Xcopri significantly reduces seizure burden in post hoc analysis of phase 3 trial

Daily administration of Xcopri resulted in high rates of sustained and complete seizure reduction, according to a post hoc analysis of a phase 3, multicenter, open-label study presented at the American Academy of Neurology Annual Meeting.

The findings presented at the meeting, which was held virtually, provided additional support for the use of Xcopri for durable reduction of seizure frequency for adults with uncontrolled focal seizures.

“During the maintenance phase, 35% of patients stopped having focal bilateral tonic-clonic seizures, a remarkable reduction in the most severe and riskiest seizure type and, overall, 85% of patients had at least a 50% reduction in their focal bilateral tonic-clonic seizures,” Michael R. Sperling, MD, chief of the division of epilepsy, vice chair of research and director of the Jefferson Comprehensive Epilepsy Center and director of the clinical neurophysiology lab at Thomas Jefferson University, said during the presentation. “These are the seizures with the greatest risk for mortality and morbidity.”

Sperling and colleagues conducted a post-hoc analysis of data from 240 patients between 18 and 70 years with uncontrolled focal seizures. Patients had a mean baseline seizure frequency of 18.1 seizures every 28 days and were taking stable doses of one to three antiseizure medications. Patients received daily doses of the antiseizure medication Xcopri (cenobamate tablets, SK Biopharmaceuticals/SK Life Science Inc.) over 12 weeks starting with 12.5 mg/day, with an increase in the dosage every 2 weeks until 200 mg/day. In addition to the concomitant antiseizure medications, the study protocol also allowed for dose adjustments of Xcopri.

During a median treatment exposure of 30.2 months, 25.8% of patients had 100% seizure reduction for 1 year or more upon final evaluation, while 33.9% of patients continuing on Xcopri at the latest visit (73.8% of the total study population) experienced 100% seizure reduction for 1 year or more. Meanwhile, 36.3% of the total study population experienced 100% seizure reduction for 1 year or more at any evaluation. Complete seizure reductions occurred for 6 months or more in 35% of patients and 3 months or more in 44.6% of patients.

Among patients enrolled for the entire maintenance phase of the trial (n = 214), the researchers observed response rates of 50% in 75.7% of patients (n = 162), 75% in 57.5% of patients (n = 123), 90% in 40.2% of patients (n = 86) and 100% in 13.6% of patients (n = 29).

Common adverse events included fatigue, dizziness and somnolence.

The data further support “durable seizure frequency reduction with [Xcopri] in adults with uncontrolled focal seizures,” according to Sperling and colleagues.

“We saw long-term efficacy in a lot of patients,” Sperling said. “Three quarters of patients did show a very nice, sustained response with either complete control or reduction in seizure in this post hoc analysis of the open-label phase 3 trial for all seizure types.”