Rufinamide efficacy and association with phenotype and genotype in children with intractable epilepsy: A retrospective single center study.

OBJECTIVE: To assess long-term efficacy and tolerability of rufinamide in children with epilepsy and a broad spectrum of underlying epileptic etiologies. METHODS: Patients with epilepsy treated with rufinamide between 1/1/2009 and 1/1/2018 at Seattle Children's Hospital were included. Data were collected via retrospective chart review. Rufinamide efficacy was defined as seizure reduction from baseline including seizure free, >50% reduction, any reduction, no reduction, or worsening seizures. Pearson's chi-square test was used for statistical analysis. RESULTS: 183 patients (70 females and 113 males) with a broad spectrum of epileptic aetiologies (genetic/metabolic, hypoxic-ischemic, structural and others) were included. 45.9% of the patients had Lennox Gastaut syndrome. Rate of any seizure reduction was at 47.5%, seizure reduction >50% at 35%, and seizure free at 3.3%. Mean rufinamide dosage was 33.9 mg/kg/d (SD = 14.12). Mean duration of treatment was 44.48 months (SD 32.33). Suspected adverse effects occurred at 10.9%, most often as fatigue. Rufinamide achieved better seizure reduction in girls compared to boys [OR = 0.52, 95% CI (0.28, 0.97), p = 0.038]. Seizures were activated in a patient with a SCN1A mutation, fully controlled in a patient with a SCN8A mutation. Patients with certain genetic abnormalities such as DEPDC5, KCNQ2, SPATA5, and 47XYY achieved significant seizure reduction. CONCLUSIONS: Rufinamide is an effective and well-tolerated drug for long-term treatment in pediatric patients with intractable epilepsy. Certain genotypes such as SCN8A showed good response to rufinamide. Girls seemed to respond better than boys.