Trials That Matter: Two Faces of Progress in the Treatment of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a common ocular condition that may destroy central vision and have a devastating effect on the quality of life of people over the age of 55. Since the population of the United States is now living longer, more people are at risk for developing the disease as the population ages. By age 70, nearly 1 of 3 people shows signs of at least mild AMD on ophthalmologic examination.

The earliest recognizable manifestation of AMD is the presence of drusen—white deposits that can be observed in the macula during an ophthalmoscopic examination. Patients with drusen are classified as having early (dry) AMD. These patients may have no visual symptoms or may require additional light to read small print. Most patients with dry AMD will never develop severe vision loss or progress to late (wet) AMD.

Some patients with drusen, however, develop leaky blood vessels, a form of wet AMD known as choroidal neovascularization. Leakage of fluid or blood from choroidal neovascularization can cause a precipitous loss of central vision. Fluorescein angiography, a diagnostic technique used frequently by retina specialists, facilitates the categorization of patients with choroidal neovascularization into 3 groups: predominantly classic, minimally classic, and occult. These angiographic categories have been useful in predicting the outcome of the disease and in developing guidelines for photodynamic therapy of AMD.

Until recently, the only pharmacologically based therapies for treatment of patients with wet macular degeneration have been photodynamic therapy with verteporfin and intravitreous injections of pegaptanib sodium. Although the pathophysiology of AMD is still poorly understood, it is increasingly clear that vascular endothelial growth factor A plays an important role in the promotion of neovascularization and the vessel leakage that leads to loss of central vision. While vascular endothelial growth factor A occurs in several biologically active forms, …