Modified Rheumatoid Arthritis Protocol for Rituximab in Pemphigus: A Retrospective Case Series

Background: Rituximab, an anticluster of differentation 20 antibody, has been shown in open series studies to be effective in treating pemphigus. In the literature, lymphoma (dose of 375mg/m², four-week infusion) and rheumatoid arthritis (two infusions of 1,000mg each, 15 days apart) are two protocols extensively used for rituximab treatment in pemphigus. Objective: We investigated whether a modified rheumatoid arthritis protocol, in which the patient received a single treatment course ranging from 2 to 5 infusions of 1,000mg of rituximab during an interval of four weeks is safe and effective in pemphigus management. Methods: Patients with pemphigus were treated with a single treatment course ranging from 2 to 5 infusions of 1,000mg of rituximab during an interval of four weeks. Clinical consensus late endpoints and desmoglein 1 and desmoglein 3 indices were monitored. Results: We enrolled 32 patients in the study: four with pemphigus foliaceus (PF) and 28 with pemphigus vulgaris (PV). The follow-up period was 98.22±20.65 weeks (range: 40-140 weeks). All 32 patients responded to therapy. Nineteen patients achieved complete remission during a median period of 46 weeks (8 on minimal therapy, 11 off therapy). Thirteen patients achieved partial remission during a median period of 46 weeks (8 on minimal therapy, 5 off therapy). Relapses were seen in five (15.63%) patients between 72 and 96 weeks (median: 96 weeks) after the start of therapy. The antidesmoglein index correlated well with clinical improvement in PV or PF. Conclusion: Modified rheumatic arthritis protocol for rituximab was shown to be effective and safe in treating patients with pemphigus.