Treatment of Refractory Pemphigus with the Anti-CD20 Monoclonal Antibody (Rituximab)

Abstract

Background: Pemphigus is a severe blistering disorder caused by autoantibodies to desmogleins 1 and 3. Because some patients with pemphigus never enter into remission, new immunosuppressants are warranted. Rituximab is a chimeric monoclonal antibody binding to the CD20 antigen on B cells, which proved to be effective in recalcitrant pemphigus. Objectives: To evaluate the efficacy and safety of rituximab in refractory pemphigus and to investigate its effects on the autoantibody profile. Patients and Methods: Six patients with recalcitrant pemphigus were treated. Rituximab was administered intravenously at a dosage of 375 mg/m² body surface once weekly for 4 weeks. Results: Three pemphigus foliaceus patients and 1 with mucocutaneous pemphigus vulgaris (PV) showed complete response over a follow-up period of up to 18 months. In one oral PV, control of the disease was achieved using pulse therapy with cyclophosphamide following rituximab withdrawal. In one PV with vegetating features, good improvement was obtained after 6 rituximab infusions. All patients tolerated the treatment well. Anti-desmoglein autoantibodies significantly decreased only in pemphigus foliaceus. Conclusions: This study highlights that rituximab is a valuable drug for refractory pemphigus, although the response of mucous membranes and cutaneous folds may be delayed.