Wet AMD

New Drug Study for Wet AMD

A drug called rhuFab has shown impressive results in early trials to treat newly onset wet age-related macular degeneration (wet AMD). Manufactured by Genentech, rhuFab is currently being evaluated at Shiley Eye Center, in conjunction with the FDA approved Visudyne. Visudyne is a laser therapy which selectively destroys the “bad” blood vessels, without causing damage to the “healthy” retinal tissue in the surrounding area.

Macular Degeneration (AMD), the leading cause of blindness in those over 65 years of age, occurs in two forms dry and wet. Both versions affect the part of the retina responsible for sharp central vision, called the macula. Although only 10 percent of all people with AMD have the wet form, it accounts for 90 percent of all severe vision loss from the disease. Wet AMD occurs when new blood vessels behind the retina start to grow toward the macula, because these new vessels tend to be very fragile they will often leak blood and fluid, thus the term ‘wet.’ This leakage causes damage that can lead to rapid loss of central vision.

Though results are not established, multiple injections of rhuFab administered over several months appear to stop wet AMD from progressing, and in some cases, restore vision. At one trial site, after just one week on rhuFab a patient went from 20/400 to 20/40 in his treated eye and returned to playing tennis.

However, Shiley Retina Surgeon William R. Freeman, M.D. who has been working closely with Genentech cautions, “While the early indications are promising enough for Shiley to begin enrolling suitable patients, further study is needed to determine the best use of rhuFab.” So far, doctors testing the drug estimate that roughly one-quarter to one-third of people with newly diagnosed wet AMD have had significant improvement in their treated eye. In most of the rest, there may be a slowing of the disease.

(A retina affected by wet AMD)

Researchers hope the new classification of drugs like rhuFab will revolutionize the care of wet AMD and other eye diseases. RhuFab works by binding to a growth promoting protein called vascular endothelial growth factor (VEGF). It successfully blocks VEGF’s ability to induce blood vessel growth (a process called anti-angiogenesis) beneath the retina, as well as blood vessel leakiness. A similar disease process occurs in diabetic retinopathy, the leading cause of blindness in working-age people. Though retina specialists believe drugs like rhuFab will successfully treat diabetic retinopathy, the current study does not include these patients.

Prospective patients should be at least 50 years of age, with a recent onset of wet AMD, and have never experienced a vitreous hemorrhage in the study eye. Dr. Freeman has been working with Genentech to evaluate this compound and design the next phase of studies. Dr. Freeman is now the principle investigator of the rhuFab study, a will bnde working with Michael Goldbaum, M.D., Co-Chief of the Retina Division, and the other Shiley retina specialists, all who will be treating eligible patients with rhuFab. To learn more about the criteria or to enroll in the study call Denie Cochran, clinical trial coordinator, at 619-543-5099.

Since Fall of 2001, Dr. Freeman has been working with Genentech on the development of anti-angiogenic compounds. He and his colleagues have begun work on another compound not made by Genentech, which may work to inhibit forms of wet AMD that appear to be resistant to the anti-VEGF drugs, like rhuFab. Recently, Dr. Freeman’s team completed an initial animal study on this compound with plans to report the results this Spring at the International meeting of the Association of Research in Vision and Ophthalmology (ARVO). With the FDA’s approval, a patient clinical trial is expected to commence at Shiley in late 2003.