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Macugen Approved by FDA for Treatment for
Age-Related Macular Degeneration
Dec. 21, 2004 - The Food and Drug Administration
yesterday announced the approval of Macugen (pegaptanib sodium
injection), a new therapy to slow vision loss in people with the eye
disease neovascular (wet) age-related macular degeneration (AMD), the
major cause of vision loss in senior citizens.
(Below news story see facts about AMD.)
The wet form of macular degeneration is caused by
the abnormal growth of fragile blood vessels in the retina that leak
blood and cause damage to the light-sensitive photoreceptor cells.
The new drug, called Macugen, works by blocking
vascular endothelial growth factor (VEGF), a protein that promotes blood
vessel growth. Pegaptanib is a selective vascular endothelial growth
factor (VEGF) antagonist. Macugen has the potential for helping all
patients with the wet form of the disease, whereas the currently
approved treatment, photodynamic therapy, is only approved for patients
that have a subtype of wet macular degeneration.
"Macugen is a revolutionary, breakthrough treatment
for neovascular age-related macular degeneration as it targets the
pathologic processes underlying the disease," said Donald J. D'Amico,
M.D., Professor of Ophthalmology, Harvard Medical School. "Preserving
vision will make a significant difference to AMD patients, since AMD can
severely compromise a patient's ability to function independently.
Neovascular AMD can lead to a rapid loss of central vision that impairs
activities such as recognizing faces, reading, driving a car, crossing
streets and basic tasks. As loss of vision progresses, patients often
need help performing basic activities of daily living."
Clinical trials indicated that Macugen can slow
vision loss. Some showed evidence it can also improve vision.
"Macugen is among the first treatments to target
the underlying biology of wet age-related macular degeneration," said
Dr. Lester M. Crawford, Acting Commissioner of the Food and Drug
Administration. "Macugen provides a needed addition to the treatment of
patients with this disease."
AMD, a retinal disease causing severe and irreversible vision loss, is a
major cause of blindness in individuals older than 55 years. Untreated,
the majority of eyes affected with wet AMD may become functionally
blind.
Wet AMD, which makes up approximately 10 percent of
AMD, is caused by the growth of abnormal leaky blood vessels that
eventually damage the area of the eye responsible for central vision,
which is essential for most fine detail visual activities, including
reading, driving, and recognizing faces.
There are 15 million people in the United
States living with some form of AMD, with more than 1.6 million
experiencing the active blood vessel growth and blood vessel leakage
associated with neovascular AMD. There are over 200,000 new cases of
neovascular AMD each year and this number is expected to increase
significantly as the baby boom generation ages and overall life
expectancy increases. Presently, over 500,000 people worldwide lose
their sight annually from the disease.
"The FDA's approval of Macugen for all
neovascular age-related macular degeneration represents an important
paradigm shift in the treatment of this devastating disease. Macugen
is a novel treatment based on elegant science that for the first
time targets the underlying cause of the disease, which has lead to
our broad AMD label, including all subtypes and sizes," said David
R. Guyer, M.D., Chief Executive Officer and Co-founder of Eyetech
Pharmaceuticals, Inc.
Karen Katen, Pfizer's president of global
pharmaceuticals, said, "Macugen represents a significant milestone
in Pfizer's ongoing commitment to develop innovative ophthalmologic
treatments for people whose quality of life and independence may be
threatened by debilitating vision loss."
The safety and efficacy of Macugen was studied in
two trials in patients with wet AMD for two years. Patients treated with
Macugen exhibited a significant decrease in vision loss in both trials.
Serious adverse events related to the injection procedure included
infections, retinal detachment, and traumatic cataract. Other frequently
reported adverse events in patients treated with Macugen were eye
irritation, eye pain, hemorrhage under the outer membrane of the eye
(conjunctiva), and blurred vision.
The NDA for Macugen was received and approved in 6
months.
Macugen therapy is being co-developed by Eyetech
Pharmaceuticals, Inc. and Pfizer Inc. Eyetech and Pfizer will co-market
the product in the United States.
About Eyetech Pharmaceuticals, Inc.
Eyetech Pharmaceuticals, Inc. is a biopharmaceutical company that
specializes in the development and commercialization of novel
therapeutics to treat diseases of the eye. Eyetech's initial focus is on
diseases affecting the back of the eye. The company's most advanced
product candidate is Macugen (pegaptanib sodium injection), which
Eyetech is developing with Pfizer Inc for the prevention and treatment
of diseases of the eye and related conditions.
For further information, please visit
www.eyetech.com and
www.macugen.com/
Facts About
Age-Related Macular Degeneration (AMD) and Use of Macugen
Information from
www.macugen.com, provided by
Pfizer, Inc., and EyeTech.
Age-related macular degeneration (AMD) is a
chronic, progressive disease of the macula that can result in the loss
of central vision. The macula is the small central portion of the
retina that is responsible for the acute central vision necessary for
general mobility, including driving and activities such as reading, face
recognition and watching television, as well as for color vision.
Symptoms
The most common symptoms of AMD are a central
blurred or blank spot or distortion of objects. Peripheral vision
usually remains intact. The disease typically affects patients
initially in one eye, with a high likelihood of it occurring in the
second eye within five years.
Epidemiology
> AMD is the leading cause of severe vision loss
and blindness in patients over the age of 50 in the western world. As
many as 15 million people are diagnosed with AMD in the United States,
and 1.6 million people have late AMD.
> Approximately 200,000 new cases of neovascular
AMD arise each year in the United States.
> The rate of AMD
increases sharply with age, from 18 percent among people 70 to 74 years
of age to 47 percent among people 85 years and older.
