The FDA has approved oral and injected drugs that circulate throughout the body to treat psoriasis that is moderate, severe, or disabling. These systemic drugs are very powerful, and while some may be used continuously, others can only be used for a limited time because of their severe side effects. Once a drug is discontinued, the psoriasis may reactivate. The risk of birth defects prevents many systemics from being taken by pregnant women or women planning to become pregnant.
Systemic drugs that may be prescribed for psoriasis include acitretin, methotrexate, cyclosporine, and biologics, which are drugs made from proteins of living cells. Methotrexate, cyclosporine, and the biologic drugs are immunosuppressants, meaning they lower the body's normal immune response. "These drugs suppress the immune cells that cause psoriasis, but they don't distinguish these cells from the immune cells that protect our body from infections," says Elektra Papadopoulos, M.D., an FDA dermatologist.
Acitretin, a retinoid that is given orally for severe psoriasis, helps normalize the growth of skin cells. One of the side effects is raised fat (lipid) levels in the blood, and people taking this drug must get regular blood tests to monitor their cholesterol and triglyceride levels.
Methotrexate and cyclosporine slow the growth of skin cells. Methotrexate, taken orally or by injection, is also a chemotherapy drug for cancer patients. Cyclosporine, taken orally, was first approved to prevent organ rejection in transplant recipients. People using either of these drugs must be closely monitored and should use them only for short periods of time because of serious, potentially fatal, side effects.
Biologics are the newest systemic psoriasis treatments. Since 2003, the FDA has licensed three biologics to treat moderate-to-severe plaque psoriasis: Amevive (alefacept), manufactured by Biogen Inc.; Raptiva (efalizumab), made by Genentech Inc.; and Enbrel (etanercept), marketed by Amgen Inc. and Wyeth Pharmaceuticals. Enbrel was first licensed in 2002 to treat the arthritis associated with psoriasis, and in 2004 to treat psoriasis itself.
"All are immunosuppressive and have different proposed mechanisms," says Papadopoulos. Amevive simultaneously reduces the number of immune cells, including T cells, and inhibits T-cell activation. Raptiva inhibits the activation of T cells and the migration of those cells across blood vessels and into tissues, including the skin.
Enbrel inhibits the action of an inflammatory chemical messenger in the immune system called tumor necrosis factor-alpha (TNF-alpha), which is believed to play a role in both the skin and the joint symptoms of psoriasis.
All three biologics are injected. The FDA has licensed Amevive to be given in a physician's office, either injected into the muscle or into a vein (intravenously). It's a once-a-week treatment for 12 weeks; further treatments may be given after a waiting period.
The FDA has licensed Raptiva and Enbrel for home treatment. People can inject themselves with Raptiva under the skin once a week or with Enbrel once or twice a week. Both drugs are recommended for continuous use to maintain results.
Since biologic drugs are immunosuppressants, they may carry an increased risk of infection and cancer. Rare but serious effects have also included blood abnormalities and autoimmune diseases such as lupus. Other side effects are flu-like symptoms and pain and inflammation at the injection site.
Some dermatologists prescribe biologics alone for psoriasis or in combination with topical treatments. Leonardi says when he prescribes biologics, "I don't have to resort to adding other systemic therapies such as methotrexate, cyclosporine, acitretin, or phototherapy."
"Biologics are an alternative treatment to some of the traditional therapies," says Papadopoulos.
"Now we need to get the expense down," says Leonardi, who has patients who pay $30,000 per year on drugs to treat psoriasis.
Bird feels fortunate that her insurance company covers most of the expense of Enbrel, which is prescribed for both her psoriasis and psoriatic arthritis. Because of the arthritis pain, she has used a cane to help her walk and has had surgery on her wrist to correct some of the arthritis damage. Although Enbrel has been less effective over time for the psoriasis, she says, it's reduced her arthritic pain by about 95 percent. "I can jog down to the corner to chase after the dog," she says. "And last summer, I went hiking with my children in Colorado."