Ustekinumab: an evidence-based review of its effectiveness in the treatment of psoriasis.

Introduction: Psoriasis is a chronic inflammatory skin disease affecting approximately 2% to 3% of the population worldwide. Discoveries over the past 3 to 5 years have significantly altered our view of psoriasis as primarily a T-cell mediated condition. The most recent research has demonstrated the essential role of specific cytokines in the development of this complex disease, including TNF-alpha, interleukin-23 (IL-23), and potentially, IL-22. These are all part of a newly defined autoimmune pathway directed by specialized T cells called Th17 helper T cells. Ustekinumab is a fully human monoclonal antibody that targets IL-12 and IL-23, thus targeting both Th1 and Th17 arms of immunity. It has a promising efficacy and safety profile that not only represents a valuable treatment alternative, but also a continuation in our constantly evolving understanding of this disorder.

Aims: To review the emerging evidence supporting the use of ustekinumab in the management of moderate to severe plaque psoriasis.

Evidence review: There is clear evidence that ustekinumab is effective in the treatment of moderate to severe psoriasis. Phase III trials (PHOENIX 1 and 2) demonstrated a statistically significant difference between Psoriasis Area and Severity Index (PASI) 75 responses achieved by patients receiving ustekinumab, given as a 45 mg or 90 mg subcutaneous injection every 12 weeks, than their placebo counterparts. Treatment with this novel agent resulted in a rapid onset of action, with over 60% of treated patients attaining Physician's Global Assessment (PGA) scores of "cleared" or "minimal" by week 12. Quality of life assessments paralleled clinical improvements.

Clinical potential: Ustekinumab is an effective and efficient therapeutic option for patients with moderate to severe psoriasis. Although further studies are required to establish ustekinumab's place in the therapy of psoriasis, with its convenient dosing schedule and rapid onset of action, this drug could provide a great addition to the current therapeutic armamentarium available for psoriatic patients.