A unique drug that targets renegade immune cells to control hard-to-treat psoriasis won Food and Drug Administration approval Friday, offering a long-awaited new option to patients covered in the itchy skin disease.
Called Amevive, the drug has been eagerly awaited by physicians because it works differently than the many other psoriasis treatments on the market.
Amevive has not yet been compared to any other treatments so there's no way to know if it will prove a better option for patients, the FDA cautioned.
Still, about 1.5 million Americans have moderate to severe psoriasis. While it's not yet curable, many are searching for new options to control the stubborn disease that can cover much of the skin in red, scaly, itchy patches. Particularly severe forms also can cause a type of arthritis.
Amevive, which comes in intravenous and intramuscular injection forms, will begin selling Monday, said maker Biogen Inc. It will cost $7,000 to $10,000 for a 12-week course of treatment; each weekly dose is given in a doctor's office.
Psoriasis is thought to form when the immune system runs amok and cells called memory effector T cells prompt skin inflammation.
Current treatments for psoriasis range from ointments to ultraviolet therapy to other injected drugs that can broadly suppress the immune system.
Amevive, known chemically as alefacept, was designed to target only the harmful T cells, not the rest of the immune system.
"That's certainly a hope, that you have a much more selective effect" than with other medications, said FDA's Dr. Karen Weiss. But, she cautioned, "it's too soon to say it's a very selective and therefore a very safe therapy."
In fact, patients will require a blood test before each weekly Amevive dose to ensure their levels of infection-fighting immune cells haven't dipped too low, which would require postponing a dose. Another theoretical concern is that by suppressing the immune system, the risk of cancer might increase.
Biogen-sponsored studies enrolled patients with chronic psoriasis that covered at least 10 percent of their bodies, and gave them either Amevive or dummy injections. About 40 percent of Amevive patients saw their psoriasis symptoms cut in half, compared with about 10 percent of placebo-treated patients.
A small number even saw their lesions almost vanish, for at least a while.
How long the effect lasted varied, but a small subset of patients went seven months or longer before needing additional treatment, FDA said.
The FDA didn't restrict the number of times patients can repeat Amevive therapy when their psoriasis recurs. But Cambridge, Mass.-based Biogen did agree to track such patients to provide more safety data, Weiss said.
One additional warning: No one knows if the drug will harm a developing fetus, and many psoriasis patients are women of childbearing age. So doctors are encouraged to list any patients who become pregnant while using the drug in a Biogen pregnancy registry, by calling 1-866-AMEVIVE.
By Lauran Neergaard