June 20, 2007 Extended exposure to the psoriasis medication etanercept does not appear to cause more infections or adverse events than placebo, and improvements in several measures of disease severity were observed for up to 96 weeks of therapy, according to a recent article.
Psoriasis, a chronic inflammatory skin disorder, usually requires long-term therapy, according to background information in the article. "Serum and affected tissue levels of tumor necrosis factor (TNF) are elevated in patients with psoriasis compared with levels in uninvolved skin of patients with psoriasis and in healthy individuals, suggesting that TNF plays an important role in the pathogenesis of the disease," the authors write. Etanercept, which binds with TNF, has been approved to treat several inflammatory diseases, including psoriasis.
Stephen Tyring, M.D., Ph.D., The University of Texas Health Science Center at Houston, and colleagues conducted a phase 3 randomized, double-blind trial with an open-label extension (during which all patients were aware that they were taking the active drug) from May 23, 2003, through June 22, 2005.
After a 12-week period during which 618 patients with moderate to severe psoriasis were randomly assigned to receive either placebo or 50 milligrams of etanercept twice weekly (the current recommended dosage for psoriasis) for 12 weeks, all 591 continuing patients (average age 45.7) received etanercept for up to 84 weeks. During this open-label period, safety and efficacy evaluations were completed every 12 weeks. Psoriasis severity was measured using the Psoriasis Area and Severity Index (PASI) score, where zero means no disease and 72 is the most severe disease.
"Exposure-adjusted rates of adverse events, serious adverse events, infections and serious infections were similar for placebo and etanercept treatments," the authors write. "Patients responded within two weeks to etanercept, with statistically significant differences in the Psoriasis Area and Severity Index and Dermatology Life Quality Index between the etanercept and placebo groups at week 12. At week 24, after 12 weeks of open-label etanercept treatment, patients in the original placebo group had clinical benefits comparable to those of patients in the original etanercept group."
Improvements in PASI scores peaked at week 48, and at the end of the study, 51.6 percent of the original placebo group and 51.1 percent of the original etanercept group improved by at least 75 percent. A total of 18.3 percent of patients developed antibodies to etanercept during the study, but these antibodies did not appear to cause adverse events or reduce the drug's effectiveness.
"In conclusion, this study represents, to our knowledge, the longest continuous exposure of patients with psoriasis to 50 milligrams of etanercept biweekly and provides further insights into the safety and efficacy of high-dose etanercept therapy for the management of moderate to severe psoriasis," the authors conclude.
Reference: Arch Dermatol. 2007;143:719-726.
This study was supported by Immunex Corporation, a wholly owned subsidiary of Amgen Inc, and by Wyeth Pharmaceuticals.
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