Enbrel acts like a very specific sponge that soaks up only one thing: a chemical messenger called tumor necrosis factor or TNF. TNF plays a major role in psoriasis by triggering inflammatory, skin-damaging, arthritis-causing immune responses.
Because TNF also helps the body fight off infection and cancer, there have been nagging worries that safety problems might arise in patients on long-term Enbrel treatment -- especially those who need higher doses. Also, doctors wondered whether the drug's psoriasis-easing effects would wear off over time.
To answer these questions, Stephen Tyring, MD, PhD, of the University of Texas Health Science Center at Houston and colleagues signed up 618 adult psoriasis patients for the study.
To enter the study, patients had to have at least "moderate" psoriasis -- that is, psoriasis affecting 10% of their body surface. Study patients tended to have much more severe disease, with an average 27% of their body surface affected. also, at least one systemic psoriasis treatment or phototherapy had to have failed to help.
Patients received twice-weekly injections (under the skin) of Enbrel at the 50-milligram dose for 96 weeks -- nearly two years. Half the patients received placebo injections for the first 12 weeks of the study. After that, everyone in the study got Enbrel.
The results: At week 96, half the patients in both groups had at least a 75% reduction in psoriasis severity without any increase in infections or other serious diseases.
Enbrel: Safe & Effective So Far
"Safety is always of utmost concern," Tyring tells WebMD. "We saw no increased risk of heart attacks or anything else. And safety did not appear to be a problem in terms of cancers or malignancies."
A main question for long-term Enbrel treatment is whether its effects wear off for patients who take high doses for a long time.
"The answer is, psoriasis clearance was maintained," Tyring says. "The bottom line is that all of this is an understatement. In real life we rarely tell patients, 'Just use this Enbrel and that is it.' We use these psoriasis medications in combination -- a topical solution on the legs or scalp, and also light therapy. When we do that, we see efficacy far beyond that noted in the study."