Avastin, its application in age-related macular degeneration (AMD)

Use of Avastin in age-related macular
degeneration (AMD)
January, 2007

Angiogenesis, the growth of new blood vessels from existing blood
vessels, is responsible for vision loss in a variety of ophthalmic
diseases. In neovascular age-related macular degeneration (AMD),
the leading cause for legal blindness in many industrialised countries,
abnormal blood vessels grow in the macula and cause blindness. [A2]

A fully alert 83-year-old woman with occult choroidal neovascularization
(CNV) left eye (OS) experienced a progressive visual loss to 20/800 OD
and 20/400 OS. Another patient with occult CNV both eyes (OU)
experienced decreased vision of 20/800 OU.

One day and three days After the injection of 1.25 mg Avastin in the left
eyes of both patients, they both experienced structured hallucinations
including trees, faces, and water for approximately 15 to 30 minutes. [A1]

The researchers believed that the reduced retinal edema and realignment
of the photoreceptors promoted the release phenomenon and triggered
hallucinatory episodes. [A1]

WHAT IS AVASTIN? Avastin-first line treatment for patients with
metastatic colorectal cancer- is a genetically engineered version of a
mouse antibody that contains both human and mouse components.
(Antibodies are substances produced by the body's immune system to
fight foreign substances.) Avastin was shown to extend patients' lives by
about five months when given intravenously as a combination treatment
along with standard chemotherapy drugs for colon cancer. However,
Avastin will not cure metastatic colorectal cancer.

MECHANISM Avastin works by targeting and inhibiting the function of a
natural protein called "vascular endothelial growth factor" (VEGF) that
stimulates new blood vessel formation. When VEGF is targeted and
bound to Avastin, it cannot stimulate the growth of blood vessels, thus
denying tumors blood, oxygen and other nutrients needed for growth.

SAFETY AND EFFICACY The safety and efficacy of Avastin was primarily
shown in a randomized, double-blind clinical trial of more than 800
patients with metastatic colorectal cancer designed to find out whether
Avastin extended the lives of patients. Overall, patients given Avastin in
combination with IFL survived about five months longer and the average
time before tumors started regrowing or new tumors appeared was four
months longer than patients receiving IFL alone. The overall response
rate to the treatment was 45% compared to 35% for the control arm of
the trial.

Special Warning and Side Effects of Avastin: Avastin may cause
gastrointestinal perforation (holes in the stomach, intestines or colon)
requiring surgery to repair. Avastin may impair wound healing or cause
wounds to open up. Avastin may cause severe infusion reactions such as
trouble breathing during the first or later doses.

Other, more common, side-effects are high blood pressure, tiredness,
blood clots, diarrhea, decreased white blood cells (lowering immunity to
diseases) headache, appetite loss and mouth sores.
MORE ABOUT AVASTIN

Reference
[A1] Meyer CH, et al, Visual Hallucinations After Intravitreal Injection of
Bevacizumab in Vascular Age-related Macular Degeneration. Am J Ophthalmol.
2007 Jan;143(1):169-170. Epub 2006 Sep 7. [A2] Michels S et al, Promising new
treatments for neovascular age-related macular degeneration. Expert Opin Investig
Drugs. 2006 Jul;15(7):779-93.

For more detailed information about Avastin or other questions, ask your health
care provider or pharmacist. This article can be used only as a reference. Publisher
does not guarantee its accuracy. ALL RIGHTS RESERVED 2007 zhion.

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