Incidence of infection during efalizumab therapy for psoriasis: analysis of the clinical trial experience.

Background: Because many therapies for psoriasis disrupt the normal inflammatory cascade and could theoretically impair the body's ability to respond to external pathogens, a possible increase in the incidence of infection is a concern with any new psoriasis therapy that affects the immune system. Efalizumab is a biologic therapy targeted to inhibit T cells. Its efficacy has been shown in clinical trials encompassing >3500 patients with psoriasis.

Objectives: The aims of this article were to review the incidence of infection observed in efalizumab-treated patients during 12-week, Phase III clinical trials, compare the incidence rate with that in patients receiving placebo, and evaluate the incidence of infection observed in patients with extended (>12-week) efalizumab use.

Methods: Adverse events (AEs) of infection were tabulated from a pooled data set of 2335 patients enrolled to receive 12 weeks of subcutaneous (SC) efalizumab 1 or 2 mg/kg . wk or placebo in 4 randomized, double-blind, placebo-controlled, Phase III efalizumab clinical studies. The incidence of infection was further evaluated using pooled data from 1115 patients who received up to 24 weeks of efalizumab therapy during 5 clinical trials with treatment extension arms and from 170 patients who received up to 108 weeks (27 months) of continuous therapy in an open-label, Phase III efalizumab trial of 36 months' total duration.

Results: The incidence and severity of AEs of infection during 12 weeks of efalizumab therapy were comparable to those observed in patients receiving placebo (overall, 28.6% vs 26.3%). Infections did not appear to increase with extended therapy of up to 27 months. Serious infections requiring hospitalization occurred in 1.1% of efalizumab-treated patients.

Conclusion: The present review of the available Phase III clinical trial suggests that efalizumab is not associated with an increased risk for infection in patients receiving initial or long-term (27-month) treatment for moderate to severe chronic plaque psoriasis.