Low-Dose Rituximab for Active Moderate to Severe Graves' Orbitopathy Resistant to Conventional Treatment.

Purpose: To report low-dose rituximab effect in Graves' orbitopathy (GO) resistant to conventional treatment. Methods: Retrospective analysis of medical records, filled in according to the European Group on Graves' Orbitopathy (EUGOGO) standards, of patients with active moderate-to-severe GO who received low-dose rituximab after failure of conventional treatment. Efficacy was defined by a decrease of the clinical activity score of 2 points or <4/10. Results: Among 219 patients treated between 2012 and 2016 by pulse methylprednisolone, possibly followed by oral steroids and/or orbital radiotherapy, 15 (6.8%) finally received 100 mg rituximab doses (cumulative dose, 100-400 mg) owing to persistent active disease. Rituximab showed efficacy within 2 months in 13 of 15 (87%), stable at 1 year. No significant effect was observed on proptosis, lid fissure width, and eye motility. Conclusion: Low-dose rituximab showed sustained anti-inflammatory effect in most patients with active GO resistant to conventional treatment.