Long-term Outcomes of Rituximab Therapy in Pemphigus

BACKGROUND: Rituximab induces a rapid remission in most patients with pemphigus.

OBJECTIVE: Our aim was to assess the long-term efficacy of rituximab in this disease.

METHOD: We conducted a retrospective study of 59 patients with pemphigus treated with rituximab and observed over a median period of 104 months.

RESULTS: The rate of complete remission off therapy (CRoff) after the first rituximab cycle was 39%, increasing to 61% with additional rituximab courses. Long-term CRoff was achieved in 27% of patients. The recurrence rate after the first rituximab cycle was 63%, decreasing to approximately 40% with subsequent rituximab cycles. Median time to relapse after the first and subsequent rituximab cycles was 25 months. Renewed rituximab therapy reinduced complete remission in 94% of cases. Baseline anti-desmoglein antibody levels of ≤ 250 U/ml were significantly associated with the outcome of CRoff. In paired serum samples obtained before the first and six months after the last rituximab therapy significant reductions of desmoglein-specific autoantibodies were observed. Patients relapsing after a complete remission induced by the first rituximab cycle were more likely to achieve CRoff than patients relapsing after a less favourable outcome and non-responders. There was no significant difference in age, sex, pemphigus subtype, rituximab dosing and disease duration between patients achieving CRoff and those not meeting this endpoint.

CONCLUSIONS: Lower desmoglein-specific antibody levels at baseline were predictive of CRoff. In patients receiving multiple rituximab cycles, complete remission after the first cycle was associated with a favourable long-term outcome. Repeated rituximab courses were highly effective for relapsed disease and improved the overall outcome.