Clinical experiences of different dosing schedules of rituximab in pemphigus with various disease severities

Abstract

Rituximab, a monoclonal antibody directed against B lymphocytes, has been found to be a therapeutic agent for severe, refractory autoimmune bullous diseases. However, a dosing schedule or treatment indication of rituximab has not yet been established. We investigated the efficacy of rituximab and different dosing schedules for different disease severities, retrospectively. A total of 23 patients with pemphigus who received rituximab were evaluated by a review of medical records. Group 1 patients (n=10) with severe pemphigus were treated with three or four infusions of rituximab at a dose of 375mg/m(2) at 1-week intervals. Group 2 (n=13) patients with mild to moderate pemphigus were treated with two infusions of rituximab at the same dose. Late end points, occurrence of relapse and adverse events and numbers of B cells were evaluated. The mean follow-up period was 25.6months in group 1 and 17.8months in group 2. In group 1, six patients (60.0%) achieved complete remission (CR), including two patients off therapy (CR OFF) and four patients on therapy (CR ON). The other four patients (40.0%) achieved partial remission on therapy (PR ON). In group 2, nine patients (69.2%) achieved CR (4 CR OFF, 5 CR ON) and four patients (30.8%) achieved PR ON. During the follow-up period, relapse occurred in five patients of group 1 and three patients of group 2. No serious adverse events were observed in any patients. We concluded that rituximab is an effective and safe treatment method not only in severe, recalcitrant pemphigus but also in mild to moderate pemphigus. Low dose of rituximab seemed to be sufficient to treat mild to moderate pemphigus.