A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures (X-TOLE3)

Who May Qualify: - Be properly informed of the nature and risks of the study and give willing to sign a consent form in writing, prior to entering the study - Diagnosis (≥2 years) of focal epilepsy according to the International League Against Epilepsy (ILAE) Classification of Epilepsy (2017). Subject must have had adequate trials of at least 2 ASMs, which were given (and tolerated) at adequate therapeutic doses, without achieving sustained seizure freedom. - Treatment with a stable dose of 1 to 3 allowable current ASMs for at least one month prior to screening, during baseline, and throughout the duration of the DBP - Able to keep accurate seizure diaries Who Should NOT Join This Trial: - Previously documented electroencephalogram which shows any pattern not consistent with focal etiology of seizures. - History of focal aware non-motor seizures only, non-epileptic psychogenic seizure, primary generalized seizure, developmental and epileptic encephalopathy, including Lennox-Gastaut syndrome. - Seizures secondary to drug or alcohol use, ongoing infection, neoplasia, demyelinating disease, degenerative neurological disease, metabolic illness, progressive structural lesion, encephalopathy, or progressive central nervous system (CNS) disease. - History of status epilepticus or repetitive seizures within the 12-month period preceding Visit 1 where the individual seizures cannot be counted. - History of neurosurgery for seizures \<1 year prior to Visit 1, or radiosurgery \<2 years prior to enrollment. - Any medical condition or personal circumstance that, in the opinion of the investigator, exposes the subject to unacceptable risk by participating in the study or prevents adherence to the protocol. Always talk to your doctor about whether this trial is right for you.