Rituximab Use for Relapse Prevention in Anti-NMDAR Antibody-Mediated Encephalitis. A Multicenter Cohort StudyN. Seery, R. Wesselingh, P. Beech, L. McLaughlin, T. Rushen, A. Halliday, L Ter Horst, S. Griffith, M. Forcadela, T. Tan, C. Kazzi, C. Nesbitt, J. Broadley, K. Buzzard, A. Duncan, W. D'Souza, Y. Tran, A. Van Der Walt, G. Skinner, B. Taylor, A. Swayne, A. Brodtmann, D. Gillis, E. Gerard Butler, T. Kalincik, U. Seneviratne, R. Macdonell, S. Blum, S. Ramanathan, C. Malpas, S. Reddel, T. Hardy, T. O’Brien, P. Sanfilippo, H. Butzkueven, M. Monif for the Australian Autoimmune Encephalitis Consortium.Background and Objectives: Rituximab is an anti-CD20 monoclonal antibody used in patients with anti-NMDAR antibody (Ab)-mediated encephalitis as both an acute escalation therapy and a longer-term relapse risk–reduction treatment. The potential long-term benefit of a single course administered during the acute disease phase on future relapse risk is uncertain. Moreover, the optimal dosing duration to reduce relapse risk is unknown. The aim of this study was to evaluate the effect of a single course of rituximab on relapse incidence. We also studied the duration of effect of a course of rituximab in adult patients with anti-NMDAR Ab-mediated encephalitis.Methods: We recruited 67 patients with anti-NMDAR Ab-mediated encephalitis from 10 Australian hospitals. Rituximab exposure was quantified as a time-varying covariate in Cox proportional hazard models.
Results: A single course of rituximab was associated with longer time to first relapse (hazard ratio [HR]: 0.11, 95% CI: 0.02–0.70,
p
= .02). For patients in whom redosing is considered, rituximab was associated with longer time to first relapse at 6 months after the last infusion, after adjusting for concurrent immunotherapies and the presence of ovarian teratoma at disease onset (HR: 0.05, 95% CI: 0.00–0.48,
p
= .005). The treatment effect did not persist out to 12 months after a given course (HR: 0.60, 95% CI: 0.15–2.44,
p
= .47).
Discussion: A single course of rituximab reduces the risk of relapse of anti-NMDAR antibody-mediated encephalitis. In select patients for whom redosing of rituximab is considered, administration at 6 months delays relapses.Classification of Evidence: This study provides Class IV evidence that rituximab delays relapses in patients with anti-NMDAR antibody-mediated encephalitis.Acute and Long-Term Immune-Treatment Strategies in Anti-LGI1 Antibody-Mediated Encephalitis: A Multicenter Cohort StudyN. Seery, R. Wesselingh, P. Beech, L. McLaughlin, T. Rushen, A. Halliday, L. Horst, S. Griffith, M. Forcadela, T. Tan, C. Kazzi, C. Nesbitt, J. Broadley, K. Buzzard, A. Duncan, W. D'Souza, Y. Tran, A. Van Der Walt, G. Skinner, B. Taylor, A. Swayne, A. Brodtmann, D. Gillis, E. Butler, T. Kalincik, U. Seneviratne, R. Macdonell, S. Blum, S. Ramanathan, C. Malpas, S. Reddel, T. Hardy, T. O'Brien, P. Sanfilippo, H. Butzkueven, M. Monif for the Australian Autoimmune Encephalitis Consortium.Background and Objectives: Few studies have evaluated acute immunotherapy and relapse prevention strategies in patients with anti–leucine–rich glioma-inactivated 1 (LGI1) antibody (Ab)-mediated encephalitis. The objective of this study was to analyze the outcomes of acute and long-term immunotherapy strategies in this population.Methods: We undertook a multicenter cohort study of 55 patients with anti-LGI1 Ab-mediated encephalitis, either recruited prospectively or identified retrospectively from 10 Australian hospitals as part of the Australian Autoimmune Encephalitis Consortium. Clinical data were collected, including treatment durations of all relevant immunotherapies. Clinical outcomes that we examined included (1) time to first clinical relapse, (2) improvement on modified Rankin Scale (mRS), and (3) favorable binary composite clinical-functional outcome at 12 months. A favorable outcome was defined as fulfilling all three of mRS less than 3, a score of 1 or less in the memory dysfunction component of the Clinical Assessment Scale in Autoimmune Encephalitis, and absence of drug-resistant epilepsy.
Results: Rituximab, adjusted for concomitant use of other immunotherapies, was associated with increased time to first relapse (hazard ratio: 0.10; 95% CI: 0.001–0.85;
p
= .03). Intravenous pulsed methylprednisolone was associated with an improvement in mRS (OR: 4.48; 95% CI: 1.03–21.3;
p
= .048) and a favorable composite clinical-functional outcome (OR: 4.96; 95% CI: 1.07–27.2;
p
= .049) at 12 months.
Discussion: Rituximab may be effective at preventing relapses in patients with anti-LGI1 Ab-mediated encephalitis. Acute methylprednisolone treatment may be associated with favorable outcomes at 12 months.Classification of Evidence: This study provides Class IV evidence that for patients with anti-LGI1 Ab-mediated encephalitis, rituximab prevents relapses and acute methylprednisolone is associated with favorable outcomes at 12 months.