Safer psoriasis drug works well in trials
More than 4.5 million Americans have psoriasis, a disorder characterized by raised, thickened patches of red skin covered with silvery scales. Although the condition is common, scientists only recently learned that it is an autoimmune disorder.
Now that discovery has paid off. A new injectable drug relieves symptoms by blocking the immune system reaction without the sometimes serious side effects of current treatments.
“Now we have a drug that is as effective but much safer,†said Dr. Mark Lebwohl, a dermatologist at Mount Sinai School of Medicine in New York, who has tested the drug, Amevive, on patients.
Most people with psoriasis experience only mild symptoms, which can be soothed with topical creams. But 1 million sufferers have more debilitating symptoms, including constant itching, cracked skin and painful lesions.
These symptoms can be controlled with ultraviolet light or medications that dampen the immune response, such as cyclosporine (a transplant anti-rejection drug) and the cancer medication methotrexate. However, getting UV treatment three times a week for months is inconvenient; methotrexate can damage the liver and cause anemia; and cyclosporine can cause headaches and kidney damage.
University of Michigan scientists, led by Kevin Cooper, discovered in the 1980s that when certain types of white blood cells hook up to other immune cells, known as antigen-presenting cells, the white blood cells send a signal that prompts skin cells to grow wildly out of control.
That team later collaborated with Biogen scientists, including Paula S. Hochman and Barbara P. Wallner. In 1986, Wallner cloned a gene that produces a compound to block this activation. The trick, says Wallner, was to devise a drug that blocked the immune reaction without weakening the immune system.
Two more years of tinkering produced a substance potent enough to work on human skin cells in the test tube, and several more years of tests were conducted before the drug was injected in the first patient in 1995.
It turned out to be quite effective. A 2001 study of 229 patients with chronic psoriasis, some of whom had as much as 50% of their body covered with plaques, compared weekly injections of Amevive with a placebo.
In those treated with the drug, psoriasis severity declined by about half, and a quarter said their skin cleared completely.
In some patients, the drug kept the disease from flaring up for a year or more after the 12-week treatment was over. The drug is awaiting FDA approval.
“Some of them had suffered with severe psoriasis for 20 years and had given up because nothing really worked,†says Hochman. “They were thrilled -- it really changed their life.â€
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Other Options
Another promising psoriasis drug, Raptiva, may be available by the end of 2003. Like Amevive, it is part of a new generation of therapies that fight psoriasis by blocking the immune system reaction involved in the disorder.
Recent tests in 1,000 patients with moderate to severe psoriasis showed the drug is as effective as Amevive.
Raptiva can be injected under the skin by patients at home (Amevive must be injected intravenously in a doctor’s office). The drug also works faster than Amevive, providing almost immediate relief.
Two other drugs already on the market also may be able to treat psoriasis. Enbrel, for rheumatoid arthritis, and Remicade, for Crohn’s disease, have proven effective in some studies.
