To assess potential correlates among demographic or clinical parameters and Time to First Rituximab (RTX) Discontinuation (TFRD) in neuromyelitis optica spectrum disorder (NMOSD) patients in the CIRCLES study from 2013–2020.

NMOSD is a rare autoimmune disease in which off-label RTX is often used to prevent or mitigate relapses. However, variables associated with RTX maintenance therapy in NMOSD are unclear. Real-world data were analyzed for correlates of RTX discontinuation in patients with NMOSD.

The IRB-approved CIRCLES longitudinal, observational study was implemented at 15 North American sites.  Patients having ≥ 60 day follow-up and  ≥ 2 RTX doses were evaluated.  Cox proportional hazards models estimated hazard ratios (HR) for TFRD based on:  i) no re-dosing within 1 year; and ii) initiation of a new maintenance therapy.  Multivariate models assessed gender, race/ethnicity, AQP4-IgG serostatus, age at NMOSD onset, disease duration, onset disease phenotype, autoimmune comorbidity, pre-study annual relapse rate (ARR), and on-study relapses vs. TFRD.

In CIRCLES patients, relapse activity and comorbid autoimmune disease significantly associated with reduced TFRD. Thus, ongoing disease activity and/or complicated by comorbidity may drive RTX discontinuation. Non-clinical factors not studied here may also contribute to treatment change. These insights may aid in prediction of patients who may benefit from treatment change as approved therapeutic options emerge.