Long-term safety profile of siplizumab, a humanized anti-CD2 monoclonal antibody, in subjects with chronic plaque psoriasis

Abstract

Background: Prolonged depletion of activated T cells via targeted therapy may reduce disease activity in chronic plaque psoriasis, but may potentially lead to increased risk of serious infection.Objectives: To evaluate the long-term safety profile of siplizumab, an anti-CD2 monoclonal antibody, in chronic plaque psoriasis subjects who experienced persistent siplizumabinduced lymphocyte depletion.Methods: Subjects (n=94) with absolute lymphocyte counts (ALC) >30% lower than baseline or absolute CD4 count <250 cells/μL post-siplizumab treatment were followed prospectively for up to 5.25 years from last siplizumab dose for occurrence of selected medically important events: infection, malignancy, and autoimmune diseases.Results: Five selected medical events were reported: cholecystitis, colitis, myelofibrosis, encephalitis, and bronchitis; first three met serious adverse event criteria, none were considered siplizumab-related. Repletion of ALC to normal levels occurred in 53% of subjects within 2 years after treatment cessation.Conclusion: Preselected medically important events were uncommon in subjects with siplizumab-induced lymphocyte depletion. This study was funded by MedImmune, LLC.