Long-term efficacy of maintenance therapy with Rituximab for IgG4-related disease

Background: IgG4-Related Disease (IgG4-RD) promptly responds to glucocorticoids but relapses in most patients. Rituximab (RTX) represents a promising strategy to avoid IgG4-RD flares but its administration for maintaining disease remission has never been assessed in terms of optimal timing of infusion, dosage, and duration of treatment. In the present study we aimed to evaluate the efficacy and safety of RTX for maintenance of IgG4-RD remission. Methods: Fourteen patients with IgG4-RD were treated with RTX as induction of remission therapy at the San Raffaele Scientific Institute in Milan, Italy. The cohort was then divided into two study groups: patients re-treated only in case of disease relapse (Group 1, n = 7), and patients regularly re-treated with RTX every 6 months for maintenance therapy (Group 2, n = 7). Data on free-relapse rate and adverse events were collected and retrospectively analysed. Results: Median follow-up time and baseline clinical-serological features were similar between Group 1 and 2 (p > 0.05). The free relapse rate 18 months after induction of remission treatment was significantly lower in Group 1 (29%) than in Group 2 (100%) (p = 0.006). Infectious complications developed in 6/14 patients (3 in Group 1 and 3 in Group 2). Conclusion: Administration of RTX every 6 months as maintenance of remission therapy prevents IgG4-RD flares.