Abstract
Systemic therapy for psoriasis has undergone a considerable metamorphosis. Traditional agents, such as methotrexate, cyclosporin and systemic retinoids (predominantly acitretin), have dominated systemic therapy over the past 35 years, with second-tier systemic agents, such as fumaric acid, also known to be beneficial. With the primary role of activated T cells in the immunopathogenesis of psoriasis, targeted biological therapy has finally come of age. This article will review the traditional agents, as well as two main groups of biological drugs: T-cell agents (alefacept and efalizumab) and tumor necrosis factor antagonists (adalimumab, etanercept, and infliximab). Lessons learned from the use of this latter group of drugs in the disciplines of rheumatology (rheumatoid arthritis) and gastroenterology (Crohn’s disease) are reviewed, together with a summary of each individual drug. Potential new biological drugs over the ensuing 5 years are likely to further increase the scope of systemic therapy for psoriasis, the most exciting of which is an anti-interleukin-12 molecule, which has recently completed Phase II clinical studies. Dermatologists and patients alike are indeed fortunate to have this therapeutic arsenal available to them for a systemic disease that is frequently neglected, but with major quality of life implications on a par with other major chronic diseases.