The efficacy of Inebilizumab, a mainstay therapy for NMOSD, is dependent on the sustained depletion of B-cells. In our real-world Hispanic-predominant population, infusion access is precarious and susceptible to health-system related and logistical barriers.

We conducted a single-center retrospective review of 16 AQP4(+) NMOSD patients (94% Hispanic, 94% female) treated with inebilizumab (2019–2025). Infusion-timing barriers were defined as missed appointments, delayed infusions, or pharmacy delivery problems. Outcomes included on-treatment relapses and EDSS trajectory from baseline to last follow-up.

On-treatment relapses occurred in 7/16 patients (44%). Three patients (19%) had documented infusion-timing barriers, accounting for 3/7 (43%) of relapse events and most disability worsening. In contrast, 4/7 relapses (57%) occurred in fully compliant patients despite B-cell suppression, underscoring true breakthrough disease and potential limits of current dosing strategies. Relapses most often occurred + 2 weeks of expected infusion appointment, highlighting the clinical cost of unreliable access. The EDSS score improved in a total of 3 patients (19%), was stable in 5 (31%), and worsened in 8 (50%). 

This Hispanic-predominant NMOSD cohort linked 43% of relapses to infusion delays or access failures. However, over half (57%) of relapses occurred despite full patient compliance. This indicates that both health-system barriers and treatment response affect real-world outcomes. System-level interventions may be required to secure timely infusion delivery and could aid in preventing the majority of relapses in this patient subset. Monitoring is needed to detect and act on true breakthrough disease requiring escalation beyond inebilizumab.