Clinical studies on three new drugs have
shown their effectiveness in reducing vision loss from wet age related macular
degeneration (AMD) in early clinical studies.
These drugs are Genentech’s rhuFab, Eyetech’s Macugen and Alcon’s
Anecortave Acetate. The preliminary studies for each of these drugs have shown
that these treatments are reducing vision loss, helping to prevent severe
vision loss and inhibiting abnormal blood vessel growth in wet macular
degeneration patients.
AMD is the leading cause of legal blindness
in the
United States
in adults over the age of 65. There are two types of macular degeneration, the
“wet” and “dry” forms. Dry AMD is a deterioration of the retinal cells
in and around the macula. The macula is a small area of the retina that is
responsible for our fine detail vision. Macular degeneration causes a dark
spot in patient’s vision which makes reading and seeing faces and other
detail difficult.
Wet macular degeneration is when new
abnormal blood vessels form and grow in the macular region. These blood
vessels can leak and hemorrhage causing severe vision loss. Approximately 10
percent of all AMD cases are of the wet form, but in most cases, it is more
visually devastating than dry AMD. These new medications may help slow or stop
the growth of the new blood vessels; therefore there is less leakage and
retinal damage.
These anti-neovascular drugs are injected
into the eye using specially designed syringes to deliver the drugs to the
area of diseased retina. These injections were repeated multiple time
depending upon the drug. The two drugs, rhuFab and Macugen, work by binding in
the eye to the free floating protein called VEGF, the vascular endothelial
growth factor. This binding of the medication to the protein blocks the
ability of the eye to induce blood vessel growth beneath the retina and
decreases blood vessel leakiness. Anecortave acetate is a steroid and works by
a slightly different mechanism, but also inhibits the signaling of new blood
vessel growth in the macula which leads to the progression of wet AMD.
At the current time, all of these drugs are
in clinical trials. The results of these trials will not be known for a few
years, and the safety and effectiveness of these drugs are still uncertain.
However, the preliminary studies appear promising that researchers are on the
right path to finding good treatment options for those with wet macular
degeneration.
