CLYBL and epilepsy: In patients with non–brain tumor–related epilepsy (BTRE), CLB seems to perform reasonably well (12-month retention of approximately 60%–80% in patients with refractory epilepsy) compared with other ASMs, but large comparative efficacy trials are lacking.9,10 Four double-blind placebo-controlled randomized controlled trials have been conducted in the past decades, representing only 197 patients, evaluating CLB as add-on in patients with non-BTRE drug-resistant epilepsy.