The drug infliximab, normally prescribed for arthritis, seems also to work against the chronic skin disease psoriasis. The benefits were akin to those induced by cyclosporin, a potent immune suppressant routinely prescribed for psoriasis.
Scientists gave 33 psoriasis patients three intravenous infusions over 6 weeks. A third of the participants received a low dose of infliximab, a third got a high dose, and the rest received a placebo. Four weeks after the last treatment, 19 of the 22 patients getting infliximab had far fewer skin lesions than at the start of the experiment, whereas only 2 of 11 in the placebo group had improved, the researchers report in the June 9 Lancet. Patients’ responses to the low and high drug doses were approximately the same.
The skin lesions “cleared quickly, in 6 to 8 weeks” after the start of treatment in most patients receiving infliximab, says study coauthor Alice B. Gottlieb, an immunologist at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School in New Brunswick.
The cause of psoriasis, an immune disorder marked by accelerated growth of skin cells, is unknown. The resulting skin lesions can be painful and itchy. Some patients also develop joint damage. Cyclosporin and other drugs allay some symptoms by broadly suppressing the immune system, but they can have severe side effects in long-term use, Gottlieb says.
In contrast, more than 100,000 patients have taken infliximab for rheumatoid arthritis without serious adverse effects. The drug, sold commercially as Remicade, is a monoclonal antibody that attacks a protein that’s made by immune cells called tumor necrosis factor alpha (TNF-alpha).
TNF-alpha induces production of certain inflammatory proteins dubbed interleukin-1, -6, and -8.
These and other inflammatory molecules show up in high concentrations in the skin lesions common to psoriasis, Gottlieb says. Inflammation also underlies rheumatoid arthritis.
Gottlieb is now working on a longer test of infliximab. Preliminary data from that study show that some patients are free of skin lesions more than 6 months after treatment, she says.