What to Do When Second-Line Immunotherapy Fails in Children Under 18 with Severe Anti-NMDA-receptor Encephalitis
This protocol applies to children (age <18 years) with NMDA receptor antibody encephalitis classified as severe disease who have not achieved adequate improvement following a first course of second-line immunotherapy given approximately 1–3 months earlier.
Clinical Scenario — Severe Disease in Children Under 18
Severe disease is defined by issues affecting safety and function. Classification requires at least one severity marker to be present: intensive care need, airway support, dysautonomia threatening safety, being bed-bound, suicidal thoughts, or an adapted mRS score of 4–5.
Any single qualifying marker is sufficient to place the patient in the severe category, which determines both initial treatment intensity and the threshold for escalation when response is inadequate.
Previous Treatment — and Why Escalation is Needed
For severe disease, second-line immunotherapy — rituximab or cyclophosphamide — is offered approximately 2 weeks after first-line initiation. Adequate clinical improvement is reassessed at approximately 1–3 months following that start.
This protocol is indicated when that 1–3 month reassessment shows the first second-line agent did not produce adequate improvement. The failure to meet that improvement target is what triggers this escalation step.
Next Treatment Step (Overview Only)
When the first second-line agent has not produced an adequate response, the approach involves switching to an alternative second-line immunotherapy. In the most refractory cases — those who still fail to improve after this switch — further escalation to an additional targeted therapy may be considered. The full protocol details which agents apply in which order and under what conditions.
Goal: adequate improvement assessed approximately 1–3 months after the next treatment step.
References
DOI: 10.1212/NXI.0000000000001052
- Severe is defined by issues affecting SAFETY and FUNCTION.
- Any (≥1) of the severity markers present below (items a-i) scoring “severe” rather than “standard” would classify as severe disease.
- Another second-line therapy (i.e., CYC, if RTX was used first, or vice versa) can be used in any patient with severe disease who fails to improve adequately 1–3 mo following initiation of the first second-line immunotherapy.
- Escalation to IV tocilizumab should be considered only in the most refractory patients who fail to improve adequately after about 1–3 mo of treatment with RTX and/or CYC.
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