Summary  Background Alefacept, human LFA‐3/IgG₁ fusion protein, is a novel biological agent currently being developed for the treatment of chronic plaque psoriasis. Alefacept selectively reduces the memory‐effector T cells that have been implicated in the pathogenesis of the disease; as a result, alefacept is classified as a therapy that induces remission (so‐called ‘remittive’ therapy). In a previously published randomized, placebo‐controlled phase II study of intravenous alefacept in 229 patients with chronic plaque psoriasis, clinical improvement was observed during dosing as well as in the postdosing follow‐up period.

Objectives To assess the remission period following alefacept therapy.

Methods The time before re‐treatment was required was measured in patients who were ‘clear’ or ‘almost clear’ of disease according to a physician global assessment at the end of the follow‐up phase.

Results In these patients, responses were sustained for a median of 10 months, and for up to 18 months. No patient reported disease rebound after cessation of alefacept.

Conclusions Alefacept is a biological agent for the treatment of chronic plaque psoriasis that provides disease‐free intervals and time off drug therapy.