Efalizumab: results of a 3-year continuous dosing study for the long-term control of psoriasis

Summary Background  Efalizumab, a T-cell-targeted, recombinant, humanized, monoclonal IgG1 antibody, inhibits key T-cell-mediated steps in the pathogenesis of psoriasis. Efalizumab is approved for the treatment of moderate-to-severe chronic plaque psoriasis in adults in more than 50 countries. Objectives  To evaluate the efficacy and safety of long-term, continuous efalizumab therapy in patients with psoriasis. Methods  This open-label, multicentre phase III study enrolled 339 patients with moderate-to-severe chronic plaque psoriasis. During the initial 3-month phase, patients received subcutaneous efalizumab 2 mg kg−1 weekly with randomization to receive concomitant fluocinolone acetonide or placebo ointment during month 3. The second phase was a long-term observational period; patients achieving a ≥ 50% improvement in the Psoriasis Area and Severity Index (PASI) score were eligible to receive efalizumab 1 mg kg−1 weekly for up to 33 months. The final 3-month treatment period was an optional transition period for patients who completed the 33-month segment before efalizumab became commercially available. Results  After 3 months, 41·3% of patients achieved a ≥ 75% improvement in PASI (PASI-75) and 13·0% achieved a ≥ 90% improvement (PASI-90). Continued improvement was observed: 45·4% and 24·5% achieved PASI-75 and PASI-90, respectively, at the end of the observational phase. The safety profile was stable, with no new or no increase in common events over 36 months of treatment. Conclusions  This was the longest continuous study using a biologic therapy for psoriasis. Clinical benefit of efalizumab improved over the first 18 months and was maintained during 36 months of continuous therapy. Long-term efalizumab therapy is appropriate for many patients with plaque psoriasis.