New drug takes eyesight from 20-100 to 20-20
An
estimated 200,000 new cases of wet macular degeneration are diagnosed
in the United States annually. About 4 million U.S. diabetics have
some degree of retinopathy, and 24,000 go blind each year.
Both
diseases result from misguided growth of blood vessels in the eyes.
Since the new drugs attack this underlying problem, doctors hope they
will work for both diseases.
The
need for new treatments is expecially dire in wet macular
degeneration, because nothing can be done for most victims. Blindness
often follows within months or even weeks of the first symptoms.
It
occurs when leaky blood vessels sprout behind the retina, probably in
a mistaken attempt to fix the slow breakdown of light-sensitive cells
that occurs with age. These vessels ooze fluid and damage the fragile
tissue that controls straight-ahead vision.
To
doctors' amazement, experimental new medicines are rescuing people
from the brink of blindness so they can read and drive and sometimes
even regain perfect vision.
Around
the country, about 70 patients with wet macular degeneration have been
treated with, Genentech's rhuFab.
About half were treated by Dr. Jeffrey Heier of Ophthalmic
Consultants of Boston, who says, "I can honestly say I have never
seen anything as exciting as this."
Experts
caution that most of the results from the studies on this and similar
drugs will not be known for at least a year or two. And for now, the
treatments are available only to study volunteers.
None
of the drugs are intended for the more common but less aggressive
"dry" kind of macular degeneration, nor will they work after
eyesight has been gone for months.
Guessing
the drugs' ultimate effectiveness based on early testing is risky.
Still, doctors estimate that roughly one-quarter to one-third of
people with newly diagnosed wet macular degeneration have had
significant improvement in their eyesight. In most of the rest, loss
of sight is stopped, at least temporarily
These
lucky few are the first beneficiaries of an entirely new category of
drugs that many hope will revolutionize the care of common eye
diseases.
Several
competing medicines are in development, all based on similar
principles. They are designed to stop the two top causes of adult
blindness _ the "wet" form of macular degeneration, which
affects the elderly, and diabetic retinopathy, the biggest source of
blindness in working-age people.
Vision
loss seems halted for most if they take the drugs soon after their
symptoms begin. Some experience stunning reversals of what would have
been inevitable blindness.
The
new drugs vary, although most of them, like rhuFab, zero in on a
growth-promoting protein called vascular epidermal growth factor, or
VEGF. It appears to be an especially important trigger of damaging
blood vessels in both forms of blindness.
Other
drugs in testing include:
--Anecortave
acetate from Alcon, a new steroid injected next to the eye once every
six months for macular degeneration.
--Eyetech
Pharmaceuticals' EYE001, which is injected into the eyeball like
rhuFab for macular degeneration.
--Bausch
& Lomb's Retisert implant, which exudes a steroid into the eye for
up to three years and is being used for diabetic retinopathy and
macular degeneration.
--Lilly's
LY333531, the only pill among the new drugs; used to prevent worsening
eye disease in diabetics. Source: American Diabetes
Association
Publication date: 2002-07-02
Kristina
Sandstedt,
MS,
Clinical
Exercise
Physiologist,
Diabetes
Educator
New
Drug Restores Eyesight*
