Background: Neuromyelitis optica spectrum disorder (NMOSD) is associated with significant morbidity and mortality. Several therapies have been recommended for NMOSD and more recently clinical trials have demonstrated efficacy for three monoclonal antibody therapies. We present a retrospective observational study of treatment response in NMOSD.

Methods: This was a retrospective, unblinded, observational study of treatment efficacy for rituximab and traditional immunosuppressive therapy in patients with AQP4 antibody positive NMOSD. Treatment efficacy was assessed using annualised relapse rates (ARR), time to first relapse and expanded disability status scale (EDSS) scores.

Results: Complete relapse and treatment data were available for 43/68 (63%) of AQP4 antibody positive NMOSD cases covering 74 episodes of treatment. In a time to first relapse analysis rituximab showed a risk ratio of 0.23 (95% CI 0.08 – 0.65) when compared with no treatment and there was a non-significant reduction in ARR of 35% compared to pre-treatment. β-interferon (p = 0.0002) and cyclophosphamide (p = 0.0034) were associated with an increased ARR compared to pre-treatment. Rituximab (median 4.0 [range 0.0 – 7.0]; p = 0.042) and traditional immunosuppressive therapy (median 4.0 [range 0.0 – 8.0]; p = 0.016) were associated with a lower final EDSS compared to β-interferon (median 6.0 [range 4.0 – 7.5]).

Conclusions: These data provide additional support for the use of rituximab in preference to traditional immunosuppressive agents and MS disease modifying therapies as first line treatment of NMOSD.

NMOSDneuromyelitis opticaAQP4aquaporin-4ARRannualised relapse rateEDSSexpanded disability status scaleCNScentral nervous systemMSmultiple sclerosisSDstandard deviationRRrelative riskCIconfidence intervalLESCLlongitudinally extensive spinal cord lesionIVMPintravenous methylprednisoloneRxtreatmentIRRincidence rate ratio