Cenobamate treatment of focal-onset seizures: Quality of life and outcome during up to eight years of treatment

A large proportion of patients with focal-onset epilepsy have frequent seizures despite treatment with newer anti-seizure medications (ASMs). We describe our experience optimizing cenobamate treatment for 49 patients treated at one center for up to eight years. We assessed the influence of treatment response on measurements of quality of life (QOLIE). Forty-nine patients were evaluated from three cenobamate regulatory trials: two open-label extensions of randomized placebo-controlled studies and one open-label safety study at the Johns Hopkins Hospital (JHU). Patients had focal-onset seizures despite treatment with one to three ASMs and were 18 years of age and older. Patients kept seizure diaries for the duration of the study and had tri-monthly evaluations. Seizure responder rates were determined, and patients with long-term seizure freedom (≥six months seizure free) were identified. Cenobamate doses were adjusted within the range of 100–400 mg/day. Johns Hopkins Hospital patients who were continuing treatment when the studies ended (n = 37) were administered the QOLIE-31 survey and a separate survey to assess changes in independence and epilepsy-linked disability at the end of the study at JHU. Thirty-seven of 49 (76%) patients continued treatment for three to eight years (median 5.6 years). In their final three months of treatment, 45% of patients achieved ≥75% seizure reduction, 29% had ≥90% reduction, and 16% were seizure free (responder rates computed with n = 49). Posttraumatic etiologies did not reduce treatment responses. Increased dosage of cenobamate across 150–400 mg/day range was significantly associated with higher responder rates (p < 0.001). High seizure responses—particularly ≥90% reduction—correlated with high QOLIE scores. Patients with drug-resistant focal-onset epilepsy had stable treatment responses during up to eight years of cenobamate treatment. Patients often tolerated high doses of cenobamate; high responders appeared to benefit with high QOLIE scores.