Long-Term Cenobamate Treatment Provides Maintainence of Seizure Reductions Without New Safety Signals

 Participants (n=355) in the long-term open label study (NCT01866111) who were treated with cenobamate (Xcopri; SK Life Sciences, Paramus, NJ) for a median 54 months maintained high seizure reduction rates with no new safety signals. Participants had completed the 18-week double-blind, placebo-controlled study of cenobamate, before which they had uncontrolled focal seizures, regardless of taking 1 to 3 antiseizure medications (ASMs). During an 8-week baseline period prior to starting any study treatment, participants all had 8 or more documented seizures. 

During any 12-month period, 13% to 16% of participants achieved seizure freedom. For participants who achieved 100% seizure reduction, the median duration of seizure freedom during each 12-month interval was 48 months, 47.2 months, and 45.1 months, respectively.

"We were pleased to see these results in such a difficult to treat population," said Pavel Klein, MD, epileptologist and neurologist, Mid-Atlantic Epilepsy and Sleep Center, Bethesda, MD. "More than three-quarters of patients treated with cenobamate experienced a reduction in seizure frequency of 50% or more during years 3 and 4 of the study. Physicians may want to consider whether patients with partial-onset (focal) seizures are appropriate candidates for adjunctive treatment with cenobamate."

As of July 2019, 59% (209/355) participants continued on treatment with cenobamate. At 12, 24, 36, and 48 months, 83%, 71%, 65%, and 62%, respectively, remained in the study. The most common reasons for discontinuation were lack of efficacy (17%, 59/355), withdrawal by participant, (9%, 31/355), and adverse events (8%, 27/355). The most common adverse events reported were dizziness (34%, 122/355), fatigue (16%, 56/355), headache (16%, 54/355), and somnolence (25%, 87/355).Nervous system disorders (3%, 12/355) were the leading cause of discontinuation for adverse events.