To evaluate clinical and radiological outcomes of anti-IL6R therapy when used as add-on therapy for severe attacks in MOGAD and AQP4+ NMOSD.

IL-6 receptor blockers (anti-IL6R) are approved for relapse prevention in AQP4+ NMOSD and under investigation in MOGAD. Their use as acute therapy in systemic (e.g., cytokine release syndrome) and neurological (e.g., anti-NMDAR encephalitis) diseases suggest that they may be safe and enhance recovery from severe attacks in NMOSD and MOGAD and may enable shorter steroid tapering and earlier start of preventive therapy.

We included all patients with MOGAD or AQP4+ NMOSD who received anti-IL6R therapy during acute attacks from three referral centers (Mayo Clinic, New York University Langone, and Johns Hopkins). Patients were included if therapy was initiated within 30 days of clinical nadir. Data on attack phenotype, severity, concomitant treatments, and clinical and radiologic outcomes was collected from charts.

Eight patients received tocilizumab (intravenous, 7; subcutaneous, 1) during relapse (median age at 45 years, six females [75%]). Five had MOGAD attacks (ADEM/focal demyelination = 3, multifocal = 1, bilateral optic neuritis = 1), and three had AQP4+ NMOSD attacks (multifocal = 1, bilateral ON = 1, longitudinally extensive transverse myelitis = 1). At nadir, median EDSS was 5.5 (range, 2–9). Treatments prior to tocilizumab included intravenous methylprednisolone (n=8) plus plasma exchange (n=7) and IVIG (n=2). One patient (multifocal AQP4+ NMOSD, EDSS 9.0) received eculizumab three days after tocilizumab. Three months after onset, median EDSS was 2.0 (range 0–6). All patients improved clinically and remained relapse-free during this period.

Tocilizumab may represent a valuable add-on therapy for severe attacks in MOGAD and AQP4+ NMOSD with inadequate response to conventional treatments, promoting recovery, enabling shorter steroid tapering, and facilitating early transition to relapse prevention within the same therapeutic class.