> The number of
people in the United States age 55 or older is approximately 69 million
and is expected to increase by approximately 40 percent over the next
two decades. This increase in the number of elderly people is expected
to result in a significant increase in the number of cases of AMD in the
United States.
Types
AMD is classified into two general types:
neovascular (wet) AMD and non-neovascular (dry) AMD.
Neovascular (Wet) AMD is an eye disease in
which abnormal blood vessels leak blood and fluid into the retina,
damaging the macula and destroying central vision. Neovascular AMD is a
severe form of the disease and progresses more rapidly than the dry
type. Although it accounts for only about 10 percent of all macular
degeneration cases, neovascular AMD is responsible for 90 percent of
blindness caused by the disease and can rapidly lead to impaired visual
function. The majority of patients experience severe vision loss within
a few months to two years after diagnosis.
There are three subtypes of neovascular AMD:
predominantly classic (about 25% of cases), minimally classic
(about 35% of cases) and occult (about 40% of cases).
Non-neovascular (Dry) AMD is characterized
by the development of yellow-white deposits under the retina, known as
drusen, and sometimes the deterioration of the retina, although without
abnormal blood vessel growth and bleeding. Over time, non-neovascular
AMD cases can develop into neovascular AMD.
Risk Factors
Although researchers do not have a definitive
picture of what causes AMD, they have identified a number of factors
that might put a person at greater risk for developing this disease.
Age: This is by far the greatest risk
factor for AMD. According to some estimates, 25 percent of people
between 65 and 74 years of age have AMD or are at very high risk for
developing it. Among people age 75 and above, 33 percent have the
disease.
Genetics: Research shows that people with a
family history of AMD are at greater risk of developing the disease,
which suggests that some cases of AMD are hereditary. People with a
family history are encouraged to have their eyes checked regularly for
the condition, but because early stages of the disease are often
asymptomatic, even those without a family history of the disease should
have their eyes checked.
Other potential environmental and behavioral
risk factors being studied include:
Cigarette smoking: Two studies have found that
current and former smokers have as much as twice the risk of developing
AMD as non-smokers. Quitting smoking - while greatly reducing the risk
of certain cancers, emphysema and heart disease - does not appear to
reduce the risk of AMD. Exposure to secondhand smoke may also
contribute to the risk of developing AMD.
Overexposure to ultraviolet (UV) light: The link
between UV exposure and cellular damage has been shown in previous
studies, leading to the theory that UV exposure might damage the macula
and cause AMD. Studies to support this theory have proven inconclusive
thus far and additional studies are needed. Nonetheless, eye doctors
recommend protecting eyes from the sun and other UV light.
Dietary fat intake: Research on the link between
diet and AMD risk shows that high consumption of monounsaturated,
polyunsaturated and vegetable fats commonly found in many snack foods
was associated with double the risk of developing neovascular AMD.
High intake of linoleic acid, another fat common in snack foods, was
associated with the greatest risk of developing neovascular AMD. In the
same study, researchers found that people with limited intake of
linoleic acid and who ate two or more servings of fish per week had a
lower risk of developing AMD.
Effects on Daily Living
Neovascular AMD can severely compromise a patients
ability to function independently.
Loss of central vision can impair activities such
as reading and driving a car.
As loss of vision progresses, patients need help
performing activities of daily living, such as shopping, managing money,
preparing meals, doing housework, using the phone, and crossing the
street.
Clinical depression occurs in almost one third of
patients.
Treatment
Neovascular AMD
Macugenฎ (pegaptanib sodium
injection)
MACUGEN is indicated for the treatment of
neovascular age-related macular degeneration.
Dose is 0.3 mg once every six weeks by intravitreal
injection into the eligible eye.
The first ophthalmic drug in a new class of drugs
known as vascular endothelial growth factor (VEGF) inhibitors.
Works by selectively binding to and inhibiting VEGF
165, a protein that stimulates abnormal blood vessel growth and blood
vessel leakage, two of the underlying causes of vision loss associated
with neovascular AMD.
Macugen is well tolerated, with most adverse events
being mild, transient, ocular and attributed by investigators to the
injection procedure rather than the drug. Serious adverse events related
to the injection procedure occurring in <1% of intravitreal injections
included endophthalmitis, retinal detachment, and iatrogenic traumatic
cataract. Most frequently reported adverse events in patients treated
for up to two years were alterations in vision, anterior chamber
inflammation, cataract, conjunctival hemorrhage, corneal edema, eye
discharge, eye pain, hypertension, increased intraocular pressure (IOP),
punctate keratitis and vitreous floaters and opacities.
Photodynamic therapy
FDA-approved for only the predominantly classic
subtype of neovascular AMD.
Involves systemic administration of a
light-activated drug (Visudyneฎ) by intravenous infusion and
then delivery of low energy light to the target site to activate the
drug and destroy the newly grown abnormal blood vessels.
Non-neovascular AMD
There is no generally accepted treatment for dry
AMD, but the National Eye Institutes Age-Related Eye Disease Study (AREDS)
found that high daily doses of antioxidants and zinc may have a modest
effect in slowing the progression of intermediate AMD to advanced AMD.
MACUGEN is contraindicated in patients with ocular
or periocular infections.
Intravitreal injections including those with
MACUGEN have been associated with endophthalmitis. Proper aseptic
injection technique should always be utilized when administering MACUGEN.
In addition, patients should be monitored during the week following the
injection to permit early treatment should an infection occur.
Increases in IOP have been seen within 30 minutes
of injection. Therefore, IOP and retinal perfusion should be monitored
and managed appropriately.
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