The safety of efalizumab in patients with moderate to severe plaque psoriasis: summary of clinical trial experience 1 1 Author is consultant for Genentech, Inc.

Lack of consistent treatment efficacy, inconvenience associated with topical therapies and phototherapy, invasive monitoring for systemic therapies, the potential for serious cumulative toxicity, and increased knowledge regarding the role of T cells in psoriasis pathology have provided the impetus for the development of novel psoriasis therapies. Efalizumab is a humanized monoclonal IgG1 antibody in development for the treatment of moderate to severe plaque psoriasis. Efalizumab has been studied in more than 2,700 psoriatic patients in 13 controlled and uncontrolled trials. These trials have evaluated the effects of efalizumab during 12- and 24-week treatment periods and long-term administration (up to 2 years). Results from these psoriasis trials were pooled, yielding the largest reported cohort of psoriasis patients treated with a biologic therapy to date. Initiation of efalizumab therapy was associated with acute flu-like symptoms, typically observed during the first one or two doses; by the third dose, the incidence was comparable to that observed in placebo-treated patients. During long-term treatment, no new pattern of treatment-emergent adverse events was observed. There was no evidence of an increased risk of end-organ damage (renal, hepatic, and bone marrow), infection, or malignancy in efalizumab-treated patients often compared with placebo-treated patients or external cohorts of similar patients. The lack of end-organ damage obviates the need for frequent or invasive laboratory monitoring during long-term therapy. Efalizumab is well tolerated, with acute adverse events related primarily to the first two doses. The lack of serious toxicity supports its long-term utility in psoriasis patients, offering a much-needed therapeutic option that could provide long-term control of psoriasis symptoms.