AMEVIVE® (alefacept)

Psoriasis is an autoimmune skin disease. Normally, the body's immune system recognizes foreign invaders, like bacteria, and attacks them without affecting normal tissue. An autoimmune disorder occurs when the body mistakenly launches an attack on its own tissue.

How the Immune System Works
The immune system keeps the body healthy by attacking potentially harmful, infectious organisms, such as germs, bacteria and viruses. The body can recognize these organisms through their antigens. Antigens are identifying characteristics unique to the organism, much like a fingerprint. Every potentially harmful organism entering the body has its own antigen "fingerprint." When these organisms enter the body, they are detected by the immune system and a response is triggered. This response involves two steps: first, recognition of the antigen and, second, an immune response that destroys it.

The Soldiers of the Immune System
There are many different types of immune cells that defend the immune system - identifying, attacking and destroying the foreign invaders. T-cells play an important role in this defense. T-cells are a type of white blood cell that identify antigens and mount an attack.

There are two main types of T-cells - helper T-cells and killer T-cells. Helper T-cells travel through the blood on the lookout for antigens. When they encounter an antigen, they trigger other immune cells to attack the antigen. Killer T-cells are directed by the helper T-cells, by attacking and killing the enemy antigens.

Psoriasis: A Malfunction of the Immune System
The skin is the largest organ in the body, and is capable of generating a variety of immune reactions. Psoriasis can result when a person's immune response is inappropriately triggered. Most researchers now believe that people with psoriasis have inherited a susceptibility to this faulty immune response.

Scientists also believe that an as-yet-unknown antigen activates the chain of events leading to psoriasis. This antigen is spotted by helper T-cells. After identifying the antigen, the helper T-cells travel into the skin. Why the helper T-cells seek the skin remains unclear. But research suggests the cells are drawn by signals from other immune cells already present in the skin. Another possibility is that the skin cells are misfiring and unnecessarily calling for reinforcements.

When the helper T-cells travel into the skin, they trigger killer T-cells already present to attack the enemy antigen. Once they've been called into battle, the killer T-cells begin to multiply and coordinate an inflammatory response, as if the skin was fighting an infection. They also release inflammatory chemicals that further drive the process of psoriasis, causing skin cells to grow at an accelerated rate and pile up on the surface. This is how the red, raised, scaly lesions associated with psoriasis develop.

New Ways to Treat Psoriasis
Biologic medications offer a new treatment option for people living with psoriasis. This new class of therapies is believed to specifically interrupt the chain of events in the immune response that lead to psoriasis. AMEVIVE® (alefacept) is the first biologic approved for the treatment of moderate-to-severe chronic plaque psoriasis. For more information and full prescribing information, please visit www.Amevive.com.

Important Safety Information
Commonly observed adverse events that occurred in clinical studies more frequently with AMEVIVE® (alefacept) included: sore throat, dizziness, increased cough, nausea, itching, muscle aches, chills, injection site pain, injection site inflammation, and accidental injury.

AMEVIVE must be administered under the supervision of a physician.

AMEVIVE reduces lymphocyte counts (also called T-cells). T-cell levels should be measured weekly during the 12-week dosing period.

AMEVIVE reduces immune cell counts, which could increase your chance of developing infection or malignancy, which you should discuss with your doctor. If you develop any signs of infection or malignancy while undergoing a course of treatment with AMEVIVE, you should notify your doctor.

AMEVIVE should not be taken if you are known to be allergic to AMEVIVE or any of its components.

If you become pregnant while you are receiving AMEVIVE or within 8 weeks of finishing AMEVIVE, notify your doctor and consider enrolling in the Pregnancy Registry by calling 1-866-AMEVIVE.