Maintenance therapy with azathioprine prolonged duration of remission for pemphigus patients who received rituximab as first-line or add-on therapy

Background/purpose: Rituximab is effective in treating pemphigus both as the first-line treatment and as an add-on treatment for refractory disease. A high rate of relapse among patients receiving rituximab means that maintenance therapy is frequently required. Therefore, we aimed to evaluate the use of azathioprine as maintenance therapy for patients receiving rituximab and to investigate the efficacy and safety of one or multiple cycles of rituximab treatment. Methods: We retrospectively collected data regarding pemphigus patients treated with rituximab from 2008 to 2015 with at least one year of follow-up at a referral center in Northern Taiwan. The medical records and clinical data were reviewed to determine the efficacy and complication rate of the treatment. Results: A total of 78 pemphigus patients were identified. Ninety-one percent of the patients achieved complete remission after the first cycle of rituximab with a relapse rate of 67.9%. Repeated cycles of rituximab showed a trend to shorten the time to next complete remission and to reduce the rate of subsequent relapses. The adverse events were usually not severe and were manageable. Use of azathioprine significantly prolonged the duration of remission (21.98 ± 16.24 vs. 9.98 ± 7.93 months, P = 0.0232). This effect of azathioprine usage remained after univariate and multivariate logistic regressions. Conclusion: This study provides an insight that azathioprine could serve as a good choice of maintenance therapy for patients receiving rituximab. The efficacy and safety of rituximab remain favorable even with repeated administration. Keywords: Azathioprine, Maintenance, Pemphigus, Rituximab