion and uveitis. Affecting more than 750,000 people in the U.S. alone, and over 2.5 million world-wide, macular edema is the leading cause of visual disabilities and blindness among individuals with diabetes. Persistent macular edema, or PME, is a chronic, unresolved form of macular edema that has failed to respond to laser therapy, the current standard of care.

ABOUT OCULEX

Oculex Pharmaceuticals, Inc. is a privately held company developing innovative therapeutic products for the treatment of major, sight-threatening diseases of the eye. The company has developed the first biodegradable, sustained-release implant system designed to deliver drugs directly into the eye. This novel and proprietary platform technology overcomes the drug delivery challenges limiting the application of pharmaceuticals to the treatment of serious eye diseases. The company is using this unique technology platform to develop and commercialize its own proprietary brand name products that contain well-established generic compounds. In addition, Oculex is collaborating with strategic partners to develop and commercialize proprietary compounds for the treatment of serious diseases of the eye.

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