Rituximab in the real-world treatment of lupus nephritis: A retrospective cohort study in Japan.

OBJECTIVES: Although recommended in established international guidelines for lupus nephritis (LN), rituximab is not officially approved for LN treatment, making all such use off-label. The Japan College of Rheumatology (JCR) conducted a retrospective observational study on real-world efficacy and safety of rituximab treatment for LN in Japan. METHODS: Clinical data were collected from 47 hospitals for LN patients treated with rituximab to retrospectively investigate dosing schedule, efficacy, and safety. RESULTS: This retrospective analysis included 115 patients: 84 (73%) received 375 mg/m2 weekly up to four doses, and 31 (27%) received 1000 mg/body in one or two doses 2 weeks apart. Rituximab significantly improved findings for urinalysis, systemic lupus erythematosus serology, and systemic lupus erythematosus disease activity and was assessed as 'extremely effective' in 24.8% of patients and 'effective' in 60.2%. The renal response by the JCR-I criteria was 52.5% for overall response rate (ORR) (complete renal response rate 20.8% and partial renal response rate 31.7%) and that by the JCR-II criteria was 49.5% (21.8% and 27.7%, respectively). Corticosteroid dose was significantly reduced. Rituximab was well tolerated, with frequent but manageable adverse events of infusion reaction and infection. CONCLUSIONS: Rituximab is effective for the treatment of Japanese patients with LN refractory to conventional therapy.