Rituximab for the treatment of IgG4 related orbital disease: experience from five cases

Purpose To review the clinical efficacy and safety of rituximab for treatment of IgG4 related orbital disease (IgG4-ROD). Design Retrospective multicentre interventional case series. Methods Chart review for five cases of biopsy-confirmed IgG4-ROD (IgG4+> 410/HPF, ratio of IgG4+/IgG+> 40%) treated with rituximab. Information retrieved included the dosing schedule, adverse events and the magnitude, temporality, and duration of the clinical response. Results All cases of IgG4-ROD were either steroid dependent or steroid resistant. Rituximab doses for induction therapy included two doses of 1000mg at 2-weekly intervals, and four doses at 375mg/m(2) at weekly intervals. Two months after starting rituximab, three cases achieved complete clinical resolution and two cases achieved partial clinical resolution. Complete radiological resolution occurred in one case, and partial radiological resolution in three cases. Three cases received rituximab maintenance therapy and one case was commenced on mycophenolate. No relapse occurred during a mean follow-up of 33 months (range: 7-65 months). One disease relapse occurred when the dosing interval of rituximab maintenance therapy was extended to 6-monthly intervals; remission was swiftly achieved with rituximab reinduction therapy. The only adverse effects reported were one episode of fatigue lasting 1 week and two episodes of orbital discomfort. Conclusion Rituximab may be an effective treatment option for IgG4-ROD that is steroid dependent or steroid intolerant. Rituximab therapy resulted in swift clinical and radiological improvement, many months free of relapse, and few side effects.