Psoriatic arthritis (PsA), a chronic inflammatory disorder of the peripheral joints and axial skeleton occurs in approximately 10-30% of patients with psoriasis. Many patients with PsA have erosive disease and experience physical limitations and work-related disability. Previously, etanercept has been shown to improve the articular and cutaneous manifestations of psoriatic arthritis (PsA). In a study described in the July issue of Arthritis and Rheumatism, Mease and colleagues further evaluated the safety and efficacy of etanercept in patients with PsA.

In this placebo-controlled double-blind trial, patients with PsA (n = 205) were randomized to placebo or etanercept (25 mg SC 2x /wk) for 24 weeks. Following the 24-week phase, patients could receive open-label etanercept in a 48-week extension.

Clinical responses were observed as early as the first visit (week 4) and were maintained throughout the study. At 12 weeks, ACR20 was achieved by 59% of patients in the etanercept group and by 15% of patients in the placebo group (P < 0.0001). ACR20, ACR50, and ACR70 responses were achieved by a higher proportion of patients receiving etanercept, than those receiving placebo. Furthermore, responses on the composite measure, the PsARC, were significantly greater for etanercept patients than for the placebo group (70% vs 23%) at 24 weeks. Etanercept also significantly improved the skin lesions of psoriasis; PASI 75 response was observed in 23% of patients in the etanercept group at 24 weeks, compared with 3% of patients in the placebo group (P = 0.001). Moreover, this is the first study to demonstrate inhibition of radiographic progression in PsA patients. At 12 months, radiographic disease progression was inhibited in the etanercept group (-0.03 unit), while progression continued (+1.00 unit) in the placebo group (P = 0.0001).

Interestingly, during the open-label extension, patients originally in the placebo group showed improvements after initiating etanercept treatment. Patients from the etanercept group who continued etanercept treatment maintained or improved their clinical responses. Over the course of the study, etanercept was well tolerated. The proportions of patients with adverse events and infections were similar between groups. Moreover, the safety profile was comparable to that reported for patients with rheumatoid arthritis.

The authors concluded that etanercept therapy significantly improved the clinical symptoms and skin lesions of psoriasis in these patients. They added, "Further studies are warranted to provide longer-term observations of the safety, efficacy, and effects on disease progression of etanercept in PsA patients."

Mease PJ, Kivitz AJ, Burch FX, et al. Etanercept treatment of psoriatic arthritis: Safety, efficacy, and effect on disease progression. Arthritis Rheum. 2004;50:2264-2272.

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