SK biopharmaceuticals presented Phase 3 clinical trial results for cenobamate (Xcopri) in Northeast Asian epilepsy patients at the American Epilepsy Society (AES) annual meeting, showcasing its efficacy in reducing seizure frequency.
The multicenter, randomized, double-blind, placebo-controlled study, conducted across Korea, China, and Japan, enrolled adults aged 18 to 70 with focal seizures inadequately controlled by existing antiepileptic therapies. Participants were randomized into four groups to receive a daily dose of either placebo or cenobamate at 100 mg, 200 mg, or 400 mg as an adjunctive therapy.
Key Findings on Seizure Reduction
The trial met its primary endpoint, demonstrating a significant median reduction in seizure frequency across all cenobamate dosage groups during the six-week maintenance phase. Notably, the 400 mg group achieved a 100 percent median reduction in seizure frequency (placebo: 25.9 percent; cenobamate: 100 mg, 42.6 percent; 200 mg, 78.3 percent; 400 mg, 100 percent).
The secondary endpoint, responder rate (percentage of patients achieving seizure freedom), also showed significant results (placebo: 2.6 percent; cenobamate: 100 mg, 12.4 percent; 200 mg, 30.1 percent; 400 mg, 52.4 percent). The most common adverse events (≥20 percent) were dizziness and drowsiness.
Early Efficacy and Broad Applicability
Cenobamate demonstrated statistically significant reductions in partial seizures as early as weeks five to six of treatment (42.9 percent reduction vs. placebo: 15.4 percent). Its efficacy was consistent across various epilepsy subtypes, including simple and complex partial seizures and generalized tonic-clonic seizures.
Additional Studies and Regulatory Plans
Eight additional studies on cenobamate were presented at the conference, including analyses of its dual mechanism of action and post-hoc dose optimization strategies. Another study explored the drug’s efficacy in addressing epileptiform events in responsive neurostimulation.
SK biopharmaceuticals’ Asian partners, including Dong-A ST in Korea, Ignis Therapeutics in China, and Ono Pharmaceutical in Japan, plan to use these results, alongside prior data, to pursue regulatory approvals in their respective countries.
