Anti-CD20 Monoclonal Therapy for Neuromyelitis Optica Spectrum Disorder

Rituximab, an anti-CD20 monoclonal antibody, has been used off-label to treat neuromyelitis optica spectrum disorder (NMOSD). In a multicenter study at eight hospitals in Japan, investigators recruited 38 patients (95% women) with NMOSD who were aquaporin-4 (AQP4)–antibody positive and receiving a stable dose of oral prednisolone (5–30 mg/day). The patients were randomized to rituximab infusions (375 mg/m² weekly for 4 weeks, followed every 6 months by two 1000-mg infusions separated by 2 weeks) or placebo infusions. From week 8, prednisolone was gradually tapered to 2 mg/day.

During the 72-week study period, 7 of 19 patients (37%) assigned placebo had a relapse, whereas 0 of 19 on rituximab had a relapse, for a significant between-groups di…