Background/Purpose: Susac Syndrome (SuS) is a rare immune-mediated vasculo-occlusive disease characterized by a triad of encephalopathy, hearing loss, and branched retinal artery occlusions. Deficits can be permanent and there is limited data to guide treatment. Here, we describe the treatment trajectories of a series of patients with SuS treated with rituximab.

Methods: A retrospective chart review of patients with SuS treated with rituximab and followed in neurology and/or rheumatology clinics at three tertiary care centers in the United States was performed.

Results: Eight patients — 4 (50%) females, 7 (87.5%) with the complete SuS triad, median age of 47 years (range 21-66 years) — were included. There were 11 instances of rituximab treatment (1 patient received 3 distinct courses) — 8 (72.7%) for ≥ 6 months (3 are ongoing) and 3 (27.3%) for < 6 months. Co-treatment with prednisone occurred in 10 (90.9%) instances -- all 7 instances of rituximab ≥ 6 months reached steroid freedom; all 3 instances of rituximab < 6 months saw a decrease in daily prednisone dose by ≥ 30mg, but none reached steroid freedom. Mycophenolate mofetil (MMF) co-treated patients continued at the same dose, decreased, and weaned off MMF completely over 4 (36.4%), 2 (18.2%), 4 (36.4%) instances of rituximab treatment respectively. In the 4 (36.4%) rituximab instances involving co-treatment with intravenous immunoglobulin G (IVIg), the total monthly IVIg dose was decreased over 2 (50.0%) rituximab instances and weaned off completely over 1 (25.0%) instance. Additional co-treatments included methotrexate and azathioprine in 1 instance each, both of which were weaned off completely during rituximab treatment. No patients were co-treated with cyclophosphamide (though 1 was treated cyclophosphamide before rituximab initiation).

Conclusion: In this case series of patients with SuS, rituximab facilitated steroid freedom and tapering of other immunotherapeutic agents. These initial findings provide evidence supporting the use of rituximab in SuS.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-multicenter-retrospective-case-series-of-patients-with-susac-syndrome-treated-with-rituximab/