The Safety and Efficacy Evaluation of Everolimus as an Adjunctive Treatment for Focal Refractory Epilepsy

The aim of this study is to evaluate the clinical efficacy of everolimus as an adjunctive therapy for refractory epilepsy. The significance lies in addressing whether the mTOR inhibitor sirolimus has antiepileptic adjunctive effects for a broader range of patients with refractory epilepsy, with the hope of providing a new mTOR-targeted antiepileptic adjunctive medication regimen that is administered only during epileptic events and can be widely used for various types of refractory epilepsy.

Previous research has shown that the mTOR pathway is involved in the "epilepsy memory" process. Associating the acute seizures of the mouse kainic acid epilepsy model with a specific odor stimulus can lead to specific induction of epileptic seizures by this odor stimulus two weeks later. After epileptic seizures induced by a specific odor stimulus, the expression of the memory-related molecule pmTOR in the mouse hippocampus changes in a time-dependent manner, indicating that the mTOR signaling pathway is involved in the reconsolidation process of epilepsy memory. Further intervention in the reconsolidation process of epilepsy memory with the mTOR inhibitor everolimus (Rap) found that administering the drug within the memory consolidation window (5 min) could effectively intervene in the reinduction of epilepsy, while administering the drug outside the memory consolidation window (9 h) could not intervene. Professor Huang Zhuo's team validated the above experimental results using a conditioned epilepsy memory mouse model. Clinical experiments have found that administering the mTOR pathway inhibitor everolimus immediately after an epileptic seizure in patients can significantly reduce the interictal brain electrical activity, showing promising epilepsy treatment effects. However, this study only involved a single drug treatment, the treatment duration was short, and only the changes in epileptiform discharges after treatment with everolimus in epileptic patients were evaluated at the electrophysiological level, without evaluating the control efficacy on seizure symptoms in patients after repeated seizures with a sufficient course of treatment. Therefore, inhibiting the mTOR signaling pathway within a specific time window by intervening in the reconsolidation of the current epileptic event holds promise as a new strategy to alleviate subsequent seizures. This strategy is expected to be applicable to a broader range of treatments for refractory epilepsy, and administering medication only during epileptic events is anticipated to achieve more efficient therapeutic effects. Everolimus (sirolimus) is an inhibitor of the mammalian target of rapamycin (mTOR). In studies using animal models of tuberous sclerosis complex (TSC), mTOR inhibitors have been found to significantly reduce the frequency of epileptic seizures; furthermore, everolimus is currently undergoing phase III clinical trials as an adjunctive treatment for refractory epilepsy associated with TSC. Evidence from various animal models of epilepsy, including genetic epilepsy (such as in WAG/Rij rats) and acquired epilepsy (such as those induced by kainic acid or pilocarpine), also suggests the involvement of the mTOR signaling pathway in these forms of epilepsy and the broad inhibitory effects of mTOR inhibitors on epileptic seizures. Based on the "epilepsy memory" mechanism, combining everolimus with a memory reconsolidation paradigm holds promise as an effective adjunctive treatment for refractory epilepsy. Evaluating its efficacy and safety not only helps establish its value in epilepsy treatment but also provides important guidance for clinical practice, crucial for the transition from basic research to clinical application.