Etanercept in psoriatic arthritis.

Psoriatic arthritis (PsA), an inflammatory arthritis associated with psoriasis, can lead to disability from progressive joint destruction and bony fusion. To date, conventional disease modifying antirheumatic drugs (DMARDS) have not convincingly lessened joint pain and inflammation in PsA and there is very little data on the limitation of radiographic progression with these agents. The biological agent etanercept (Enbrel, Amgen, Inc, Thousand Oaks, California, USA) is a soluble TNF receptor fusion protein with proven efficacy in the treatment of rheumatoid arthritis (RA). In a Phase II and Phase III trial, conducted in moderate-to-severe PsA, etanercept significantly reduced joint pain and swelling and lowered the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level. A significant decline in structural damage was observed as early as 6 months after starting the drug. Etanercept also improved quality of life measures (Health Assesment Questionnaire [HAQ] and global assessment scores). Up to a third of patients experienced transient injection-site reactions. Rare cases of opportunistic infection, demyelinating disorders and aplastic anaemia have been reported, but a causal link has not been established. In summary, etanercept is a safe and effective agent for the treatment of PsA and represents a major advance in the therapy of this potentially crippling disease.