And most patients showed an improvement in their psoriasis, according to the study. Enbrel had previously been shown to be safe and effective when used over a short period of time, but the question remained whether long-term use of the drug would be safe.
"This drug is safe for long-term use," said lead author Dr. Stephen Tyring, a clinical professor of dermatology at the University of Texas Health Science Center at Houston. "During 96 weeks of follow-up, both the safety and efficacy of the drug were very good."
Enbrel (etanercept) is a drug that blocks tumor necrosis factor, a pro-inflammatory cytokine. People with an immune disease, such as psoriasis, have too much tumor necrosis factor (TNF) in their bodies. Enbrel reduces the amount of TNF to normal levels, but it can also lower the ability of the immune system to fight infections.
In the trial, Tyring's team randomly assigned 618 people with psoriasis to 12 weeks of treatment with Enbrel or a placebo. The patents received 50 milligrams of Enbrel twice a week. After the initial 12 weeks of treatment, 591 patients from both groups continued to receive Enbrel for 84 weeks.
The study researchers found that people receiving Enbrel or a placebo had a similar number of adverse reactions, including serious infections. "There was not a problem with increased infections or any other adverse events in using the drug for the long term, and this is at the higher dosage of 100 milligrams a week," Trying said.
What's more, by the end of the trial, the psoriasis had improved at least 75 percent for 51.1 percent of the original Enbrel group and 51.6 percent of the original placebo group.
The findings are published in the June issue of the Archives of Dermatology.
Tyring noted that Enbrel is not usually used alone, as it was in this trial, but in combination with other drugs, such as creams, as well as with light therapy. "So, in real life, we see better results," he said.
The main drawback to long-term Enbrel treatment is cost, Tyring said. "Like all five biological treatments for psoriasis, Enbrel is expensive, and if the patient doesn't have insurance, it is difficult to keep using this dosage and perhaps even a lower dosage," he said.
According to the National Psoriasis Foundation, Enbrel can cost $10,000 to $25,000 a year or more, depending on the dose and how often it is taken.
One skin disease expert agreed that long-term use of Enbrel is safe and effective, even at the higher dose.
"Physicians would love to use the drug this way," said Dr. Jeffrey M. Weinberg, director of the clinical research center in the department of dermatology at St. Luke's-Roosevelt Hospital Center, in New York City. "The limiting factor is cost," he added.
Some patients do well on 50 milligrams a week, Weinberg said. "But many people do better at the higher dose, especially those who weigh more," he said. "About 40 percent of patients would benefit from the higher dose."
By Steven Reinberg, HealthDay News, June 19, 2007