Psoriasis is a relatively common condition, affecting about 2 percent of persons worldwide, and can be debilitating. Many treatments for psoriasis have a cumulative toxicity that limits their usefulness. Leonardi and colleagues report on the use of etanercept, a synthetic protein that binds an inflammatory signal protein, in the treatment of psoriasis.
Adults with moderate to severe psoriasis that required phototherapy or systemic treatment were eligible for the study. A total of 652 patients received at least one dose of the study medication. Sixty-seven percent of the participants were male, 87 percent were white, and the mean age was 45.1 years. The study was sponsored by Immunex-Wyeth, the manufacturers of etanercept. Patients were randomized to twice-weekly self-administered injections of placebo or low-dosage (25 mg once-weekly), medium-dosage (25 mg twice-weekly), or high-dosage etanercept (50 mg twice-weekly) for 24 weeks. Control patients were crossed over to medium-dosage etanercept after 12 weeks.
Psoriasis severity was scored after 12 weeks of treatment. Compared with control patients, statistically significant improvements were found in patients receiving etanercept. An improvement of at least 75 percent in a psoriasis area-and-severity index was noted in 4 percent of control patients, 14 percent of patients who received low-dosage etanercept, 34 percent of patients who received medium-dosage treatment, and 49 percent of patients who received high-dosage treatment. After 24 weeks of treatment, there was at least a 75 percent improvement in 25 percent of patients receiving low-dosage treatment, in 44 percent of patients receiving medium-dosage treatment, and in 59 percent of patients receiving high-dosage treatment. Life-quality scores and patient-reported global assessment also improved.
The most common side effect was an injection site reaction, noted by 14 to 20 percent of patients taking the study drug over 24 weeks. The incidence of these reactions did not correlate with the dosage of etanercept. A total of 27 patients withdrew from the trial because of adverse effects, and 16 others withdrew because of lack of treatment efficacy. There were no reported cases of tuberculosis or other serious infection during the trial.
The authors conclude that etanercept is well tolerated and useful, in a dosage-responsive fashion, in the treatment of moderate to severe psoriasis.
editor's note: The substantial benefit noted in patients who used etanercept for treatment of psoriasis is not surprising, given the drug's proven efficacy in other chronic inflammatory conditions (e.g., rheumatoid arthritis). As with most things in medicine, however, there is no “free lunch.” Knocking out tumor necrosis factor disables a key signal in abnormal inflammation and normal, vital immune system function. Serious infections and sepsis have been reported in patients using etanercept. Enthusiasm for widespread use also will be tempered by etanercept's substantial cost (approximately $1,300 per month for the medium dosage used in this study, based on average wholesale prices in Red Book. Montvale, N.J.: Medical Economics Data, 2004). Still, it likely will have an increasing role in the treatment of patients with severe psoriasis that is refractory to usual treatment measures.—B.Z.