Introduction: Conventional systemic therapies for psoriasis are associated with serious toxicities that can limit long-term use. In recent years, biological therapies have offered the possibility of long-term therapy with improved safety and efficacy for the treatment of psoriasis. Biological therapies can be classified into three categories: the T-cell modulating agents (alefacept and efalizumab), the inhibitors of TNF-α (adalimumab, etanercept, infliximab) and the inhibitors of IL-12 and -23 (ustekinumab). Efalizumab is a humanized recombinant monoclonal IgG1 antibody. It targets multiple stages in the immunopathogenesis of psoriasis: initial T-cell activation, migration of T-cells into dermal and epidermal tissues, and T-cell reactivation. On 19 February 2009, the Committee for Medicinal Products for Human Use (CHMP) recommended the suspension of the marketing authorisation for efalizumab.

Areas covered: Numerous clinical trials have demonstrated the efficacy, safety and health-related quality of life benefits of efalizumab in patients with moderate-to-severe chronic plaque psoriasis. Efalizumab was approved by the FDA in November 2003 and by the European Medicines Evaluation Agency in September 2004 for the treatment of adult patients with moderate-to-severe chronic plaque psoriasis. Recently, three cases of progressive multifocal leukoencephalopathy were described in patients on long-term (> 3 years) efalizumab therapy, leading to its withdrawal from the market.

Expert opinion: Although initially favorable, the safety profile of efalizumab revealed the appearance of severe adverse events in long-term treated patients. Therefore, post-marketing surveillance is essential for correct evaluation of drug potential.