Use of intrathecal rituximab in autoimmune epilepsy: A retrospective study

Autoimmune encephalitis (AE) is a significant challenge in neurological practice, often proving refractory to conventional treatments. It typically manifests with recurrent seizures or status epilepticus, necessitating early diagnosis and tailored therapy for optimal outcomes. Early institution of effective treatment has been reported to reduce the mortality and morbidity associated with this condition. A subpopulation presenting with acute seizures due to autoimmune encephalitis later develop chronic epilepsy, which can be refractory to conventional modes of treatments. In addition, there is a group of chronic epilepsy patients who did not have acute symptomatic seizures who have autoimmune antibodies suggesting an immunological origin of their seizures. This study aims at evaluating the use of rituximab administered intrathecally, for treating these patients, taking pharmacodynamic properties into account.

We retrospectively evaluated the efficacy and safety of intrathecal rituximab (ITR) in 15 patients with autoimmune-related epilepsy (9 of them with acute presentation with seizures and 6 with chronic intractable epilepsy). The nature of these seizures, laboratory findings, imaging and EEG findings were compared over the course of treatment and follow up.

No significant long term side effects related to administration of ITR were noted in the 15 patients reported in this series. Improvement was noted in seizure control in the majority of the patients, especially in the acute presentation category, although definitive conclusions about efficacy could not be made since these patients were also receiving additional modes of therapies. Better seizure control was noted in all patients in 12 months follow up.

Our findings underscore the safety of intrathecal rituximab in treating autoimmune-related status epilepticus and refractory epilepsy related to autoimmune etiology.