Cytokine blockers in psoriatic arthritis

Abstract

The cellular events underlying the pathogenesis of psoriatic arthritis (PsA) and psoriasis have not yet been fully elucidated. Nevertheless, some clues to these conditions are beginning to emerge. In particular, a growing body of data supports the role of proinflammatory cytokines, such as tumour necrosis factor (TNF), in the pathophysiology of PsA and psoriasis. Raised levels of these cytokines are found in the joints of patients with PsA, as well as in psoriatic skin lesions. Physiotherapy, non-steroidal anti-inflammatory agents, corticosteroids, and disease modifying antirheumatic agents, such as methotrexate, are the most commonly used treatments for PsA. However, the data supporting the effectiveness of these treatments are limited, and disease resolution is usually incomplete. This study examined the effects of etanercept, a TNF inhibitor, in patients with PsA. Etanercept treatment was well tolerated and resulted in significant improvement in the signs and symptoms of PsA and in psoriatic skin lesions. Infliximab, another TNF inhibitor, has also been shown to be effective in patients with PsA. Such studies confirm the importance of proinflammatory cytokines in PsA, and hold out hope for patients who require new options for the treatment of their disease.

Figure 1

Clinical response as assessed by Psoriatic Arthritis Response Criteria (PsARC) in patients with psoriatic arthritis treated with etanercept or placebo. p<0.0001 v placebo. Adapted from Mease,¹³ with permission.

Figure 2

Area of skin affected by psoriatic lesions in a patient with PsA. (A) Before etanercept treatment; (B) after 12 weeks of etanercept treatment.