SK biopharmaceuticals unveils phase 3 cenobamate results in Northeast Asian epilepsy patients at AES 2024

SK biopharmaceuticals presented the results of a phase 3 clinical trial of cenobamate (U.S. brand name: Xcopri) targeting Northeast Asian epilepsy patients at this year’s American Epilepsy Society (AES) annual meeting in Los Angeles, running from last Friday to Tuesday.

SK biopharmaceuticals showcased phase 3 results for cenobamate in Northeast Asian epilepsy patients at this year’s American Epilepsy Society (AES) annual meeting, highlighting its efficacy in reducing seizure frequency. (Courtesy of SK biopharmaceuticals)

The multicenter, randomized, double-blind, placebo-controlled study was conducted across Korea, China, and Japan. It 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.

The results demonstrated that cenobamate met its primary endpoint, showing a significant median reduction in seizure frequency across all 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 notable 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.

Additionally, 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.

Eight additional studies on cenobamate were also presented at the conference, including analyses of its dual mechanism of action—distinguishing it from existing antiepileptic drugs—and post-hoc dose optimization strategies to support early seizure freedom. Another study explored the drug’s efficacy in addressing epileptiform events in responsive neurostimulation.

The findings were shared in a poster presentation, and 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.