Smith KGC et al. (2006) Long-term comparison of rituximab treatment for refractory systemic lupus erythematosus and vasculitis. Arthritis Rheum 54: 2970–2982

Current treatments for systemic lupus erythematosus (SLE) and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis include toxic immunosuppressive agents such as cyclophosphamide, and less-toxic treatments would be beneficial. A UK trial has now shown that B-cell depletion with rituximab is a safe and effective long-term treatment for both these conditions.

The study included 11 patients with SLE and 11 patients with ANCA-associated vasculitis. All patients had active disease refractory to conventional therapy. Participants received four weekly infusions of rituximab 375 mg/m2, plus one infusion of cyclophosphamide 500 mg at the same time as the first infusion of rituximab. Patients who experienced relapse received two infusions of 1 g rituximab, 2 weeks apart, without cyclophosphamide. Patients who were receiving mycophenolate mofetil or azathioprine at enrollment continued this treatment at the same dose until 6 months, when a dose reduction was allowed. The median follow-up was 24 months.

Rituximab resulted in B-cell depletion in all patients and clinical response to treatment in 21 patients. Relapses occurred in all patients with SLE after a median of 12 months, and in 6 patients with ANCA-associated vasculitis after a median of 16.5 months; all episodes of relapse were associated with B-cell regeneration, except in one patient who had undetectable B cells at treatment initiation. Re-treatment with rituximab was successful in all patients who relapsed. The most common adverse events were mild infusion reactions. Four patients had severe infections; it is not known if rituximab contributed to them.