ArticlesEtanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial
Introduction
Commonly used topical therapies for skin lesions in psoriasis include moisturisers, corticosteroids, tar, anthralin, vitamin D analogues and retinoids, and ultraviolet-light therapy. When these therapies are inadequate, systemic therapies such as psoralen-ultraviolet-light treatment, methotrexate, ciclosporin, and acitretin may be used.1, 2 However, toxicities often limit the usefulness of these therapies.3, 4, 5
Psoriatic arthritis affects from 5% to 7% of patients with psoriasis.6 Although psoriatic arthritis may present in a symmetric polyarticular form similar to rheumatoid arthritis, unique features include the potential for asymmetric, oligoarticular, axial and/or distal interphalangeal joint involvement, dactylitis, and enthesial inflammation.7 Like rheumatoid arthritis, this disorder results in joint damage, disability, and increased mortality.8, 9, 10, 11
Therapy for psoriatic arthritis has largely been derived from clinical experience in rheumatoid arthritis, without corroborating evidence from studies in patients with psoriatic arthritis.12, 13, 14 The response to therapy is often unsatisfactory. The few controlled trials assessing patients with psoriatic arthritis have not shown consistent efficacy.15, 16, 17, 18, 19, 20
Etanercept functions by inhibiting tumour necrosis factor, a proinflammatory cytokine that is involved in many inflammatory disorders, including both psoriatic arthritis and psoriasis. Tumour necrosis factor has been shown to be increased in synovial fluid and synovium in patients with psoriatic arthritis and in the skin of psoriatic lesions.21, 22, 23, 24 Tumour-necrosis-factor inhibition with etanercept has previously been shown to diminish the activity of rheumatoid arthritis.25 Our study was undertaken to assess the benefit of etanercept in psoriatic arthritis and psoriasis.
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Patients
Eligible patients were adults between 18 and 70 years who had active psoriatic arthritis (defined as ≥3 swollen joints and ≥3 tender or painful joints) at the time of study enrolment. Patients must have had an inadequate response to non-steroidal anti-inflammatory drugs and were thought candidates for immunomodulatory therapy. Patients taking methotrexate (≤25 mg/week) were allowed to continue methotrexate if the dose was stable for 4 weeks before study start and remained stable throughout the
Results
Table 1 shows baseline demographic and clinical characteristics. 60 patients were randomised, 30 in each treatment arm (figure 1). The median age was 45 years (range 24–70) and the median duration of psoriatic arthritis was 10 years (1–31). The median duration of psoriasis was 18 years (2–53) for all patients in the study and was 20 years (4–53) for the 38 patients with evaluable psoriasis (19 patients in each group). The median active joint counts at baseline were 20 tender and 14 swollen
Discussion
Few double-blind, placebo-controlled trials have been done in patients with psoriatic arthritis. Most therapies used to treat psoriatic arthritis have been attempted because they showed benefit in patients with rheumatoid arthritis or were therapies that yielded apparent benefit in open uncontrolled trials. The few controlled trials with patients with psoriatic arthritis have yielded inconsistent results.15, 16, 17, 18, 19, 20
Aside from non-steroidal anti-inflammatory agents, methotrexate has
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