A randomized, double-blind, placebo-controlled phase III study evaluating efficacy and tolerability of 2 courses of alefacept in patients with chronic plaque psoriasis

Background: In previous phase II studies, alefacept significantly improved psoriasis and was well tolerated. The clinical response to alefacept was durable. Objective: Our purpose was to further evaluate efficacy and tolerability of alefacept in a phase III study of patients (n = 553) with chronic plaque psoriasis. Methods: Two 12-week courses of once-weekly intravenous alefacept 7.5 mg or placebo were given in a randomized double-blind study; patients were followed up for 12 weeks after each course. Results: During treatment and follow-up of course 1, a 75% or greater reduction in the Psoriasis Area Severity Index (PASI) was achieved by 28% of alefacept-treated and 8% of placebo-treated patients (P < .001). Patients who received a single course of alefacept and achieved a 75% or greater reduction from baseline PASI during or after treatment, without the use of phototherapy or systemic therapies, maintained a 50% or greater reduction in PASI for a median duration of more than 7 months. Among patients who received 2 courses of alefacept, 40% and 71% of patients achieved a 75% or greater and 50% or greater reduction in PASI, respectively, during the study period. Alefacept was well tolerated over both courses. In course 1, the incidence of transient chills was higher in the alefacept group compared with the placebo group; more than 90% of cases occurred within 24 hours after the first few doses. Conclusion: Alefacept significantly improved psoriasis and produced durable clinical improvements among patients who responded. A second course of alefacept increased efficacy and was equally well tolerated.