Pfizer Pharmaceuticals, (OSI) Eyetech Inc., and the FDA are alerting health care professionals to risks associated with injections of Macugen, a medication for wet age-related macular degeneration (AMD), the leading cause of blindness among the elderly. Pfizer is a WebMD sponsor.

Since market introduction in the U.S.market introduction in the U.S. in late 2004, there have been rare reports of anaphylaxis/anaphylactoid reactions, including angioedema, following the use of Macugen along with various medications administered as part of the injection preparation.

Angioedema is similar to hives but occurs beneath the skin instead of on the surface. It is characterized by deep swelling around the eyes and lips and sometimes of the genitals, hands, and feet.

What Is Wet AMD?

The wet form of AMD accounts for about 10% of all cases of the disease but is responsible for 90% of severe vision loss associated with AMD.

Wet AMD occurs from the growth of abnormal, leaky blood vessels below the retina — the light- sensitive tissue in the back of the eye. The blood and fluid that escape cause damage to central vision, which is required for activities like reading, driving, and recognizing faces.

Macugen
Macugenwas developed to block development of these leaky blood vessels. It does this by blocking a growth factor called VEGF (vascular endothelial growth factor).

If untreated, vision can become severely impaired to the point of blindness.

The Risks

Macugen is given once every six weeks by intravitreous injection (directly into the eye). Health care professionals are being told to evaluate the patient’s medical history for hypersensitivity reactions to Macugen prior to using this product.

A direct relationship to Macugen or any of the various medications administered as part of the injection preparation procedure or other factors has not been established in these cases. The patient’s medical history for hypersensitivity reactions should be evaluated prior to performing the intravitreal injection procedure.

Label Revisions

The revisions to the label are as follows, with the new information in italics:

• Macugen is contraindicated [cannot be used] in patients with ocular or periocular infections.
• Macugen is contraindicated [cannot be used] in patients with known hypersensitivity to pegaptanib sodium or any other excipient [injection ingredient] in this product.

The label will also say:

• FOR OPHTHALMIC INTRAVITREAL INJECTION ONLY.
  
  
  
  
• Rare cases of anaphylaxis/anaphylactoid reactions, including angioedema, have been reported in the post-marketing experience following the Macugen intravitreal administration procedure.

Also included is this note about the difficulty of estimating how many people are affected by allergic reactions:

“Anaphylaxis/anaphylactoid reactions, including angioedema, have been identified during postapproval use of Macugen. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug.”

The new label will remind patients of the proper method of injecting Macugen:

“The injection procedure should be carried out under controlled aseptic conditions, which includes the use of sterile gloves, a sterile drape, and a sterile eyelid speculum (or equivalent). The patient’s medical history for hypersensitivity reactions should be evaluated prior to performing the intravitreal [injection] procedure.”

Health care professionals can report serious adverse event information associated with the use of Macugen to Pfizer Inc. at (800) 438-1985. You can also report the information directly to the FDA via the MedWatch system at (800) FDA-1088, by fax at (800) FDA-0178, by mail (using a postage-paid form), or the Internet at www.fda.gov/medwatch.

The Pfizer Medical Drug Information Department will provide information at (800) 438-1985.