Rituximab Use for Relapse Prevention in Anti-NMDAR Antibody-Mediated Encephalitis: A Multicenter Cohort Study.

Area of Science:

• Neurology
• Immunology
• Pharmacology

Background:

• Anti-N-methyl-D-aspartate receptor (NMDAR) antibody-mediated encephalitis is a severe autoimmune neurological disorder.
• Rituximab, an anti-CD20 monoclonal antibody, is used for acute treatment and relapse prevention.
• The long-term impact of a single rituximab course on relapse risk remains unclear.

Purpose of the Study:

• To evaluate the effect of a single rituximab course on relapse incidence in anti-NMDAR antibody-mediated encephalitis.
• To determine the duration of rituximab's relapse-reducing effect.

Main Methods:

• A cohort study involving 67 patients with anti-NMDAR antibody-mediated encephalitis from 10 Australian hospitals.
• Quantification of rituximab exposure as a time-varying covariate using Cox proportional hazard models.
• Analysis of relapse incidence and time to first relapse following rituximab administration.

Main Results:

• A single rituximab course was associated with a significantly longer time to first relapse (HR 0.11, p=0.02).
• For patients considered for redosing, rituximab delayed relapse by 6 months post-infusion (HR 0.05, p=0.005), adjusted for other therapies and teratoma presence.
• The protective effect of rituximab diminished by 12 months after a course (HR 0.60, p=0.47).

Conclusions:

• A single course of rituximab effectively reduces relapse risk in anti-NMDAR antibody-mediated encephalitis.
• In specific patients, rituximab administration around 6 months can delay subsequent relapses.
• The duration of rituximab's benefit appears limited, suggesting potential need for re-evaluation of treatment protocols.