Third-line tocilizumab for refractory pediatric anti-NMDA receptor encephalitis: a single-center case series.

UNLABELLED: Tocilizumab has been proposed as a third-line therapy for refractory autoimmune encephalitis; pediatric Latin American data remain limited. OBJECTIVE: To evaluate the efficacy and safety of tocilizumab in pediatric patients with severe or refractory anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. MATERIALS AND METHODS: We retrospectively reviewed pediatric patients with definite anti-NMDAR encephalitis treated with tocilizumab after inadequate response to previous therapy. RESULTS: Six patients (four males, median age at onset 4.5 years). All had severe disease (modified Rankin Scale [mRS] 4-5; Clinical Assessment Scale in Autoimmune Encephalitis [CASE] ≥10). All received first-line therapy, five received rituximab before tocilizumab. Tocilizumab was initiated 2-3 months after the last rituximab infusion. At 12 months, all achieved favorable outcomes (mRS 2; CASE ≤4). Adverse events included varicella-zoster virus infection, mild cytopenia, and dyslipidemia. CONCLUSIONS: Tocilizumab was associated with favorable outcomes and acceptable safety in this small pediatric series of refractory anti-NMDAR encephalitis. The CASE scale was a sensitive and reliable instrument for longitudinal functional assessment.