SK Biopharmaceuticals files FDA application to expand Xcopri to generalised seizures

What's the deal? SK Biopharmaceuticals filed a supplemental new drug application (sNDA) with the US Food and Drug Administration (FDA) on 3 November 2026 to expand the approved use of its epilepsy medicine Xcopri (cenobamate) to primary generalised tonic-clonic (PGTC) seizures — seizures that begin across both sides of the brain and cause loss of consciousness, stiffening and convulsions — in patients aged 12 years and older. Xcopri is currently approved in the United States only for focal-onset seizures (seizures that start in one area of the brain) in adults.

Why it matters: The application is based on a global Phase 3 trial (NCT03678753) that enrolled 169 patients aged 12 and older with PGTC seizures at 122 sites across 12 countries, including the United States, South Korea and Europe. In the trial, median PGTC seizure frequency fell 71.9% from baseline in the cenobamate arm versus 39.6% in the placebo arm (p=0.003); most reported side effects were mild to moderate and no new safety concerns emerged. If approved, Xcopri would reach a substantially larger epilepsy population in the US, where treatment options for generalised seizures are limited. The filing is part of a lifecycle strategy for SK Biopharmaceuticals, which has marketed Xcopri in the US since 2020: the company is also seeking a paediatric indication expansion (sNDA filed October 2026) and an oral suspension formulation for patients who struggle to swallow tablets (application filed March 2026). Company president Lee Dong-hoon called the PGTC filing a turning point that extends the product's long-term growth path.

Read more: Seoul Economic Daily, 04 November 2026