Treatment of neuromyelitis optica/neuromyelitis optica spectrum disorders with methotrexate

Background: To review our experience using methotrexate as a single long-term immunosuppressant (IS) therapy in neuromyelitis optica/neuromyelitis optica spectrum disorders (NMO/NMOSD). Methods: We performed a retrospective chart review of all patients with a diagnosis of NMO/NMOSD, supported by a positive NMO-IgG testing, who were treated with methotrexate. A paired sample 2 tailed t test was used to assess the annualized relapse rate during 18 months pre treatment with methotrexate to annualized relapse rate 18 months post treatment with methotrexate. Results: We followed 9 patients meeting criteria for the study for a median of 62 months. All patients were stabilized during attacks with high-dose steroids and/or plasmapheresis. Five patients (55.55%) were started on methotrexate as an initial long-term immunosuppressant strategy. Three patients (33.33%) were initially treated with pulse cyclophosphamide followed by methotrexate as a preplanned step-down strategy. One patient was started on azathioprine prior to methotrexate. No patient had side effects requiring change in methotrexate therapy. Five patients (55.55%) had stabilization of Expanded Disability Status Scale (EDSS) on methotrexate. One patient had a small increase in EDSS due to concomitant illness. Three patients (33.33%) had methotrexate treatment failure evidenced by worsening EDSS and ongoing relapses while on methotrexate, mandating a change in methotrexate therapy. Average annualized relapse rate in the entire group comparing 18 months prior versus 18 months after methotrexate treatment was reduced by an absolute value of 64% (3.11 vs 1.11). A paired t-test showed this reduction was highly significant (p = .009). Conclusion: In our experience, methotrexate is safe and possibly efficacious as a single long-term IS therapy along with low dose corticosteroids that can reasonably be offered to patients with NMO/NMOSD.